Krypton

Krypton (IPA: /ˈkrɪptən/ or /ˈkrɪptan/) is a chemical element with the symbol Kr and atomic number 36. A colorless, odorless, tasteless noble gas, krypton occurs in trace amounts in the atmosphere, is isolated by fractionally distilling liquified air, and is often used with other rare gases in fluorescent lamps. Krypton is inert for most practical purposes but it is known to form compounds with fluorine. Krypton can also form clathrates with water when atoms of it are trapped in a lattice of the water molecules.

From 1960 to 1983, the length of the meter was defined in terms of the orange-red spectral line of krypton-86, an isotope of krypton. It as well as all other noble gases can be used in lighting and photography. Krypton has an important role in production and usage of the krypton fluoride laser.