Chlorate of potassium (KCIO3) may be made thus. Pass chlorine gas through a warm and fairly strong solution of caustic potash or carbonate of potash until the alkali is quite neutralised; boil for a few minutes, and evaporate until a scum forms on the surface, and then set aside to cool. The chlorate crystals which form as the solution cools are collected, washed in cold water and purified, and again dissolved and crystallised. Chlorate of potassium crystallises in four-sided and six-sided pearly scales.