AN INVESTIGATION OF THE SHORT-RANGE ORDER STRUCTURES OF SEVERAL AMORPHOUS LANTHANIDE HYDROUS OXIDES

Amorphous dysprosium, thulium, ytterbium, and lutetium hydrous oxides were synthesized in order to study bulk short-range orders (SROs) asso ciated with each. Synthetic procedures and peripheral investigations i ncluding X-ray powder diffraction, TGA, DSC, IR, and SEM are discussed . Corrected scattering profiles, interference functions, S-i(S), reduc ed distribution functions, rG(r), and radial distribution functions, R DF, are presented for each studied compound. The lanthanide (Ln) syste ms are nine-coordinated (CN = 9) except for lutetium (CN = 6.4). Calcu lated Ln-O, O-O, and Ln-Ln distances and O-Ln-O angles for amorphous D y, Tm, Yb, and Lu hydrous oxides are tabularized. Previously studied a morphous lanthanides (Eu, Gd, Tb, Ho, and Er) are included. A regressi onal analysis of the lanthanides (Eu, ..., Lu) as related to experimen tally determined Ln-O bond lengths is presented. The RDF of amorphous lutetium hydrous oxide is compared to calculated quasi-crystalline mod els so as to discuss structure modeling.