Construction and expansion of the fortress.

By far the oldest written record of a castle on the Königstein is found in a deed by King Wenceslas I of Bohemia dating to the year 1233, in which a witness is named as "Burgrave Gebhard of Stein". At that time the region was split between the Kingdom of Bohemia and the Bishopric of Meissen. The medieval castle belonged to the Kingdom of Bohemia. Its first full description as "Königstein" ("King's Rock") occurred in the Upper Lusatian Border Charter ("Oberlausitzer Grenzurkunde") of 1241, that Wenceslas I ""in lapide regis"" (Lat.: at the rock of the king) sealed. In this charter the demarcation of the border between the Slavic "Gauen" of Milska (Upper Lusatia), Nisani (Meißen Depression) and Dacena (Tetschen region) was laid down. Because the Königstein lay left of the Elbe, it was independent of the 3 aforementioned "Gauen".  It belonged at that time to the Kingdom of Bohemia and was expanded by order of the Bohemian kings, as the Elbe became more intensively used as a trade route, into a fortified site that dominated the north of their territories, controlling the Elbe above Pirna, and an outpost of strategically important Dohna Castle located in the nearby Müglitz.  After the king and later emperor, Charles IV had Eulau Castle, which dominated the southern region, destroyed in 1348 by townsfolk from Aussig, he spent from 5 to 19 August 1359 on the Königstein and signed the authority for shipping rights. The castle was pledged several times in the 50 years that followed, including to the Donins. Because this family were enemies of the margraves of Meißen, the latter finally captured the castle in 1408 during the Dohna Feud that had been raging since 1385. But not until 25 April 1459 was the transfer of the castle to the Margraviate of Meißen finally completed once the Saxon-Bohemian border had been settled in the Treaty of Eger. Unlike the other rock castles in Saxon Switzerland the Königstein continued to be used by the Saxon dukes and prince-electors for military purposes. At one stage the Königstein was also a monastery. In 1516, Duke George the Bearded, a fierce opponent of the Reformation, founded a Celestine abbey on the Königstein, the "Kloster des Lobes der Wunder Mariae". It closed again in 1524 - after the death of Duke George, Saxony became Evangelical. It is probable that there had been a stone castle on the Königstein as early as the 12th century. The oldest surviving structure today is the castle chapel built at the turn of the 13th century. In the years 1563 to 1569 the 152.5 metre deep well was bored into the rock within the castle - until that point the garrison of the Königstein had to obtain water from cisterns and by collecting rainwater. During the construction of the well some 8 cubic metres of water had to be removed from the shaft every day.  Between 1589 and 1591/97 Prince-Elector Christian I of Saxony and his successor had the castle developed into the strongest fortification in Saxony. The hitherto very jagged table hill was now surrounded with high walls. Buildings were erected, including the Gatehouse ("Torhaus"), the "Streichwehr", the Old Barracks ("Alte Kaserne"), the "Christiansburg" ("Friedrichsburg") and the Old Armoury ("Altes Zeughaus"). The second construction period followed from 1619 to 1681, during which "inter alia" the John George Bastion ("Johann-Georgenbastion") was built in front of the "Johann-Georgenburg". The third construction period is seen as the time from 1694 to 1756, which included the expansion of the Old Barracks. From 1722 to 1725, at the behest of August the Strong, coopers under Böttger built the enormous Königstein Wine Barrel ("Königsteiner Weinfass"), the greatest wine barrel in the world, in the cellar of the Magdalenenburg which had a capacity of 249,838 litres. It cost 8,230 thalers, 18 groschen and 9 pfennigs. The butt, which was once completely filled with country wine from the Meißen vineyards, had to be removed again in 1818 due to its poor condition. Because of Böttger, Königstein Fortress is also the site where European porcelain started.  Even after the expansion during those periods of time there continued to be modifications and additions on the extensive plateau. St. John's Hall ("Johannissaal") built in 1631 was converted in 1816 into the New Armoury ("Neues Zeughaus"). In 1819 the "Magdalenenburg" castle was turned into a provisions magazine that was fortified to withstand bombardment. The old provisions store became a barracks. The Treasury ("Schatzhaus") was built from 1854 to 1855. After the fortress had been incorporated in 1871 into the fortification system of the new German Empire, battery ramparts ("Batteriewälle") were constructed from 1870 to 1895 with eight firing points, that were to have provided all-round defence for the fortress in case of an attack that, in the event, never came. This was at this time that the last major building work was done on the fortress.  Because Königstein Fortress was regarded as unconquerable, the Saxon monarchs retreated to it from Wittenberg and later Dresden during times of crisis and also deposited the state treasure and many works of art from the famous Zwinger here; it was also used as a country retreat due to its lovely surroundings.

Military significance.

The fortress played an important role in the History of Saxony, albeit less as a result of military action. The Saxon Dukes and Prince-Electors used the fortress primarily as a secure refuge during times of war, as a hunting lodge and maison de plaisance, but also as a dreaded state prison. Its actual military significance was rather marginal, although generals such as John Everard of Droste and Zützen (1662–1726) commanded it. For example, Prince-Elector Frederick Augustus II could only watch helplessly from the Königstein during the Seven Years' War, when right at the start of the war in 1756 his army surrendered without a fight to the Prussian Army at the foot of the Lilienstein on the other side of the Elbe. The commandant of the fortress from 1753 was the electoral Saxon Lieutenant General, Michael Lorenz von Pirch. In August 1813 the clash at Krietzschwitz took place in front of its gates, an engagement that proved an important precursor to the Battle of Kulm and the Battle of Leipzig. In October 1866 Alexander von Rohrscheidt (1808–1881) was nominated as commandant of the fortress. It lost its military value with the development of long-range guns at the beginning of the 19th century. The last commandant of Königstein Fortress was Lieutenant Colonel Heinicke who commanded it until 1913. The fortress had to guard the Saxon state reserves and secret archives during times of war. In 1756 and 1813 Dresden's art treasures were also stored at the Königstein. During the Second World War the large casemates of the fortress were also used for such purposes.  The fortress was never conquered, it had too much of a chilling reputation after it had been expanded by Elector Christian I. Only the chimney sweep, Sebastian Abratzky, managed to climb the vertical sandstone walls in 1848. The Abratzky Chimney ("Abratzky-Kamin") named after him is a grade IV (based on the Saxon system) climbing route that may still be climbed today. Because climbing over the wall is banned, climbers must abseil down the adjacent wall again after climbing it.

Use as a prison.

Until 1922 the fortress was the best-known state prison in Saxony. During the Franco-Prussian War and the two world wars the fortress was also used as a prisoner of war camp. In World War I the castle was used as a prisoner of war camp ("Oflag") for French and Russian officers. In World War II it again served as an "Oflag", called "Oflag IV-B", for British, French, Polish and other Allied officers.  After the Second World War the Red Army used the fortress as a military hospital. From 1949 to 1955 it was used as a so-called "Jugendwerkhof" for the reeducation of delinquent youths and those who did not fit the image of a socialist society.  Some of the more notable prisoners incarcerated at Königstein are given below (dates of imprisonment in parentheses):  Königstein was never taken, not even during World War II. However, on April 17, 1942, French General Henri Giraud successfully escaped German captivity from the castle.

Military history open-air museum.

Since 29 May 1955, the fortress has been an open-air, military history museum of high touristic value. The museum has been managed as a satellite of the Bundeswehr Military History Museum in Dresden since 1990.  In the years 1967 to 1970, a lift was built at the foot of the access path for 42 people. A second lift was built in 2005 against a vertical wall of the fortress, which transports up to 18 passengers in a lift with a panoramic view to a height of about 42 metres. The state of Saxony made 1.7 million euros available for the project. The lift opened Easter 2006.  Between 1991 and 2010, a total of about 46 million euros was invested by the Free State of Saxony on the renovation and upgrade of Königstein Fortress. The museum welcomed its 25 millionth visitor on 14 October 2005 since it opened Whitsun 1955.  Visitor numbers decreased somewhat from about 1,000,000 in 1999 to 446,000 in 2010.

The fortress in art.

Around 1756, Elector Augustus III commissioned the Italian artist Bernardo Bellotto to paint a series of five large-scale views of the fortress at Königstein. The canvasses were never delivered to the Elector due to the hostilities of the Seven Years' War and were eventually exported to Great Britain. Today, four of the Königstein paintings are held in public collections in Britain: "The Fortress of Königstein from the North" is in the National Gallery; "The Fortress of Königstein from the South" is at Knowsley Hall, Merseyside; and both "The Fortress of Königstein: Courtyard with the Brunnenhaus" and "The Fortress of Königstein: Courtyard with the Magdalenenburg", hang in the Manchester Art Gallery. The fifth canvas, "The Fortress of Königstein from the North-West", is now in the United States, on display in the National Gallery of Art in Washington D.C.  In Anthony Trollope's novel "Phineas Redux", it is during an excursion to Königstein, "the fortress constructed on that wonderful rock," that the hero, Phineas Finn, learns from his first love, who had refused his offer of marriage, that she had in fact always loved him, and continues to.

Königstein Fortress (), the "Saxon Bastille", is a hilltop fortress near Dresden, in Saxon Switzerland, Germany, above the town of Königstein on the left bank of the River Elbe. It is one of the largest hilltop fortifications in Europe and sits atop the table hill of the same name.

国王岩堡垒(,或译国王石堡垒)俗称「萨克森的巴士底监狱」,是一座位在德国萨克森小瑞士山区、易北河左岸,近德累斯顿的山顶堡垒,俯瞰著国王岩镇。它是欧洲规模最大的山顶要塞之一。


Composition.

Formulas vary, but there was a major shift after European trade with the Indies opened. In the Middle Ages sealing wax was typically made of beeswax and "Venice turpentine", a greenish-yellow resinous extract of the European Larch tree. The earliest such wax was uncoloured; later the wax was coloured red with vermilion. From the 16th century it was compounded of various proportions of shellac, turpentine, resin, chalk or plaster, and colouring matter (often vermilion, or red lead), but not necessarily beeswax. The proportion of chalk varied; coarser grades are used to seal wine bottles and fruit preserves, finer grades for documents. In some situations, such as large seals on public documents, beeswax was used. On occasion, sealing wax has historically been perfumed by ambergris, musk and other scents.  By 1866 many colours were available: gold (using mica), blue (using smalt or verditer), black (using lamp black), white (using lead white), yellow (using the mercuric mineral turpeth, also known as Schuetteite), green (using verdigris) and so on. Some users, such as the British Crown, assigned different colours to different types of documents. Today a range of synthetic colours are available.

Method of application.

Sealing wax is available in the form of sticks, sometimes with a wick, or as granules. The stick is melted at one end (but not ignited or blackened), or the granules heated in a spoon, normally using a flame, and then placed where required, usually on the flap of an envelope. While the wax is still soft and warm, the seal (preferably at the same temperature as the wax, for the best impression) should be quickly and firmly pressed into it and released.

Modern use.

The modern day has brought sealing wax to a new level of use and application. Traditional sealing wax candles are produced in Canada, Spain, France, Italy and Scotland, with formulations similar to those used historically.  Since the advent of a postal system, the use of sealing wax has become more for ceremony than security. Modern times have required new styles of wax, allowing for mailing of the seal without damage or removal. These new waxes are flexible for mailing and are referred to as glue-gun sealing wax, faux sealing wax and flexible sealing wax.

Sealing wax is a wax material of a seal which, after melting, hardens quickly (to paper, parchment, ribbons and wire, and other material) forming a bond that is difficult to separate without noticeable tampering. Wax is used to verify something such as a document is unopened, to verify the sender's identity, for example with a signet ring, and as decoration. Sealing wax can be used to take impressions of other seals. Wax was used to seal "letters close" and later, from about the 16th century, envelopes. Before sealing wax, the Romans used bitumen for this purpose.

火漆,又称封蜡(英语:sealing wax)等,是欧洲传统用于封口信件或瓶口的一种蜡材料,往往易熔化、具有黏性并且熔化后迅速凝固。主要用松脂、石蜡等加以颜料制成。


Early life.

Pre-World War I.

Josip Broz was born on 7 May 1892 in Kumrovec, a village in the northern Croatian region of Hrvatsko Zagorje. At the time it was part of the Kingdom of Croatia-Slavonia within the Austro-Hungarian Empire. He was the seventh or eighth child of Franjo Broz (1860–1936) and Marija née Javeršek (1864–1918). His parents had already had a number of children die in early infancy. Broz was christened and raised as a Roman Catholic. His father, Franjo, was a Croat whose family had lived in the village for three centuries, while his mother Marija, was a Slovene from the village of Podsreda. The villages were apart, and

World War I.

In May 1913, Broz was conscripted into the Austro-Hungarian Army, for his compulsory two years of service. He successfully requested to serve with the 25th Croatian Home Guard () Regiment garrisoned in Zagreb. After learning to ski during the winter of 1913 and 1914, Broz was sent to a school for non-commissioned officers (NCO) in Budapest, after which he was promoted to sergeant major. At 22 years of age, he was the youngest of that rank in his regiment. At least one source states that he was the youngest sergeant major in the Austro-Hungarian Army. After winning the regimental fencing competition, Broz came in second in the army fencing championships in Budapest in May 1914.  Soon after the outbreak of World War I in 1914, the 25th Croatian Home Guard Regiment marched toward the Serbian border. Broz was arrested for sedition and imprisoned in the Petrovaradin fortress in present-day Novi Sad. Broz later gave conflicting accounts of this arrest, telling one biographer that he had threatened to desert to the Russians, but also claiming that the whole matter arose from a clerical error. A third version was that he had been overheard saying that he hoped the Austro-Hungarian Empire would be defeated. After

Interwar communist activity.

Communist agitator.

Upon his return home, Broz was unable to gain employment as a metalworker in Kumrovec, so he and his wife moved briefly to Zagreb, where he worked as a waiter, and took part in a waiter's strike. He also joined the Communist Party of Yugoslavia (CPY). The CPY's influence on the political life of Yugoslavia was growing rapidly. In the 1920 elections it won 59 seats and became the third strongest party. After the assassination of Milorad Drašković, the Yugoslav Minister of the Interior, by a young communist named Alija Alijagić on 2 August 1921, the CPY was declared illegal under the Yugoslav State Security Act of 1921.  Due to his overt communist links, Broz was fired from his employment. He and his wife then moved to the village of Veliko Trojstvo where he worked as a mill mechanic. After the arrest of the

Professional revolutionary.

The CPY concentrated its revolutionary efforts on factory workers in the more industrialised areas of Croatia and Slovenia, encouraging strikes and similar action. In 1925, the now unemployed Broz moved to Kraljevica on the Adriatic coast, where he started working at a shipyard to further the aims of the CPY. During his time in Karljevica, Tito acquired a love of the warm, sunny Adriatic coastline that was to last for the rest of his life, and throughout his later time as leader, he spent as much time possible living on his yacht while cruising

Prison.

After his sentencing, his wife and son returned to Kumrovec, where they were looked after by sympathetic locals, but then one day they suddenly left without explanation and returned to the Soviet Union. She fell in love with another man and Žarko grew up in institutions. After arriving at Lepoglava prison, Broz was employed in maintaining the electrical system, and chose as his assistant a middle-class Belgrade Jew, Moša Pijade, who had been given a 20-year sentence for his communist activities. Their work allowed Broz and Pijade to

Flight from Yugoslavia.

During this time Tito wrote articles on the duties of imprisoned communists and on trade unions. He was in Ljubljana when King Alexander was assassinated by the Croatian nationalist "Ustaše" organisation in Marseilles on 9 October 1934. In the crackdown on dissidents that followed his death, it was decided that Tito should leave Yugoslavia. He travelled to Vienna on a forged Czech passport where he joined Gorkić and the rest of the Politburo of the CPY. It was decided that the Austrian government was too hostile to communism, so the Politburo travelled to Brno in Czechoslovakia, and Tito accompanied them. On Christmas Day 1934, a secret meeting of the Central Committee of the CPY was held in Ljubljana, and Tito was elected as a member of the Politburo for

General Secretary of the CPY.

In June 1937, Gorkić was summoned to Moscow, where he was arrested, and after months of NKVD interrogation, he was shot. According to Banac, Gorkić was killed on Stalin's orders. West concludes that despite being in competition with men like Gorkić for the leadership of the CPY, it was not in Tito's character to have innocent people sent to their deaths. Tito then received a message from the Politburo of the CPY to join them in Paris. In August 1937 he became acting General Secretary of the CPY. He later explained that he survived the Purge by staying out of Spain where the NKVD was active, and also by avoiding visiting the Soviet Union as much as possible. When first appointed as general secretary, he avoided travelling to Moscow by insisting that he needed to deal with some

World War II.

Resistance in Yugoslavia.

On 6 April 1941, German forces, with Hungarian and Italian assistance, launched an invasion of Yugoslavia. On 10 April 1941, Slavko Kvaternik proclaimed the Independent State of Croatia, and Tito responded by forming a Military Committee within the Central Committee of the Yugoslav Communist Party. Attacked from all sides, the armed forces of the Kingdom of Yugoslavia quickly crumbled. On 17 April 1941, after King Peter II and other members of the government fled the country, the remaining representatives of the government and military met with German officials in Belgrade. They quickly agreed to end military resistance. On 1 May 1941, Tito issued a pamphlet calling on the people to unite in a battle against the occupation. On 27 June 1941, the Central Committee of the Communist Party of Yugoslavia (CPY) appointed Tito Commander in Chief of all project national liberation military forces. On

Aftermath.

On 7 March 1945, the provisional government of the Democratic Federal Yugoslavia ("Demokratska Federativna Jugoslavija", DFY) was assembled in Belgrade by Josip Broz Tito, while the provisional name allowed for either a republic or monarchy. This government was headed by Tito as provisional Yugoslav Prime Minister and included representatives from the royalist government-in-exile, among others Ivan Šubašić. In accordance with the agreement between resistance leaders and the government-in-exile, post-war elections were held to determine the form of government. In November 1945, Tito's pro-republican People's Front, led by the Communist Party of Yugoslavia, won the elections with an overwhelming majority, the vote having been boycotted by monarchists. During the period, Tito evidently enjoyed massive popular support due to being generally viewed by the populace as

Presidency.

Tito–Stalin split.

Unlike other states in east-central Europe liberated by allied forces, Yugoslavia liberated itself from Axis domination with limited direct support from the Red Army. Tito's leading role in liberating Yugoslavia not only greatly strengthened his position in his party and among the Yugoslav people, but also caused him to be more insistent that Yugoslavia had more room to follow its own interests than other Bloc leaders who had more reasons to recognise Soviet efforts in helping them liberate their own countries from Axis control. Although Tito was formally an ally of Stalin after World War II, the Soviets had set up a spy ring in the Yugoslav party as early as 1945, giving way to an uneasy alliance.  In the immediate aftermath of World War II, several armed incidents occurred between Yugoslavia and the Western Allies. Following the war, Yugoslavia acquired the Italian territory of Istria as well as the cities of Zadar and Rijeka. Yugoslav leadership was looking to incorporate Trieste into the country as well, which was opposed by the Western Allies. This led to several armed incidents, notably attacks by Yugoslav fighter planes on U.S. transport aircraft, causing bitter criticism from the West. In 1946 alone, Yugoslav air-force shot down two U.S. transport aircraft. The passengers and crew of

Non-Alignment.

Under Tito's leadership, Yugoslavia became a founding member of the Non-Aligned Movement. In 1961, Tito co-founded the movement with Egypt's Gamal Abdel Nasser, India's Jawaharlal Nehru, Indonesia's Sukarno and Ghana's Kwame Nkrumah, in an action called The Initiative of Five (Tito, Nehru, Nasser, Sukarno, Nkrumah), thus establishing strong ties with third world countries. This move did much to improve Yugoslavia's diplomatic position. Tito saw the Non-Aligned Movement as a way of presenting himself as a world leader of an important bloc of nations that would improve his bargaining power with both the eastern and western blocs. On 1 September 1961, Josip Broz Tito became the first Secretary-General of the Non-Aligned Movement.  Tito's foreign policy led to relationships with a variety of governments, such as exchanging visits (1954 and 1956) with Emperor Haile Selassie of Ethiopia, where a street was named in his honour. In 1953, Tito visited Ethiopia and in 1954, the Emperor visited Yugoslavia. Tito's motives in befriending Ethiopia were somewhat self-interested as he wanted to send recent graduates of Yugoslav universities (whose standards were not up to those of Western universities, thus making them unemployable in the West) to work in Ethiopia, which was one of the few countries that was willing to accept them. As Ethiopia did not have much of a health care system or a university system, Haile Selassie from 1953 onward encouraged the graduates of Yugoslav universities, especially with

Reforms.

Starting in the 1950s, Tito permitted Yugoslav workers to go to western Europe, especially West Germany as "gastarbeiter" ("guest workers"). The exposure of many Yugoslavs to the West and its culture led many people in Yugoslavia to view themselves as culturally closer to Western Europe than Eastern Europe. On 7 April 1963, the country changed its official name to the Socialist Federal Republic of Yugoslavia. Reforms encouraged private enterprise and greatly relaxed restrictions on religious expression. Tito subsequently went on a tour of the Americas. In Chile, two government ministers resigned over his visit to that country. In the autumn of 1960 Tito met President Dwight D. Eisenhower at the United Nations General Assembly meeting. Tito and Eisenhower discussed a range of issues from arms control to economic development. When Eisenhower remarked that Yugoslavia's neutralism was "neutral on his side", Tito replied that neutralism did not imply passivity but meant "not

Evaluation.

Dominic McGoldrick writes that as the head of a "highly centralised and oppressive" regime, Tito wielded tremendous power in Yugoslavia, with his authoritarian rule administered through an elaborate bureaucracy that routinely suppressed human rights. The main victims of this repression were during the first years known and alleged Stalinists, such as Dragoslav Mihailović and Dragoljub Mićunović, but during the following years even some of the most prominent among Tito's collaborators were arrested. On 19 November 1956 Milovan Đilas, perhaps the closest of Tito's collaborator and widely regarded as Tito's possible successor, was arrested because of his criticism against Tito's regime. Victor Sebestyen writes that Tito "was as brutal as" Stalin. The repression did not exclude intellectuals and writers, such as Venko Markovski, who was arrested and sent to jail in January 1956 for writing poems considered anti-Titoist.  Even if after the reforms of 1961 Tito's presidency had become comparatively more liberal than other communist regimes, the Communist Party continued to alternate between liberalism and repression. Yugoslavia managed to remain independent from the Soviet Union and its brand of socialism was in many ways the envy of Eastern Europe, but Tito's Yugoslavia remained a tightly controlled police state. According to David Mates, outside the Soviet Union, Yugoslavia had more political prisoners than all of the rest of Eastern Europe combined.  Tito's secret police was modelled on the Soviet KGB. Its members were ever-present and often acted extrajudicially, with victims including middle-class intellectuals, liberals and democrats. Yugoslavia was a signatory to the International Covenant on Civil and Political Rights, but scant regard was paid to some

Final years.

After the constitutional changes of 1974, Tito began reducing his role in the day-to-day running of the state. He continued to travel abroad and receive foreign visitors, going to Beijing in 1977 and reconciling with a Chinese leadership that had once branded him a revisionist. In turn, Chairman Hua Guofeng visited Yugoslavia in 1979. In 1978, Tito travelled to the U.S. During the visit strict security was imposed in Washington, D.C. owing to protests by anti-communist Croat, Serb and Albanian groups.  Tito became increasingly ill over the course of 1979. During this time "Vila Srna" was built for his use near Morović in the event of his recovery. On 7 January and again on 11 January 1980, Tito was admitted to the Medical Centre in Ljubljana, the capital city of the SR Slovenia, with circulation problems in his legs. Tito's own stubbornness and refusal to allow doctors to follow through with the necessary amputation of his left leg played a part in his eventual death of gangrene-induced infection. His Adjutant later testified that Tito threatened to take his own life if his leg was ever to be amputated, and that he had to

Legacy.

During his life and especially in the first year after his death, several places were named after Tito. Several of these places have since returned to their original names.  For example, Podgorica, formerly Titograd (though Podgorica's international airport is still identified by the code TGD), and Užice, formerly known as Titovo Užice, which reverted to its original name in 1992. Streets in Belgrade, the capital, have all reverted to their original pre–World War II and pre-communist names as well. In 2004, Antun Augustinčić's statue of Broz in his birthplace of Kumrovec was decapitated in an explosion. It was subsequently repaired. Twice in 2008, protests took place in what was then Zagreb's Marshal Tito Square (today the Republic of Croatia Square), organised by a group called Circle for the Square ("Krug za Trg"), with an aim to force the city government to rename it to its previous name, while a counter-protest by Citizens' Initiative Against Ustašism ("Građanska inicijativa protiv ustaštva") accused the "Circle for the Square" of historical revisionism and neo-fascism. Croatian president Stjepan Mesić criticised the demonstration to change the name.  In the Croatian coastal city of Opatija the main street (also its longest street) still bears the name of Marshal Tito. Rijeka, third largest city in Croatia, also refuses to change the name of one of the squares in the city centre named after Tito. Streets in numerous towns in Serbia, mostly in the country's north. One of the main streets in downtown Sarajevo is called Marshal Tito Street, and Tito's statue in a park in front of the university campus (ex. JNA barrack "Maršal Tito") in Marijin Dvor is a place where Bosnians and Sarajevans still today commemorate and pay tribute to Tito. The largest Tito monument in the world, about high, is located at Tito Square (Slovene: ), the central square in Velenje, Slovenia. One of the main bridges in Slovenia's second largest city of Maribor is Tito Bridge (). The central square in Koper, the largest Slovenian port city, is as well named Tito Square. The main-belt asteroid 1550 Tito, discovered by Serbian astronomer Milorad B. Protić at Belgrade Observatory in 1937, was named in his honour.  The Croat historian Marijana Belaj wrote that for some people in Croatia and other parts of the former Yugoslavia, Tito

Family and personal life.

Tito carried on numerous affairs and was married several times. In 1918 he was brought to Omsk, Russia, as a prisoner of war. There he met Pelagija Belousova who was then fourteen; he married her a year later, and she moved with him to Yugoslavia. They had five children but only their son Žarko Leon (born 4 February 1924) survived. When Tito was jailed in 1928, she returned to Russia. After the divorce in 1936 she later remarried.  In 1936, when Tito stayed at the Hotel Lux in Moscow, he met the Austrian Lucia Bauer. They married in October 1936, but the records of this marriage were later erased.  His next relationship was with Herta Haas, whom he married in 1940. Broz left for Belgrade after the April War, leaving Haas pregnant. In May 1941, she gave birth to their son, Aleksandar "Mišo" Broz. All throughout his relationship with Haas, Tito had maintained a promiscuous life and had a parallel relationship with Davorjanka Paunović, who, under the codename "Zdenka", served as a courier in the resistance and subsequently became his personal secretary. Haas and Tito suddenly parted company in 1943 in Jajce during the second meeting of AVNOJ after she reportedly walked in on him and Davorjanka. The last time Haas saw Broz was in 1946. Davorjanka died of tuberculosis in 1946 and Tito insisted that she be buried in the backyard of the Beli Dvor, his Belgrade residence.  His best known wife was Jovanka Broz. Tito was just shy of his 60th birthday, while she was 27, when they finally married in April 1952, with state security chief Aleksandar Ranković as the best man. Their eventual marriage came about somewhat unexpectedly since Tito actually rejected her some years earlier when his confidante Ivan Krajacic brought her in originally. At that time, she was in her early 20s and Tito objected to her energetic personality. Not one to be discouraged easily, Jovanka continued working at Beli Dvor, where she managed the staff and eventually got another chance. Their relationship was not a happy one, however. It had gone through many, often public, ups and downs with episodes of infidelities and even allegations of preparation for a "coup d'état" by the latter pair. Certain unofficial reports suggest Tito and Jovanka even formally divorced in the late 1970s, shortly before his death. However, during Tito's funeral she was officially present as his wife, and later claimed rights for inheritance. The couple did not have any children.  Tito's grandchildren include Saša Broz, a theatre director in Croatia; Svetlana Broz, a cardiologist and writer in Bosnia-Herzegovina; and Josip Broz – Joška, Edvard Broz and Natali Klasevski, an artisan of Bosnia-Herzegovina.  As the President, Tito had access to extensive (state-owned) property associated with the office, and maintained a lavish lifestyle. In Belgrade he resided in the official residence, the Beli dvor, and maintained a separate private home. The Brijuni islands were the site of the State Summer Residence from 1949 on. The pavilion was designed by Jože Plečnik, and included a zoo. Close to 100 foreign heads of state were to visit Tito at the island residence, along with film stars such as Elizabeth Taylor, Richard Burton, Sophia Loren, Carlo Ponti, and Gina Lollobrigida.  Another residence was maintained at Lake Bled, while the grounds at Karađorđevo were the site of "diplomatic hunts". By 1974 the Yugoslav President had at his disposal 32 official residences, larger and small, the yacht "Galeb" ("seagull"), a Boeing 727 as the presidential aeroplane, and the Blue Train. After Tito's death the presidential Boeing 727 was sold to Aviogenex, the "Galeb" remained docked in Montenegro, while the Blue Train was stored in a Serbian train shed for over two decades. While Tito was the person who held the office of president for by far the longest period, the associated property was not private and much of it continues to be in use by Yugoslav successor states, as public property, or maintained at the disposal of high-ranking officials.  As regards knowledge of languages, Tito replied that he spoke Serbo-Croatian, German, Russian, and some English. Broz's official biographer and then fellow Central Committee-member Vladimir Dedijer stated in 1953 that he spoke "Serbo-Croatian... Russian, Czech, Slovenian... German (with a Viennese accent)... understands and reads French and Italian... [and] also speaks Kazakh."  In his youth Tito attended Catholic Sunday school, and was later an altar boy. After an incident where he was slapped and shouted at by a priest when he had difficulty assisting the priest to remove his vestments, Tito would not enter a church again. As an adult, he identified as an atheist.  Every federal unit had a town or city with historic significance from the World War II period renamed to have Tito's name included. The largest of these was Titograd, now Podgorica, the capital city of Montenegro. With the exception of Titograd, the cities were renamed simply by the addition of the adjective "Tito's" (""Titov""). The cities were:

Awards and decorations.

Josip Broz Tito received a total of 119 awards and decorations from 60 countries around the world (59 countries and Yugoslavia). 21 decorations were from Yugoslavia itself, 18 having been awarded once, and the Order of the National Hero on three occasions. Of the 98 international awards and decorations, 92 were received once, and three on two occasions (Order of the White Lion, Polonia Restituta, and Karl Marx). The most notable awards included the French Legion of Honour and National Order of Merit, the British Order of the Bath, the Soviet Order of Lenin, the Japanese Order of the Chrysanthemum, the West German Federal Cross of Merit, and the Order of Merit of Italy.  The decorations were seldom displayed, however. After the Tito–Stalin split of 1948 and his inauguration as president in 1953, Tito rarely wore his uniform except when present in a military function, and then (with rare exception) only wore his Yugoslav ribbons for obvious practical reasons. The awards were displayed in full number only at his funeral in 1980. Tito's reputation as one of the Allied leaders of World War II, along with his diplomatic position as the founder of the Non-Aligned Movement, was primarily the cause of the favourable international recognition.

Foreign awards.

Here follows a short list including some of the more notable foreign awards and decorations of Tito.  Some of the other foreign awards and decorations of Josip Broz Tito include Order of Merit, Order of Prince Henry, Order of Independence, Order of Merit, Order of the Nile, Order of the Condor of the Andes, Order of the Star of Romania, Order of the Gold Lion of the

Josip Broz (, ; 7 May 1892 – 4 May 1980), commonly known as Tito (;, ), was a Yugoslav communist revolutionary and statesman, serving in various roles from 1943 until his death in 1980. During World War II, he was the leader of the Partisans, often regarded as the most effective resistance movement in occupied Europe. He also served as the President of the Socialist Federal Republic of Yugoslavia from 14 January 1953 to 4 May 1980.

约瑟普·布罗兹·铁托(塞尔维亚-克罗地亚语西里尔字母:,拉丁字母:;1892年-5月7日-1980年-5月4日),本名约瑟普·布罗兹,南斯拉夫革命家、政治家,南斯拉夫共产主义者联盟总书记、主席团主席,南斯拉夫社会主义联邦共和国执政35年的总统、总理,南斯拉夫元帅。尽管执政时期被人批评为威权统治,但他的个人形象通常被视为南斯拉夫联邦内各民族统一的象征。他还是不结盟运动发起人之一,与印度总理尼赫鲁、埃及总统纳赛尔共事。他提出的政治思想被称作铁托主义。


Fundamentals.

In the 20th century, two theoretical frameworks emerged for formulating the laws of physics. The first is Albert Einstein's general theory of relativity, a theory that explains the force of gravity and the structure of spacetime at the macro-level. The other is quantum mechanics which is a completely different formulation to describe physical phenomena using the known probability principles at the micro-level. By the late 1970s, these two frameworks had proven to be sufficient to explain most of the observed features of the universe, from elementary particles to atoms to the evolution of stars and the universe as a whole.  In spite of these successes, there are still many problems that remain to be solved. One of the deepest problems in modern physics is the problem of quantum gravity. The general theory of relativity is formulated within the framework of classical physics, whereas the other fundamental forces are described within the framework of quantum mechanics. A quantum theory of gravity is needed in order to reconcile general relativity with the principles of quantum mechanics, but difficulties arise when one attempts to apply the usual prescriptions of quantum theory to the force of gravity. In addition to the problem of developing a consistent theory of quantum gravity, there are many other fundamental problems in the physics of atomic nuclei, black holes, and the early universe.  String theory is a theoretical framework that attempts to address these questions and many others. The starting point for string theory is the idea that the point-like particles of particle physics can also be modeled as one-dimensional objects called strings. String theory describes how strings propagate through space and interact with each other. In a given version of string theory, there is only one kind of string, which may look like a small loop or segment of ordinary string, and it can vibrate in different ways. On distance scales larger than the string scale, a string will look just like an ordinary particle, with its mass, charge, and other properties determined by the vibrational state of the string. In this way, all of the different elementary particles may be viewed as vibrating strings. In string theory, one of the vibrational states of the string gives rise to the graviton, a quantum mechanical particle that carries gravitational force. Thus string theory is a theory of quantum gravity.  One of the main developments of the past several decades in string theory was the discovery of certain 'dualities', mathematical transformations that identify one physical theory with another. Physicists studying string theory have discovered a number of these dualities between different versions of string theory, and this has led to the conjecture that all consistent versions of string theory are subsumed in a single framework known as M-theory.  Studies of string theory have also yielded a number of results on the nature of black holes and the gravitational interaction. There are certain paradoxes that arise when one attempts to understand the quantum aspects of black holes, and work on string theory has attempted to clarify these issues. In late 1997 this line of work culminated in the discovery of the anti-de Sitter/conformal field theory correspondence or AdS/CFT. This is a theoretical result which relates string theory to other physical theories which are better understood theoretically. The AdS/CFT correspondence has implications for the study of black holes and quantum gravity, and it has been applied to other subjects, including nuclear and condensed matter physics.  Since string theory incorporates all of the fundamental interactions, including gravity, many physicists hope that it will eventually be developed to the point where it fully describes our universe, making it a theory of everything. One of the goals of current research in string theory is to find a solution of the theory that reproduces the observed spectrum of elementary particles, with a small cosmological constant, containing dark matter and a plausible mechanism for cosmic inflation. While there has been progress toward these goals, it is not known to what extent string theory describes the real world or how much freedom the theory allows in the choice of details.  One of the challenges of string theory is that the full theory does not have a satisfactory definition in all circumstances. The scattering of strings is most straightforwardly defined using the techniques of perturbation theory, but it is not known in general how to define string theory nonperturbatively. It is also not clear whether there is any principle by which string theory selects its vacuum state, the physical state that determines the properties of our universe. These problems have led some in the community to criticize these approaches to the unification of physics and question the value of continued research on these problems.

M-theory.

Prior to 1995, theorists believed that there were five consistent versions of superstring theory (type I, type IIA, type IIB, and two versions of heterotic string theory). This understanding changed in 1995 when Edward Witten suggested that the five theories were just special limiting cases of an eleven-dimensional theory called M-theory. Witten's conjecture was based on the work of a number of other physicists, including Ashoke Sen, Chris Hull, Paul Townsend, and Michael Duff. His announcement led to a flurry of research activity now known as the second superstring revolution.

Unification of superstring theories.

In the 1970s, many physicists became interested in supergravity theories, which combine general relativity with supersymmetry. Whereas general relativity makes sense in any number of dimensions, supergravity places an upper limit on the number of dimensions. In 1978, work by Werner Nahm showed that the maximum spacetime dimension in which one can formulate a consistent supersymmetric theory is eleven. In the same year, Eugene Cremmer, Bernard Julia, and Joel Scherk of the École Normale Supérieure showed that supergravity not only permits up to eleven dimensions but is in fact most elegant in this maximal number of dimensions.  Initially, many physicists hoped that by compactifying eleven-dimensional supergravity, it might be possible to construct realistic models of our four-dimensional world. The hope was that such models would provide a

Matrix theory.

In mathematics, a matrix is a rectangular array of numbers or other data. In physics, a matrix model is a particular kind of physical theory whose mathematical formulation involves the notion of a matrix in an important way. A matrix model describes the behavior of a set of matrices within the framework of quantum mechanics.  One important example of a matrix model is the BFSS matrix model proposed by Tom Banks, Willy Fischler, Stephen Shenker, and Leonard Susskind in 1997. This theory describes the behavior of a set of nine large matrices. In their original paper, these authors showed, among other things, that the low energy limit of this matrix model is described by eleven-dimensional supergravity. These

Black holes.

In general relativity, a black hole is defined as a region of spacetime in which the gravitational field is so strong that no particle or radiation can escape. In the currently accepted models of stellar evolution, black holes are thought to arise when massive stars undergo gravitational collapse, and many galaxies are thought to contain supermassive black holes at their centers. Black holes are also important for theoretical reasons, as they present profound challenges for theorists attempting to understand the quantum aspects of gravity. String theory has proved to be an important tool for investigating the theoretical properties of black holes because it provides a framework in which theorists can study their thermodynamics.

Bekenstein–Hawking formula.

In the branch of physics called statistical mechanics, entropy is a measure of the randomness or disorder of a physical system. This concept was studied in the 1870s by the Austrian physicist Ludwig Boltzmann, who showed that the thermodynamic properties of a gas could be derived from the combined properties of its many constituent molecules. Boltzmann argued that by averaging the behaviors of all the different molecules in a gas, one can understand macroscopic properties such as volume, temperature, and pressure. In addition, this perspective led him to give a precise definition of entropy as the natural logarithm of the number of different states of the molecules (also called "microstates") that give rise to the same macroscopic features.  In the twentieth century, physicists began to apply the same concepts to

Derivation within string theory.

In a paper from 1996, Andrew Strominger and Cumrun Vafa showed how to derive the Beckenstein–Hawking formula for certain black holes in string theory. Their calculation was based on the observation that D-branes—which look like fluctuating membranes when they are weakly interacting—become dense, massive objects with event horizons when the interactions are strong. In other words, a system of strongly interacting D-branes in string theory is indistinguishable from a black hole. Strominger and Vafa analyzed such D-brane systems and calculated the number of different ways of placing D-branes in spacetime so that their combined mass and charge is equal to a given mass and charge for the resulting black hole. Their calculation reproduced the Bekenstein–Hawking formula exactly, including the factor of. Subsequent work by Strominger,

AdS/CFT correspondence.

One approach to formulating string theory and studying its properties is provided by the anti-de Sitter/conformal field theory (AdS/CFT) correspondence. This is a theoretical result which implies that string theory is in some cases equivalent to a quantum field theory. In addition to providing insights into the mathematical structure of string theory, the AdS/CFT correspondence has shed light on many aspects of quantum field theory in regimes where traditional calculational techniques are ineffective. The AdS/CFT correspondence was first proposed by Juan Maldacena in late 1997. Important aspects of the correspondence were elaborated in articles by Steven Gubser, Igor Klebanov, and Alexander Markovich Polyakov, and by Edward Witten. By 2010, Maldacena's article had over 7000 citations, becoming the most highly cited article in the field of high energy physics.

Overview of the correspondence.

In the AdS/CFT correspondence, the geometry of spacetime is described in terms of a certain vacuum solution of Einstein's equation called anti-de Sitter space. In very elementary terms, anti-de Sitter space is a mathematical model of spacetime in which the notion of distance between points (the metric) is different from the notion of distance in ordinary Euclidean geometry. It is closely related to hyperbolic space, which can be viewed as a disk as illustrated on the left. This image shows a tessellation of a disk by triangles and squares. One can define the distance between points of this disk in such a way that all the triangles and squares are the same size and the circular outer boundary is infinitely far from any point in the interior.  One can imagine a stack of hyperbolic disks where each disk represents the state of the universe at a given time. The resulting geometric object is three-dimensional anti-de Sitter space. It looks like a solid cylinder in which any cross section is a copy of the hyperbolic disk. Time runs along the vertical direction in this picture. The surface of this cylinder plays an important role in the AdS/CFT

Applications to quantum gravity.

The discovery of the AdS/CFT correspondence was a major advance in physicists' understanding of string theory and quantum gravity. One reason for this is that the correspondence provides a formulation of string theory in terms of quantum field theory, which is well understood by comparison. Another reason is that it provides a general framework in which physicists can study and attempt to resolve the paradoxes of black holes.  In 1975, Stephen Hawking published a calculation which suggested that black holes are not completely black but emit a dim radiation due to quantum effects near the event horizon. At first, Hawking's result posed a problem for theorists because it suggested that black holes destroy information. More precisely, Hawking's calculation seemed to conflict with one

Applications to nuclear physics.

In addition to its applications to theoretical problems in quantum gravity, the AdS/CFT correspondence has been applied to a variety of problems in quantum field theory. One physical system that has been studied using the AdS/CFT correspondence is the quark–gluon plasma, an exotic state of matter produced in particle accelerators. This state of matter arises for brief instants when heavy ions such as gold or lead nuclei are collided at high energies. Such collisions cause the quarks that make up atomic nuclei to deconfine at temperatures of approximately two trillion kelvin, conditions similar to those present at around seconds

Applications to condensed matter physics.

The AdS/CFT correspondence has also been used to study aspects of condensed matter physics. Over the decades, experimental condensed matter physicists have discovered a number of exotic states of matter, including superconductors and superfluids. These states are described using the formalism of quantum field theory, but some phenomena are difficult to explain using standard field theoretic techniques. Some condensed matter theorists including Subir Sachdev hope that the AdS/CFT correspondence will make it possible to describe these systems in the language of string theory and learn more about their behavior.  So far some success has been achieved in using string theory methods to describe

Phenomenology.

In addition to being an idea of considerable theoretical interest, string theory provides a framework for constructing models of real world physics that combine general relativity and particle physics. Phenomenology is the branch of theoretical physics in which physicists construct realistic models of nature from more abstract theoretical ideas. String phenomenology is the part of string theory that attempts to construct realistic or semi-realistic models based on string theory.  Partly because of theoretical and mathematical difficulties and partly because of the extremely high energies needed to test these theories experimentally, there is so far no experimental evidence that would unambiguously point to any of these models being a correct fundamental description of nature. This has led some in the community to criticize these approaches to unification and question the value of continued research on these problems.

Particle physics.

The currently accepted theory describing elementary particles and their interactions is known as the standard model of particle physics. This theory provides a unified description of three of the fundamental forces of nature: electromagnetism and the strong and weak nuclear forces. Despite its remarkable success in explaining a wide range of physical phenomena, the standard model cannot be a complete description of reality. This is because the standard model fails to incorporate the force of gravity and because of problems such as the hierarchy problem and the inability to explain the structure of fermion masses

Cosmology.

The Big Bang theory is the prevailing cosmological model for the universe from the earliest known periods through its subsequent large-scale evolution. Despite its success in explaining many observed features of the universe including galactic redshifts, the relative abundance of light elements such as hydrogen and helium, and the existence of a cosmic microwave background, there are several questions that remain unanswered. For example, the standard Big Bang model does not explain why the universe appears to be same in all directions, why it appears flat on very large distance scales, or why certain hypothesized particles such as magnetic monopoles are not observed in experiments.  Currently, the leading candidate for a theory going beyond the Big Bang is the theory of cosmic inflation. Developed by Alan

Connections to mathematics.

In addition to influencing research in theoretical physics, string theory has stimulated a number of major developments in pure mathematics. Like many developing ideas in theoretical physics, string theory does not at present have a mathematically rigorous formulation in which all of its concepts can be defined precisely. As a result, physicists who study string theory are often guided by physical intuition to conjecture relationships between the seemingly different mathematical structures that are used to formalize different parts of the theory. These conjectures are later proved by mathematicians, and in this way, string theory serves as a source of new ideas in pure mathematics.

Mirror symmetry.

After Calabi–Yau manifolds had entered physics as a way to compactify extra dimensions in string theory, many physicists began studying these manifolds. In the late 1980s, several physicists noticed that given such a compactification of string theory, it is not possible to reconstruct uniquely a corresponding Calabi–Yau manifold. Instead, two different versions of string theory, type IIA and type IIB, can be compactified on completely different Calabi–Yau manifolds giving rise to the same physics. In this situation, the manifolds are called mirror manifolds, and the

Monstrous moonshine.

Group theory is the branch of mathematics that studies the concept of symmetry. For example, one can consider a geometric shape such as an equilateral triangle. There are various operations that one can perform on this triangle without changing its shape. One can rotate it through 120°, 240°, or 360°, or one can reflect in any of the lines labeled,, or in the picture. Each of these operations is called a "symmetry", and the collection of these symmetries satisfies certain technical properties making it into what mathematicians call a group. In this particular example, the group is known

History.

Early results.

Some of the structures reintroduced by string theory arose for the first time much earlier as part of the program of classical unification started by Albert Einstein. The first person to add a fifth dimension to a theory of gravity was Gunnar Nordström in 1914, who noted that gravity in five dimensions describes both gravity and electromagnetism in four. Nordström attempted to unify electromagnetism with his theory of gravitation, which was however superseded by Einstein's general relativity in 1919. Thereafter, German mathematician Theodor Kaluza combined the fifth dimension with general relativity, and only Kaluza is usually credited with the idea. In 1926, the Swedish physicist Oskar Klein gave a physical interpretation of the unobservable extra dimension—it is wrapped into a small circle. Einstein introduced a non-symmetric metric tensor, while much later Brans and Dicke added a scalar component to gravity. These ideas would be revived within string theory, where they are demanded by consistency conditions.  String theory was originally developed during the late 1960s and early 1970s as a never completely successful theory of hadrons, the subatomic particles like the proton and neutron that feel the strong interaction. In the 1960s, Geoffrey Chew and

First superstring revolution.

In the early 1980s, Edward Witten discovered that most theories of quantum gravity could not accommodate chiral fermions like the neutrino. This led him, in collaboration with Luis Álvarez-Gaumé, to study violations of the conservation laws in gravity theories with anomalies, concluding that type I string theories were inconsistent. Green and Schwarz discovered a contribution to the anomaly that Witten and Alvarez-Gaumé had missed, which restricted the gauge group of the type I string theory to be SO(32). In coming to understand this calculation, Edward Witten became convinced that string theory was truly a consistent theory of gravity, and he became a high-profile advocate. Following Witten's lead, between 1984 and 1986, hundreds of physicists started to work in this field, and this is sometimes called the first superstring revolution.  During this period, David Gross, Jeffrey Harvey, Emil Martinec, and Ryan Rohm discovered heterotic strings. The gauge group of these closed strings was two copies of E8, and either copy could easily and naturally include the standard model. Philip

Second superstring revolution.

In 1995, at the annual conference of string theorists at the University of Southern California (USC), Edward Witten gave a speech on string theory that in essence united the five string theories that existed at the time, and giving birth to a new 11-dimensional theory called M-theory. M-theory was also foreshadowed in the work of Paul Townsend at approximately the same time. The flurry of activity that began at this time is sometimes called the second superstring revolution.  During this period, Tom Banks, Willy Fischler, Stephen Shenker and Leonard Susskind formulated matrix theory, a full holographic description of M-theory using IIA D0 branes. This was the first definition of string theory that was fully non-perturbative and a concrete mathematical realization of the holographic principle. It is an example of a gauge-gravity duality and is now understood to be a special case of the AdS/CFT correspondence. Andrew Strominger and Cumrun Vafa calculated the entropy of certain configurations of D-branes and found agreement with the semi-classical answer for extreme charged

Criticism.

Number of solutions.

To construct models of particle physics based on string theory, physicists typically begin by specifying a shape for the extra dimensions of spacetime. Each of these different shapes corresponds to a different possible universe, or "vacuum state", with a different collection of particles and forces. String theory as it is currently understood has an enormous number of vacuum states, typically estimated to be around, and these might be sufficiently diverse to accommodate almost any phenomenon that might be observed at low energies.  Many critics of string theory have expressed concerns about the large number of possible universes described by string theory. In his book "Not Even Wrong", Peter Woit, a lecturer in the mathematics department at Columbia University, has argued that the large number of different physical scenarios renders string theory vacuous as a framework for constructing models of particle physics. According to Woit,  Some physicists believe this large number of solutions is actually a virtue because it may allow a natural anthropic explanation of the observed

Compatibility with dark energy.

No vacuum in the string theory landscape is known to support a metastable, positive cosmological constant, except possibly one unconfirmed model described by Kachru "et al." in 2003. In 2018, a group of four physicists advanced

Background independence.

One of the fundamental properties of Einstein's general theory of relativity is that it is background independent, meaning that the formulation of the theory does not in any way privilege a particular spacetime geometry.  One of the main criticisms of string theory from early on is that it is not manifestly background independent. In string theory, one must typically specify a fixed reference geometry for spacetime, and all other possible geometries are described as perturbations of this fixed one. In his

Sociology of science.

Since the superstring revolutions of the 1980s and 1990s, string theory has become the dominant paradigm of high energy theoretical physics. Some string theorists have expressed the view that there does not exist an equally successful alternative theory addressing the deep questions of fundamental physics. In an interview from 1987, Nobel laureate David Gross made the following controversial comments about the reasons for the popularity of string theory:  Several other high-profile theorists and commentators have expressed similar views, suggesting that there are no viable alternatives to string theory.  Many critics of string theory have commented on this state of affairs. In his book criticizing string theory, Peter Woit views the status of string theory research as

Further reading.

Popular science.

General

Textbooks.

For physicists

External links.

Websites  Video

In physics, string theory is a theoretical framework in which the point-like particles of particle physics are replaced by one-dimensional objects called strings. It describes how these strings propagate through space and interact with each other. On distance scales larger than the string scale, a string looks just like an ordinary particle, with its mass, charge, and other properties determined by the vibrational state of the string. In string theory, one of the many vibrational states of the string corresponds to the graviton, a quantum mechanical particle that carries gravitational force. Thus string theory is a theory of quantum gravity.

弦理论,又称弦论,是发展中理论物理学的一支,结合量子力学和广义相对论为万有理论。弦理论用一段段“能量弦线”作最基本单位以说明宇宙里所有微观粒子如电子、夸克、微中子都由这一维的“能量线”所组成;换而言之,弦论主张「弦」以不同的振动模式对应到自然界的各种基本粒子。


Physical and atomic properties.

Like other groups of the periodic table, the members of group 12 show patterns in its electron configuration, especially the outermost shells, which result in trends in their chemical behavior: The group 12 elements are all soft, diamagnetic, divalent metals. They have the lowest melting points among all transition metals. Zinc is bluish-white and lustrous, though most common commercial grades of the metal have a dull finish. Zinc is also referred to in nonscientific contexts as "spelter". Cadmium is soft, malleable, ductile, and with a bluish-white color. Mercury is a liquid, heavy, silvery-white metal. It is the only common liquid metal at ordinary temperatures, and as compared to other metals, it is a poor conductor of heat, but a fair conductor of electricity.  The table below is a summary of the key physical properties of the group 12 elements. Very little is known about copernicium, and none of its physical properties have been confirmed except for its boiling point (tentative).  Zinc is somewhat less dense than iron and has a hexagonal crystal structure. The metal is hard and brittle at most temperatures but becomes malleable between 100 and 150 °C. Above 210 °C, the metal becomes brittle again and can be pulverized by beating. Zinc is a fair conductor of electricity. For a metal, zinc has relatively low melting (419.5 °C, 787.1 F) and boiling points (907 °C). Cadmium is similar in many respects to zinc but forms complex compounds. Unlike other metals, cadmium is resistant to corrosion and as a result it is used as a protective layer when deposited on other metals. As a bulk metal, cadmium is insoluble in water and is not flammable; however, in its powdered form it may burn and release toxic fumes. Mercury has an exceptionally low melting temperature for a d-block metal. A complete explanation of this fact requires a deep excursion into quantum physics, but it can be summarized as follows: mercury has a unique electronic configuration where electrons fill up all the available 1s, 2s, 2p, 3s, 3p, 3d, 4s, 4p, 4d, 4f, 5s, 5p, 5d and 6s subshells. As such configuration strongly resists removal of an electron, mercury behaves similarly to noble gas elements, which form weak bonds and thus easily melting solids. The stability of the 6s shell is due to the presence of a filled 4f shell. An f shell poorly screens the nuclear charge that increases the attractive Coulomb interaction of the 6s shell and the nucleus (see lanthanide contraction). The absence of a filled inner f shell is the reason for the somewhat higher melting temperature of cadmium and zinc, although both these metals still melt easily and, in addition, have unusually low boiling points. Gold has atoms with one less 6s electron than mercury. Those electrons are more easily removed and are shared between the gold atoms forming relatively strong metallic bonds.  Zinc, cadmium and mercury form a large range of alloys. Among the zinc containing ones, brass is an alloy of zinc and copper. Other metals long known to form binary alloys with zinc are aluminium, antimony, bismuth, gold, iron, lead, mercury, silver, tin, magnesium, cobalt, nickel, tellurium and sodium. While neither zinc nor zirconium are ferromagnetic, their alloy exhibits ferromagnetism below 35 K. Cadmium is used in many kinds of solder and bearing alloys, due to a low coefficient of friction and fatigue resistance. It is also found in some of the lowest-melting alloys, such as Wood's metal. Because it is a liquid, mercury dissolves other metals and the alloys that are formed are called amalgams. For example, such amalgams are known with gold, zinc, sodium, and many other metals. Because iron is an exception, iron flasks have been traditionally used to trade mercury. Other metals that do not form amalgams with mercury include tantalum, tungsten and platinum. Sodium amalgam is a common reducing agent in organic synthesis, and is also used in high-pressure sodium lamps. Mercury readily combines with aluminium to form a mercury-aluminium amalgam when the two pure metals come into contact. Since the amalgam reacts with air to give aluminium oxide, small amounts of mercury corrode aluminium. For this reason, mercury is not allowed aboard an aircraft under most circumstances because of the risk of it forming an amalgam with exposed aluminium parts in the aircraft.

Chemistry.

Most of the chemistry has been observed only for the first three members of the group 12. The chemistry of copernicium is not well established and therefore the rest of the section deals only with zinc, cadmium and mercury.

Periodic trends.

All elements in this group are metals. The similarity of the metallic radii of cadmium and mercury is an effect of the lanthanide contraction. So, the trend in this group is unlike the trend in group 2, the alkaline earths, where metallic radius increases smoothly from top to bottom of the group. All three metals have relatively low melting and boiling points, indicating that the metallic bond is relatively weak, with relatively little overlap between the valence band and the conduction band. Thus, zinc is close to the boundary between metallic and metalloid elements, which is usually placed between gallium and germanium, though gallium participates in semi-conductors such as gallium arsenide.  Zinc and cadmium are electropositive while mercury is not. As a result, zinc and cadmium metal are good reducing agents. The elements of group 12 have an oxidation state of +2 in which the ions have the rather stable d electronic configuration, with a full sub-shell. However, mercury can easily be reduced to the +1 oxidation state; usually, as in the ion, two mercury(I) ions come together to form a metal-metal bond and a diamagnetic species. Cadmium can also form species such as [CdCl] in which the metal's oxidation state is +1. Just as with mercury, the formation of a metal-metal bond results in a diamagnetic compound in which there are no unpaired electrons; thus, making the species very reactive. Zinc(I) is known mostly in the gas phase, in such compounds as linear ZnCl, analogous to calomel. In the solid phase, the rather exotic compound decamethyldizincocene (Cp*Zn–ZnCp*) is known.

Classification.

The elements in group 12 are usually considered to be d-block elements, but not transition elements as the d-shell is full. Some authors classify these elements as main-group elements because the valence electrons are in ns orbitals. Nevertheless, they share many characteristics with the neighboring group 11 elements on the periodic table, which are almost universally considered to be transition elements. For example, zinc shares many characteristics with the neighboring transition metal, copper. Zinc complexes merit inclusion in the Irving-Williams series as zinc forms many complexes with the same stoichiometry as complexes of copper(II), albeit with smaller stability constants. There is little similarity between cadmium and silver as compounds of silver(II) are rare and those that do exist are very strong oxidizing agents. Likewise the common oxidation state for gold is +3, which precludes there being much common chemistry between mercury and gold, though there are similarities between mercury(I) and gold(I) such as the formation of linear dicyano complexes, [M(CN)]. According to IUPAC's definition of transition metal as "an element whose atom has an incomplete d sub-shell, or which can give rise to cations with an incomplete d sub-shell", zinc and cadmium are not transition metals, while mercury is. This is because only mercury is known to have a compound where its oxidation state is higher than +2, in mercury(IV) fluoride (though its existence is disputed, as later experiments trying to confirm its synthesis could not find evidence of HgF). However, this classification is based on one highly atypical compound seen at non-equilibrium conditions and is at odds to mercury's more typical chemistry, and Jensen has suggested that it would be better to regard mercury as not being a transition metal.

Relationship with the alkaline earth metals.

Although group 12 lies in the d-block of the modern 18-column periodic table, the d electrons of zinc, cadmium, and (almost always) mercury behave as core electrons and do not take part in bonding. This behavior is similar to that of the main-group elements, but is in stark contrast to that of the neighboring group 11 elements (copper, silver, and gold), which also have filled d-subshells in their ground-state electron configuration but behave chemically as transition metals. For example, the bonding in chromium(II) sulfide (CrS) involves mainly the 3d electrons; that in iron(II) sulfide (FeS) involves both the 3d and 4s electrons; but that of zinc sulfide (ZnS) involves only the 4s electrons and the 3d electrons behave as core electrons. Indeed, useful comparison can be made between their properties and the first two members of group 2, beryllium and magnesium, and in earlier short-form periodic table layouts, this relationship is illustrated more clearly. For instance, zinc and cadmium are similar to beryllium and magnesium in their atomic radii, ionic radii, electronegativities, and also in the structure of their binary compounds and their ability to form complex ions with many nitrogen and oxygen ligands, such as complex hydrides and amines. However, beryllium and magnesium are small atoms, unlike the heavier alkaline earth metals and like the group 12 elements (which have a greater nuclear charge but the same number of valence electrons), and the periodic trends down group 2 from beryllium to radium (similar to that of the alkali metals) are not as smooth when going down from beryllium to mercury (which is more similar to that of the p-block main groups) due to the d-block and lanthanide contractions. It is also the d-block and lanthanide contractions that give mercury many of its distinctive properties.

Compounds.

All three metal ions form many tetrahedral species, such as. Both zinc and cadmium can also form octahedral complexes such as the aqua ions [M(HO)] which are present in aqueous solutions of salts of these metals. Covalent character is achieved by using the s and p orbitals. Mercury, however, rarely exceeds a coordination number of four. Coordination numbers of 2, 3, 5, 7 and 8 are also known.

Extensions.

Although copernicium is the heaviest known group 12 element, there has been some theoretical work regarding possible heavier group 12 elements. Although a simple extrapolation of the periodic table would put element 162, unhexbium (Uhb), under copernicium, relativistic Dirac-Fock calculations predict that the next group 12 element after copernicium should actually be element 164, unhexquadium (Uhq), which is predicted to have an electron configuration of [Og] 5g 6f 7d 8s 8p. The 8s and 8p orbitals are predicted to be so strongly stabilized relativistically that they become core electrons and do not participate in chemical reactions, unlike the earlier group 12 elements where the s electrons behave as valence electrons. However, the 9s and 9p levels are expected to be readily available for hybridization and bonding, so that unhexquadium should still behave chemically like a normal transition metal. Calculations predict that the 7d electrons of unhexquadium should participate very readily in chemical reactions, so that unhexquadium should be able to show stable +6 and +4 oxidation states in addition to the normal +2 state in aqueous solutions with strong ligands. Unhexquadium should thus be able to form compounds like Uhq(CO), Uhq(PF) (both tetrahedral), and (linear), which is very different behavior from that of lead, which unhexquadium would be a heavier homologue of if not for relativistic effects. Nevertheless, the divalent state would be the main one in aqueous solution, and unhexquadium(II) should behave more similarly to lead than unhexquadium(IV) and unhexquadium(VI).  Unhexquadium should be a soft metal like mercury, and metallic unhexquadium should have a high melting point as it is predicted to bond covalently. It is also expected to be a soft Lewis acid and have Ahrlands softness parameter close to 4 eV. It should also have some similarities to oganesson as well as to the other group 12 elements. Unhexquadium should be at most moderately reactive, having a first ionization energy that should be around 685 kJ/mol, comparable to that of molybdenum. Due to the lanthanide, actinide, and superactinide contractions, unhexquadium should have a metallic radius of only 158 pm, very close to that of the much lighter magnesium, despite its being expected to have an atomic weight of around 474 u, about 19.5 times as much as that of magnesium. This small radius and high weight cause it to be expected to have an extremely high density of around 46 g·cm, over twice that of osmium, currently the most dense element known, at 22.61 g·cm; unhexquadium should be the second most dense element in the first 9 periods of the periodic table, with only its neighbour unhextrium (element 163) being more dense (at 47 g·cm). Metallic unhexquadium should be quite stable, as the 8s and 8p electrons are very deeply buried in the electron core and only the 7d electrons are available for bonding. Metallic unhexquadium should have a very large cohesive energy due to its covalent bonds, most probably resulting in a high melting point.  Theoretical interest in the chemistry of unhexquadium is largely motivated by theoretical predictions that it, especially the isotope Uhq (with 164 protons and 318 neutrons), would be at the center of a hypothetical second island of stability (the first being centered around Ubb, with 122 protons and 184 neutrons).

History.

The elements of group 12 have been found throughout history, being used since ancient times to being discovered in laboratories. The group itself has not acquired a trivial name, but it has been called "group IIB" in the past.

Zinc.

Zinc has been found being used in impure forms in ancient times as well as in alloys such as brass that have been found to be over 2000 years old. Zinc was distinctly recognized as a metal under the designation of "Fasada" in the medical Lexicon ascribed to the Hindu king Madanapala (of Taka dynasty) and written about the year 1374. The metal was also of use to alchemists. The name of the metal was first documented in the 16th century, and is probably derived from the German for the needle-like appearance of metallic crystals.  The isolation of metallic zinc in the West may have been achieved independently by several people in the 17th century. German chemist Andreas Marggraf is usually given credit for discovering pure metallic zinc in a 1746 experiment by heating a mixture of calamine and charcoal in a closed vessel without copper to obtain a metal. Experiments on frogs by the Italian doctor Luigi Galvani in 1780 with brass paved the way for the discovery of electrical batteries, galvanization and cathodic protection. In 1880, Galvani's friend, Alessandro Volta, invented the Voltaic pile. The biological importance of zinc was not discovered until 1940 when carbonic anhydrase, an enzyme that scrubs carbon dioxide from blood, was shown to have zinc in its active site.

Cadmium.

In 1817, cadmium was discovered in Germany as an impurity in zinc carbonate minerals (calamine) by Friedrich Stromeyer and Karl Samuel Leberecht Hermann. It was named after the Latin "cadmia" for "calamine", a cadmium-bearing mixture of minerals, which was in turn named after the Greek mythological character, Κάδμος Cadmus, the founder of Thebes. Stromeyer eventually isolated cadmium metal by roasting and reduction of the sulfide.  In 1927, the International Conference on Weights and Measures redefined the meter in terms of a red cadmium spectral line (1 m = 1,553,164.13 wavelengths). This definition has since been changed (see krypton). At the same time, the International Prototype Meter was used as standard for the length of a meter until 1960, when at the General Conference on Weights and Measures the meter was defined in terms of the orange-red emission line in the electromagnetic spectrum of the krypton-86 atom in vacuum.

Mercury.

Mercury has been found in Egyptian tombs which have been dated back to 1500 BC, where mercury was used in cosmetics. It was also used by the ancient Chinese who believed it would improve and prolong health. By 500 BC mercury was used to make amalgams (Medieval Latin amalgama, "alloy of mercury") with other metals. Alchemists thought of mercury as the First Matter from which all metals were formed. They believed that different metals could be produced by varying the quality and quantity of sulfur contained within the mercury. The purest of these was gold, and mercury was called for in attempts at the transmutation of base (or impure) metals into gold, which was the goal of many alchemists.  Hg is the modern chemical symbol for mercury. It comes from "hydrargyrum", a Latinized form of the Greek word Ύδραργυρος ("hydrargyros"), which is a compound word meaning "water-silver" (hydr- = water, argyros = silver) — since it is liquid like water and shiny like silver. The element was named after the Roman god Mercury, known for speed and mobility. It is associated with the planet Mercury; the astrological symbol for the planet is also one of the alchemical symbols for the metal. Mercury is the only metal for which the alchemical planetary name became the common name.

Copernicium.

The heaviest known group 12 element, copernicium, was first created on February 9, 1996, at the Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, Germany, by Sigurd Hofmann, Victor Ninov et al. It was then officially named by the International Union of Pure and Applied Chemistry (IUPAC) after Nicolaus Copernicus on February 19, 2010, the 537th anniversary of Copernicus' birth.

Occurrence.

Like in most other d-block groups, the abundance in Earth's crust of group 12 elements decreases with higher atomic number. Zinc is with 65 parts per million (ppm) the most abundant in the group while cadmium with 0.1 ppm and mercury with 0.08 ppm are orders of magnitude less abundant. Copernicium, as a synthetic element with a half-life of a few minutes, may only be present in the laboratories where it was produced. Group 12 metals are chalcophiles, meaning the elements have low affinities for oxides and prefer to bond with sulfides. Chalcophiles formed as the crust solidified under the reducing conditions of the early Earth's atmosphere. The commercially most important minerals of group 12 elements are sulfide minerals. Sphalerite, which is a form of zinc sulfide, is the most heavily mined zinc-containing ore because its concentrate contains 60–62% zinc. No significant deposits of cadmium-containing ores are known. Greenockite (CdS), the only cadmium mineral of importance, is nearly always associated with sphalerite (ZnS). This association is caused by the geochemical similarity between zinc and cadmium which makes geological separation unlikely. As a consequence, cadmium is produced mainly as a byproduct from mining, smelting, and refining sulfidic ores of zinc, and, to a lesser degree, lead and copper. One place where metallic cadmium can be found is the Vilyuy River basin in Siberia. Although mercury is an extremely rare element in the Earth's crust, because it does not blend geochemically with those elements that constitute the majority of the crustal mass, mercury ores can be highly concentrated considering the element's abundance in ordinary rock. The richest mercury ores contain up to 2.5% mercury by mass, and even the leanest concentrated deposits are at least 0.1% mercury (12,000 times average crustal abundance). It is found either as a native metal (rare) or in cinnabar (HgS), corderoite, livingstonite and other minerals, with cinnabar being the most common ore.  While mercury and zinc minerals are found in large enough quantities to be mined, cadmium is too similar to zinc and therefore is always present in small quantities in zinc ores from where it is recovered. Identified world zinc resources total about 1.9 billion tonnes. Large deposits are in Australia, Canada and the United States with the largest reserves in Iran. At the current rate of consumption, these reserves are estimated to be depleted sometime between 2027 and 2055. About 346 million tonnes have been extracted throughout history to 2002, and one estimate found that about 109 million tonnes of that remains in use. In 2005, China was the top producer of mercury with almost two-thirds global share followed by Kyrgyzstan. Several other countries are believed to have unrecorded production of mercury from copper electrowinning processes and by recovery from effluents. Because of the high toxicity of mercury, both the mining of cinnabar and refining for mercury are hazardous and historic causes of mercury poisoning.

Production.

Zinc is the fourth most common metal in use, trailing only iron, aluminium, and copper with an annual production of about 10 million tonnes. Worldwide, 95% of the zinc is mined from sulfidic ore deposits, in which sphalerite (ZnS) is nearly always mixed with the sulfides of copper, lead and iron. Zinc metal is produced using extractive metallurgy. Roasting converts the zinc sulfide concentrate produced during processing to zinc oxide: For further processing two basic methods are used: pyrometallurgy or electrowinning. Pyrometallurgy processing reduces zinc oxide with carbon or carbon monoxide at into the metal, which is distilled as zinc vapor. The zinc vapor is collected in a condenser. Electrowinning processing leaches zinc from the ore concentrate by sulfuric acid: After this step electrolysis is used to produce zinc metal.  Cadmium is a common impurity in zinc ores, and it is most isolated during the production of zinc. Some zinc ores concentrates from sulfidic zinc ores contain up to 1.4% of cadmium. Cadmium is isolated from the zinc produced from the flue dust by vacuum distillation if the zinc is smelted, or cadmium sulfate is precipitated out of the electrolysis solution.  The richest mercury ores contain up to 2.5% mercury by mass, and even the leanest concentrated deposits are at least 0.1% mercury, with cinnabar (HgS) being the most common ore in the deposits. Mercury is extracted by heating cinnabar in a current of air and condensing the vapor.  Superheavy elements such as copernicium are produced by bombarding lighter elements in particle accelerators that induces fusion reactions. Whereas most of the isotopes of copernicium can be synthesized directly this way, some heavier ones have only been observed as decay products of elements with higher atomic numbers. The first fusion reaction to produce copernicium was performed by GSI in 1996, who reported the detection of two decay chains of copernicium-277 (though one was later retracted, as it had been based on data fabricated by Victor Ninov):

Applications.

Due to the physical similarities which they share, the group 12 elements can be found in many common situations. Zinc and cadmium are commonly used as anti-corrosion (galvanization) agents as they will attract all local oxidation until they completely corrode. These protective coatings can be applied to other metals through by hot-dip galvanizing a substance into the molten form of the metal, or through the process of electroplating which may be passivated by the use of chromate salts. Group 12 elements are also used in electrochemistry as they may act as an alternative to the standard hydrogen electrode in addition to being a secondary reference electrode.  In the US, zinc is used predominantly for galvanizing (55%) and for brass, bronze and other alloys (37%). The relative reactivity of zinc and its ability to attract oxidation to itself makes it an efficient sacrificial anode in cathodic protection (CP). For example, cathodic protection of a buried pipeline can be achieved by connecting anodes made from zinc to the pipe. Zinc acts as the anode (negative terminus) by slowly corroding away as it passes electric current to the steel pipeline. Zinc is also used to cathodically protect metals that are exposed to sea water from corrosion. Zinc is also used as an anode material for batteries such as in zinc–carbon batteries or zinc-air battery/fuel cells. A widely used alloy which contains zinc is brass, in which copper is alloyed with anywhere from 3% to 45% zinc, depending upon the type of brass. Brass is generally more ductile and stronger than copper and has superior corrosion resistance. These properties make it useful in communication equipment, hardware, musical instruments, and water valves. Other widely used alloys that contain zinc include nickel silver, typewriter metal, soft and aluminium solder, and commercial bronze. Alloys of primarily zinc with small amounts of copper, aluminium, and magnesium are useful in die casting as well as spin casting, especially in the automotive, electrical, and hardware industries. These alloys are marketed under the name Zamak. Roughly one quarter of all zinc output, in the United States (2009), is consumed in the form of zinc compounds, a variety of which are used industrially.  Cadmium has many common industrial uses as it is a key component in battery production, is present in cadmium pigments, coatings, and is commonly used in electroplating. In 2009, 86% of cadmium was used in batteries, predominantly in rechargeable nickel-cadmium batteries. The European Union banned the use of cadmium in electronics in 2004 with several exceptions but reduced the allowed content of cadmium in electronics to 0.002%. Cadmium electroplating, consuming 6% of the global production, can be found in the aircraft industry due to the ability to resist corrosion when applied to steel components.  Mercury is used primarily for the manufacture of industrial chemicals or for electrical and electronic applications. It is used in some thermometers, especially ones which are used to measure high temperatures. A still increasing amount is used as gaseous mercury in fluorescent lamps, while most of the other applications are slowly phased out due to health and safety regulations, and is in some applications replaced with less toxic but considerably more expensive Galinstan alloy. Mercury and its compounds have been used in medicine, although they are much less common today than they once were, now that the toxic effects of mercury and its compounds are more widely understood. It is still used as an ingredient in dental amalgams. In the late 20th century the largest use of mercury was in the mercury cell process (also called the Castner-Kellner process) in the production of chlorine and caustic soda.

Biological role and toxicity.

The group 12 elements have multiple effects on biological organisms as cadmium and mercury are toxic while zinc is required by most plants and animals in trace amounts.  Zinc is an essential trace element, necessary for plants, animals, and microorganisms. It is "typically the second most abundant transition metal in organisms" after iron and it is the only metal which appears in all enzyme classes. There are 2–4 grams of zinc distributed throughout the human body, and it plays "ubiquitous biological roles". A 2006 study estimated that about 10% of human proteins (2800) potentially bind zinc, in addition to hundreds which transport and traffic zinc. In the U.S., the Recommended Dietary Allowance (RDA) is 8 mg/day for women and 11 mg/day for men. Harmful excessive supplementation may be a problem and should probably not exceed 20 mg/day in healthy people, although the U.S. National Research Council set a Tolerable Upper Intake of 40 mg/day.  Mercury and cadmium are toxic and may cause environmental damage if they enter rivers or rain water. This may result in contaminated crops as well as the bioaccumulation of mercury in a food chain leading to an increase in illnesses caused by mercury and cadmium poisoning.

Group 12, by modern IUPAC numbering, is a group of chemical elements in the periodic table. It includes zinc (Zn), cadmium (Cd) and mercury (Hg). The further inclusion of copernicium (Cn) in group 12 is supported by recent experiments on individual copernicium atoms. Formerly this group was named "IIB" (pronounced as "group two B", as the "II" is a Roman numeral) by CAS and old IUPAC system.

! colspan=2 style="text-align:left;" | ↓! 4! 5! 6! 7 12族元素(常称锌族元素)是指元素周期表上第12族(IIB族)的元素,位于11族元素和硼族元素之间。12族元素包含锌(Zn)、镉(Cd)、汞(Hg)、<unk>(Cn),均为过渡金属元素,其中<unk>为人造元素,具极高的放射性。