HYDROTHERMAL SYNTHESIS OF TRANSITION-METAL FLUORIDES IN BINARY, TERNARY AND QUATERNARY SYSTEMS

The crystal growth of 3d transition metal fluorides by the hydrothermal method is examined. Ternary systems H//2O -(AF or BaF//2)-(MF//2 or M prime F//3) and quaternary systems H//2O -(AF or BaF//2)-MF//2-M prime F//3 (A equals alkaline or ammonium; M**I**I equals Mn, Fe, Ni, Cu; M prime **I**I**I equals Al, V, Cr, Fe) are investigated. The temperature, the concentration of hydrofluorohydric acid and the presence of reducing agents greatly influence the nature of the crystallization. Besides the known species, low-temperature varieties, hydrates or ammonium compounds are reported.