THE FRAMEWORK TOPOLOGY OF ZSM-57 - A NEW SYNTHETIC ZEOLITE

ZSM-57 is a new zeolitic phase with a novel framework topology: structure code MFS, space group lmm2, a = 7.4510(7) Å, b = 14.1711(8) Å, c = 18.767(2) Å, 18.2T 1000Å3. Although the structure is closely related to ZSM-35 (FER), ZSM-57 has 4-rings lacking in the ferrierite framework. There is a channel system of intersecting 8- and 10-rings. Although the dimensions of the 8-ring (3.5 × 4.8 Å) channel differ only marginally from ZSM-35, the 10-ring channels (5.1 × 5.8 Å) are significantly larger than are the analogous channels in ZSM-35 and slightly larger than are the 10-rings in ZSM-5. © 1990.