The Structure of Iron Oxide Implanted Zeolite Y, Determined by High-Resolution Electron Microscopy and Refined with Selected Area Electron Diffraction Amplitudes
✍ Scribed by Anna Carlsson; Takeo Oku; Jan-Olov Bovin; Gunnel Karlsson; Yasuaki Okamoto; Naoyuki Ohnishi; Osamu Terasaki
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 174 KB
- Volume
- 5
- Category
- Article
- ISSN
- 0947-6539
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✦ Synopsis
It has been shown for the first time that iron atom positions can be determined inside the framework of zeolite crystals, such as the FAU structure of zeolite Y [Na 48 (Fe 2 O 3 ) 38 ][Al 48- Si 144 O 384 ], by means of electron crystallographic methods for three-dimensional reconstruction from high-resolution electron micrographs and selected area electron diffraction. The iron-containing zeolite with the FAU structure type was refined in the space group Fd3m (a 24.7 ) with 42 unique reflection amplitudes from electron diffraction. The Fe 6 O n molecule is situated in the sodalite cage with the iron atoms facing the square windows of the cage. The FeÀFe distance is 3.6 and the FeÀO distances to the nearest oxygen atoms in the sodalite cage are close to 2.2 . As a verification and a comparison, the structure of [Na 48 ][Al 48 Si 144 O 384 ] without iron was also determined by the same method, and the atom positions of the Si/Al network were found to coincide with those of the structure determined from single-crystal X-ray diffraction methods.