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The reddish--brown prismatic crystal of the title compoundK6PMo7V2W3O40., (H2O)16,, (Mr.= 2518. 8) crystallizes in tetragonal system, space groupP4n2(# 118), with a= 14. 083(1), b= 14. 083(2), c= 12. 572(3) A, V=2493. 6(l)A3 D.= 2. 72 g/cm’3 Z= 2.λ(MoKa) = 0. 71073 A, μ= 108. 9 cm-l, F(000) 1840, final R= 0. 038 and Rw= 0. 050 for 1388 observed reflections with I>3. 0σ(I).. The title compound contains heteropolyanion [(Mo7W3,V2)PO40]6- linked together byK+ ions and water molecules. The heteropolyanion has the well--known Keggin structure. The 12 metal atoms in the cage of the anion comprise seven Mo, three W and twoV atoms in a random distribution. The M--M (M= 7/12 Mo+ l/4W + l/6 V) average distance in the anion is 3. 535 A. The P--M distance is 3. 537A. The P--O distance is 1. 54 A, and the M--O distances are from 1. 64 to 2. 42A for O atoms coordinated to one, two and three M atoms respectively. Potassium ions are coordinated byeight O atoms from the anion and water molecules.
The reddish-brown prismatic crystal of the title compound K6PMo7V2W3O40. (H2O) 16 ,, (Mr. = 2518.8) crystallizes in a tetragonal system, space group P4n2 (# 118) with a = 14. 083 = 14. 083 (2), c = 12. 572 (3) A, V = 2493. 6 (l) A3 D. = 2.72 g / cm’3 Z = 2.λ (MoKa) = 0. 71073 A, μ = 108. 9 cm-1, F (000) 1840, final R = 0.038 and Rw = 0. 050 for 1388 observed reflections with I> 3. 0σ (I) .. The title compound contains heteropolyanion [ (Mo7W3, V2) PO40] 6-linked together by K + ions and water molecules. The heteropolyanion has the well-known Keggin structure. The 12 metal atoms in the cage of the anion comprise seven Mo, three W and twoV atoms in a random The M - M (M = 7/12 Mo + 1 / 4W + 1/6 V) average distance in the anion is 3. 535 A. The P - M distance is 3. 537A. The P - O distance is 1. 54 A, and the M - O distances are from 1. 64 to 2. 42A for O atoms coordinated to one, two and three M atoms respectively. Potassium ions are coordinated by light O atoms from the anion and water molecules .