The structure of iron oxide implanted zeolite Y, determined by high-resolution electron microscopy and refined with selected area electron diffraction amplitudes

It has been shown for the first time that iron atom positions can be determ ined inside the framework of zeolite crystals, such as the FAU structure of zeolite Y [Na-48(Fe2O3)(38)][Al48Si144O384] by means of electron crystallo graphic methods for three-dimensional reconstruction from high-resolution e lectron micrographs and selected area electron diffraction. The iron-contai ning zeolite with the FAU structure type was refined in the space group Fd3 m (a = 24.7 Angstrom) with 42 unique reflection amplitudes from electron di ffraction, The Fe6On molecule is situated in the sodalite cage with the iro n atoms facing the square windows of the cage. The Fe-Fe distance is 3.6 An gstrom and the Fe-O distances to the nearest oxygen atoms in the sodalite c age are close to 2.2 Angstrom. As a verification and a comparison, the stru cture of [Na-48][Al48Si144O384] without iron was also determined by the sam e method, and the atom positions of the Si/Al network were found to coincid e with those of the structure determined from single-crystal X-ray diffract ion methods.