Progress in crystal chemistry of new fumarole minerals discovered in 2014-2024 and their synthetic analogues

This review highlights the key findings from the study of new anhydrous minerals discovered by the research team in the fumaroles of the Tolbachik volcano (Kamchatka) over the past decade. The synthesis conditions for analogues of these fumarole minerals and the distinctive features of their crystal chemistry are discussed. Special attention is given to minerals containing sulfate or vanadate anions, the discovery of which has led to the development of extensive families of inorganic compounds and materials with rich and intriguing crystal chemistry. A dedicated section focuses on advancements in high-temperature X-ray diffraction (HT XRD). Additionally, several rare topotactic single crystal-to-single crystal (SC-SC) transformations observed in vergasovaite and aleutite are described.