[HxTeV₉O₂₈](5–x)– (x = 1 and 2): Vanadotellurates with Decavanadate Structure

Two new vanadotellurates, [HTeV(9)O(28)](4-) and [H(2)TeV(9)O(28)](3-) have been synthesized and structurally characterized as tetra-n-butylammonium (TBA) salts: TBA(4)[HTeV(9)O(28)]·2CH(3)CN [triclinic, space group P ̅1, a = 16.7102(6) Å, b = 17.4680(7) Å, c = 17.9634(7) Å, α = 74.412(1)°, β = 67.494(1)°, γ = 74.160(2)°, Z = 2] and TBA(3)[H(2)TeV(9)O(28)] [monoclinic, space group P2(1)/c, a = 13.0013(5) Å, b = 19.157(1) Å, c = 28.453(1) Å, β = 97.222(2)°, Z = 4]. The results of the structural analyses indicate that the four O atoms that bridge two V atoms on the Te side are the most basic ones in the structure. The results of density-functional theory (DFT) calculations support this view.