Growth of Crystals of Solid Solutions with Tysonite Structure in the PbF2–RF3 Systems (R = Pr, Nd)

Crystals of the R1 – yPbyF3 – y (R = Pr (0 ≤ y ≤ 0.09) or Nd (0 ≤ y ≤ 0.10)) solid solutions with a tysonite structure (sp. gr. $$P\bar {3}c1$$) have been grown for the first time by the vertical directional melt crystallization in a fluorinating atmosphere using a special crucible for maintaining overpressure. The experimental data have been used to calculate the concentration dependences of the lattice parameters of the R1 – yPbyF3 – y (R = Pr, Nd) solid solutions.