Abstract: ³¹PNMRspectra of about 80 thiiphisphates synthesized in our laboratory weredetermined. An empirical additivity equation, a set of chemical shift parameters and stereo-electronic effect parameters, which were proposed by the authors, can be used for calculatingslPchemical shifts of phosphates and thiophosphates more accurately.The mean error andthe standard deviation between calculated and observed values of 31 Pchemical shifts are±0.096 and ±0.13 respectively. Structures of thiophosphates can be predicted by using theadditivity equation. The dependence of the ³¹Pchemical shifts upon electronegativity, bond-angle and stereoelectronic effect was discussed theoretically.

Key words: Thiophosphates, ³¹P NMR, Additivity rule, Stereoelectronic effect