Barium green color. Barium sulfate is used as an insoluble additive to oil well drilling fluid, as well as in a purer form, as X-ray radiocontrast agents for imaging the human gastrointestinal tract. The soluble barium ion and soluble compounds are poisonous, and have been used as rodenticides. Barium is a soft, silvery-white metal, with a slight golden shade when ultrapure. The silvery-white color of barium metal rapidly vanishes upon oxidation in air yielding a dark gray oxide layer. Barium has a medium specific weight and good electrical conductivity. Ultrapure barium is very difficult to prepare, and therefore many properties of
Barium carbonate barium sulfide either by treatment with sodium carbonate at 60 to 70 °C (soda ash method) or by passing carbon dioxide at 40 to 90 °C. In the soda ash process, solid or dissolved sodium carbonate is added to barium sulfide solution, and the barium carbonate precipitate is filtered, washed and dried. Barium carbonate reacts with acids such as hydrochloric acid to form soluble barium salts, such as barium chloride: However, the reaction with sulfuric acid is poor, because barium sulfate is highly insoluble. Barium carbonate is widely used in the ceramics industry as an ingredient in glazes. It acts