Synthesis and Crystal Structure of Potassium–Nickel Heteropoly Hexatungstonickelate (II) K3Ni0,5[Ni(OH)6W6O18]·12H2O with Anderson-Type Anion and Potassium–Nickel Paratungstate B K6Ni2[W12O40(OH)2]·22H2O

Abstract

Conditions necessary for the formation of potassium–nickel paratungstate B K6Ni2[W12O40(OH)2]·22H2O (1) and potassium–nickel heteropoly hexatungstonickelate (II) with Anderson type anion K3Ni0,5[Ni(OH)6W6O18]·12H2O (2) in Ni(NO3)2–K2WO4–HNO3–H2O solution, acidified up to Z = ν(H+)/ν(WO4 2−) = 1,00, were established. The synthesized salts 1 and 2 were examined using chemical analysis, X-ray single crystal analysis and FTIR spectroscopy. The compound 1 crystallizes in the triclinic system, space group $$ \bar{P} $$ , Mr = 3,628.59, a = 10.617(3) A, b = 11.818(2) A, c = 13.454(3) A, α = 68.034(18)°, β = 76.96(2)°, γ = 63.53(2)°, V = 1,398.0(5); the compound 2 crystallizes in the monoclinic system, space group P2 1 /n, Mr = 1,914.71, a = 11.2586(3) A, b = 11.4933(6) A, c = 26.1158(15) A, α = 100.938(4)°, V = 3,318.0(3) A3. In the structure 1 paratungstate B anion [W12O40(OH)2]10− is centrosymmetric and occupies the center [[1/2,0,1/2]], while 2D layers consist of isopolyanion and potassium polyhedra KOn (n = 8, 10), forming the 3D structure through NiO6 octahedra. The structure 2 comprises Anderson type anions [Ni(OH)6W6O18]4−, cationic polyhedra NiO6, KO8 and uncoordinated H2O molecules.