Single crystals of trilithium(I) aluminium(III) bis-[dioxidomolybdenum(VI)] dioxide bis-[arsenate(V)], Li(3)AlMo(2)As(2)O(14), have been prepared by solid-state reaction at 788 K. The structure consists of AsO(4) tetra-hedra, AlO(6) octa-hedra and Mo(2)O(10) groups sharing corners to form a three-dimensional framework containing channels running respectively along the [100] and [010] directions, where the Li(+) ions are located. This structure is compared with compounds having (MX(2)O(12))(n) chains (M = Mo, Al and X = P, As) and others containing M(2)O(10) (M = Mo, Fe) dimers.