Binary pnictogen azides--an experimental and theoretical study: [As(N3)4]-, [Sb(N3)4]-, and [Bi(N3)5(dmso)]2-.

[PPh(4)][EI(4)] (E=As, Sb, Bi) salts were reacted with four and five equivalents of AgN(3) to form tetraazidopnictates and pentaazidopnictates of the type [PPh(4)][E(N(3))(4)] and PPh(4)[E(N(3))(5)], respectively. The synthesis of [PPh(4)][P(N(3))(4)] was also attempted from the reaction of P(N(3))(3) with [PPh(4)]N(3), but it yielded only the starting materials. Herein, we report the synthesis and structure elucidation of [PPh(4)]E(N(3)) (E=As, Sb) and pentaazidobismuthate, stabilized as the dimethyl sulfoxide (DMSO) anion adduct, PPh(4)[Bi(N(3))(5)(dmso)]. Successive anion formation along the series E(N(3))(3)+nN(3)(-) (n=1-3) and E(N(3))(5)+N(3)(-) was studied by density functional theory.