Monomeric, dimeric, and trimeric triselenometaphosphate

Monomeric triselenometaphosphate PSe3- (1), its dimer (2) and trimer (3) ar e obtained for the first time in solution by oxidation of P4Se3 with M2Se2 (M = Li, Na) and elemental selenium and are fully characterized by P-31 and Se-77 NMR. The equilibrium between 1, 2 and 3 depends strongly on the solv ent and is shifted to the side of PSe3- in HMPA or DMPU. Monomeric trithiom etaphosphate PS3- (4) is obtained by the analogous reaction of P4S3 with Li 2S2 and elemental sulfur. 1 reacts with Se-2(2-) and with P4Se3 to give the new selenophosphates P2Se84- and P4Se72, respectively. Further reaction of P4Se72- with P4Se3 yields the new anion P9Se143-; its structure in the Bu4 P+ salt is determined by X-ray crystallography.