The New Niobium Cluster Azides (NH4)4[Nb6Cl12(N3)6](H2O)2 and Na1.15(3)La0.85(3)[Nb6Cl12(N3)6](H2O)13(1). Syntheses and Crystal Structure Determination

Abstract

The cluster compounds (NH4)4[Nb6Cl12(N3)6](H2O)2 (1) and Na1.15(3)La0.85(3)[Nb6Cl12(N3)6]- (H2O)13(1) (2) have been synthesized by the reaction of an aqueous solution of Nb6Cl14 with an excess of NaN3 and the respective chloride salts. 1 crystallizes isotypically to the other alkali metal cluster azides in the space group P1̄̄ (no. 2) with the lattice parameters a = 908.97(8), b = 932.78(8), c = 1045.78(9) pm; and α = 95.94(1), β = 101.68(1) and γ = 102.41(1)°, while 2 is found to be nearly isostructural to the alkaline earth metal cluster azides crystallizing in the space group Fd3̄m (no. 227) with the lattice parameter a = 1996.9(1) pm. The stoichiometry of 2 was confirmed by EDX analyses which also led to a reconsideration of the water content of alkaline earth metal cluster azide compounds. The title compounds and results obtained from the reevaluation of the alkaline earth metal cluster azides are compared.