nitrogen

A nonmetallic element that constitutes nearly four-fifths of the air by volume, occurring as a colorless, odorless, almost inert diatomic gas, N₂, in various minerals and in all proteins and used in a wide variety of important manufactures, including ammonia, nitric acid, TNT, and fertilizers. Atomic number 7; atomic weight 14.0067; melting point -209.86°C; boiling point -195.8°C; valence 3, 5. See Table at element.