Crystal Structure of beta-Cs2Mo4O13

beta-Modification of cesium tetramolybdate Cs2Mo4O13 was prepared by hydrothermal reaction of lindgrenite Cu-3(MoO4)(2)(OH)(2) with a CsNO3 solution. The compound crystallizes in the triclinic system, space group P (1) over bar, a = 8.396(5), b = 8.655(5), c = 10.413(5) angstrom, alpha = 106.158(5)degrees, beta = 103.686(5)degrees, gamma = 109.761(5)degrees, V = 636.6(6) angstrom(3). The Mo atoms are coordinated by O atoms to form strongly distorted MoO6 octahedra. The Cs atoms coordinate nine O atoms each. Eight MoO66- octahedra are combined in octamolybdate complexes by sharing common edges. These fragments, in turn, are linked in zigzag chains oriented along a-axis via peripheral octahedra sharing common edges. The compound is isostructural to the previously known alkali metal tetramolybdates A(2)Mo(4)O(13) (A = K, Rb), but differs essentially from alpha-Cs2Mo4O13.