Sodium heteropolyhexamolybdenumnickelate (II) Na4[Ni(OH)6Mo6O18]•16H2O with an anderson anion: Synthesis and crystal structure

Conditions are determined for the formation of sodium heteropolyhexamolybdenumnickelate(II) Na 4 [Ni(OH) 6 Mo 6 O 18 ]•16H 2 O ( I ) in a Ni(NO 3 ) 2 –Na 2 МоO 4 –HNO 3 –H 2 O solution acidified to Z = = ν(H + )/ν(МоO 4 2− ) = 1.00. Synthesized salt I is investigated by chemical analysis, single crystal XRD, powder XRD, thermal analysis, and IR spectroscopy. The heteropolyanion is shown to belong to the Anderson type. Compound I is analyzed by single crystal XRD ( M r = 1404.61, triclinic, space group , a = 8.0586(4) Å, b = 10.5445(6) Å, c = 12.1374(5) Å, α = 69.557(5)°, β = 70.604(4)°, γ = 84.123(4)°, V = 911.45(8) Å 3 ) to find that it is isostructural to Na 4 [Ni(OH) 6 Mo 6 O 18 ]•16H 2 O. All metal atoms in the structure of I are in an octahedral environment: the coordination sphere of the Ni heteroatom consists of OH groups; that of Mo consists of O atoms and OH groups; Na atoms are linked to the heteropolyanion via the terminal O atoms of the polyanion and surrounded by water molecules. In the crystal packing, the [Ni(OH) 6 Mo 6 O 18 ] 4– anions lie in planes parallel to and the polyanion layers alternate with those formed by the paired octahedra [Na 2 (μ-H 2 O) 2 (H 2 O) 6 (O) 2 ] in the direction of the y axis.