C12C = NOH, a compound occurring as colorless crystals with a melting point of 39.5°–40°C and a boiling point of 129°C. Dichloroformoxime has a volatility (maximum concentration) of 23 mg/liter at 20°C; it acts as an asphyxiant, general poison, and vesicant. (In contrast to mustard gas, there is no delay in the appearance of the blisters.)
Dichloroformoxime is soluble in water and many organic solvents; it reacts with water to form stable hydrates, which slowly decompose to yield hydroxylamine and hydrochloric and carbonic acids. Alkalies and ammonia break down the compound rapidly and completely. Dichloroformoxime is obtained from the action of chlorine on either formoxime or mercury fulminate. The compound was first mentioned in the literature in 1929.