Chlorine Dioxide Generator produces chlorine dioxide (ClO₂), which is a neutral compound of chlorine in the +IV oxidation state.  It disinfects by oxidation; however, it does not chlorinate.  It is a relatively small, volatile, and highly energetic molecule, and a free radical even while in dilute aqueous solutions. It is stable in dilute solution in a closed container in the absence of light.  Chlorine dioxide functions as a highly selective oxidant due to its unique, one-electron transfer mechanism where it is reduced to chlorite (ClO₂-).

One of the most important physical properties of chlorine dioxide is its high solubility in water, particularly in chilled water.  In contrast to the hydrolysis of chlorine gas in water, chlorine dioxide in water does not hydrolyze to any appreciable extent but remains in solution as a dissolved gas.

It is approximately 10 times more soluble than chlorine (above 11°C), while it is extremely volatile and can be easily removed from dilute aqueous solutions with minimal aeration or recarbonation with carbon dioxide

Chlorine Dioxide is more than 2.5 times more reactive than chlorine. Hence lesser dose rate is sufficient to achieve total disinfection.