Gadolinium ytterbium trifluoride, Gd0.81Yb0.19F3
Abstract
A new gadolinium ytterbium trifluoride has been grown for the first time by the Czochralski technique. Although GdF3 and YbF3 both present a high-temperature phase transition, the mixed compound Gd0.81Yb0.19F3 maintains its crystallographic structure upon cooling to room temperature. Taking into account that both Gd3+ and Yb3+ ions are distributed randomly on a single site (Wyckoff position 4c), this is attributed to a mean cationic radius coincident with that of the Tb3+ ion, so that the stability of the crystal structure resembles that of TbF3. The grown crystal melts noncongruently at 1413 K, it is transparent and colourless, and it has a high density.