CRYSTAL-GROWTH AND STRUCTURAL STUDY OF THE NEW SERIES Y(OH)CRO4, DY-LU(OH)CRO4 - CRYSTAL-STRUCTURE OF ER(OH)CRO4

Single crystals of the new series Ln(OH)CrO4 (Ln = Y, DyLu) have been obtained by hydrothermal procedures. The structure of Er(OH)CrO4 has been determined by single-crystal X-ray techniques. The compound has monoclinic symmetry, space group P21 n, Z = 8, with a = 8.106(3), b = 11.324(2), c = 8.251(1) Å, β = 94.14(2)° and V = 755.4(3) Å3. Final R values were R = 0.034, Rw = 0.049, for 2207 observed reflections. X-ray powder data show that all compounds of the title series are isomorphous. The coordination polyhedron of the lanthanide cations can be considered a square antiprism, with hydrogen bonds linking CrO4 and LnO8 groups. The X-ray data in this series provide evidence for the lanthanide contraction. © 1991.