CRYSTALLINE AND MOLECULAR-STRUCTURES OF ANHYDROUS LANTHANIDE PERCHLORATES LN(CLO4)(3) WITH LN = LA, CE, PR, SM, EU, HO, ER, TM, AND LU

The anhydrous perchlorates Ln(ClO4)(3), where ClO4 is coordinated to L n atoms (Ln = La, Ce, Pr, Sm, Eu, Ho, Er, Tm, and Lu) crystallize in t wo distinct groups of isostructural species, Rietveld refinements show that from lanthanum to thulium (low temperature form), the crystal sy stem is hexagonal(space group P6(3)/m, Z = 2) with 9.400(3) Angstrom < a < 9.201(1) Angstrom and 5.918(1) Angstrom < c < 5.563(1) Angstrom. The Rietveld refinement converged to R-F = 0.033, R-p = 0.029, and R-w p = 0.053 for Eu(ClO4)(3), The channeled structure is built on the bas is of slightly distorted tricaped trigonal Eu centered prisms of nine oxygen atoms belonging to nine tridentate [ClO4]. Thullium thigh tempe rature form) and lutetium crystallize in trigonal R3c unit cells (Z = 6) with, respectively, a = 8.13286(2) Angstrom, c = 24.1586(1) Angstro m, and a 8.11559(4) Angstrom, c = 24.0047(1) Angstrom. For Lu(ClO4)(3) , R-F, R-p, and R-wp mere 0.039, 0.046, and 0.061, respectively, Its m olecular structure consists of infinite layers of Lu atoms in a tricap ed trigonal antiprism surrounding of oxygens. Layers and linkages betw een layers are ensured by simultaneously bridging and chelating triden tate [ClO4](3). (C) 1998 Academic Press.