The new synthetic hydrous layer silicate with code RUB-39, H2[Si18O38]·2(C8H20N)·xH2O, was
synthesized from hydrothermal solution after 3 weeks at 150 °C and autogenous pressure. The material
crystallized as a colorless, fine-grained powder of sub-micrometer crystallite size. The powder diagram
was indexed in the monoclinic space group P2/c with a = 7.33122(5) Å, b = 10.72380(13) Å, c =
17.51354(12) Å, and β = 115.69(6)°. The Rietveld refinement of the crystal structure was refined from
laboratory powder X-ray diffraction data based on a structure model derived from the condensation product,
zeolite RRO, with final residuals of R
wp = 12.3% and χ2 = 3.1. The silicate layers of the new hydrous
layer silicate are known as subunits of the silicate framework of the natural zeolite mineral heulandite
and represent a basic construction principle of silicate framework structures. They are interconnected
through strong interlayer hydrogen bonds. The remaining residual void space is filled with the organic
template cation and hydrate water. The condensation process has been studied with solid-state NMR and
differential thermal analysis/thermogravimetric analysis experiments. A mechanism for the condensation
is proposed explaining the almost perfect crystallinity of the three-dimensional framework.
Synthesis and Crystal Structure of Zeolite RUB-41 Obtained as Calcination Product of a Layered Precursor: A Systematic Approach to a New Synthesis Route.-The new all-silica zeolite RUB-41 is synthesized by calcination of the layer silicate RUB-39 at 520°C for 12 h. As revealed by powder XRD it crystallizes in the monoclinic space group P2/c with Z = 18 (SiO2 units per unit cell) and has a two-dimensional channel system with intersecting 8-and 10-membered ring pores. The material shows high sorption interaction for C4 alkenes and excludes isobutane from the pore system. Its almost uniform pore size, its hydrophobic character, and its high thermal stability makes it suitable for various gas-phase sorption and separation processes, in particular as a function of pressure. -(WANG, Y. X.; GIES*, H.; MARLER, B.; MUELLER, U.; Chem.
Silicon I 0058 Crystal Structure of the New Layer Silicate RUB-39 and Its Topotactic Condensation to a Microporous Zeolite with Framework Type RRO. -The new hydrous layer silicate (Me2Pr2N)2H2[Si18O38] is hydrothermally synthesized from an aqueous dispersion of silica gel using Me2Pr2NOH as the structure directing agent (autoclave, 150°C, 21 d), and characterized by Rietveld refinement of powder XRD data. The compound crystallizes in the monoclinic space group P2/c. The silicate layers are interconnected through strong interlayer hydrogen bonds which are responsible for topotactic condensation of layers upon calcination to a three-dimensional microporous framework silicate. -(WANG, Y. X.; GIES*, H.; LIN, J. H.; Chem.
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