摘要
标题化合物的晶体属P2_1/m空间群,α=13.821(2),b=15.355(3),c=11.597(2),β=107.50(2)°,V=2347.2~3,M_r=2091.46,Z=2,D_c=2.959 g·cm^(-3),μ(MoK_o)=30.77cm^(-1),F(000)=1992。用4049个独立可观测衍射精修结构,R=0.033。杂多酸阴离子[PMo_(10)V_2O_(40)]^(5-)具有准Keggin结构,12个金属原子呈无序分布,中心原子P与两个齿顶原子M(Mo/V)在对称面上。P—O平均键长1.541(2),M—O键长1.671(2)-2.432(2)。除一个Na—O配位多面体为畸变三方锥外,其余四个Na—O配位体均为六配位。讨论了Na^+离子呈无序分布的晶体结构特征并初步总结[PMo_(10)V_2O_(40)]^(5-)在不同晶相中的构型。
Na3H2[PMo10V2O40]·16H2O, Mr = 2091. 46, monoclinic, P21/m, a = 13. 821(2), b = 15. 355(2), c=11. 597(2)(?), β=107. 50(2)°, 7 = 2347. 2(?)3, Z = 2, Do = 2. 959 g.cm-3, λ (MoKα) = 0. 71073(?), μ= 30. 77cm-1, F (000) = 1992, R = 0. 0326 for 4049 unique reflections with I>3σ(I). The stucture is isomorphous with Na3H2 [PMo6V6O40]·16H2O and contains heteropolyanions linked together by Na -O coordination polyhedra and water molecules. The 12 metal atoms in the cage of the anion comprise 10 Mo and 2 V atoms in a random distribution. The central PO4 is ordered, mean P -O = l. 541(2)(?), M(Mo/V) is 6-coordinated with M-O = 1. 674(2) - 2. 420(2)(?), and the Na+ ions are disordered with distorted Na - O coordination octahedra except Na(3), which is 5-coordinated. Isostructural phases containing the het-eropolyanion [PMo10V2O40]5- as well as its geometry in different phases are briefly discussed.