STRUCTURE OF E(AUPH3)4+, E = N, P, AS - TD OR C4V

Quasirelativistic pseudopotential methods at HF and MP2 levels are used for optimizing the geometry of the title compounds. The naked clusters EM4+ (M = H, Ag, Au) are also considered. In agreement with experiment, N(AuPH3)4+ is T(d) and the As(AuPH3)4+ ion is a C4v square pyramid with an apical As atom. P(AUPH3)4+ is predicted to favor C4v. The calculated MP2 Au ... Au distance for E = As is 296 (experimental 290) pm, and the Au-As-Au is angle 69.1(70.7)-degrees. The bonding is analyzed. The secondary Au ... Au bond is attributed to correlation, not 5d6s6p hybridization.