Intracrystalline channels in levynite and some related zeolites

Barrer, R. M.; Kerr, I. S.

doi:10.1039/tf9595501915

Cited by 56 publications

(19 citation statements)

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“…Levyne is typically found as a hydrothermal mineral in vugs of massive volcanic rocks. Merlino et al (1975) solved its structure in the space group R3m, on the basis of the model previously proposed by Barrer and Kerr (1959). Levyne framework is built up from alternating double (D6R) and single 6-membered rings (6mR) of tetrahedra along [0001], following the stacking sequence AABCCABBC of single tetrahedral layers.…”

Section: Chemical and Structural Data Of Levynementioning

confidence: 99%

“…The porous materials with levyne topology (LEV) are represented by the natural zeolite levyne (Brewster 1825;Barrer and Kerr 1959) and several synthetic phases including the aluminophosphate AlPO-35 (Zhu et al 1997), the silicoaluminophosphate SAPO-35 (Lok et al 1984), the metal aluminophosphate Ti,Co,Mg,Mn,and Zn), and the metal silicoaluminophosphate ElAPSO-35 (with El = As, B, and Ge) systems (Flanigen et al 1986). Moreover, boron-substituted levynes were first synthesized by Millini et al (1992).…”

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confidence: 99%

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A new framework topology in the dehydrated form of zeolite levyne

Arletti

Vezzalini

Quartieri

et al. 2013

American Mineralogist

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The thermoelastic behavior and structural evolution of a natural levyne-R3m; a = 13.377(4) Å, c = 22.870(1) Å, V = 3544.1(3) Å 3 ] were studied by both T-resolved synchrotron X-ray powder diffraction (SR-XRPD) between room temperature and 800 °C, and by conventional-source high-temperature single-crystal X-ray diffraction (SC-XRD). Above 230 °C, water loss and reallocation of extraframework cations induce the straining and consequent breaking of T-O-T bridges in the D6R, with resulting migration of tetrahedral cations to new tetrahedral sites. The new tetrahedra share an edge with the previously occupied tetrahedra. This phenomenon gives rise to a new topology, which coexists to about 40%, with the original one. The new framework consists of a sequence of a novel zeolitic cage (described as a 20-hedron formed by fourteen 6mR and six 4mR) and two consecutive cancrinite cages along [0001]. This topology, which is reported in the database of the hypothetical zeolite structures as 166_2_293, belongs to the ABC-6 family and can be described by the following sequence of 6-rings: ABCBCACAB, to be compared with that of levyne AABCCABBC. In the new topology the extraframework cations are distributed over 3 new sites: one at the center of the 6mR ⊥ [0001] shared by the two cancrinite cages, one near the center of the 6mR ⊥ [0001] at the base of the new cage, and a last one in a 6mR window of the new cage. The 8mR bidimensional channel system originally present in levyne is therefore absent in the new topology and hence molecular diffusion is likely to be partially hindered in the dehydrated form. The phase transition is not completely reversible, at least in the short term, as only partial rehydration was demonstrated.

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Section: Chemical and Structural Data Of Levynementioning

confidence: 99%

mentioning

confidence: 99%

A new framework topology in the dehydrated form of zeolite levyne

Arletti

Vezzalini

Quartieri

et al. 2013

American Mineralogist

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“…These authors demonstrated the possibility of completely replacing Al with B in the levyne framework using both FTIR and 11 B MAS NMR analyses. Merlino et al [38] worked out the first crystal structure description of zeolite levyne on the basis of the framework model previously proposed by Barrer and Kerr [39]. It can be built by alternating double and single 6-membered rings of tetrahedra linked together through single 4-rings.…”

Section: Introductionmentioning

confidence: 99%

Template burning effects on stability and boron coordination in boron levyne studied by in situ time resolved synchrotron powder diffraction

Leardini

Martucci²,

Alberti³

et al. 2013

Microporous and Mesoporous Materials

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“…The diffraction experiment revealed that the new material, called SIZ-14, is a CoAlPO with the levyne (LEV) framework topology ( Figure 3). The LEV topology was first prepared as an aluminosilicate zeolite by Barrer and Kerr in 1959, [26] but has subsequently been prepared as a CoAlPO material (called Co-DAF4) using 2-methylcyclohexylamine as the template, [27] as well as in several other compositions. [28,29] Unlike SIZ-13, where the Co 2+ ions are perfectly ordered on one particular site, in SIZ-14 they are disordered through the structure, substituting for aluminum.…”

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Ionothermal Synthesis of Unusual Choline‐Templated Cobalt Aluminophosphates

et al. 2007

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Crystalline porous solids, such as zeolites and metal-organic frameworks, are of interest in a number of areas of modern science, particularly in those associated with catalysis [1] and gas adsorption. [2][3][4] Recently, we developed a new method of preparing aluminophosphate molecular-sieve analogues, [5][6][7][8][9][10] as well as other materials, [11][12][13] based on the use of ionic liquids as both the solvent and the structure-directing agent (or template). This new method, which we call ionothermal synthesis, has some interesting features and potential advantages over the traditional methods of molecular-sieve synthesis. For example, most ionic liquids have vanishingly small vapor pressures, which means that no autogenous pressure is produced on heating and that ionothermal synthesis can take place at ambient pressure. In addition, altering the solvent system from a molecular solvent (e.g. water) to an ionic liquid also changes the chemistry involved. One particularly attractive feature of the method is that the cation of the ionic liquid can also act as the structure-directing agent, around which the final solid material forms during the reaction process. It should be noted that, while ionothermal synthesis takes place in a predominantly ionic environment, it does not preclude the presence of small, reactant quantities of molecular species, such as water. In fact, this property can be beneficial, as it allows precise control over the water content in the reaction, leading to more subtle control over the hydrolysis occurring in the reaction process.Deep-eutectic solvents (DESs) are ionic liquids comprising mixtures of compounds for which there is a depression in the freezing point compared with that of the separate components. One class of such DESs comprises mixtures of organic halide salts, such as choline chloride, with hydrogenbond donors, such as amides, amines, alcohols, and carboxylic acids. [14,15] Choline itself is a very attractive template, as it is cheap and toxicologically very benign. However, in our recent work using a choline chloride-urea DES, [5,8] the urea portion of the liquid acted as the template. Clearly, in a competition between choline and urea-derived ammonium cations, it is the latter that provide the better templating. To remove this competition, it is necessary to replace the urea in the DES with a component that is not likely to act as a template. Herein, we report the use of choline chloride-carboxylic acid DESs in the ionothermal synthesis of cobalt aluminophosphate (CoAlPO) materials. Two of the materials we report are a CoAlPO zeolite analogue with the levyne (LEV) framework topology, and a novel and unusual zeolite-related layered material in which the cobalt atoms are ordered and form terminal Co À Cl bonds. These Co À Cl units are normally not accessible using traditional routes, because they are sensitive to hydrolysis in the presence of excess water. This work illustrates how changing the chemistry of the synthesis system from molecular to ionic can lead to novel typ...

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Intracrystalline channels in levynite and some related zeolites

Cited by 56 publications

References 2 publications

A new framework topology in the dehydrated form of zeolite levyne

A new framework topology in the dehydrated form of zeolite levyne

Template burning effects on stability and boron coordination in boron levyne studied by in situ time resolved synchrotron powder diffraction

Ionothermal Synthesis of Unusual Choline‐Templated Cobalt Aluminophosphates

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