Complete Li+ exchange into zeolite X (FAU, Si/Al = 1.09) from undried methanol solution

Complete exchange of Li + into zeolite Na-X, |Na 92 |[Si 100 Al 92 O 384 ]-FAU, was accomplished using undried methanol solvent (water concentration 0.02 M). A crystal of Na-X was treated with 0.1 M LiNO 3 in the solvent at 333 K, followed by vacuum dehydration at 673 K and 1 × 10 −6 Torr for 2 days. Its structure was determined by single-crystal synchrotron X-ray diffraction techniques, in the cubic space group Fd 3 ¯ at 100(1) K. The 92 Li + ions per unit cell are found at three different crystallographic sites. The 32 Li + ions occupy at site I’ in the sodalite cavity: these Li + ions are recessed 0.28 Å into the sodalite cavity from their 3-oxygens plane [Li–O = 1.903(5) Å and O–Li–O = 117.8(3)°]. Another 32 Li + ions are found at site II in the supercage, being recessed 0.26 Å into the supercage [Li–O = 1.968(5) Å and O–Li–O = 118.3(3)°]. The remaining 28 Li + ions are located at site III in the supercage [Li–O = 2.00(8) Å].