Barium chlorate

Barium chlorate, Ba(ClO₃)₂, is the barium salt of chloric acid. It commonly exists as the monohydrate, Ba(ClO₃)₂·H₂O. It is a white crystalline solid, and like all soluble barium compounds, toxic. It is sometimes used in pyrotechnics to produce a green colour. It also finds use in the production of chloric acid.

Barium chlorate can be produced through a double replacement reaction between solutions of barium chloride and sodium chlorate:

After concentrating and cooling the resulting mixture, barium chlorate precipitates. This is perhaps the most common preparation, exploiting the lower solubility of barium chlorate compared to sodium chlorate.^{[citation needed]}

The above method does result in some sodium contamination, which is undesirable for pyrotechnic purposes, where the strong yellow colour 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.

At the melting point, barium chlorate alone will decompose to barium chloride and oxygen:

When barium chlorate is used as an oxidizer in a mixture with any fuel, it burns to produce a vibrant green light. It is one of the only oxidizers which can be used in a binary mixture to produce a high quality color; simple mixtures of Ba(ClO₃)₂ and shellac are sufficient to produce a high quality green. It was falling out of use by the mid 20th century, but when it was used more heavily in pyrotechnics, purely barium chlorate oxidized star formulas were reserved for higher quality exhibition devices due to the high cost and the high percentage of barium chlorate in said formulas.