Li(MoO2)2O(AsO4)

Single crystals of the molybdenum arsenate Li(MoO 2 ) 2 -O(AsO 4 ) [lithium bis(dioxomolybdenum) arsenate oxide] have been prepared by solid-state reaction. The framework of Li(MoO 2 ) 2 O(AsO 4 ) consists of corner-shared Mo 2 AsO 12 structural units, which form layers parallel to the ab plane. The Mo 2 AsO 12 units result from the association of corner-shared AsO 4 tetrahedra and Mo 2 O 9 dimers. The Li + ions are located between layers in a square-based-pyramidal environment. This structure is compared with those containing M 2 O 9 dimers (M = Mo, Fe or V). The As, Li and one of the O atoms lie at sites with mm symmetry, while the Mo atom and two of the O atoms lie at sites with m symmetry.