Li2GeMo3O8: a novel reduced molybdenum oxide containing Mo3O13cluster units

Abstract

The crystal structure of the title compound, dilithium germanium trimolybdenum octaoxide, consists of distorted hexagonal-close-packed oxygen layers with stacking sequenceABACalong [001] that are held together by alternating lithium–germanium and molybdenum layers. The two Li+and Ge4+ions all have site symmetry 3m. and occupy, respectively, tetrahedral and octahedral sites in the ratio 2:1. The Mo atom has a formal oxidation state of +3.3 and occupies an octahedral site (site symmetry .m.) and forms strongly bonded triangular cluster units [Mo—Mo distance = 2.4728 (8) Å] involving three MoO6octahedra that are each shared along two edges, constituting an Mo3O13unit.