Argon is an inert gas. Ar is the atomic symbol of argon, 18 is the atomic number and 39.94 is the atomic weight. Argon is a colorless, odorless, tasteless and non-explosive gas. The melting point of argon is -189.2ºC and its boiling point is -185.7ºC. Argon is used in electric bulbs, neon tubes, and fluorescent tubes. It is also used in arc welding as a gas shield. The various tank sizes of argon that are available are 131, 330 and 4754 liquid cubic feet.