CRYSTAL-STRUCTURES OF DEHYDRATED H CHABAZITE PRETREATED AT 320-DEGREES-C AND AT 600-DEGREES-C AFTER STEAMING

被引:15
作者
MORTIER, WJ [1 ]
KING, GSD [1 ]
SENGIER, L [1 ]
机构
[1] CATHOLIC UNIV LEUVEN,KRISTALLOG LAB,B-3000 LOUVAIN,BELGIUM
关键词
D O I
10.1021/j100480a017
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Two crystal structures of dehydrated NH4-exchanged chabazite crystals were studied by use of single-crystal X-ray diffraction methods after dehydration at 320 °C, and at 600 °C following a steaming period. No significant differences are observed between the two structures; there is no preference of the protons for a single oxygen species nor any indication of Al removal from the framework after steaming. A strong correlation between T-O-T bond angles and T-O distances in adjacent tetrahedra shows an identical slope with that of dehydrated H mordenite. The framework oxygens, all pointing either to the hexagonal prisms or to the centers of the framework eight-rings, prohibit the free vibration of OH bonds in the large cavity. This explains the 30 cm-1 decrease of the HF bands as compared to the value predicted from the framework composition. © 1979 American Chemical Society.
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页码:2263 / 2266
页数:4
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