Barium chlorate, Ba(ClO3)2, is the barium salt of chloric acid. It is a white crystalline solid and, like all soluble barium compounds, is irritating and toxic. It is sometimes used in pyrotechnics to create a green color. It is also used in the production of chloric acid.
Barium chlorate can be produced by a double displacement reaction between barium chloride and sodium chlorate solution:
BaCl2 + 2 NaClO3 → Ba(ClO3)2 + 2 NaCl
Upon concentration and cooling of the resulting mixture, barium chlorate precipitated. This is probably the most common preparation method, taking advantage of the lower solubility of barium chlorate compared to sodium chlorate.
The above method does result in some sodium contamination, which is undesirable for pyrotechnic purposes, since the strong yellow color of sodium easily overshadows the green color of barium. Sodium-free barium chlorate can be produced directly by electrolysis:
BaCl2 + 6 H2O → Ba(ClO3)2 + 6 H2
It can also be prepared by reacting barium carbonate with boiling ammonium chlorate solution: [Unreliable source? ]
2 NH4ClO3 + BaCO3 + Q → Ba(ClO3)2 + 2 NH3 + H2O + CO2
The reaction initially produces barium chlorate and ammonium carbonate; boiling the solution breaks down the ammonium carbonate and expels the resulting ammonia and carbon dioxide, leaving only barium chlorate in solution.
The green color seen in this firework is produced by barium chlorate and barium nitrate.
When heated, barium chlorate alone decomposes to barium chloride and oxygen:
Ba(ClO3)2 → BaCl2 + 3 O2
A white crystalline solid. Forms very flammable mixtures with combustible materials. Mixtures may be ignited by friction and may be explosive if the combustible material is finely divided. Contact with concentrated sulfuric acid solutions may cause fires or explosions. May spontaneously decompose and ignite when mixed with ammonium salt. May explode under prolonged exposure to heat or fire. Used in explosives and pyrotechnics, in dyeing textiles, and to make other chlorates.
BARIUM CHLORATE is an oxidizing agent. Liberates explosive chlorine dioxide gas in the presence of a strong acid. Heating a moist metal chlorate and a dibasic organic acid liberates chlorine dioxide and carbon dioxide [Bretherick 1979 p. 100]. Mixtures with ammonium salts, powdered metals, silicon, sulfur, or sulfides are readily ignited and potentially explosive [Bretherick 1979 p. 806]. A combination, in finely divided form with finely divided aluminum can explode by heat, percussion, or friction [Mellor 2:310 1946-4].