title: Structure and synthesis of SSZ-63: toward an ordered form of zeolite beta.
abstract: The synthesis, characterization, and structure elucidation of the borosilicate zeolite SSZ-63 are described. SSZ-63 is synthesized using the 1-cyclodecyl-1-methylpyrrolidinium cation as a structure-directing agent. The structural model for SSZ-63 was determined by comparison of its powder X-ray diffraction pattern with those of zeolite beta and its polytype structures. Whereas conventional zeolite beta may be described as a random intergrowth of polytypes A and B, SSZ-63 is more accurately described as a random intergrowth of polytypes B and C(H) (the hypothetical polytype C proposed by Higgins). Polytype C(H) is essentially an ordered intergrowth (of polytypes A and B) in which one of the crystallographic projections is equivalent to those in polytype A and another projection is equivalent to those in polytype B. Unlike zeolite beta, which possesses significant disorder related to layer shifts along both the a- and b-crystallographic axes, the structure of SSZ-63 has little disorder associated with the translations of layers in the a-direction. DIFFaX simulations of the powder diffraction patterns, electron diffraction, and high-resolution transmission electron microsocopy data all support the proposed model.
authors.affiliation: ChevronTexaco Energy Research and Technology Company, Richmond, CA 94802, USA.
authors.forename: Allen W
authors.initials: AW
authors.lastname: Burton
authors.forename: Saleh
authors.initials: S
authors.lastname: Elomari
authors.forename: Ignatius
authors.initials: I
authors.lastname: Chan
authors.forename: Ajit
authors.initials: A
authors.lastname: Pradhan
authors.forename: Charles
authors.initials: C
authors.lastname: Kibby