Cationic networks in the structures of borates, tungstates, and borotungstates forming in the Ln2O3-B2O3-WO3 systems

The influence of the structures of binary compounds on the formation of ternary mixed-anion compounds—borotungstates—in ternary Ln2O3-B2O3-WO3 systems was studied. The structures of borotungstates either inherit the predominant type of cationic network from the structures of the binary compounds (anisotropic cationic networks in Ln (BO2)(WO4)) or represent a sum of equivalent anisotropic and isotropic cationic networks, forming combined cationic networks (in Ln3BWO9). In the lanthanide series, the ranges of existence of borotungstates coincide with the ranges of existence of the structure types most abundant in the binary compounds.