A comparative study for stepwise chlorinatxion–chemical vapor transport characteristics of pure rare earth oxides from Sc2O3 to Lu2O3 mediated by the vapor complexes LnAlnCl3n+3

A systematic study has been carried out for the stepwise chlorination-chemical vapor transport (SC-CVT) characteristics of pure rare earth oxides from Sc2O3 to Lu2O3 mediated by the vapor complexes LnAl(n)Cl(3n + 3) (where Ln = rare earth elements) under identical conditions. The results show that the total transported amount of the produced chlorides is the highest for YCl3; it is also high for ScCl3, but low for LaCl3, and then increases systematically from the early lanthanide chlorides to the end lanthanide chlorides except CeCl3, EuCl3 and GdCl3. The results also show that the main deposition temperature df the chlorides is in the increasing order ScCl3 < YCl3 < LaCl3 and then with a systematically decreasing trend from the early lanthanide chlorides to the end lanthanide chlorides. Based on the literature data for the solid complexes LnAl(3)Cl(12) and LnAl(3)Br(12), a similar coordination structure assumption is introduced for the vapor complexes LnAl(3)Cl(3n + 3) from Ln = Sc to Ln = Lu with the same stoichiometry to explain the SC-CVT characteristics of the pure rare earth oxides from Sc2O3 to Lu2O3 using a 4f electron hybridization assumption. (C) 1999 Elsevier Science S.A. All rights reserved.