Hydrothermal synthesis of single crystals of transition metal vanadates in the glaserite phase

A series of transition metal vanadate crystals were prepared using a high temperature (580°C) hydrothermal method. The compounds all had the general formula A₂AEM(VO₄)₂ (A=K, Na, Li; AE=Ba, Sr; M=Co, Fe, Mn). They are all variations of the glaserite structural type and range in symmetry from P-3m1 to P-3 to P2₁/c. Most of the derivatives contain a planar three-fold rotation operation, making them possible spin frustration candidates. Single crystal structural analyses were performed on many of the derivatives to obtain a detailed understanding of the distortions of the tetrahedral building blocks that accommodate the symmetry distortions. A hydrothermal growth method was developed to grow high quality single crystals of sizes up to 2-3 mm/edge. This method can be generalized for large crystal growth to enable magnetic and neutron diffraction studies that require relatively large single crystals.