31P solid state NMR studies of metal selenophosphates containing [P2Se6]4-, [P4Se10]4-, [PSe4]3-, [P2Se7]4-, and [P2Se9]4- ligands

31P solid-state nuclear magnetic resonance (NMR) spectra of 12 metal-containing selenophosphates have been examined to distinguish between the P(2)Se(6)](4-), PSe(4)](3-), P(4)Se(10)](4-), P(2)Se(7)](4-), and P(2)Se(9)](4-) anions. There is a general correlation between the chemical shifts (CSs) of anions and the presence of a Pbond]P. The P(2)Se(6)](4-) and P(4)Se(10)](4-) anions both contain a Pbond]P and resonate between 25 and 95 ppm whereas the PSe(4)](3-), P(2)Se(7)](4-), and P(2)Se(9)](4-) anions do not contain a Pbond]P and resonate between -115 and -30 ppm. The chemical shift anisotropies (CSAs) of compounds containing PSe(4)](3-) anions are less than 80 ppm, which is significantly smaller than the CSAs of any of the other anions (range: 135-275 ppm). The smaller CSAs of the PSe(4)](3-) anion are likely due to the unique local tetrahedral symmetry of this anion. Spin-lattice relaxation times (T(1)) have been determined for the solid compounds and vary between 20 and 3000 s. Unlike the CS, T(1) does not appear to correlate with P-P bonding. (31)P NMR is also shown to be a good method for impurity detection and identification in the solid compounds. The results of this study suggest that (31)P NMR will be a useful tool for anion identification and quantitation in high-temperature melts.