Barium sulfate groups that are sensitive to overreduction. With a low surface area, the contact time of the substrate with the catalyst is shorter and thus selectivity is achieved. Palladium on barium sulfate is also used as a catalyst in the Rosenmund reduction. As barium compounds emit a green light when burned, barium salts are often used in green pyrotechnic formulas, but the nitrate and chlorate salts are more common. Barium sulfate is commonly used as a component of "strobe" pyrotechnic compositions. As barium sulfate has high burning point and is insoluble in water, it is used as a coating material in
Barium Barium vapor is condensed and packed into molds in an atmosphere of argon. This method is used commercially, yielding ultrapure barium. Commonly sold barium is about 99% pure, with main impurities being strontium and calcium (up to 0.8% and 0.25%) and other contaminants contributing less than 0.1%. A similar reaction with silicon at yields barium and barium metasilicate. Electrolysis is not used because barium readily dissolves in molten halides and the product is rather impure. The barium mineral, benitoite (barium titanium silicate), occurs as a very rare blue fluorescent gemstone, and is the official state gem of California. Barium, as