CRYSTAL STRUCTURE OF DOUBLE SODIUM–COPPER(II) PARATUNGSTATE B: Na2Cu3(CuOH)2[W12O40(OH)2]·32H2O
S. V. Radio1, N. A. Melnik1, E. S. Ivantsova1, V. N. Baumer2,3
1Donetsk National University, Donetsk, Ukraine
2Institute for Single Crystals, National Academy of Sciences of Ukraine, Kharkov, Ukraine
3Karazin Kharkov National University, Kharkov, Ukraine
Keywords: paratungstate B anion, isopolytungstate, crystal structure, FTIR spectroscopy, single crystal X-ray diffraction study
Abstract
From the solution of the Na2WO4–HNO3–Cu(NO3)2–H2O system acidified to Z = n(H+)/n(WO42–) = 1.17, the light blue crystals of sodium-copper(II) paratungstate B Na2Cu3(CuOH)2[W12O40(OH)2]×32H2O are isolated. Using FTIR spectroscopy, isopoly anion is shown to belong to the structure type of paratungstate B. By single crystal X-ray diffraction analysis, the structure of Na2Cu3(CuOH)2[W12O40(OH)2]×32H2O is solved: triclinic, space group P-1, a = 10.6836(4) Å, b = 12.9066(6) Å, c = 13.6475(5) Å, α = 73.561(4)°, β = 75.685(3)°, γ = 67.666(4)°, V = 1648.68(12) Å3 at T = 293 K, Z = 1, dcalc = 3.882 g/cm3. The paratungstate B anion in the structure is surrounded by two centrosymmetric pairs of octahedra {Na(μ–H2O)2(H2O)3O} and {Cu(4)(μ–OH)2(H2O)3O} and six CuO6 octahedra forming a three-dimensional structure, in the voids of which uncoordinated H2O molecules are located.
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