Hydrothermal crystal synthesis of solid solutions in the system SrF₂LaF₃

The possibility of the hydrothermal crystal synthesis/growth of the SrF₂-solid solutions by spontaneous nucleation is studied in the system SrF₂LaF₃. The lattice parameters of the solid solutions synthesized at 750°C by solid state reaction for 23 days in vacuum, or by hydrothermal reaction for 1 day under 100 MPa in 10 wt% LiCl solution, were identical. The composition of the Sr_1-sLa_xF_2+x crystals could be controlled by the starting composition. Single cubic crystals (x = 0·4) about 0·2 mm in size were grown at 650°C for 7 days under 100 MPa in 10 wt% LiCl aqueous solution from the composition containing 50 wt% SrF₂. Single hexagonal plate-like cyrstals of LaF₃-solid solution were also obtained, being about 0·2 mm in size. Hydroxyl ions (OH^-) were not detected in the products by infrared spectroscopy.