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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 13, Number 2
BKCSDE 13(2)
February 20, 1992 

Structure and Bonding of Perovskites A(Cu1/3Nb2/3)O3 (A=Sr, Ba and Pb) and their Series of Mixed Perovskites
Hyu-Bum Park, Hwang Huh, Si-Joong Kim*
Some perovskites A(Cu1/3Nb2/3)O3 (A=Sr2+, Ba2+ and Pb2+) and their series of mixed perovskites have been prepared by solid state reaction. Single perovskite phase was obtained in Sr or Ba rich samples, but pyrochlore phase was found in Pb rich samples. The stability of perovskite phase is dependent on the ionicity of bonding as well as the tolerance factor. All the obtained perovskites have tetragonal symmetry distorted by Jahn-Teller effect of Cu2+. In the case of Sr(Cu1/3Nb2/3)O3, some superlattice lines caused by threefold enlarging of fundamental unit cell were observed. And, the symmetry of B site octahedron and the bonding character of B-O bond have been studied by IR, ESR and diffuse reflection spectroscopy. It appeared that the symmetry and the bonding character are influenced by such factors as the size and the basicity of A cation.
122 - 127
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