| Popis: |
The framework structure of ZSM-12, a high-silica zeolite, was determined by analysis of electron and X-ray powder diffraction data combined with model building. The monoclinic ceil parameters of ZSM-12 ( Si Al -ratio = 310) are a = 24.88 ± 0.04A, b = 5.02 ± 0.02A, c = 12.15 ± 0.03A, and β = 107.7 ± 0.1°. The ideal framework symmetry is C2/m with 28 T-atoms per unit cell. The calculated density (SiO2 end-member) is 1.93 g cm−3. The structure contains elements of the ab-projection of ferrierite linked via 4-rings to produce a net with 12-rings. The bc-projection is a 6-ring net. The 12-ring channels (5.7 × 6.1 A) are linear and noninterpenetrating. |
