95981 ā
Compounds containing elements of Groups 5 or 15 of the Periodic System; Phosphorus compounds with one or more PāC bonds; Phosphonic acids RP(=O)(OH); Thiophosphonic acids, i.e. RP(=X)(XH)2 (X = S, Se); Esters thereof the acid moiety containing a substituent or a structure which is considered as characteristic; Esters of poly(thio)phosphonic acids containing sulfur substituents