title: Synthesis and in situ transformation of PST-1: a potassium gallosilicate natrolite with a high Ga content.
abstract: The synthetic details of a novel potassium gallosilicate natrolite with Si/Ga = 1.28, denoted PST-1, are described. The presence of K(+) and Ga with well-defined levels of concentration in the synthesis mixture is essential for directing its crystallisation. PST-1 transforms rapidly into TNU-6 under hydrothermal conditions, behaviour that contrasts sharply with its very high thermal and hydrothermal stability, which is unusual for a material of such a high Ga content. These stability issues are discussed and rationalized based on chemical composition, likely violations of Loewenstein's rule and the temperature of dehydration of as-made K-PST-1. The crystal structure of TNU-6 has been resolved through the combined use of synchrotron X-ray and electron diffraction data; it has the BaFeGaO(4) structure type with an additional radical 3a x radical 3a "GeAlO(4)" superstructure that arises from tilting of some of the tetrahedral units in all of the 6-rings.
authors.affiliation: School of Environmental Science and Engineering and Department of Chemical Engineering, POSTECH, Pohang, 790-784, Korea.
authors.forename: Jiho
authors.initials: J
authors.lastname: Shin
authors.forename: Seok Han
authors.initials: SH
authors.lastname: Kim
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Camblor
authors.forename: Stewart J
authors.initials: SJ
authors.lastname: Warrender
authors.forename: Stuart R
authors.initials: SR
authors.lastname: Miller
authors.forename: Wuzong
authors.initials: W
authors.lastname: Zhou
authors.forename: Paul A
authors.initials: PA
authors.lastname: Wright
authors.forename: Suk Bong
authors.initials: SB
authors.lastname: Hong
mesh_terms: D005857:Germanium / Q000737:chemistry*; D010316:Particle Size; D011188:Potassium / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry*; D013696:Temperature; D014961:X-Ray Diffraction; D017641:Zeolites / Q000737:chemistry*
chemical_list: D017640:Silicates; D005857:Germanium; D017641:Zeolites; D011188:Potassium