Barium chlorate acid, the formal precursor to all chlorate salts, through its reaction with dilute sulfuric acid, which results in a solution of chloric acid and insoluble barium sulfate precipitate: Both the chlorate and the acid should be prepared as dilute solutions before mixing, such that the chloric acid produced is dilute, as concentrated solutions of chloric acid (above 30%) are unstable and prone to decompose, sometimes explosively. Fireworks Barium chlorate, when burned with a fuel, produces a vibrant green light. Because it is an oxidizer, a chlorine donor, and contains a metal, this compound produces a green color that is unparalleled.
Chlorate were once widely used in pyrotechnics for this reason, though their use has fallen due to their instability. Most pyrotechnic applications that formerly used chlorates now use the more stable perchlorates instead. The chlorate ion cannot be satisfactorily represented by just one Lewis structure, since all the Cl–O bonds are the same length (1.49 Å in potassium chlorate), and the chlorine atom is hypervalent. Instead, it is often thought of as a hybrid of multiple resonance structures: Metal chlorates can be prepared by adding chlorine to hot metal hydroxides like KOH: In this reaction, chlorine undergoes disproportionation, both reduction and