Sodium chlorite [7758-19-2], NaClO2, Mr 90.45, is the sodium salt of the unstable chlorous acid; it exists as an anhydrous and a trihydrated form (transition point 38 ?C). Very pure NaClO2 crystals are white, but they usually have a greenish tint because traces of chlorine dioxide are present. 

The stability of sodium chlorite lies between that of hypochlorite and chlorate. For further information Sodium chlorite is not sensitive to impact if organic matter is excluded. It can be struck with a clean metal surface without detonation. However, in the presence of organic matter – the film usually occurring on a hammer suffices – the impact may result in a spontaneous puffing. 

As a strong oxidizing agent, solid sodium chlorite forms explosive mixtures with such oxidizable materials as sulfur, powdered coal, metal powders, or organic compounds. Sodium chlorite solutions should never be allowed to dry on fabrics because this would result in a flammable combination.

Uses

Sodium chlorite is a very efficient bleaching agent. Its oxidation potential allows a controlled bleaching that is not attainable with other bleaching agents. Therefore, it is widely used as a bleaching agent in the textile industry. Another important use of sodium chlorite is the small-scale production of chlorine dioxide.