Argon

Argon, chemical element, symbol Ar; for physical constants see Periodic Table. Argon was discovered by Lord Rayleigh and Sir William Ramsay in 1894. It is prepared by fractionation of liquid air, the atmosphere containing almost 1% of the element. Argon is a colorless, odorless, and chemically inert gas. It is not known to form chemical compounds, as do krypton, xenon, and radon. It is available in high purity, and is used in electric light bulbs, as a nonreactive shield in arc welding and in the production of reactive metals, and as a protective atmosphere for growing silicon, and germanium crystals.