Single-crystal Structure of Fully Dehydrated Sodium Zeolite Y (FAU), ¦Na71¦[Si121Al71O384]-FAU

The crystal structure of ¦Na71¦[Si121Al71O384]-FAU, a = 24.946(3)Å, dehydrated at 673 K and 1 × 10-6 Torr, was determined by single-crystal X-ray diffraction techniques in the cubic space group Fd3m at 294 K. About 71 Na+ ions per unit cell are found at an unusually large number of crystallographically distinct positions, seven. Five Na+ ions are at the centers of double 6-rings (D6Rs, site I). Two site-I′ positions (in the sodalite cavities opposite D6Rs) are occupied by eight and fourteen Na+ ions, respectively, per unit cell. Thirteen and fifteen Na+ ions per unit cell are found at two site-II positions, in the supercages opposite S6Rs. The remaining twelve and four Na+ ions occupy two sites III′ near triple 4-rings in the supercage.