Barium chlorate in some sodium contamination, which is undesirable for pyrotechnic purposes, where the strong yellow of sodium can easily overpower the green of barium. Sodium-free barium chlorate can be produced directly through electrolysis: It can also be produced by the reaction of barium carbonate with boiling ammonium chlorate solution: The reaction initially produces barium chlorate and ammonium carbonate; boiling the solution decomposes the ammonium carbonate and drives off the resulting ammonia and carbon dioxide, leaving only barium chlorate in solution. When exposed to heat, barium chlorate alone will decompose to barium chloride and oxygen: Barium chlorate is used to produce chloric
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