A tetragonal form of dysprosium orthomolybdate at room temperature

Abstract

In the present tetra-gonal modification of dysprosium orthomolybdate, Dy 2(MoO 4) 3, the Dy, one Mo and one O atom are located on a mirror plane with Wyckoff symbol 4e, while another Mo atom is located on a fourfold inverse axis, Wyckoff symbol 2a. A single crystal was selected from a polycrystalline mixture of the Dy 2O 3-ZrO 2-MoO 3 system and was stable at room temperature for at least three months. The structure refinement does not indicate the presence of Zr on the Dy sites (to within 1% accuracy). Thus, the stabilization of the tetra-gonal form is due to disordered positions for a second O atom and split positions for a third O atom that also maintain the DyO 7 coordination, which is not expected for short Dy - O distances [2.243 (6)-2.393 (5) Å]. © 2011 International Union of Crystallography.