Cronstedt’s zeolite

In this work the framework type was assigned to 1370 zeolite crystals included in the Inorganic Crystal Structure Database. Ca7.19Na1.13(Si32.72Al15.28O96) (H2O)16 100553 ANA Calcium Tecto-dialumotetrasilicate Hydrate (0.96/1/1.82) Ca0.959(Al2Si4O12) (H2O)1.82 98197 ANA Calcium Sodium Tecto-dialumotetrasilicate Hydrate (0.93/0.06/1/2) Ca0.928Na0.06(Al2Si4O12) (H2O)2 98198 ANA Calcium Sodium Tecto-dialumotetrasilicate Hydrate (0.92/0.08/1/2) Ca0.922Na0.08(Al2Si4O12) (H2O)2 98199 ANA Calcium Tecto-dialumotetrasilicate Hydrate (0.95/1/0.62) Ca0.946(Al2Si4O12) (H2O)0.62 98200 ANA Calcium Tecto-dialumotetrasilicate (0.96/1) Ca0.958(Al2Si4O12) 98201 ANA Caesium Sodium Tecto-gallosilicate Cs6.81Na7.10(Ga13.92Si34.09O96) 69666 ANA Caesium Sodium Tecto-gallosilicate Hydrate Cs5.96Na7.92(Ga13.87Si34.13O96) (H2O)10.05 69663 ANA Caesium Sodium Tecto-gallosilicate Cs5.96Na7.92(Ga13.87Si34.13O96) 69664 ANA Caesium Sodium Tecto-gallosilicate Hydrate Cs6.81Na7.10(Ga13.92Si34.09O96) (H2O)9.2 69665 ANA Caesium Tecto-alumosilicate-Ht Cs(AlSiO4) 80612 ANA Ammonium Aquazinc Tris(zincoarsenate(V)) (NH4)(Zn (H2O))(ZnAsO4)3 93116 ANA Ammonium Zinc Boron Phosphorus(V) Oxide (16/16/8/24/96) (Ca1.97Al3.8Si8.2O24)(CO)1.83 100105 CHA Silver Alumosilicate Ag3.38Al3.7Si8.3O24 201589 CHA Sodium Calcium Tecto-alumosilicate Hydrate Na0.15Ca0.9(Al1.95Si4.05O12) (H2O)6 29070 CHA Calcium Tecto-dialumotetrasilicate Trichloride Ca((Al2Si4)O12)(Cl3) 34173 CHA Calcium Tecto-dialumotetrasilicate Trichloride Ca((Al2Si4)O12)(Cl3) 34174

Journal of the American Chemical Society, 1977

The structure of vacuum-dehydrated Cs7K~A112Si12048, zeolite A with all Na+ ions replaced by Cs+ and K+ as indicated, has been determined by single-crystal x-ray diffraction techniques in the cubic space group Pm3m ( a = 12.266 (2) A).

2012

The crystal structure, including H positions, of the monoclinic zeolite mineral parthéite (space group C2/c) of framework type-PAR from Denezhkin Kamen (Urals, Russia) was refined, from single-crystal X-ray data to R 1 = 3.46%. In addition, in situ single-crystal X-ray data have been measured in steps of 25 °C up to 375 °C to analyze dehydration behavior. In situ Raman spectra of the natural (room temperature) and partly dehydrated varieties of parthéite have been recorded at 100, 150, and 275 °C. The structure of parthéite, Ca 2 Al 4 Si 4 O 15 (OH) 2 ⋅4H 2 O, is characterized by a tetrahedral framework interrupted by an OH-group forming the apex of one AlO 4 tetrahedron. In addition, this OH-group coordinates extraframework Ca together with two H 2 O molecules and four framework oxygen sites. The structure has four strong hydrogen bonds with H•••O interactions below 2 Å. The fifth hydrogen associated with a H 2 O molecule, exhibits two potential acceptors of weak hydrogen bonds with H•••O distances of ca. 2.5 Å. This softly bound H 2 O molecule is released at 150 °C without severe impact on framework distortions but with decrease of Ca coordination from seven to six. Concurrently with loss of the second H 2 O molecule at 250 °C, the structure further compacts and becomes severely distorted. The space group C2/c and the tetrahedral connectivity are preserved but β changes from 91 to 79° and the volume drops from 1730 to 1600 Å 3. Ca is still six-coordinated by five framework O atoms and OH.

The Journal of Physical Chemistry B, 1997

The crystal structures of vacuum-dehydrated, fully Mg 2+ -, Ca 2+ -, and Ba 2+ -exchanged zeolite X (Mg 46 (H 2 O) 4 -X, Ca 46 -X, and Ba 46 -X; X ) Si 100 Al 92 O 384 ) have been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd3 h at 21°C (a ) 24.671(5), 25.024(4), and 25.266(5) Å, respectively). Their structures were refined to the final error indices R w ) 0.046 with 439 reflections, 0.037 with 434 reflections, and 0.049 with 485 reflections, respectively, for which I > 3σ(I). In Mg 46 (H 2 O) 4 -X, Mg 2+ ions are found at four crystallographic sites: 14 per unit cell are located at site I at the center of the hexagonal prism (Mg-O ) 2.262(6) Å), only four are at site I′ in the sodalite cavity near the hexagonal prism (Mg-O ) 2.221(5) Å), four, each coordinated to an H 2 O molecule, are located at site II′ in the sodalite cavity (Mg-O ) 2.223(12) Å), and the remaining 24 are at site II near single six-oxygen rings in the supercage (Mg-O ) 2.184(5) Å). In Ca 46 -X, Ca 2+ ions are found at only two sites: 16 per unit cell fill site I (Ca-O ) 2.429(8) Å) and the remaining 30 at site II (Ca-O ) 2.276(5) Å). In Ba 46 -X, Ba 2+ ions are again found at three sites: 14.5 per unit cell are at site I (Ba-O ) 2.778(11) Å), only 1.5 are at site I′ (Ba-O ) 2.44(3) Å), and 30 are at site II (Ba-O ) 2.667(8) Å).

Acta Crystallographica Section B Structural Science, 2000

An accurate knowledge of zeolite structure is required for understanding their selective sorption capacities and their catalytic properties. In particular, the positions of the exchangeable cations and their interactions with the framework are essential. The present study deals with the accurate crystal structure determination of a fully exchanged and fully dehydrated CaA zeolite (Ca48Al96Si96O384, Fm\bar 3c, a = 24.47 Å) using single-crystal high-resolution synchrotron X-ray diffraction [(sin θ/λ)max = 1.4 Å−1]. It is shown that cation exchange severely distorts the skeleton, especially around the O2 atom. The high-resolution synchrotron data reveal that this latter O atom is disordered and lies out of the mirror plane it occupies in other A-type zeolites. This feature is related to that observed for Ca2+ cations.

American Mineralogist, 2014

The results of a combined electron probe microanalysis, single crystal X-ray diffraction and Fourier transform infrared study of a crystal of armstrongite from Khan Bogdo deposit (Gobi, Mongolia) are reported. Major element analysis provided (wt%): CaO 9.2(1), ZrO 2 20.9(2) and SiO 2 62.5(2). Significant concentrations of REE (0.45 wt%) were also detected. From singlecrystal structural refinement, armstrongite resulted monoclinic (space group C2/m, a = 14.0178(7) Å, b = 14.1289(6) Å, c = 7.8366(3) Å, β = 109.436(3)°, V = 1463.6(1) Å 3 , Z = 4) and twinned with two individuals rotated around a twin 2-fold axis parallel to [100]. The analyzed crystal was refined up to R = 3.3% (R w = 2.9%). The structural refinement showed that the investigated armstrongite has only two water groups per formula unit consistent with the infrared analysis. Indeed, the occurrence in the infrared spectrum of the armstrongite (here reported for the first time) of two bending vibration bands at about 1640 and 1610 cm-1 testifies to the presence of two water groups environments. The results of this integrated approach converged to the following empirical formula (based on Si = 6 atoms per formula unit): (Ca 0.96 Ce 0.01 Yb 0.01)Zr 0.99 Si 6 O 14.97 • 2.02H 2 O. Finally, the studied mineral shows a framework density (FD = 21.86) lying in the range of zeolites and microporous heterosilicates with tetrahedral-octahedral frameworks. The determined crystal chemical features are relevant for the possible employment of this mineral or of its synthetic analogues for technological applications.

Studies in Surface Science and Catalysis, 2007

In this report we discuss the synthesis and physicochemical characterizations of three zeolites with unsolved crystal structures: SSZ-57, SSZ-74, and IM-5. The diffraction data of SSZ-57 are similar to, but distinct from, the data for ZSM-5, ZSM-11, or ZSM-5/11 intergrowths. The powder diffraction data of SSZ-74 can be indexed in a unit cell with dimensions similar to those found in ZSM-5 and ZSM-11. The organic structure directing agents (SDA) used to prepare SSZ-74 and IM-5 are similar to SDA molecules that often yield multidimensional 10-ring zeolites. The micropore volumes, adsorption uptake rates of 2,2dimethylbutane, and the constraint index tests of these three unknown materials are also consistent with those expected for multidimensional 10-ring zeolites.

Single-crystal X-ray investigations showed that tschortnerite is a zeolite; the structure contains interconnection of double six-rings, double eight-rings, sodalite cages, truncated cubo-octahedra, and previously unknown 96-mem- bered cages (tschortnerite cage). A new structural unit is the (Cu 12(OH)24)Ca8O24(H2O)8 cluster centered within the truncated cubo-octahedron. The cluster is formed by a rhomb- dodecahedron-like arrangement of corner connected CuO4 squares, the eight CaO7 poly- hedra are branched. The sodalite cage houses Ca4(OH)4O12 clusters of edge-sharing CaO6 octahedra. Half-occupied (K,Ca,Sr,Ba) positions were located in the basal and top face of the double eight-rings, i.e., the border to the tschortnerite cage. Within the large tschort- nerite cage only H2O molecules were localized.

The Canadian Mineralogist, 2004

Calcium catapleiite, CaZrSi 3 O 9 •2H 2 O, the calcium-dominant analogue of catapleiite, Na 2 ZrSi 3 O 9 •2H 2 O, firstly described as hexagonal, space group P6 3 /mmc, with a 7.32, c 10.15 Å, is actually orthorhombic, space group Pbnn, a 7.378(1), b 12.779(1), c 10.096(1) Å, V 951.89 Å 3 and Z = 4. The crystals display three-fold twinning ("Drilling") about the c axis, with the three individuals rotated 120° one from the other. The crystal structure of calcium catapleiite from the type locality, the Burpala massif, northern Baikal Region, Siberia, Russia, has been determined by direct methods from single-crystal X-ray-diffraction data and refined to a final R = 0.0528 (wR 2 = 0.1604) for 2167 reflections with F o > 6(F o ). It is characterized by a mixed framework of regular [ZrO 6 ] octahedra and three-membered silicate rings [Si 3 O 9 ], very similar to the framework of catapleiite. The H 2 O molecules also are similarly placed in the two minerals. The Ca 2+ cations in calcium catapleiite are distributed over two distinct sites, with 0.8 and 0.2 occupancies, which contrasts with the fully disordered distribution of the Na + cations in catapleiite.