Syntheses and Crystal Structures of(H_3O)(C_3H_5N_2)[Mn(OH)_6Mo_6O_(18)]·3.5H_2O and (H_3O)_3[Co(OH)_6Mo_6O_(18)]·7H_2O

The crystals of the title compounds (H3O)(C3H5N2)[Mn(OH)6Mo6O18]?3.5H2O 1 and (H3O)3[Co(OH)6Mo6O18]?7H2O 2 have been prepared and structurally determined by X-ray single-crystal diffraction. Compound 1 crystallizes in monoclinic, space group C2/c with a = 21.5018(9), b = 10.9331(5), c = 11.8667(5) ?, β = 95.3570(10)o, V = 2777.5(2) ?3, Z = 4, Dc = 2.802 g/cm3, Mr = 1171.80, μ(MoKα) = 3.173 mm-1, F(000) = 223, the final R = 0.0458 and wR = 0.1041 for 2093 observed reflections (I 2σ(I)); Compound 2 crystallizes in monoclinic, space group P21/c with a = 11.4042(12), b = 10.9481(11), c = 11.6722(12) ?, β = 99.948(2)o, V = 1435.4(3) ?3, Z = 2, Dc = 2.794 g/cm3, Mr = 1207.80, μ(MoKα) = 3.223 mm-1, F(000) = 1160, the final R = 0.0544 and wR = 0.1066 for 1906 observed reflections (I 2σ(I)). Both compounds 1 and 2 adopt the Anderson structure, in which the anion is of centrosymmetry and formed by six octahedral edge-sharing MoO6units surrounding the central MO6 (M = Mn or Co) octahedron.