Barium oxalate Barium oxalate Barium oxalate (BaCO), a barium salt of oxalic acid, is a white odorless powder that is sometimes used as a green pyrotechnic colorant generally in specialized pyrotechnic compositions containing magnesium. Though largely stable, barium oxalate can be reactive with strong acids. A mild skin irritant, the substance is considered toxic when ingested, causing nausea, vomiting, renal failure, and injury to the gastrointestinal tract. It is different from most pyrotechnic colorants in that it is a reducing agent and not an oxidizing agent. It is extremely insoluble in water and converts to the oxide form when heated. The raw
Barium sulfate from barite, which is often highly impure. Barite is processed by carbothermal reduction (heating with coke) to give barium sulfide: In contrast to barium sulfate, barium sulfide is soluble in water and readily converted to the oxide, carbonate, and halides. To produce highly pure barium sulfate, the sulfide or chloride is treated with sulfuric acid or sulfate salts: Barium sulfate produced in this way is often called "blanc fixe", which is French for "permanent white." Blanc fixe is the form of barium encountered in consumer products, such as paints. In the laboratory barium sulfate is generated by combining solutions of