STRUCTURE OF GDMO5O8

Gadolinium pentamolybdate, GdMo5O8, M(r) = 764.95, monoclinic, P2(1)/c, a = 7.559 (3), b = 8.9926 (9), c = 9.923 (3) angstrom, beta = 109.81 (2)-degrees, V = 634.6 (3) angstrom 3, Z = 4, D(x) = 8.006 g cm-3, lambda-(Mo K-alpha) = 0.71073 angstrom, mu = 197.4 cm-1, F(000) = 1352, T = 298 K, R = 0.028 for 2098 observed reflections. The title compound is isostructural with LaMo5O8 and contains bioctahedral Mo10O18 cluster units strongly linked by Mo(1)-Mo(1) intercluster bonds [2.674 (1) angstrom] to form infinite molybdenum oxide chains. These are interconnected through Mo-O-Mo bonds to create channels where the Gd3+ ions are located. The Mo-Mo distances in the Mo10 cluster lie between 2.598 (1) and 2.832 (1) angstrom (average 2.746 angstrom). The Mo-O distances range between 1.994 (5) and 2.142 (5) angstrom (average 2.074 angstrom). The Gd3+ ions are ten coordinated to O atoms with Gd-O distances ranging from 2.315 (5) to 2.959 (5) angstrom (average 2.614 angstrom).