title: Reversed Crystal Growth of RHO Zeolitic Imidazolate Framework (ZIF).
abstract: RHO zeolitic imidazolate framework (ZIF), Zn1.33 (O.OH)0.33 (nim)1.167 (pur), crystals with a rhombic dodecahedral morphology were synthesized by a solvothermal process. The growth of the crystals was studied over time using scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (PXRD) and Brunauer-Emmett-Teller (BET) analyses, and a reversed crystal growth mechanism was revealed. Initially, precursor materials joined together to form disordered aggregates, which then underwent surface recrystallization forming a core-shell structure, in which a disordered core is encased in a layer of denser, less porous crystal. When the growth continued, the shell became less and less porous, until it was a layer of true single crystal. The crystallization then extended from the surface to the core over a six-week period until, eventually, true single crystals were formed.
authors.affiliation: EaStCHEM, School of Chemistry, University of St Andrews, St Andrews KY16 9ST (UK), Fax: (+44) 1334-468308.
authors.forename: Katherine
authors.initials: K
authors.lastname: Self
authors.affiliation: EaStCHEM, School of Chemistry, University of St Andrews, St Andrews KY16 9ST (UK), Fax: (+44) 1334-468308.
authors.forename: Michael
authors.initials: M
authors.lastname: Telfer
authors.affiliation: EaStCHEM, School of Chemistry, University of St Andrews, St Andrews KY16 9ST (UK), Fax: (+44) 1334-468308.
authors.forename: Heather F
authors.initials: HF
authors.lastname: Greer
authors.affiliation: EaStCHEM, School of Chemistry, University of St Andrews, St Andrews KY16 9ST (UK), Fax: (+44) 1334-468308. wzhou@st-andrews.ac.uk.
authors.forename: Wuzong
authors.initials: W
authors.lastname: Zhou
keywords: crystal growth; electron microscopy; metal-organic frameworks; zeolitic imidazolate frameworks