Barium oxalate materials that are required to prepare barium oxalate are oxalic acid and barium hydroxide (or its octahydrate). It can also be prepared by using an oxalic acid solution and a barium chloride solution, with the reaction as follows: 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
Barium borate 1 GW/cm at 1064 nm and 500 MW/cm at 355 nm. Beta barium borate, β-BaBO, is a nonlinear optical material transparent in the range ~190–3300 nm. It can be used for spontaneous parametric down-conversion. Its Mohs hardness is also 4.5. Barium borate has strong negative uniaxial birefringence and can be phase-matched for type I ("ooe") second-harmonic generation from 409.6 to 3500 nm. The temperature sensitivity of the indices of refraction is low, leading to an unusually large (55 °C) temperature phase-matching bandwidth. Barium borate can be prepared by reaction of an aqueous solution of boric acid with barium hydroxide. The