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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 21, Number 10
BKCSDE 21(10)
October 20, 2000 

Trimeric Chromium Oxyformate Route to Chromia-Pillared Clay
Joo-Byoung Yoon, Sung-Ho Hwang, Jin-Ho Choy
A chromia-pillared clay has been prepared by ion exchange type intercalation reaction between the sodium ion in montmorillonite and the trimeric chromium oxyformate (TCF) ion, and by subsequent heat-treatment. The structural and thermal properties have been systematically studied by thermal analysis, powder XRD, IR spec-troscopy, and XAS. The gallery height of~6.8 Å upon intercalation of the TCF ion suggests that the Cr₃O plane is parallel to the aluminosilicate layers. Even though the basal spacing of TCF intercalated clay decreases slightly upon heating, the layer structure was retained up to 550℃ as confirmed by XRD and TG/DTA. Ac-cording to the EXAFS spectroscopic analysis, it is identified that the (Cr-Cr) distance of 3.28 Å between vertex-linked CrO6 octahedra in TCF splits into 2.64 Å, 2.98 Å, and 3.77 Å due to the face-, edge-, and corner-shared CrO6 octahedra after heating at 400℃, implying that a nano-sized chromium oxide phase was stabilized within the interlayer space of clay.
989 - 994
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