CRYSTAL-STRUCTURE OF SILICA-ZSM-12 BY THE COMBINED USE OF HIGH-RESOLUTION SOLID-STATE MAS NMR-SPECTROSCOPY AND SYNCHROTRON X-RAY-POWDER DIFFRACTION

The crystal structure of the synthetic zeolite silica-ZSM-12, 56 SiO2, has been solved by the combined use of high-resolution solid-state MAS NMR spectroscopy and high-resolution synchrotron X-ray powder diffraction. ZSM-12 crystallizes in the monoclinic space group C2/c with a0 = 24.863 Å, b0 = 5.012 Å, C0 = 24.328 Å, and β = 107.7°. The zeolite host structure is built from corner-linked SiO4 tetrahedra to give a three-dimensional 4-connected net. The pores of the structure are one-dimensional channels that do not intersect, with 12-membered ring pore openings of approximately 5.6 × 7.7 Å. The structure of ZSM-12 is frequently twinned with (100) as the twin plane, which indicates a new zeolite structure type. © 1990 American Chemical Society.