[3] This reaction can be performed in the absence of water but requires heating to 150–250 °C; as dichlorine monoxide is unstable at these temperatures[4] it must therefore be continuously removed to prevent thermal decomposition.

The bond angle is slightly larger than normal, likely due to steric repulsion between the bulky chlorine atoms.

In the solid state, it crystallises in the tetrahedral space group I41/amd, making it isostructural to the high pressure form of water, ice VIII.

The rate of hydrolysis is slow enough to allow the extraction of Cl2O with organic solvents such as CCl4,[3] but the equilibrium constant ultimately favours the formation of hypochlorous acid.

[7] Despite this, it has been suggested that dichlorine monoxide may be the active species in the reactions of HOCl with olefins and aromatic compounds,[8][9] as well as in the chlorination of drinking water.

Room temperature mixtures with oxygen could not be detonated by an electric spark until they contained at least 23.5% Cl2O[18] which is an exceedingly high minimum explosive limit.