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 sulfate mixture and make it hard to see the color of the indicator. Barium sulfate added to the mixture binds with these particles, making them heavier so they fall to the bottom, leaving a clearer solution. In colorimetry, barium sulfate is used as a near-perfect diffuser when measuring light sources. In metal casting, the moulds used are often coated with barium sulfate in order to prevent the molten metal from bonding with the mould. It is also used in brake linings, anacoustic foams, powder coatings, and root canal filling. Barium sulfate is used as a catalyst support when selectively hydrogenating functional