original question: Who discovered the elements [Oxygen] and [Barium]?
answer: carl wilhelm scheele
answer type: Chemical Element Discoverer.
auxiliary information: Barium is a chemical element with symbol Ba and atomic number 56. It is the fifth element in Group 2, a soft silvery metallic alkaline earth metal. Because of its high chemical reactivity barium is never found in nature as a free element. Its hydroxide was known in pre-modern history as baryta; this substance does not occur as a mineral, but can be prepared by heating barium carbonate. The most common naturally occurring minerals of barium are barite and witherite, both being insoluble in water. Barium's name originates from the alchemical derivative "baryta", which itself comes from Greek Œ≤Œ±œÅœçœÇ, meaning "heavy." Barium was identified as a new element in 1774, but not reduced to a metal until 1808, shortly after electrolytic isolation techniques became available. Barium has only a few industrial applications. The metal has been historically used to scavenge air in vacuum tubes. It is a component of YBCO and electroceramics, and is added to steel and cast iron to reduce the size of carbon grains within the microstructure of the metal. Barium compounds are added to fireworks to impart a green color.Oxygen:;Type: Chemical Element. ;
The elements [Oxygen] and [Barium] were discovered by whom?