Beiträge zur Chemie des Phosphors, 96 [1] Darstellung und ³¹P-Kernresonanzspektrum von isotopen-substituiertem Trilithium-heptaphosphid, ⁶Li₃P₇ / Contributions to the Chemistry of Phosphorus, 96 [1] Preparation and ³¹P NMR Spectrum of Isotopicly Substituted Trilithiumheptaphosphide, ⁶Li₃P₇

Abstract

Abstract The P7-skeleton of trilithiumheptaphosphide, Li 3 P 7 (1), was proved to possess the earlier reported tricyclic structure [2] by complete analysis of the 31 P NMR spectrum of 6 Li 3 P 7 observed at - 60 °C. The 6 Li isotopic substitution was carried out to avoid the line broadening caused by the large quadrupole moment of the 7 Li isotope. The unambiguous elucidation of the Li 3 P 7 structure confirmed that the exchange process which causes all P atoms to become equivalent above room temperature is analogous to that in bullvalene. A comparison of the chemical shifts with those of (Me 3 Si) 3 P 7 leads to the result that the P 7 -skeleton in Li 3 P 7 is noticeably compressed along its threefold axis, thus indicating a predominant ionic character.