is the element tin a metal nonmetal or metalloid
Metalloid


. reported that astatine appeared to be more polonium-like than halogen-like. They did so on the basis of detailed comparative studies of the known and interpolated properties of 72 elements. In the periodic table, some of the elements adjacent to the commonly recognised metalloids, although usually classified as either metals or nonmetals, are occasionally referred to as "near-metalloids" or noted for their metalloidal character. To the left of the metal–nonmetal dividing line, such elements include gallium, tin and bismuth. They show
5142382
Metalloid


molybdenum, tungsten, tin, lead, and aluminium. The p-block metals, and nonmetals (such as carbon or nitrogen) that can form alloys with metals or modify their properties have also occasionally been considered as metalloids. No widely accepted definition of a metalloid exists, nor any division of the periodic table into metals, metalloids, and nonmetals; Hawkes questioned the feasibility of establishing a specific definition, noting that anomalies can be found in several attempted constructs. Classifying an element as a metalloid has been described by Sharp
5142295
Metalloid


or near the notional dividing line between metals and nonmetals, exhibit more pronounced metallic, metalloidal or nonmetallic behaviour than others. The existence of such allotropes can complicate the classification of the elements involved. Tin, for example, has two allotropes: tetragonal "white" β-tin and cubic "grey" α-tin. White tin is a very shiny, ductile and malleable metal. It is the stable form at or above room temperature and has an electrical conductivity of 9.17 × 10 S·cm (~1/6th that of copper)
5142384
Metalloid


a binary classification can facilitate the establishment of rules for determining bond types between metals and nonmetals. Metalloids are variously grouped with metals, regarded as nonmetals or treated as a sub-category of nonmetals. Other authors have suggested that classifying some elements as metalloids "emphasizes that properties change gradually rather than abruptly as one moves across or down the periodic table". Some periodic tables distinguish elements that are metalloids and display no formal dividing line between metals and nonmetals. Metalloids are shown as occurring in a diagonal band or diffuse region.
5142303
Properties of metals, metalloids and nonmetals


Metalloids, straddling the metal-nonmetal border, are mostly distinct from either, but in a few properties resemble one or the other, as shown in the shading of the metalloid column below and summarized in the small table at the top of this section. Authors differ in where they divide metals from nonmetals and in whether they recognize an intermediate metalloid category. Some authors count metalloids as nonmetals with weakly nonmetallic properties. Others count some of the metalloids as post-transition metals. Within each category, elements can be found with
21150996
Metal


are shown in yellow on the periodic table below. The elements shown as having unknown properties are likely to be metals. The remaining elements are either metalloids (B, Si, Ge, As, Sb, and Te being commonly recognised as such) or nonmetals. Astatine (At) is usually classified as either a nonmetal or a metalloid; it has been predicted to be a metal. It is here shown as a metalloid. An alloy is a substance having metallic properties and which is composed of two or more elements
19379047
Nonmetal


, elements in the periodic table vicinity of where the metals meet the nonmetals are inconsistently classified by different authors. Elements sometimes also classified as nonmetals are the metalloids boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), and astatine (At). The nonmetal selenium (Se) is sometimes instead classified as a metalloid, particularly in environmental chemistry. Nonmetals show more variability in their properties than do metals. These properties are largely
13626077
Periodic table


the periodic table, has no group numbers and comprises lanthanides and actinides. According to their shared physical and chemical properties, the elements can be classified into the major categories of metals, metalloids and nonmetals. Metals are generally shiny, highly conducting solids that form alloys with one another and salt-like ionic compounds with nonmetals (other than noble gases). A majority of nonmetals are coloured or colourless insulating gases; nonmetals that form compounds with other nonmetals feature covalent bonding. In between metals and nonmetals are metalloids, which have
3472844
Nonmetal


. In scheme (5), hydrogen is placed by itself on account of it being "so different from all other elements". The remaining nonmetals are divided into "nonmetals", "halogens", and "noble gases", with the unnamed category being distinguished by including nonmetals with relatively strong interatomic bonding, and the metalloids being effectively treated as a third super-category alongside metals and nonmetals. Characteristic and other properties of metalloids, reactive nonmetals, and noble gases are summarized in the following table. Metalloids have
13626100
Origin and use of the term metalloid


. As late as 1888, classifying the elements into metals, metalloids, and nonmetals, rather than metals and metalloids, was still regarded as peculiar and potentially confusing. Beach, writing in 1911, explained it this way: In or around 1917, the Missouri Board of Pharmacy wrote that: During the 1920s the two meanings of the word metalloid appeared to be undergoing a transition in popularity. Writing in "A Dictionary of Chemical Terms," Couch defined 'metalloid' as an old, obsolescent term for 'nonmetal.
20978441
Origin and use of the term metalloid


aspects, but are in others widely different'); and IV. metals. In 1864, calling nonmetals 'metalloids' was still sanctioned 'by the best authorities' even though this did not always seem appropriate. The greater propriety of applying the word metalloid to other elements, such as arsenic, had been considered. By as early as 1866 some authors were instead using the term nonmetal, rather than metalloid, to refer to nonmetallic elements. In 1875, Kemshead observed that the elements had been subdivided into two classes—'non
20978439
Metalloid


astatine. On a standard periodic table, all eleven elements are located in a diagonal region of the p-block extending from boron at the upper left to astatine at lower right. Some periodic tables include a dividing line between metals and nonmetals and the metalloids may be found close to this line. Typical metalloids have a metallic appearance, but they are brittle and only fair conductors of electricity. Chemically, they behave mostly as nonmetals. They can form alloys with metals. Most of their other physical properties and chemical properties are
5142290
Metalloid


effect of increasing nuclear charge is generally outweighed by the effect of additional electrons being further away from the nucleus. Atoms generally become larger, ionization energy falls, and metallic character increases. The net effect is that the location of the metal–nonmetal transition zone shifts to the right in going down a group, and analogous diagonal similarities are seen elsewhere in the periodic table, as noted. Depictions of metalloids vary according to the author. Some do not classify elements bordering the metal–nonmetal dividing line as metalloids, noting that
5142302
Chemical element


viewed metals and nonmetals. The version of this classification used in the periodic tables presented here includes: actinides, alkali metals, alkaline earth metals, halogens, lanthanides, transition metals, post-transition metals, metalloids, reactive nonmetals, and noble gases. In this system, the alkali metals, alkaline earth metals, and transition metals, as well as the lanthanides and the actinides, are special groups of the metals viewed in a broader sense. Similarly, the reactive nonmetals and the noble gases are nonmetals viewed in the
5775733
Properties of metals, metalloids and nonmetals


. Some metalloids (As, Sb) conduct electricity like metals. The metalloids, as the smallest major category of elements, are not subdivided further). Nonmetals have open structures (unless solidified from gaseous or liquid forms); tend to gain or share electrons when they react with other substances; and do not form distinctly basic oxides. Most are gases at room temperature; have relatively low densities; are poor electrical and thermal conductors; have relatively high ionisation energies and electronegativities; form acidic oxides; and are found naturally
21150994
Origin and use of the term metalloid


The origin and usage of the term "metalloid" is convoluted. Its origin lies in attempts, dating from antiquity, to describe metals and to distinguish between typical and less typical forms. It was first applied to metals that floated on water (lithium, sodium and potassium), and then more popularly to nonmetals. Only recently, since the mid-20th century, has it been widely used to refer to elements with intermediate or borderline properties between metals and nonmetals. Ancient conceptions of metals as solid, fusible and malleable substances can
20978432
Origin and use of the term metalloid


-metals or metalloids, and metals.' He added that '[t]he former term, although not so convenient, because a compound word, is more correct, and is now universally employed.' In 1876, Tilden protested against, 'the [still] too common though illogical practice of giving the name metalloid to such bodies as oxygen, chlorine or fluorine'. He instead divided the elements into ('basigenic') true metals, metalloids ('imperfect metals') and ('oxigenic') nonmetals
20978440
Chemical element


characterize the general physical and chemical properties of the chemical elements. A first distinction is between metals, which readily conduct electricity, nonmetals, which do not, and a small group, (the "metalloids"), having intermediate properties and often behaving as semiconductors. A more refined classification is often shown in colored presentations of the periodic table. This system restricts the terms "metal" and "nonmetal" to only certain of the more broadly defined metals and nonmetals, adding additional terms for certain sets of the more broadly
5775732
Nonmetal


2), the nonmetals can simply be divided based on their physical forms at room temperature and pressure. The fluid nonmetals (bromine and the gaseous nonmetals) have the highest ionisation energy and electronegativity values among the elements, with the exception of hydrogen which tends to be anomalous in whichever category it is placed in. The solid nonmetals are collectively the most metallic of the nonmetallic elements, apart from the metalloids. In scheme (3), the nonmetals are divided based on a loose correlation between electronegativity and oxidizing power. Very
13626097
Chalcogen


and tellurium have the hexagonal crystal structure, while polonium has a cubic crystal structure. Oxygen, sulfur, and selenium are nonmetals, and tellurium is a metalloid, meaning that its chemical properties are between those of a metal and those of a nonmetal. It is not certain whether polonium is a metal or a metalloid. Some sources refer to polonium as a metalloid, although it has some metallic properties. Also, some allotropes of selenium display characteristics of a metalloid, even though selenium is usually considered a nonmetal. Even though
6127390
Metalloid


A metalloid is a type of chemical element which has properties in between, or that are a mixture of, those of metals and nonmetals. There is neither a standard definition of a metalloid nor complete agreement on the elements appropriately classified as such. Despite the lack of specificity, the term remains in use in the literature of chemistry. The six commonly recognised metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium. Five elements are less frequently so classified: carbon, aluminium, selenium, polonium, and
5142289
Metalloid


properties, became widespread in 1940–1960. Metalloids are sometimes called semimetals, a practice that has been discouraged, as the term "semimetal" has a different meaning in physics than in chemistry. In physics, it specifically refers to the electronic band structure of a substance. A metalloid is an element that possesses properties of both metals and non metals, and which is therefore hard to classify as either a metal or a nonmetal. This is a generic definition that draws on metalloid attributes consistently cited in the literature. Difficulty of categorisation
5142292
Metal


are commonly instead recognised as metalloids, on account of their predominately non-metallic chemistry. Around 95 of the 118 elements in the periodic table are metals (or are likely to be such). The number is inexact as the boundaries between metals, nonmetals, and metalloids fluctuate slightly due to a lack of universally accepted definitions of the categories involved. In astrophysics the term "metal" is cast more widely to refer to all chemical elements in a star that are heavier than the lightest two, hydrogen and helium, and
19379032
Post-transition metal


loosely or explicitly, to metals with incomplete metallic character in crystalline structure, electrical conductivity or electronic structure. Examples include gallium, ytterbium, bismuth, mercury and neptunium. Metalloids, which are in-between elements that are neither metals nor nonmetals, are also sometimes instead called semimetals. The elements commonly recognised as metalloids are boron, silicon, germanium, arsenic, antimony and tellurium. In old chemistry, before the publication in 1789 of Lavoisier's 'revolutionary' "Elementary Treatise on Chemistry", a semimetal was a metallic
19783975
Metalloid


have electrical conductivities approaching those of metals. Selenium and polonium are suspected as not in this scheme, while astatine's status is uncertain. Metalloids lie on either side of the dividing line between metals and nonmetals. This can be found, in varying configurations, on some periodic tables. Elements to the lower left of the line generally display increasing metallic behaviour; elements to the upper right display increasing nonmetallic behaviour. When presented as a regular stairstep, elements with the highest critical temperature for their groups (Li, Be, Al
5142299
Metalloid


Metalloids usually look like metals but behave largely like nonmetals. Physically, they are shiny, brittle solids with intermediate to relatively good electrical conductivity and the electronic band structure of a semimetal or semiconductor. Chemically, they mostly behave as (weak) nonmetals, have intermediate ionization energies and electronegativity values, and amphoteric or weakly acidic oxides. They can form alloys with metals. Most of their other physical and chemical properties are intermediate in nature. Characteristic properties of metals, metalloids, and nonmetals are summarized in the table. Physical properties
5142304
Properties of metals, metalloids and nonmetals


in uncombined states in large amounts. Some nonmetals (C, black P, S and Se) are brittle solids at room temperature (although each of these also have malleable, pliable or ductile allotropes). From left to right in the periodic table, the nonmetals can be subdivided into the reactive nonmetals which, being nearest to the metalloids, show some incipient metallic character, and the monatomic noble gases, which are almost completely inert. properties of metals and nonmetals are quite distinct, as shown in the table below.
21150995
Metalloid


It has been referred to as either a very poor metal, a metalloid, a nonmetal or a near metalloid. The diamond allotrope of carbon is clearly nonmetallic, being translucent and having a low electrical conductivity of 10 to 10 S·cm. Graphite has an electrical conductivity of 3 × 10 S·cm, a figure more characteristic of a metal. Phosphorus, sulfur, arsenic, selenium, antimony, and bismuth also have less stable allotropes that display different behaviours. The table gives crustal abundances of the elements commonly to rarely recognised as metalloids
5142386
Metalloid


is a metallic conductor with an electrical conductivity of around 5.3 × 10 S•cm. Most of the chemistry of antimony is characteristic of a nonmetal. Antimony has some definite cationic chemistry, SbO and Sb(OH) being present in acidic aqueous solution; the compound Sb(GaCl), which contains the homopolycation, Sb, was prepared in 2004. It can form alloys with one or more metals such as aluminium, iron, nickel, copper, zinc, tin, lead, and bismuth. Antimony has fewer tendencies to anionic behaviour than ordinary nonmetals
5142358
Nonmetal


and germanium, which generally behave chemically like nonmetals, and are included here for comparative purposes. In this sense they can be regarded as the most metallic of nonmetallic elements. Based on shared attributes, the nonmetals can be divided into the two categories of "reactive nonmetal," and "noble gas." The metalloids and the two nonmetal categories then span a progression in chemical nature from weakly nonmetallic, to moderately nonmetallic, to strongly nonmetallic (oxygen and the four nonmetallic halogens), to almost inert. Analogous categories occur
13626085
Origin and use of the term metalloid


' In contrast, "Webster's New International Dictionary" noted that use of the term metalloid to refer to nonmetals was the norm. Its application to elements resembling the typical metals in some way only, such as arsenic, antimony and tellurium, was recorded merely on a 'sometimes' basis. Use of the term metalloid subsequently underwent a period of great flux up to 1940. Consensus as to its application to intermediate or borderline elements did not occur until the ensuing years, between 1940 and 1960. In 1947, Pauling
20978442
Nonmetal


less electronegative of them, such as carbon and sulfur, mostly have weak to moderately strong nonmetallic properties and tend to form covalent compounds with metals. The more electronegative of the reactive nonmetals, such as oxygen and fluorine, are characterised by stronger nonmetallic properties and a tendency to form predominantly ionic compounds with metals. The noble gases are distinguished by their great reluctance to form compounds with other elements. The distinction between categories is not absolute. Boundary overlaps, including with the metalloids, occur as outlying elements in each category show or
13626074
Period (periodic table)


Completing the fourth period are the post-transition metals zinc and gallium, the metalloids germanium and arsenic, and the nonmetals selenium, bromine, and krypton. Period 5 has the same number of elements as period 4 and follows the same general structure but with one more post transition metal and one fewer nonmetal. Of the three heaviest elements with biological roles, two (molybdenum and iodine) are in this period; tungsten, in period 6, is heavier, along with several of the early lanthanides. Period 5 also includes
5268639
Nonmetal


nonmetal, rather than a metalloid; and the remaining nonmetals are referred to as "other nonmetals". If selenium is counted as a metalloid rather than another nonmetal, the resulting set of less active nonmetals (H, C, N, P, O, S) are sometimes instead referred to or categorised as "organogens", "CHONPS" elements or "biogens". Collectively these six nonmetals comprise the bulk of life on Earth; a rough estimate of the composition of the biosphere is CHONPS. In scheme (
13626096
Nonmetal


18 elements, credible predictions on its status as either a metal or a nonmetal (or a metalloid) appear to be absent. The nonmetals are sometimes instead divided according to either (1) the relative homogeneity of the halogens; (2) physical form; (3) electronegativity; (4) molecular structure; or (5) the peculiar nature of hydrogen, and the relative homogeneity of the halogens. In scheme (1), the halogens are in a category of their own; astatine is classed as a
13626095
Metalloid


nonmetal dividing line are metalloids. Stott labels aluminium as a weak metal. It has the physical properties of a metal but some of the chemical properties of a nonmetal. Steele notes the paradoxical chemical behaviour of aluminium: "It resembles a weak metal in its amphoteric oxide and in the covalent character of many of its compounds ... Yet it is a highly electropositive metal ... [with] a high negative electrode potential". Moody says that, "aluminium is on the 'diagonal borderland' between metals and non-metals in
5142371
Metalloid


metallic properties and is sometimes instead classified as either a metalloid or (less often) as a metal. Immediately following its production in 1940, early investigators considered it a metal. In 1949 it was called the most noble (difficult to reduce) nonmetal as well as being a relatively noble (difficult to oxidize) metal. In 1950 astatine was described as a halogen and (therefore) a reactive nonmetal. In 2013, on the basis of relativistic modelling, astatine was predicted to be a monatomic metal, with a face
5142377
Post-transition metal


this context. The group 12 metals are also noted as having slightly distorted structures; this has been interpreted as evidence of weak directional (i.e. covalent) bonding. Rayner-Canham and Overton use the term "chemically weak metals" to refer to the metals close to the metal-nonmetal borderline. These metals behave chemically more like the metalloids, particularly with respect to anionic species formation. The nine chemically weak metals identified by them are beryllium, magnesium, aluminum, gallium, tin, lead, antimony, bismuth, and
19783963
Dividing line between metals and nonmetals


the "amphoteric line," the "metal-nonmetal line," the "metalloid line," the "semimetal line," or the "staircase." It is also erroneously referred to as the "Zintl border" or the "Zintl line." The last two terms instead refer to a vertical line sometimes drawn between groups 13 and 14. This particular line was christened by Laves in 1941. It differentiates group 13 elements from those in and to the right of group 14. The former generally combine with
1357448
Metalloid


, by itself, or with silicon. Sometimes tellurium is not regarded as a metalloid. The inclusion of antimony, polonium, and astatine as metalloids has been questioned. Other elements are occasionally classified as metalloids. These elements include hydrogen, beryllium, nitrogen, phosphorus, sulfur, zinc, gallium, tin, iodine, lead, bismuth, and radon. The term metalloid has also been used for elements that exhibit metallic lustre and electrical conductivity, and that are amphoteric, such as arsenic, antimony, vanadium, chromium,
5142294
Nonmetal


a poor oxidising agent (Sb + 3e → SbH = –0.51 at pH 0). As a metalloid, its chemistry is largely covalent in nature, noting it can form alloys with one or more metals such as aluminium, iron, nickel, copper, zinc, tin, lead and bismuth, and has an extensive organometallic chemistry. Most alloys of antimony with metals have metallic or semimetallic conductivity. The common oxide of antimony (SbO) is amphoteric. Oxygen is a colourless, odourless, and unpredictably reactive diatomic gas
13626122
Nonmetal


among the metals in the form of the weakly metallic (the post-transition metals), the moderately metallic (most of the transition metals), the strongly metallic (the alkali metal and alkaline earth metals, and the lanthanides and actinides), and the relatively inert (the noble transition metals). As with categorisation schemes generally, there is some variation and overlapping of properties within and across each category. One or more of the metalloids are sometimes classified as nonmetals. Among the reactive nonmetals, carbon, phosphorus,
13626086
Nonmetal


selenium, and iodine—which border the metalloids—show some metallic character, as does hydrogen. Among the noble gases, radon is the most metallic and begins to show some cationic behaviour, which is unusual for a nonmetal. The seven metalloids are boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), and astatine (At). On a standard periodic table, they occupy a diagonal area in the p-block
13626087
Post-transition metal


Astatine, which is usually classified as a nonmetal or a metalloid, has been predicted to have a metallic crystalline structure. If so, it would be a post-transition metal. Elements 112–118 (copernicium, nihonium, flerovium, moscovium, livermorium, tennessine, and oganesson) may be post-transition metals; insufficient quantities of them have been synthesized to allow sufficient investigation of their actual physical and chemical properties. Which elements start to be counted as post-transition metals depends, in periodic table terms, on where the
19783906
Nonmetal


Chemically the metalloids generally behave like (weak) nonmetals. They have moderate ionisation energies, low to high electron affinities, moderate electronegativity values, are poor to moderately strong oxidising agents, and demonstrate a tendency to form alloys with metals. The reactive nonmetals have a diverse range of individual physical and chemical properties. In periodic table terms they largely occupy a position between the weakly nonmetallic metalloids to the left and the noble gases to the right. Physically, five are solids, one is a liquid (bromine), and five
13626089
Nonmetal


valences other than the lowest for their group (that is, 3, 2, 1, or 0) for example in PCl, SF, IF, and XeF. Period four elements immediately after the first row of the transition metals, such as selenium and bromine, have unusually small atomic radii because the 3d electrons are not effective at shielding the increased nuclear charge, and smaller atomic size correlates with higher electronegativity. Immediately to the left of most nonmetals on the periodic table are "metalloids" such as boron, silicon,
13626084
Periodic table


intermediate or mixed properties. Metal and nonmetals can be further classified into subcategories that show a gradation from metallic to non-metallic properties, when going left to right in the rows. The metals may be subdivided into the highly reactive alkali metals, through the less reactive alkaline earth metals, lanthanides and actinides, via the archetypal transition metals, and ending in the physically and chemically weak post-transition metals. Nonmetals may be simply subdivided into the polyatomic nonmetals, being nearer to the metalloids and show some incipient metallic character;
3472845
Nonmetal


and living beings. The balance is made of dark energy and dark matter, both of which are poorly understood at present. Hydrogen, carbon, nitrogen, and oxygen constitute the great bulk of the Earth's atmosphere, oceans, crust, and biosphere; the remaining nonmetals have abundances of 0.5 per cent or less. In comparison, 35 per cent of the crust is made up of the metals sodium, magnesium, aluminium, potassium and iron; together with a metalloid, silicon. All other metals and metalloids have abundances
13626159
Lists of metalloids


, on the basis of relativistic modelling, predict astatine will be a monatomic metal. One or more of carbon, aluminium, phosphorus, selenium, tin or bismuth, these being periodic table neighbours of the elements commonly classified as metalloids, are sometimes recognised as metalloids. Selenium, in particular, is commonly designated as a metalloid in environmental chemistry on account of similarities in its aquatic chemistry with that of arsenic and antimony. There are fewer references to beryllium, in spite of its periodic table position adjoining the dividing line between metals
1293710
Metalloid


a structure has few slip systems and "leads to very low ductility and hence low fracture resistance". Polonium shows nonmetallic character in its halides, and by the existence of polonides. The halides have properties generally characteristic of nonmetal halides (being volatile, easily hydrolyzed, and soluble in organic solvents). Many metal polonides, obtained by heating the elements together at 500–1,000 °C, and containing the Po anion, are also known. As a halogen, astatine tends to be classified as a nonmetal. It has some marked
5142376
Metal


can occur. Consequently, semiconductors and nonmetals are relatively poor conductors. The elemental metals have electrical conductivity values of from 6.9 × 10 S/cm for manganese to 6.3 × 10 S/cm for silver. In contrast, a semiconducting metalloid such as boron has an electrical conductivity 1.5 × 10 S/cm. With one exception, metallic elements reduce their electrical conductivity when heated. Plutonium increases its electrical conductivity when heated in the temperature range of around −175 to +125 °C. Metals are relatively good conductors of heat.
19379043
Post-transition metal


thallium, while moscovium(III) oxide (McO) should be amphoteric, like that of bismuth. Selenium is a soft (MH 2.0) and brittle semi-metallic element. It is commonly regarded as a nonmetal, but is sometimes considered a metalloid or even a heavy metal. Selenium has a hexagonal polyatomic (CN 2) crystalline structure. It is a semiconductor with a band gap of 1.7 eV, and a photoconductor meaning its electrical conductivity increases a million-fold when illuminated. Selenium forms covalent bonds with most other elements
19783950
Block (periodic table)


. Helium, though being in the top of group 18, is not included in the p-block. Their general valence configuration is "n"s "n"p. This block contains a variety of elements and is the only block that contains all three types of elements: metals, nonmetals, and metalloids. Generally, the p-block elements are best described in terms of element type or group. The p-block elements are unified by the fact that their valence electrons (outermost electrons) are in the p orbital.
2070044
Nonmetal


greater than 64 per cent) of compounds. Silicon, a metalloid, was in 10th place. The highest rated metal, with an occurrence frequency of 2.3 per cent, was iron, in 11th place. Carbon, sulfur, and antimony were known in antiquity. The earliest known use of charcoal dates to around 3750 BCE. The Egyptians and Sumerians employed it for the reduction of copper, zinc, and tin ores in the manufacture of bronze. Diamonds were probably known from as early as 2500 BCE. The first true
13626166
Silicon


as well as bases (though this takes some effort), and is hence often referred to as a [[metalloid]] rather than a nonmetal. However, metallicity does not become clear in group 14 until germanium and dominant until tin, with the growing importance of the lower +2 oxidation state. Silicon shows clear differences from carbon. For example, [[organic chemistry]] has very few analogies with silicon chemistry, while [[silicate]] minerals have a structural complexity unseen in [[oxocarbon]]s. Silicon
7347426
Post-transition metal


transition metals are taken to end. In the 1950s, most inorganic chemistry textbooks defined transition elements as finishing at group 10 (nickel, palladium and platinum), therefore excluding group 11 (copper, silver and gold), and group 12 (zinc, cadmium and mercury). A survey of chemistry books in 2003 showed that the transition metals ended at either group 11 or group 12 with roughly equal frequency. Where the post-transition metals end depends on where the metalloids or nonmetals start. Boron, silicon, germanium
19783907
Period 5 element


Another large application for tin is corrosion-resistant tin plating of steel. Because of its low toxicity, tin-plated metal is also used for food packaging, giving the name to tin cans, which are made mostly of steel. Antimony () is a toxic chemical element with the symbol Sb and an atomic number of 51. A lustrous grey metalloid, it is found in nature mainly as the sulfide mineral stibnite (SbS). Antimony compounds have been known since ancient times and were used for cosmetics, metallic antimony
1859390
Metalloid


are listed in order of ease of determination; chemical properties run from general to specific, and then to descriptive. The above table reflects the hybrid nature of metalloids. The properties of "form, appearance", and "behaviour when mixed with metals" are more like metals. "Elasticity" and "general chemical behaviour" are more like nonmetals. "Electrical conductivity, band structure, ionization energy, electronegativity," and "oxides" are intermediate between the two. Metalloids are too brittle to have any structural uses
5142305
Valence electron


at a higher principal quantum number. In these simple cases where the octet rule is obeyed, the valence of an atom equals the number of electrons gained, lost, or shared in order to form the stable octet. However, there are also many molecules which are exceptions, and for which the valence is less clearly defined. Valence electrons are also responsible for the electrical conductivity of an element; as a result, an element may be classified as a metal, a nonmetal, or a semiconductor (or metalloid).
11942318
Post-transition metal


, arsenic, antimony and tellurium are commonly recognised as metalloids; other authors treat some or all of these elements as nonmetals. The diminished metallic nature of the post-transition metals is largely attributable to the increase in nuclear charge going across the periodic table, from left to right. The increase in nuclear charge is partially offset by an increasing number of electrons but as these are spatially distributed each extra electron does not fully screen each successive increase in nuclear charge, and the latter therefore dominates. With some irregularities, atomic radii
19783908
Metalloid


former, including with the coinage metals. Its alloys include pewter (a tin alloy with up to 20% antimony) and type metal (a lead alloy with up to 25% antimony). Tellurium readily alloys with iron, as ferrotellurium (50–58% tellurium), and with copper, in the form of copper tellurium (40–50% tellurium). Ferrotellurium is used as a stabilizer for carbon in steel casting. Of the non-metallic elements less often recognised as metalloids, selenium—in the form of ferroselenium (
5142309
Nonmetal


gases exist as isolated atoms (He, Ne, Ar, Kr, Xe, Rn) with no fixed nearest neighbour. This gradual reduction in the number of nearest neighbours corresponds (approximately) to a reduction in metallic character. A similar progression is seem among the metals. Metallic bonding tends to involve close-packed centrosymmetric structures with a high number of nearest neighbours. Post-transition metals and metalloids, sandwiched between the true metals and the nonmetals, tend to have more complex structures with an intermediate number of nearest neighbours
13626099
Properties of metals, metalloids and nonmetals


metals; the less reactive alkaline earth metals, lanthanides and radioactive actinides; the archetypal transition metals, and the physically and chemically weak post-transition metals. Specialized subcategories such as the refractory metals and the noble metals also exist. (Metalloids are metallic looking brittle solids; tend to share electrons when they react with other substances; have weakly acidic or amphoteric oxides; and are usually found naturally in combined states. Most are semiconductors, and moderate thermal conductors, and have structures that are more open than those of most metals
21150993
Properties of metals, metalloids and nonmetals


Be, Al) or very high melting points, are liquids at or near room temperature, are brittle (e.g. Os, Bi), not easily machined (e.g. Ti, Re), or are noble (hard to oxidise) or have nonmetallic structures (Mn and Ga are structurally analogous to, respectively, white P and I). Metals comprise the large majority of the elements, and can be subdivided into several different categories. From left to right in the periodic table, these categories include the highly reactive alkali
21150992
Nonmetal


(a metastable ductile mixture of allotropes) have nonmetallic properties. Selenium has several nonmetallic allotropes, all of which are much less electrically conducting than its standard state of grey "metallic" selenium. Iodine is also known in a semiconducting amorphous form. Under sufficiently high pressures, just over half of the nonmetals, starting with phosphorus at 1.7 GPa, have been observed to form metallic allotropes. Most metalloids, like the less electronegative nonmetals, form allotropes. Boron is known in several crystalline and amorphous forms. The discovery of a
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Origin and use of the term metalloid


used in this sense (around that time) by, for example, the French. In 1969 the classic and authoritative "Hackh's Chemical Dictionary" included entries for both 'metalloid' and 'semimetal'. The latter term was described as obsolete. In 1970 IUPAC recommended abandoning the term metalloid because of its continuing inconsistent use in different languages. They suggested using the terms metal, semimetal and nonmetal instead. Despite this recommendation, use of the term 'metalloid' increased dramatically. Google Ngram Viewer showed a fourfold increase
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Nonmetal


extending from boron at the upper left to astatine at lower right, along the dividing line between metals and nonmetals shown on some periodic tables. They are called "metalloids" mainly in light of their physical resemblance to metals. While they each have a metallic appearance, they are brittle and only fair conductors of electricity. Boron, silicon, germanium, tellurium are semiconductors. Arsenic and antimony have the electronic band structures of semimetals although both have less stable semiconducting allotropes. Astatine has been predicted to have a metallic crystalline structure.
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Metalloid


in their most stable forms. The origin and usage of the term "metalloid" is convoluted. Its origin lies in attempts, dating from antiquity, to describe metals and to distinguish between typical and less typical forms. It was first applied in the early 19th century to metals that floated on water (sodium and potassium), and then more popularly to nonmetals. Earlier usage in mineralogy, to describe a mineral having a metallic appearance, can be sourced to as early as 1800. Since the mid-20th century it has been
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Post-transition metal


] covalent nonmetals (H, C, N, O, P, S and the halogens); and [8] monatomic nonmetals (that is, the noble gases). The "metametals" are zinc, cadmium, mercury, indium, thallium, tin and lead. They are ductile elements but, compared to their metallic periodic table neighbours to the left, have lower melting points, relatively low electrical and thermal conductivities, and show distortions from close-packed forms. Sometimes beryllium and gallium are included as metametals
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Pnictogen


the other pnictogen pentafluorides, making it an extremely powerful fluorinating agent. This effect is even more pronounced for moscovium, prohibiting it from attaining a +5 oxidation state. The pnictogens consist of two nonmetals (one gas, one solid), two metalloids, one metal, and one element with unknown chemical properties. All the elements in the group are solids at room temperature, except for nitrogen which is gaseous at room temperature. Nitrogen and bismuth, despite both being pnictogens, are very different in their physical properties. For instance
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Post-transition metal


Post-transition metals are a set of metallic elements in the periodic table located between the transition metals to their left, and the metalloids to their right. Depending on where these adjacent groups are judged to begin and end, there are at least five competing proposals for which elements to include: the three most common contain six, ten and thirteen elements, respectively (see image). All proposals include gallium, indium, tin, thallium, lead, and bismuth. Physically, post-transition metals are soft (or
19783902
Metalloid


a nonmetal. It shows some cationic behaviour. The dioxide dissolves in acid to yield the trihydroxotellurium(IV) Te(OH) ion; the red Te and yellow-orange Te ions form when tellurium is oxidized in fluorosulfuric acid (HSOF), or liquid sulfur dioxide (SO), respectively. It can form alloys with aluminium, silver, and tin. Tellurium shows fewer tendencies to anionic behaviour than ordinary nonmetals. Its solution chemistry is characterised by the formation of oxyanions. Tellurium generally forms compounds in which it has an oxidation state of
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Metalloid


the chemical sense." Selenium shows borderline metalloid or nonmetal behaviour. Its most stable form, the grey trigonal allotrope, is sometimes called "metallic" selenium because its electrical conductivity is several orders of magnitude greater than that of the red monoclinic form. The metallic character of selenium is further shown by its lustre, and its crystalline structure, which is thought to include weakly "metallic" interchain bonding. Selenium can be drawn into thin threads when molten and viscous. It shows reluctance to acquire "the high positive oxidation numbers
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Metalloid


intermediate in nature. Metalloids are usually too brittle to have any structural uses. They and their compounds are used in alloys, biological agents, catalysts, flame retardants, glasses, optical storage and optoelectronics, pyrotechnics, semiconductors, and electronics. The electrical properties of silicon and germanium enabled the establishment of the semiconductor industry in the 1950s and the development of solid-state electronics from the early 1960s. The term "metalloid" originally referred to nonmetals. Its more recent meaning, as a category of elements with intermediate or hybrid
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Origin and use of the term metalloid


included a reference to metalloids in his classic and influential textbook, "General chemistry: An introduction to descriptive chemistry and modern chemical theory." He described them as 'elements with intermediate properties ... occupy[ing] a diagonal region [on the periodic table], which includes boron, silicon, germanium, arsenic, antimony, tellurium, and polonium.' In 1959 the International Union of Pure and Applied Chemistry (IUPAC) recommended that '[t]he word metalloid should not be used to denote nonmetals' although it was still being
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Superalloy


these Ni based superalloys can be tailored to a certain extent through the addition of many other elements, both common and exotic, including not only metals, but also metalloids and nonmetals; chromium, iron, cobalt, molybdenum, tungsten, tantalum, aluminium, titanium, zirconium, niobium, rhenium, yttrium, vanadium, carbon, boron or hafnium are some examples of the alloying additions used. Each of these additions has been chosen to serve a particular purpose in optimizing the properties for high temperature application. Creep resistance is dependent
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Nonmetal


In chemistry, a nonmetal (or non-metal) is a chemical element that mostly lacks the characteristics of a metal. Physically, a nonmetal tends to have a relatively low melting point, boiling point, and density. A nonmetal is typically brittle when solid and usually has poor thermal conductivity and electrical conductivity. Chemically, nonmetals tend to have relatively high ionization energy, electron affinity, and electronegativity. They gain or share electrons when they react with other elements and chemical compounds. Seventeen elements are generally classified as nonmetals:
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Semimetal


the result of the fact that both energy bands are broad. In addition they typically show high diamagnetic susceptibilities and high lattice dielectric constants. The classic semimetallic elements are arsenic, antimony, bismuth, α-tin (gray tin) and graphite, an allotrope of carbon. The first two (As, Sb) are also considered metalloids but the terms semimetal and metalloid are not synonymous. Semimetals, in contrast to metalloids, can also be chemical compounds, such as mercury telluride (HgTe), and tin, bismuth,
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Nonmetal


and sodium iodide NaI); "natural gas": H, He, S; and from "ores", as processing byproducts: Ge (zinc ores); As (copper and lead ores); Se, Te (copper ores); and Rn (uranium bearing ores). Astatine is produced in minute quantities by irradiating bismuth. Nonmetals do not have any universal or near-universal applications. This is not the case with metals, most of which have structural uses; nor the metalloids, the typical
13626161
Carbon group


as the size of the atom increases, as it does with increasing atomic number. Carbon alone forms negative ions, in the form of carbide (C) ions. Silicon and germanium, both metalloids, each can form +4 ions. Tin and lead both are metals while flerovium is a synthetic, radioactive (its half life is very short), element that may have a few noble gas-like properties, though it is still most likely a post-transition metal. Tin and lead are both capable of forming +2
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Nonmetal


within the crust, oceans or biosphere of 0.2 per cent or less. Nonmetals, and metalloids, in their elemental forms are extracted from: "brine": Cl, Br, I; "liquid air": N, O, Ne, Ar, Kr, Xe; "minerals": B (borate minerals); C (coal; diamond; graphite); F (fluorite); Si (silica) P (phosphates); Sb (stibnite, tetrahedrite); I (in sodium iodate NaIO
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Post-transition metal


the group 13–15 metals in periods 4–6: gallium, indium and thallium; tin and lead; and bismuth. Other elements sometimes included are the group 11 metals copper, silver and gold (which are usually considered to be transition metals); the group 12 metals zinc, cadmium and mercury (which are otherwise considered to be transition metals); and aluminium, germanium, arsenic, selenium, antimony, tellurium, and polonium (of which germanium, arsenic, antimony, and tellurium are usually considered to be metalloids).
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Metalloid


solar modules for its high conversion efficiency, low manufacturing costs, and large band gap of 1.44 eV, letting it absorb a wide range of wavelengths. Bismuth telluride (BiTe), alloyed with selenium and antimony, is a component of thermoelectric devices used for refrigeration or portable power generation. Five metalloids—boron, silicon, germanium, arsenic, and antimony—can be found in cell phones (along with at least 39 other metals and nonmetals). Tellurium is expected to find such use. Of the less often recognised
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Metalloid


, glass-forming oxide TeO. It is a "conditional" glass-forming oxide—it forms a glass with a very small amount of additive. Tellurium has an extensive organometallic chemistry (see Organotellurium chemistry). Carbon is ordinarily classified as a nonmetal but has some metallic properties and is occasionally classified as a metalloid. Hexagonal graphitic carbon (graphite) is the most thermodynamically stable allotrope of carbon under ambient conditions. It has a lustrous appearance and is a fairly good electrical conductor. Graphite has a layered structure. Each layer
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Nonmetal


least incipient metallic properties. The oxides of oganesson, OgO and OgO, are predicted to be amphoteric. Some pairs of nonmetals show additional relationships, beyond those associated with group membership. Hydrogen in group 1, and carbon in group 14, show some out-of-group similarities. These include proximity in ionization energies, electron affinities and electronegativity values; half-filled valence shells; and correlations between the chemistry of H–H and C–H bonds. Just as the metalloids cluster along a diagonal path, similar
13626150
Period 3 element


alloys are vital to the aerospace industry and are important in other areas of transportation and structural materials. The most useful compounds of aluminium, at least on a weight basis, are the oxides and sulfates. "Silicon" (symbol Si) is a tetravalent metalloid. It is less reactive than its chemical analog carbon, the nonmetal directly above it in the periodic table, but more reactive than germanium, the metalloid directly below it in the table. Controversy about silicon's character dates to its discovery: silicon was first prepared
19045114
Origin and use of the term metalloid


mineral variety of pyroxene 'with metallic splendour.' In 1808, Erman and Simon suggested using the term metalloid to refer to the newly discovered elements sodium and potassium. These elements were lighter than water and many chemists did not regard them as proper metals. Erman and Simon's proposal may have been made '[in] an attempt to revive this old distinction between metals and substances resembling metals'. Their suggestion was ignored by the chemical community. In 1811, Berzelius referred to nonmetallic elements as metalloids, in reference to
20978436
Post-transition metal


regarded as a nonmetal, less commonly as a metalloid and occasionally as a metal. Unlike its lighter congener iodine, evidence for diatomic astatine is sparse and inconclusive. In 2013, on the basis of relativistic modelling, astatine was predicted to be a monatomic metal, with a face-centered cubic crystalline structure. As such, astatine could be expected to have a metallic appearance; show metallic conductivity; and have excellent ductility, even at cryogenic temperatures. It could also be expected to show significant nonmetallic character, as is normally
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Heavy metals


, zinc at 2.5 g, and lead at 0.12 g comprising the three main constituents), 2% light metals (~1.4 kg, the weight of a bottle of wine) and nearly 98% nonmetals (mostly water). A few non-essential heavy metals have been observed to have biological effects. Gallium, germanium (a metalloid), indium, and most lanthanides can stimulate metabolism, and titanium promotes growth in plants (though it is not always considered a heavy metal). Heavy metals are often assumed to
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Metal


conducting electricity at a temperature of absolute zero. Many elements and compounds that are not normally classified as metals become metallic under high pressures. For example, the nonmetal iodine gradually becomes a metal at a pressure of between 40 and 170 thousand times atmospheric pressure. Equally, some materials regarded as metals can become nonmetals. Sodium, for example, becomes a nonmetal at pressure of just under two million times atmospheric pressure. In chemistry, two elements that would otherwise qualify (in physics) as brittle metals—arsenic and antimony—
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Post-transition metal


brittle), have poor mechanical strength, and have melting points lower than those of the transition metals. Being close to the metal-nonmetal border, their crystalline structures tend to show covalent or directional bonding effects, having generally greater complexity or fewer nearest neighbours than other metallic elements. Chemically, they are characterised—to varying degrees—by covalent bonding tendencies, acid-base amphoterism and the formation of anionic species such as aluminates, stannates, and bismuthates (in the case of aluminium, tin, and bismuth, respectively
19783903
Post-transition metal


metals 'fairly definitely, though not perfectly sharply' into the "ordinary metals" and the "peculiar metals", the latter of which verge on the nonmetals. The peculiar metals occur towards the ends of the rows of the periodic table and include 'approximately:' gallium, indium, and thallium; carbon, silicon '(both of which have some metallic properties, though we have previously treated them as nonmetals),' germanium and tin; arsenic, antimony, and bismuth; and selenium '(which is
19783972
Nonmetal


a metalloid the chemistry of germanium is largely covalent in nature, noting it can form alloys with metals such as aluminium and gold. Most alloys of germanium with metals lack metallic or semimetallic conductivity. The common oxide of germanium (GeO) is amphoteric. Nitrogen is a colourless, odourless, and relatively inert diatomic gas with a density of 1.251 × 10 g/cm (marginally heavier than air). It condenses to a colourless liquid at −195.795 °C and freezes into an ice- or snow-like solid at −210.00 °
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Nonmetal


oxidising agent (As + 3e → AsH = –0.22 at pH 0). As a metalloid, its chemistry is largely covalent in nature, noting it can form brittle alloys with metals, and has an extensive organometallic chemistry. Most alloys of arsenic with metals lack metallic or semimetallic conductivity. The common oxide of arsenic (AsO) is acidic but weakly amphoteric. Antimony is a silver-white solid with a blue tint and a brilliant lustre. It is stable in air and moisture at room temperature. Antimony has a
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Metalloid


metals and nonmetallic covalent network solids (such as diamond). The energy required to transform B, C, N, Si, and P from nonmetallic to metallic states has been estimated as 30, 100, 240, 33, and 50 kJ/mol, respectively. This indicates the proximity of boron to the metal-nonmetal borderline. Most of the chemistry of boron is nonmetallic in nature. Unlike its heavier congeners, it is not known to form a simple B or hydrated [B(HO)] cation. The small
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Selenium


Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, and also has similarities to arsenic. It rarely occurs in its elemental state or as pure ore compounds in the Earth's crust. Selenium (from Ancient Greek (selḗnē) "Moon") was discovered in 1817 by Jöns Jacob Berzelius, who noted the similarity of the new element to
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Nonmetal


begin to show less-distinct, hybrid-like, or atypical properties. Although five times more elements are metals than nonmetals, two of the nonmetals—hydrogen and helium—make up over 99 percent of the observable universe. Another nonmetal, oxygen, makes up almost half of the Earth's crust, oceans, and atmosphere. Living organisms are composed almost entirely of nonmetals: hydrogen, oxygen, carbon, and nitrogen. Nonmetals form many more compounds than metals. There is no rigorous definition of a nonmetal. Broadly
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Lists of metalloids


This is a list of sources that each list metalloids: elements classified as metalloids. The sources are listed in chronological order. Lists of metalloids differ since there is no rigorous definition of metalloid (or its occasional alias, 'semi-metal'). Individual lists share common ground, with variations occurring at the margins. The elements most often regarded as metalloids are boron, silicon, germanium, arsenic, antimony and tellurium. Wikipedia generally categorises these six as metalloids, with the addition of astatine. Other sources may subtract
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Properties of metals, metalloids and nonmetals


Metals appear lustrous (beneath any patina); form mixtures (alloys) when combined with other metals; tend to lose or share electrons when they react with other substances; and each forms at least one predominantly basic oxide. Most metals are silvery looking, high density, relatively soft and easily deformed solids with good electrical and thermal conductivity, closely packed structures, low ionisation energies and electronegativities, and are found naturally in combined states. Some metals appear coloured (Cu, Cs, Au), have low densities (e.g.
21150991
Type metal


exceptionally soft, malleable, and ductile but with little tensile strength. Lead is a poison, that primarily damages brain function. Tin (Sn) It promotes the fluidity of the molten alloy and makes the type tough, giving the alloy resistance to wear. It is harder, stiffer and tougher than lead. Antimony (Sb) is a metalloid element, which melts at . Antimony has a crystalline appearance while being both brittle and fusible. When alloyed with lead to produce type metal, antimony gives it the hardness it needs
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