A Review of the Synthesis and Structural Chemistry of Platinum-Group Metal Oxoselenates(IV)

This review summarizes recent advances in the synthesis and structural chemistry of platinum-group metal oxoselenates, with particular emphasis on their crystal chemistry and structure–composition relationships. The rational design of inorganic solids with specific structural features remains a central challenge in modern solid-state chemistry, especially for systems involving polyvalent chalcogen–oxygen anions. Recent progress in the chemistry of oxoselenates(IV) of platinum-group metals has revealed a remarkable structural diversity arising from variations in coordination environments, bonding modes of the selenite anion, and synthetic conditions. Approaches such as hydrothermal synthesis, controlled oxidation, and compositional modification have enabled the formation of discrete molecular units, low-dimensional frameworks, and extended three-dimensional networks. Special attention is given to palladium- and platinum-containing selenites, in which the interplay between square-planar metal coordination and the stereochemically active lone pair of Se(IV) governs the resulting architectures. The review summarizes known crystal structures, discusses structure–property relationships, and outlines trends in the stabilization of distinct structural motifs. The collected structural data establish a foundation for systematic exploration of oxoselenates of other platinum-group metals and related inorganic systems.