Chemistry of Materials vol:17 issue:23 pages:5618-5624
In this paper we propose a structure for the novel zeolite material COK-5. COK-5 has a distinct X-ray diffraction pattern, showing unique peaks and broad features. This suggests a layered structure with stacking disorder, consistent with SEM and TEM observations. The proposed structure builds on modified structure elements of MFS type zeolite. The building layers can be stacked in various ways, leading to three new structures, termed Mirror, Glide, and Centre. We propose COK-5 is an intergrowth of these new structures and MFS. The COK-5 channel system comprises four types of pores with windows circumscribed with 10- or 12-rings of oxygen atoms. The refined constraint index of 2.7 situates COK-5 at the transition between 10-ring and 12-ring zeolites. The presence of four pore systems in the same material is unusual and promises high catalytic potential of COK-5.