Structure, magnetism, and electrochemistry of the multinickel polyoxoanions [Ni6As3W24O94(H2O)2]17-, [Ni3Na(H2O)2(AsW9O34)2]11-, and [Ni4Mn2P3W24O94(H2O)2]17-.

The three novel, multi-nickel-substituted heteropolytungstates [Ni6As3W24O94(H2O)2]17- (1), [Ni3Na(H2O)2(AsW9O34)2]11- (2), and [Ni4Mn2P3W24O94(H2O)2]17- (3) have been synthesized and characterized by IR, elemental analysis, electrochemistry, and magnetic studies. Single-crystal X-ray analysis was carried out on Na16.5Ni0.25[Ni6As3W24O94(H2O)2]·54H2O, which crystallizes in the triclinic system, space group P1, with a = 17.450(4) A, b = 17.476(4) A, c = 22.232(4) A, α = 85.73(3)°, β = 89.74(3)°, γ = 84.33(3)°, and Z = 2, Na11[Ni3Na(H2O)2(AsW9O34)2]·30.5H2O, which crystallizes in the triclinic system, space group P1, with a = 12.228(2) A, b = 16.743(3) A, c = 23.342(5) A, α = 78.50(3)°, β = 80.69(3)°, γ = 78.66(3)°, and Z = 2, and Na17[Ni4Mn2P3W24O94(H2O)2]·50.5H2O, which crystallizes in the monoclinic system, space group P21/c, with a = 17.540(4) A, b = 22.303(5) A, c = 35.067(7) A, β = 95.87(3) A, and Z = 4. Polyanion 1 consists of two B-α-(Ni3AsW9O40) Keggin moieties linked via a unique AsW6O16 fragmen...