Barium sulfide

Barium sulfide is the inorganic compound with the formula BaS. BaS is an important precursor to other barium compounds including BaCO3 and the pigment lithopone, ZnS/BaSO4. Like other chalcogenides of the alkaline earth metals, BaS is a short wavelength emitter for electronic displays. It is colorless, although like many sulfides, it is commonly obtained in impure colored forms. Barium sulfide is the inorganic compound with the formula BaS. BaS is an important precursor to other barium compounds including BaCO3 and the pigment lithopone, ZnS/BaSO4. Like other chalcogenides of the alkaline earth metals, BaS is a short wavelength emitter for electronic displays. It is colorless, although like many sulfides, it is commonly obtained in impure colored forms. BaS was prepared by Vincentius (or Vincentinus) Casciarolus (or Casciorolus, 1571-1624) via reduction of BaSO4 (available as the mineral barite).It is currently manufactured by an improved version of Casciarolus's process using coke in place of flour. This kind of conversion is called a carbothermic reaction: The phosphorescence of the material made by Casciarolus made it a curiosity. BaS crystallizes with the NaCl structure, featuring octahedral Ba2+ and S2− centres. The observed melting point of barium sulfide is highly sensitive to impurities. BaS is quite poisonous, as are related sulfides, such as CaS, which evolve toxic hydrogen sulfide upon contact with water.