KIn_0.33^IIITe_0.67^VITe₂^IVO₇: Zirconolite-like Mixed-Valent Metal Oxide with a 3D Framework

We provide the material synthesis method, crystal structure information, and characterization of a novel mixed-valent metal oxide KIn_0.33^IIITe_0.67^VITe₂^IVO₇, closely related to zirconolite (CaZrTi₂O₇), a radioactive waste immobilized material, having a 3D framework. The reported metal oxide containing an alkali-metal cation (K⁺), main-group cation (In³⁺), tellurate, and tellurite has been synthesized as both single crystals and a pure polycrystalline phase through a hydrothermal synthesis method. Single-crystal X-ray diffraction indicates that KIn_0.33Te_2.67O₇ crystallizing in the orthorhombic space group Cmcm (No. 63) reveals a 3D framework structure with a 1D channel consisting of Te/InO₆ octahedra and TeO₄ polyhedra. An interesting transition reaction from KIn_0.33Te_2.67O₇ to KIn­(TeO₃)₂ under hydrothermal conditions at 230 °C is discussed.