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 Matthiessen obtained pure barium by electrolysis of a molten mixture of barium chloride and ammonium chloride. The production of pure oxygen in the Brin process was a large-scale application of barium peroxide in the 1880s, before it was replaced by electrolysis and fractional distillation of liquefied air in the early 1900s. In this process barium oxide reacts at with air to form barium peroxide, which decomposes above by releasing oxygen: Barium sulfate was first applied as a radiocontrast agent in X-ray imaging of the digestive system in 1908. The abundance of barium is 0.0425% in the Earth's crust and 13