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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 21, Number 3
BKCSDE 21(3)
March 20, 2000 

Ce LIII-edge X-ray Absorption Spectroscopic Studies on the Tetrameric Ce-Polyoxyhydroxy Cation Intercalated Aluminosilicate
Joo-Byoung Yoon, Sung-Ho Hwang, Dong-Kuk Kim, Seong-Gu Kang, Jin-Ho Choy*
The cerium ion intercalated aluminosilicate was prepared by ion exchange reaction between Na + in montmo-rillonite and Ce 4+ in aqueous solution. The X-ray absorption near edge structure (XANES) analyses indicate that the Ce 4+ ions are partially reduced to the Ce 3+ ones during the intercalation into layered aluminosilicate due to a charge transfer between host and intercalant. From the EXAFS analysis, two different (Ce-O) bonding pairs could be characterized with the distances and coordination numbers of 2.31 (±.02) Å×8.2 (±1.5) and 2.66 (±.02) Å×2.7 (±.0), respectively, with the oxygen atoms as the first nearest neighbor, and two (Ce-Ce) pairs at 3.78 Åas the second neighbor. It is therefore concluded that the most probable Ce-species stabilized in the interlayer space of aluminosilicate after the intercalation is the tetrameric Ce-polyoxy/hydorxy cations with the mixed valent state of 0.75 Ce 4+ /0.25 Ce 3+.
305 - 309
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