A new mechanism of the Atherton–Todd reaction is discussed. The first step of the reaction between diesters of H-phosphonic acid and carbon tetrachloride in the presence of a base is a salt formation between carbon tetrachloride and the base [amine·Cl]⁺CCl₃⁻. The trichloromethanide anion [CCl₃⁻] deprotonates dialkyl H-phosphonate to form chloroform and dialkyl phosphonate anion [(RO)₂P(O)]⁻. The latter anion reacts with the chlorine cation to furnish dialkyl chlorophosphate.