Hydroxylamine

Hydroxylamine (also known as hydroxyammonia) is an inorganic compound with the chemical formula NH2OH. The compound exists as hygroscopic colorless crystals. Hydroxylamine is almost always provided and used as either an aqueous solution or, more often, as one of its salts, such as hydroxylammonium sulfate, a water-soluble solid. Hydroxylamine and its salts are consumed almost exclusively to produce Nylon-6. The oxidation of NH3 to hydroxylamine is a step in biological nitrification. The crystal structure of hydroxylamine was first determined in 1955 under the direction of Nobel laureate William Lipscomb, although the positions of the hydrogen atoms were not localized at that time due to methodological limitations. In 2026, under the direction of M. A. Navasardyan, a high-precision crystal structure of hydroxylamine with unambiguous anisotropic refinement of all hydrogen atoms was successfully obtained, which also revealed the first observation of a cyclic hydroxylamine dimer (NH₂OH)₂.