Krypton is a noble gas with a mass of 83.80 u that melts at 115.79 K and boils at 119.93 K. It was discovered in 1898 and, like other noble gases, is used in lighting and photography due to its high light output in plasmas. Krypton plays an important role in many high-powered gas lasers and there is also a specific krypton fluoride laser.