In the present tetragonal modification of dysprosium orthomolybdate, Dy2(MoO4)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 Dy2O3–ZrO2–MoO3 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 tetragonal form is due to disordered positions for a second O atom and split positions for a third O atom that also maintain the DyO7 coordination, which is not expected for short Dy—O distances [2.243 (6)–2.393 (5) Å].