Yang, Xiaobo Camblor, Miguel A. Lee, Yongjae Liu, Haiming Olson, David H. Synthesis and Crystal Structure of As-Synthesized and Calcined Pure Silica Zeolite ITQ-12 The small-pore pure silica zeolite ITQ-12 has been synthesized with fumed silica as the silica source in the presence of 1,3,4-trimethylimidazolium hydroxide and hydrofluoric acid under hydrothermal conditions at 448 K. Rietveld refinement using synchrotron X-ray diffraction data of the calcined ITQ-12 product taken at 298 K confirms the proposed topology, framework type code <b>ITW</b>, which can be described by a monoclinic unit cell [Si<sub>24</sub>O<sub>48</sub>] having <i>Cm</i> symmetry. Unit cell parameters are <i>a</i> = 10.3360(4), <i>b</i> = 15.0177(6), and <i>c </i>= 8.8639(4) Å, β = 105.356(3)°, and cell volume <i>V</i> = 1326.76(9) Å<sup>3</sup>. For as-synthesized ITQ-12, the occluded fluoride anion is located inside the double four-membered ring, while the flat 1,3,4-trimethylimidazolium cation lies on the equatorial plane of the slit-shaped [4<sup>4</sup>5<sup>4</sup>6<sup>4</sup>8<sup>4</sup>] cage, with its longest dimension in the [010] direction. The monoclinic unit cell |(C<sub>6</sub>N<sub>2</sub>H<sub>11</sub>)<sup>+</sup><sub>2</sub>F<sup>-</sup><sub>2</sub>|[Si<sub>24</sub>O<sub>48</sub>], having <i>Cm</i> symmetry, has parameters <i>a</i> = 10.4478(3), <i>b</i> = 14.9854(4), and <i>c</i> = 8.8366(3) Å, β = 105.935(2)°, and cell volume <i>V</i> = 1330.34(7) Å<sup>3</sup> at 298 K. Cooperative structure-directing effects during the crystallization of ITQ-12 are discussed in terms of the structure of the as-made material. Cm symmetry;cell volume V;framework type code ITW;trimethylimidazolium;Si 24 O 48;ITQ;Unit cell parameters;298 K 2004-08-25
    https://acs.figshare.com/articles/dataset/Synthesis_and_Crystal_Structure_of_As_Synthesized_and_Calcined_Pure_Silica_Zeolite_ITQ_12/3327337
10.1021/ja0481474.s003