RARE EARTH ORTHOGALLATES

Single crystals of the rare earth orthogallates, REGaO3 with RE = Sm-Lu, have been synthesized by the decomposition of the respective garnets at high pressure in the presence of a flux. Previously reported crystals of LaGaO3, PrGaO3, and NdGaO3 have been prepared by the flux method at atmospheric pressure. The rare earth orthogallates are isostructural with the rare earth orthoferrites; namely, they have the orthorhombic perovskite-like structure. Their lattice parameters have been calculated by the least-squares method. The parameters a and c increase smoothly in going from Lu to La. However, the lattice parameter b goes through a maximum. It seems that this anomalous variation of the b parameter can be explained in terms of a variation of the coordination number of the rare earth cation. © 1968, American Chemical Society. All rights reserved.