Krypton (Kr)
Overview of Krypton
Krypton is a colorless, odorless noble gas with atomic number 36. It is one of the rarest gases in Earth’s atmosphere and belongs to the family of chemically inert elements. The name krypton comes from the Greek word kryptos, meaning “hidden,” which reflects its elusive nature when it was first discovered.
Why Is Krypton So Useful?
Although rare and mostly unreactive, krypton’s unique spectral and inert properties give it several specialized applications:
Lighting: Krypton is used as a filling gas in fluorescent lamps, high-performance bulbs, and flash lamps for high-speed photography.
Lasers: Krypton fluoride (KrF) is used in excimer lasers, which emit ultraviolet light. These are applied in nuclear fusion research, semiconductor manufacturing, and medical procedures.
Measurement standard: From 1960 to 1983, the isotope krypton-86 defined the international standard of length. One metre was officially measured as 1,650,763.73 wavelengths of a specific krypton spectral line.
Nuclear forensics: Radioactive krypton isotopes are a by-product of nuclear reactors. During the Cold War, scientists monitored atmospheric krypton levels to estimate nuclear material production.
Natural Abundance and Production of Krypton
Atmospheric rarity: Krypton makes up only about 1 part per million of Earth’s atmosphere.
Extraction: It is commercially obtained by the fractional distillation of liquid air, alongside other rare gases like neon and xenon.
History of Krypton
1898 – Discovery: British chemists William Ramsay and Morris Travers discovered krypton while investigating the constituents of liquefied air. By slowly evaporating the lighter gases, they were left with a residual fraction that revealed krypton’s presence.
Spectral confirmation: Its existence was confirmed through spectroscopy, which showed its distinctive spectral lines.
Biological Role of Krypton
Krypton has no known biological role and is considered non-toxic.