A zeolite CAN-type aluminoborate with gigantic 24-ring channels

2016 ◽  
Vol 52 (8) ◽  
pp. 1729-1732 ◽  
Author(s):  
Gao-Juan Cao ◽  
Qi Wei ◽  
Jian-Wen Cheng ◽  
Lin Cheng ◽  
Guo-Yu Yang
Keyword(s):  
Framework Density

A well crystalline chiral aluminoborate with extra-large 24-ring channels was solvothermally made by using amines as templates. It exhibits a rare zeolite CAN-type net with very low framework density and high nonframework volume by incorporating B5O10 clusters and AlO4 tetrahedra.

Anion packing density: a universal quantity for both dense and porous crystalline inorganic phases

2002 ◽  
Vol 58 (3) ◽  
pp. 457-462 ◽  
Author(s):  
F. Liebau ◽  
H. Küppers
Keyword(s):  
High Pressure ◽  
Packing Density ◽  
Three Dimensional ◽  
Ionic Radii ◽  
Generalized Framework ◽  
Molal Volumes ◽  
Definition Of ◽  
Anion Packing ◽  
Very High ◽  
Framework Density

To compare densities of inorganic high-pressure phases their molal volumes or specific gravities are usually employed, whereas for zeolites and other microporous materials the so-called framework density, FD, is applied. The definition of FD, which refers only to phases with three-dimensional tetrahedron frameworks, is extended to a `generalized framework density' d f, which is independent of the dimensionality of the framework and the coordination number(s) of the framework cations. In this paper the anion packing density, d ap, is introduced as a new quantity which is not only applicable to any inorganic phase but, in contrast to FD and d f, also allows quantitative comparisons to be made for crystalline inorganic phases of any kind. The anion packing density can readily be calculated if the volume and content of the unit cell and the radii of the anions of a phase are known. From d ap values calculated for high-pressure silica polymorphs studied under very high pressure, it is concluded that Shannon–Prewitt effective ionic radii do not sufficiently take into account the compressibility of the anions.

Rapid and facile synthesis of hierarchical nanocrystalline SSZ-13 via the interzeolite transformation of ZSM-5

2020 ◽  
Vol 44 (14) ◽  
pp. 5501-5507
Author(s):  
Qiang Li ◽  
Liancheng Bing ◽  
Fangni Li ◽  
Jiajia Liu ◽  
Dezhi Han ◽  
...  
Keyword(s):  
Facile Synthesis ◽  
Hydrothermal Conditions ◽  
Framework Density

Hierarchical SSZ-13 was successfully synthesized via the interzeolite conversion of ZSM-5 with high framework density (FD = 18.4 T/1000 Å3) in the presence of N,N,N-trimethyl-1-adamantanamine hydroxide (TMAdaOH) under hydrothermal conditions.

Synthesis and structure of pure SiO2 chabazite: the SiO2 polymorph with the lowest framework density

1998 ◽  
pp. 1881-1882 ◽  
Author(s):  
María-José Díaz-Cabañas ◽  
Philip A. Barrett
Keyword(s):  
Pure Sio2 ◽  
Framework Density

Issues in the Synthesis of Crystalline Molecular Sieves: Towards the Crystallization of Low Framework-Density Structures

ChemInform ◽  
2004 ◽  
Vol 35 (49) ◽  
Author(s):  
Avelino Corma ◽  
Mark E. Davis
Keyword(s):  
Molecular Sieves ◽  
Framework Density

Novel aluminophosphate Na6[Al3P5O20] with the original microporous crystal structure established in the study of a pseudomerohedric microtwin

2021 ◽  
Vol 77 (2) ◽  
pp. 232-240
Author(s):  
Olga V. Yakubovich ◽  
Galina V. Kiriukhina ◽  
Anatoliy S. Volkov ◽  
Olga V. Dimitrova ◽  
Elena Yu. Borovikova
Keyword(s):  
Crystal Structure ◽  
Unit Cell Parameters ◽  
Monoclinic Crystal ◽  
Cell Parameters ◽  
Monoclinic Crystal Structure ◽  
Generalized Framework ◽  
Microporous Zeolite ◽  
Phosphate Groups ◽  
Framework Density

The synthesis and characterization of a new aluminophosphate, Na6[Al3P5O20], obtained as single crystals in the same experiment together with Cl-sodalite, Na8[Al6Si6O24]Cl2, is reported. Na6[Al3P5O20], with a strongly pseudo-orthorhombic lattice, is described by the monoclinic crystal structure established in the study of a pseudomerohedric microtwin. The design of Na6[Al3P5O20] can be interpreted as an alternative to sodalite, with a monoclinic (pseudo-orthorhombic) 2×4×1 super-structure and unit-cell parameters multiples of those of sodalite: a ≃ 2a s, b ≃ 4b s and c ≃ c s. The triperiodic framework is built by AlO6, AlO4 and PO4 polyhedra having vertex-bridging contacts. While all the oxygen vertices of the Al-centred octahedra and tetrahedra are shared with phosphate groups, some of the PO4 tetrahedra remain `pendant', e.g. containing vertices not shared with other polyhedra of the aluminophosphate construction. Na atoms occupy framework channels and cavities surrounded by eight-, six- and four-membered windows with maximal effective pore widths of 4.86 × 3.24 and 4.31 × 3.18 Å. The generalized framework density is equal to 19.8, which means that the compound may be classified as a microporous zeolite. The Na6[Al3P5O20] crystal structure is discussed as being formed from octahedral rods arranged in two perpendicular directions, similar to the rods elongated in one direction in the NASICON-type compounds, which have been intensively investigated as promising materials for batteries. Analogous properties can be expected for phases with a modified composition of the Na6Al3P5O20 topology, where the Al atoms at the centres of octahedra are replaced by Fe, V or Cr.

framework density

2020 ◽  
Keyword(s):  
Framework Density

Issues in the Synthesis of Crystalline Molecular Sieves: Towards the Crystallization of Low Framework-Density Structures

ChemPhysChem ◽  
2004 ◽  
Vol 5 (3) ◽  
pp. 304-313 ◽  
Author(s):  
Avelino Corma ◽  
Mark E. Davis
Keyword(s):  
Molecular Sieves ◽  
Framework Density

Synthesis and characterizations of two NbO topological gallium phosphites with low framework density

2014 ◽  
Vol 196 ◽  
pp. 321-326 ◽  
Author(s):  
Liangliang Huang ◽  
Yong Fan ◽  
Hongwei Ma ◽  
Caixia Li ◽  
Li Wang
Keyword(s):  
Framework Density

LTN-type zeolite framework as an interpenetrating net of KFI- and SOD-type parts homeomorphic to cuprite, Cu2O

2007 ◽  
Vol 63 (2) ◽  
pp. 229-234 ◽  
Author(s):  
Werner H. Baur ◽  
Reinhard X. Fischer
Keyword(s):  
Pure Form ◽  
The Other ◽  
Zeolite Framework ◽  
Type Zeolite ◽  
Tetrahedral Frameworks ◽  
Diamond Type ◽  
Framework Density

The complex LTN-type zeolite framework is described as consisting of two interpenetrating parts in order to understand the connectivities of their underlying nets. Both parts are homeomorphic to diamond-type tetrahedral frameworks, arranged in principle in the same manner as the two interpenetrating frameworks in cuprite, Cu2O. However, in cuprite the two frameworks are identical, while in the LTN-type framework one is made up of two kinds of truncated octahedra (toc units) and can be described as one half of the sodalite-type framework (SOD). The other consists of large cages, so-called truncated cubo-octahedra (grc units) connected by hexagonal prisms (double six-rings) and corresponds to one half of the KFI-type framework. Neither of the sub-frameworks has so far been observed in any other zeolite topology. The two sub-frameworks of SOD and KFI types in the interpenetrating LTN-type framework are models for very open interrupted frameworks, which possibly could be synthesized separately in a pure form. Their framework density would be 7.6 T atoms per 1000 Å3 if they could be prepared as aluminosilicates.

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