Scheelite-type NaEr(MoO(4))(2)

Explorations of the A (1+)–RE (3+)–Mo(6+)–O(2−) (A (1+) is an alkali metal cation, RE (3+) is a rare-earth metal cation) quaternary systems prepared by the high-temperature solution growth method led to the title structure, sodium erbium bis­(molyb­date), NaEr(MoO(4))(2). It is isostructural to the scheelite structure (CaWO(4)) and is composed of [MoO(4)](2−) tetra­hedra with [Image: see text] symmetry and [(Na/Er)O(8)](14−) polyhedra. The [(Na/Er)O(8)](14−) polyhedron is a distorted tetra­gonal anti­prism, also with [Image: see text] symmetry, with statistically mixed Na/Er atoms at its centre. There are two sets of Na/Er—O bond lengths [2.420 (4) and 2.435 (3) Å], but just one set of Mo—O bond lengths [1.774 (4) Å].