title: Synthesis and structure determination of a new microporous zeolite with large cavities connected by small pores.
abstract: A new small-pore germanosilicate zeolite, named as ITQ-49, has been synthesized using a new ditetraalkylphosphonium dication as an organic structure-directing agent, and its structure has been solved by direct methods applied to the powder X-ray diffraction pattern of the calcined solid. This new zeolite crystallizes in the space group Immm with cell parameters a = 19.6007(8) Å, b = 18.3274(7) Å, and c = 16.5335(6) Å. The pore topology of ITQ-49 consists of large, nonspherical cavities that are connected to each other through small eight-membered-ring windows, resulting in a unidirectional small-pore zeolite that has a relatively large adsorption capacity. Also, ITQ-49 contains double four-membered-ring units where Ge is preferentially located, and fluoride anions are placed inside these units.
authors.affiliation: Instituto de Tecnología Química (UPV-CSIC), Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Av. de los Naranjos s/n, 46022 Valencia, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Hernández-Rodríguez
authors.forename: Jose L
authors.initials: JL
authors.lastname: Jordá
authors.forename: Fernando
authors.initials: F
authors.lastname: Rey
authors.forename: Avelino
authors.initials: A
authors.lastname: Corma