T. Miyanaga et S. Sudoh, Hydrated structures and dehydration processes of lanthanoid(III) chloranilates studied by EXAFS, POLYHEDRON, 18(26), 1999, pp. 3433-3439
The local structures of lanthanoid(III) chloranilate complexes of Pr(III),
Nd(III), Tb(III) and Er(III) have been studied by EXAFS (extended X-ray abs
orption fine structure). Hydrated structures of the lanthanoid(III) ions in
these complexes have been investigated with respect to their coordination
numbers and interatomic distances. Six or four water molecules coordinate t
o the lanthanoid(III) ion of Pr(III) or Nd(III), respectively, just after p
reparation of the complexes. The temperature dependence of the first coordi
nated structures has been studied in order to reveal the behavior of the co
ordinated water molecules in dehydration process. The coordination number a
round the central lanthanoid(III) ion decreases stepwise as temperature inc
reases, depending on the type of central lanthanoid(III) ion present. The i
nteratomic distance between the central lanthanoid(III) ion and oxygen atom
s in the first shell decreases, accompanying the decrease of the coordinati
on numbers. A parameter representing proportion shows the reduction of inte
ratomic distance as one coordinated water molecule removes from the central
ion, depending on the type of lanthanoid(III) ions. (C) 1999 Elsevier Scie
nce Ltd. All rights reserved.