Specific features of the phase formation in the titanate systems Ln2TiO5-Ln′2TiO5 (Ln = La, Gd, Tb, Er; Ln′ = Tb, Lu)

The specific features in the crystal chemistry and phase formation of the systems Ln 2TiO5-Ln′2TiO5 (Ln = La, Gd, Tb, Er; Ln′ = Tb, Lu) are established. The relation between the topology of the phase diagrams and the structure of the Ln 2TiO5 compound is investigated as a function of the ionic radius of the rare-earth cation.