Extensive intrazeolitic hydrolysis of Zn(II): partial structures of partially and fully hydrated Zn(II)-exchanged zeolite X

摘要: Abstract Complete Zn2+ exchange of two single crystals zeolite X (Na92Si100Al92O384) was attempted at 80°C from aqueous Zn(NO3)2 (pH=5.5 23°C). The structures crystal 1 (partially dehydrated by evacuation 23°C and 10−3 Torr for days) 2 (fully hydrated) were determined X-ray diffraction techniques in the cubic space group Fd 3 (ao=24.750(5) 24.872(6) A, respectively). They refined using all intensities to final error indices R1=0.126 0.116 based on 428 348 reflections, respectively, which Fo>4σ(Fo). Each has about 54 ions per unit cell, indicating uptake eight excess Zn(OH)2 molecules. In both crystals, further extensive hydrolysis is seen. Many non-framework oxygens not found. 1, 34 cell occupy conventional cationic sites: 10 are site I′, 12 II, III′. Three each coordinate a framework oxygen non-conventional supercages. centers sodalite cavities tetrahedrally four give (likely) Zn(OH)2(H2O)2 hydrogen bonds multiply framework. At three supercage positions, 14 that do Per 37 H3O+ found: 20 I′ 17 II. It presumed, considering number ions, latter hydrolyzed likely hydrated molecules, some bridging. 2, 33 found I, different sites seven As supercage. 18 40 II′ 22 Only 16 cell: water molecules supercages and, cages, hydroxide participate formation nearly Zn4(OH)44+ clusters.