Argon (Ar) is an inert colorless, odorless, tasteless, non-corrosive, non-flammable, and non-toxic gas. It is the most abundant noble gas in Earth's crust, comprising 0.00015% of the crust.

Characteristics

Although argon is a noble gas, it can form some compounds under various extreme conditions. Argon fluorohydride (HArF), a compound of argon with fluorine and hydrogen that is stable below 17 K (?256.1 °C; ?429.1 °F), has been demonstrated. 

Although the neutral ground-state chemical compounds of argon are presently limited to HArF, argon can form clathrates with water when atoms of argon are trapped in a lattice of water molecules. Ions, such as ArH+, and excited-state complexes, such as ArF, have been demonstrated. Theoretical calculation predicts several more argon compounds that should be stable but have not yet been synthesized.

Uses

Argon is used in gas-filled electric light bulbs, radio tubes, and Geiger counters. It also is widely utilized as an inert atmosphere for arc-welding metals, such as aluminum and stainless steel; for the production and fabrication of metals, such as titanium, zirconium, and uranium; and growing crystals of semiconductors, such as silicon and germanium.

Nonflammability

Argon is a noble gas, it is generally nonflammable.

Safety

Although argon is non-toxic, it is 38% more dense than air and therefore considered a dangerous asphyxiant in closed areas. It is difficult to detect because it is colorless, odorless, and tasteless.