Chlorine oxyanions are strong oxidizing agents. Their strength correlates directly with the number of oxygen atoms in the formula.

Highly oxidized chlorine oxyanions such as perchlorate and chlorate are so strong that they have explosive properties. They are, therefore, used in fireworks, flares, matches, airbag initiators, etc. The oxyacids of perchlorate and chlorate (perchloric and chloric acid) are strong oxidizing agents. They are, therefore, used in the synthesis of other chemicals. Additionally, the high reactivity of perchloric acid means we can use it as rocket fuel!

Less oxidized oxyanions such as chlorite and hypochlorite have applications in disinfectant manufacture, such as bleach. Finally, the oxyacid of hypochlorite is probably the most well-known chlorine compound; we use it as a disinfectant in swimming pools.