Festkörper‐NMR‐Untersuchungen an Natriumoxothiophosphaten(V)

Solid State NMR Investigations on Sodium Oxothiophosphates(V) Sodium monothiophosphate(V) Na₃PO₃S is dimorphic. The metastable high temperature modification β‐Na₃PO₃S crystallizes hexagonal with a = 8.996(4) and c = 5.216(2)Å. According to ³¹P solid state NMR experiments, α‐Na₃PO₃S exhibits at 20 °C a non‐axial‐symmetric environment for the phosphorus nuclei in contrast to the results of the refined crystal structure. This discrepancy is discussed assuming ordered and disordered structural models. However, at 490 °C the chemical shift tensor of the phosphorus nuclei in α‐Na₃PO₃S is axial‐symmetric. So, the distortion of the phosphorus environment is abolished by the thermal motion of the atoms. The number of crystallographically distinguishable positions for phosphorus and for sodium in Na₃PO₂S₂ and Na₃POS₃ can be confirmed in good agreement with their crystal structures using solid state NMR spectroscopy.