Chlorine dioxide has an irritant, pungent odor that resembles that of a mixture of chlorine and ozone. Chlorine dioxide is an extremely unstable gas, readily decomposing into chlorine and oxygen even on mild heating. It is explosive as a gas or liquid at high concentration.

Uses

Chlorine dioxide is the most widely used bleaching agent, in particular for high-quality cellulose. It destroys lignin without attacking cellulose, yielding a characteristically white cellulose. The general trend is to eliminate chlorine and hypochlorite as bleaching agents altogether and replace them with chlorine dioxide. 

Chlorine dioxide is used in the pulp and paper, textile, and food industries. In the pulp and paper industry, a unique whiteness can be achieved in kraft pulp, sulfite pulp, and soda pulp. In the textile industry, chlorine dioxide produces high-quality fibers with additional special advantages. Shrinkproof wool owes its quality to the reaction of chlorine dioxide with the cross-linking sulfur atoms of the wool. 

Chlorine dioxide is also used in sanitization, e.g., of industrial and municipal waters, sewage, algae, or decomposed vegetables. Waterworks use chlorine dioxide to handle taste and odor problems of household water.