HPM‐14: A New Germanosilicate Zeolite with Interconnected Extra‐Large Pores Plus Odd‐Membered and Small Pores**
Zihao Gao, Jian Li, Cong Lin, Álvaro Mayoral, Junliang Sun, Miguel Á. Camblor
Abstract
Abstract HPM‐14 is a new extra‐large pore zeolite synthesized using imidazolium‐based organic structure‐directing agents (SDAs), fluoride anions, and germanium and silicon as tetrahedral components of the framework. Owing to the presence of stacking disorder, the structure elucidation of HPM‐14 was challenging, and different techniques were necessary to clarify the details of the structure and to understand the nature of the disorder. The structure has been solved by three‐dimensional electron‐diffraction technique (3D ED) and consists of an intergrowth of two polymorphs possessing a three‐dimensional channel system, including an extra‐large pore opened through windows made up of sixteen tetrahedral atoms (16‐membered ring, 16MR) as well as two additional sets of odd‐membered (9MR) and small (8MR) pores. The intergrowth has been studied by scanning transmission electron microscopy (C s ‐STEM) and powder X‐ray diffraction simulations (DIFFaX), which show a large predominance of the monoclinic polymorph A.