Definition: Inorganic or organic derivatives of phosphonic acid with the general formula ROP(OH)2 or RP(=O)(OH)2. The tautomeric form of this compound (P(OH)3) is PHOSPHOROUS ACIDS. Nucleoside phosphonates have a phosphate-carbon bond that is more resistant to enzymatic cleavage than the normal phosphate-oxygen bond.
do not confuse with PHOSPHINIC ACIDS; for nucleoside phosphonates coordinate with PURINES or PYRIMIDINES