Abstract
The anhydrous perchloratesLn(ClO4)3, where ClO4is coordinated toLnatoms (Ln=La, Ce, Pr, Sm, Eu, Ho, Er, Tm, and Lu) crystallize in two distinct groups of isostructural species. Rietveld refinements show that from lanthanum to thulium (low temperature form), the crystal system is hexagonal (space groupP63/m,Z=2) with 9.400(3) Å<a<9.201(1) Å and 5.918(1) Å<c<5.563(1) Å. The Rietveld refinement converged toRF=0.033,Rp=0.029, andRwp=0.053 for Eu(ClO4)3. The channeled structure is built on the basis of slightly distorted tricaped trigonal Eu centered prisms of nine oxygen atoms belonging to nine tridentate [ClO4]. Thullium (high temperature form) and lutetium crystallize in trigonalR3cunit cells (Z=6) with, respectively,a=8.13286(2) Å,c=24.1586(1) Å, anda=8.11559(4) Å,c=24.0047(1) Å. For Lu(ClO4)3,RF,Rp, andRwpwere 0.039, 0.046, and 0.061, respectively. Its molecular structure consists of infinite layers of Lu atoms in a tricaped trigonal antiprism surrounding of oxygens. Layers and linkages between layers are ensured by simultaneously bridging and chelating tridentate [ClO4].