Chlorine dioxide is a relatively small, volatile and highly energetic molecule. Chlorine dioxide is never transported as a compressed gas because of its instability; rather, it is typically generated as needed, at the point of use.
Chlorine dioxide gas has an intense greenish yellow color with a distinctive odor similar to that of chlorine. Chlorine dioxide is highly soluble in water but, unlike chlorine, chlorine dioxide does not react with water. It exists in aqueous solution as a dissolved gas.
Chlorine dioxide functions as a highly selective oxidant owing to unique, one-electron transfer mechanisms, wherein it attacks electron-rich centers in organic molecules and, in the process, is reduced to chlorite ion.
Because chlorine dioxide oxidizes but does not chlorinate, chlorinated organic by-products (e.g., THM, HAA, dioxins, furans) typically are not produced. Neither does chlorine dioxide produce appreciable amounts of aldehydes, ketones, ketoacids or other problematic compounds associated with oxidation of organic matter by other, less selective means.
Chlorine dioxide is an effective bleaching agent for many colored compounds. High-purity chlorine dioxide is less destructive/corrosive than chlorine to most materials, including stainless steel. Much of the corrosion and other materials damage often attributed to chlorine dioxide are, in fact, caused by chlorine gas that exists as a contaminant in chlorine dioxide produced by conventional processes. Also, in the presence of light with a UV component, chlorine dioxide rapidly decomposes to form chlorine, oxygen and a variety of transient intermediate oxychlorine compounds which may be highly corrosive.