A New Layered Silicate with Structural Motives of Silicate Zeolites: Synthesis, Crystals Structure, and Properties

A new layered silicate, RUB-51, [Si 12 O 24 (OH) 4 ][C 6 H 5 CH 2 N(CH 3 ) 3 ] 4, was synthesized from hydrothermal experiments using benzyl trimethylammonium hydroxide as the structure-directing agent (SDA) in the SiO 2 −H 3 BO 3 −SDA−H 2 O system. Its crystal structure was refined from X-ray powder diffraction data collected at both room temperature and 180 °C. It crystallizes in the orthorhombic space group Pca 2 1 (No. 29) with a = 8.3855(2) Å, b = 14.4122(5) Å, c = 11.7246(4) Å and a = 8.4047 (1) Å, b = 14.5238 (2) Å, c = 11.7705 (2) Å at room temperature and 180 °C, respectively. RUB-51 has the same silicate layer as RUB-15, another layered silicate that was first described in 1996, but with a different stacking sequence and intercalate SDA. The stacking sequence of the silicate layers in RUB-51, a segment of the structure of zeolite sodalite, is AA rather than ABAB as in RUB-15. Other characterization experiments using techniques like SEM, DTA-TG, and solid-state NMR complement and confirm the diffraction study.