Synthesis and Crystal Structures of the Quaternary Zintl Phases RbNa8Ga3Pn6 (Pn = P, As) and Na10NbGaAs6

Abstract

The new Zintl compounds RbNa8Ga3Pn6 (Pn = P, As) and Na10NbGaAs6 have been synthesized from the corresponding elements at high temperatures. RbNa8Ga3P6 and RbNa8Ga3As6 crystallize with a novel structure type that features trigonal planar [Ga3P6]9– and [Ga3As6]9– motifs, which are isosteric with the 1,3,5-trioxanetrione (a cyclic trimer of carbon dioxide). Na10NbGaAs6, an unforeseen side product of the same reactions boasts a structure, which is based on NbAs4 and GaAs4 tetrahedra, condensed by sharing common edges into [NbGaAs6]10– dimers. The bonding characteristics of both structures are discussed. All three compounds reported herein represent the first compounds found in the respective quaternary systems.