Sodalite Cages Research Articles

Restricting Linker Rotation in Nanocages of ZIF-8 Membranes using Crown Ether "Molecular Locks" for Enhanced Propylene/Propane Separation.

ZIF-8 membranes have long been prized for their exceptional C3H6/C3H8 separation performance. On the other hand, ZIF-8 has structural flexibility, where the external pressure triggers channel expansion, potentially deteriorating the molecular sieving ability. Here, we demonstrate a reliable strategy to fine-tune the flexible pore structure of ZIF-8 by embedding crown ether within a ZIF-8 membrane. Benzo-15-crown-5 (15C5) was selected as the cavity occupant and perfectly confined in the sodalite (SOD) cage of ZIF-8. The 15C5 molecules, which have a size comparable to the nanocage, impose a spatial constraint on linker rotation, enabling the phase transition to a rigid structure in the flexible ZIF-8. The corresponding 15C5@ZIF-8 membranes achieve an ultrahigh C3H6/C3H8 selectivity of 220, outperforming that of most membranes. Unlike their flexible counterparts, the resulting membranes manifest a positive increase in the C3H6/C3H8 separation factor with elevated pressure, securing a record-high C3H6/C3H8 separation factor of 331 under 7 bar. More importantly, extraordinary separation stability was demonstrated with continuous measurement, which is highly desirable for practical applications.

Zeolites as Solid Solvents: Explaining the Chloromethane Hydrolysis over Metal-Exchanged Zeolite Y by DFT Calculations.

We report a theoretical DFT study of the reaction pathways for chloromethane hydrolysis over metal-exchanged zeolites (Li+, Na+, K+, and Mg2+). A cluster of 78 T atoms (T referring to Si or Al atoms), comprising the zeolite Y super cavity coupled with the sodalite cage and three hexagonal prism units (Si(78-x)Al x O129H54; x = 1 or 2), was used in the calculations. The study was carried out using the ONIOM method. The high layer was computed at M062X/6-31++G(d,p), whereas the low layer was computed at the PM6 level of theory. The energy profile was obtained by single-point calculations at the M062X/6-31++G(d,p) for the entire structure. The first step studied was the adsorption of chloromethane on the zeolite, which involves an ion-dipole interaction between the metal cation and the chlorine atom. Then, two mechanistic pathways were investigated: one via formation of an adsorbed methoxide and the other involving a direct, one-step, nucleophilic attack of the water molecule to the adsorbed chloromethane. In all systems studied, the direct mechanism showed a lower energy of activation than the route involving the methoxide intermediate. The same behavior was also observed for chloromethane methanolysis to afford dimethyl ether on the metal-exchanged zeolites. The theoretical results are in agreement with the experiments of chloromethane hydrolysis over metal-exchanged zeolite Y, explaining the formation of dimethyl ether upon chloromethane methanolysis on zeolites of low or no acidity. The transition state for the direct route resembles a SN2 process assisted by the surface, reinforcing the concept of zeolites as solid solvents, providing a polar nanoenvironment that favors and assists the formation of ionic transition states and intermediates.

Coupling Different Periodic Building Units for Intergrowth Zeolites.

Multiple-phase disordered zeolites, i.e., intergrowth zeolites, are important industrial catalysts, like single-phase ordered zeolites, but little is known about their rational synthesis and phase competition, mainly due to current poor understanding of the zeolite crystallization mechanism. Here, we theoretically demonstrated that sodalite and cancrinite cage layers, the periodic building units (PerBUs) of FAU/EMT and SBT/SBS structures, respectively, could be nondefectively connected to each other across double rings of 6 tetrahedral atoms when inverted and mirrored. We then synthesized an unprecedented family of FAU/SBT/SBS intergrowths with controllable FAU portions (named as the PST-34 family of intergrowth zeolites) using a multiple inorganic cation approach, providing clear experimental evidence for the layer-by-layer crystal growth mechanism of zeolites. This study shows that control of interactive cooperation extent between different inorganic structure-directing agents in the presence of an unselective organic structure-directing agent may enable repeated stacking of different but structurally related PerBUs in intergrowth zeolite synthesis.

Investigation on the active site location, structure and ultra-deep desulfurization performance of CuY zeolite

Y zeolites modified with Cu are promising sorbents for adsorption desulfurization due to their cost-effectiveness. Only the supercage, which is larger than thiophene molecule, is the potential location of active sites for thiophene removal. However, numerous copper species cannot serve as effective active sites due to their inability to be located in the supercages. Based on this consideration, two strategies to regulate Cu location in Y zeolite to address the aforementioned challenges were explored. One is to adjust the molecular size of copper-ammonia ligands through pH value of cuprammonia solution, and the other is to prevent the migration of copper to small cages by heat treatment. The results showed that these two strategies could effectively regulate the location of copper active sites in Y zeolite. During heat treatment, Cu could transfer into supercages from sodalite cages at 350 °C. More effective copper would be targeted to be located in the supercages in the process of adjusting pH. For the best Cu10.74Y350 sorbent, which was prepared at 350 °C under pH of 10.74, the Cu content in the supercages was the highest (25 %), and thus it has an excellent desulfurization efficiency of 82.3 %.

Disclosing the enhanced NH3-SCR-DeNOx activity of Cu-containing zeolite Y prepared with 15-Crown-5

The phase-pure zeolite Y with a high n(Si)/n(Al) ratio is obtained with the cyclic polyether 15-Crown-5 as a structure-directing agent. In copper-exchanged for this new zeolite outperformed other Cu-containing zeolite Y counterparts during NH3-SCR-DeNOx with more than 80% NO conversion and more than 85% N2 selectivity in the temperature range of 100 – 500 °C. The presence of Cu+ species located in sodalite cages with elevated redox cyclability guarantees high activity and N2 selectivity up to 400 °C over CuY-Crown. Above 400 °C, a high activity and N2 selectivity are related to the accessibility of chemisorbed NH3 to the gaseous NO during the NH3-SCR-DeNOx.

Single crystal polarization-orientation Raman spectroscopy of zeolite LTA with confined S3− anions - High dielectric constant nanoporous material

We apply polarization-orientation Raman spectroscopy, as an alternative to X-ray diffraction, to LTA single crystals containing S3− in sodalite cages additionally to S8 rings in large cavities. The sample was obtained via sulfur vapor adsorption at ∼550 °C (LTA-S-550). We show that S3− is located in the (110) plane with its 2-fold axis along the LTA 4-fold axis. The anion position suggests strong interaction of its terminal atoms with Na+ localized in LTA 6-membered rings. The anions display optical absorption band at ∼590 nm (2.1 eV) and resonant Raman enhancement. We observe a record-high S3− bond-bending mode frequency ∼274 cm−1 due to a strong bond-angle contraction. This leads to the Fermi resonance of its overtone with the symmetric bond-stretching mode in the frequency range of 544–552 cm−1. An anomalous Raman downshift of the S3− bond-stretching modes with a decrease of temperature is observed and attributed to partial compressive stress relaxation. Luminescence band at ∼845 nm is observed suggesting considering LTA-S-550 as an interesting light-emitting material. We discuss a role of S3− in the high dielectric constant up to ∼160 and a possible contribution of the anion to the ion-exchange selectivity to Sr2+/Cs+ enhancements of LTA with sulfur.

Identification of ortho-positronium annihilation sites in Y zeolites by positron lifetime measurements in different environments

The annihilation sites of ortho-positronium formed by positrons incident on Y zeolites with different Si/Al ratios are investigated by positron annihilation lifetime spectroscopy in different environments. Comparison of the measured ortho-positronium lifetimes by exposure of the zeolites to argon, nitrogen, water or vacuum enables us to determine the annihilation process and the specific annihilation site within the zeolite samples. The third lifetime component is ascribed to ortho-positronium pick-off annihilation in or around the apertures of the sodalite cage and in the connecting channels, and is reduced in water because of the physisorbed molecules that hinder the ortho-positronium mobility. The longest fourth lifetime component is attributed to ortho-positronium self-annihilation in the interparticle gaps, but is significantly suppressed in the presence of polar molecules, which suggests a contribution from ortho-positronium pick-off annihilation in the supercage.

Electrochemical recognition for D and L-Cysteine using an achiral monodisperse Cu catalyst restricted by nanosized SOD zeolite cage domain

The recognition for D and L-Cysteine (Cys) broke through to 0.008 pM by the electrochemistry catalyst Cu Sodalite (SOD) zeolite without enzymes or noble metals. The SOD structured zeolite supplied nanosized SOD cages which are highly consistent with the spatial configuration of cysteine. And the applied electric field magnified the subtle differences in binding energy between D and L-Cys through the highly active Cu catalyst. Under electrochemical aspects, these results manifest themselves as distinguishable current peaks and potential intervals. Unlike the related literature, the sharp and sensitive current peak created by Cu catalyst is set as baseline with the absence of cysteine. With the continually increasing concentration of D or L-Cys, L-Cys shifts to the positive potential, and D-Cys shifts to the negative potential. The result reveals good reproducibility and high specificity that the catalyst is insensitive to other amino acids. The novel catalyst is featured by low cost and high stability, besides higher activity than enzymes.

Examining the impact of different anions in Cu precursors on sulfur adsorption through zeolites with Cu ion-exchange

The majority of hydrogen is generated by converting hydrocarbons, with natural gas reforming accounting for over 50% of the total hydrogen production. However, the utilization of natural gas in generating hydrogen causes catalyst deactivation during the reforming process because of presence of sulfur compounds as odorants in commercial natural gas. Therefore, the removal of sulfur compounds from natural gas should be prioritized before its application in hydrogen production. Adsorption using Cu-ion-exchanged zeolites is an effective method for removing sulfur compounds from natural gas. In this study, the adsorptive desulfurization performance of tetrahydrothiophene (THT) was evaluated using pristine NaY and Cu-ion-exchanged Y zeolites. In particular, the effects of anions in the Cu compounds used for the ion exchange of zeolites were investigated using three Cu precursors (Cu(NO3)2, Cu(Ac)2, and CuSO4). Among the tested zeolite adsorbents, the NaY zeolite ion-exchanged with Cu(Ac)2 exhibited the highest adsorption uptake, whereas the NaY zeolite ion-exchanged with CuSO4 demonstrated the lowest adsorption uptake for THT. The analytical results indicated that following the exchange of Cu ions, a rearrangement of Si and Al was observed within the zeolite framework, resulting in the Si site distribution. The rearrangement of the framework and distribution of Si sites was influenced by the anions present in the Cu precursors. In addition, it was observed that Cu2+ primarily occupied two locations within the zeolite, namely the supercage and the sodalite cage, and the distribution of Cu2+ between these two sites varied amongst the Cu-ion-exchanged zeolites. This discrepancy was linked to the adsorption uptake for THT.

Loading single lanthanide ion into aluminum molecular rings: water-stable sodalite cage for removal of nuclear-industry anions

Loading single lanthanide ion into aluminum molecular rings: water-stable sodalite cage for removal of nuclear-industry anions

Anti-Aging and Lightening Effects of Au-Decorated Zeolite-Based Biocompatible Nanocomposites in Epidermal Delivery Systems.

The main challenges in developing zeolites as cosmetic drug delivery systems are their cytotoxicities and the formation of drug-loading pore structures. In this study, Au-decorated zeolite nanocomposites were synthesized as an epidermal delivery system. Thus, 50 nm-sized Au nanoparticles were successfully deposited on zeolite 13X (super cage (α) and sodalite (β) cage structures) using the Turkevich method. Various cosmetic drugs, such as niacinamide, sulforaphane, and adenosine, were loaded under in vitro and in vivo observations. The Au-decorated zeolite nanocomposites exhibited effective cosmetic drug-loading efficiencies of 3.5 to 22.5 wt% under various conditions. For in vitro cytotoxic observations, B16F10 cells were treated with various cosmetic drugs. Niacinamide, sulforaphane, and adenosine-loaded Au-decorated zeolite nanocomposites exhibited clear cell viability of over 80%. Wrinkle improvement and a reduction in melanin content on the skin surface were observed in vivo. The adenosine delivery system exhibited an enhanced wrinkle improvement of 203% compared to 0.04 wt% of the pure adenosine system. The niacinamide- and sulforaphane-loaded Au-decorated zeolite nanocomposites decreased the skin surface melanin content by 123% and 222%, respectively, compared to 2 and 0.01 wt% of pure niacinamide and sulforaphane systems, respectively. As a result, Au-decorated zeolite nanocomposites show great potential as cosmetic drug epidermal delivery systems for both anti-aging and lightening effects.

Vapour phase Guerbet condensation of ethanol to 1-butanol on CsX zeolite

Nowadays, the conversion of ethanol into valuable chemical products is getting wider application.One of such promising processes is Guerbet condensation of alcohols, which permits the obtaining of 1-butanol from renewable raw materials that are alternatives to petroleum ones.Oxide systems combining acid and basic sites in their composition are promising catalysts for such a transformation.In this study, the efficiency of the magnesium-aluminum oxide and zirconium-oxide catalysts was compared to the activity of the cesium form of X-type zeolite produced by hydrothermal ion exchange in the condensation of ethanol to 1-butanol. The integrity of the zeolite structure was confirmed by using the XRD and XRF analysis, as well as by the IR spectroscopy.The depth of exchange of native sodium for cesium was 82%. It was also found that cesium cations are localized only in ion-exchange positions of faujasite, in places SIII (supercages) and SI` (sodalite cages). CsX zeolite acid to basic sites ratio was found tobe close to optimal for this reaction. Cesium-containing zeolite at 300 °C showsethanol 35-55 % conversion and 20-25 % selectivity for 1-butanol, which is higher than the same characteristics for zirconium samples, but slightly inferior to magnesium-aluminum oxide catalysts. The obtained results indicate the promising use of zeolites of a similar nature in the process of condensation of ethanol to 1-butanol.

Zeolites catalyze the halogen exchange reaction of alkyl halides

Simple zeolites (NaY, NaX,…) catalyze the halogen switch between two different alkyl halides under either batch or flow reaction conditions. Sodalite cages are proposed to trigger the transformation.

Optical study of oriented double-Se8-ring clusters and luminescent Se2− anions in LTA at extremely high selenium loading density

Recently, LTA-Se(1–8) samples with 1–8 Se atoms per cavity (simplified unit cell, large cavity + sodalite cage) obtained via adsorption at the temperature of ∼450 °C were reported. It was shown that single Se8 or single Se12 ring are formed in the large LTA cavities, Se8/Se12 ring concentration ratio decreasing with an increase in the Se loading density. Contrary, in the present work, using Se vapour adsorption at ∼550 °C, we succeeded in encapsulation of ∼17 Se atoms per cavity (LTA-Se(17)) with a significant increase in the Se8/Se12 concentration ratio manifesting double Se8-ring cluster formation in the most of the LTA large cavities, which is a step towards cluster crystal fabrication. According to our polarization/orientation Raman spectroscopic study of LTA-Se(17) single crystals, the orientations of the Se8 and Se12 appeared to be similar to those in previously investigated LTA-Se(1–8). Importantly, luminescent Se2− anions, oriented along the LTA 4-fold axes and located in the sodalite cages, are detected via Raman polarization/orientation dependencies of LTA-Se(17). Bright Se2− light emission with a maximum at ∼1.56 eV and vibronic structure is observed in the 1.3–1.8 eV spectral range. We show that the anions experience a compression in LTA which is slightly relaxing with a decrease in temperature producing an anomalous Raman band downshift. The compression of Se2− in LTA is weaker/stronger than that in sodalite/cancrinite, luminescence band photon energy depending on its strength. High concentration of regularly arranged Se2− in LTA suggests considering LTA-Se(17) as an important novel light-emitting material.

Slyudyankaite, Na28Ca4(Si24Al24O96)(SO4)6(S6)1/3(CO2)·2H2O, a new sodalite-group mineral from the Malo-Bystrinskoe lazurite deposit, Baikal Lake area, Russia

Abstract The new sodalite-group mineral species slyudyankaite, ideally Na28Ca4(Si24Al24O96) (SO4)6(S6)1/3(CO2)·2H2O, was discovered in altered lazurite-bearing metasomatic rock at the Malo-Bystrinskoe gem lazurite deposit, Baikal Lake area, eastern Siberia, Russia. The associated minerals are diopside, calcite, fluorapatite, phlogopite, lazurite, and pyrite. Slyudyankaite forms green to pale blue isolated anhedral equant grains up to 0.5 cm across and their aggregates. The streak is white and the luster is vitreous. Slyudyankaite is brittle, with a Mohs hardness of 5½. Cleavage and parting are not observed. Density measured by flotation in heavy liquids is equal to 2.46(2) g·cm–3. Density, calculated using the empirical formula and unit-cell volume refined from single-crystal XRD data, is 2.454 g·cm–3. Slyudyankaite was characterized using the IR, Raman, ESR, near infrared (NIR), visible (Vis), and ultraviolet (UV) absorption, XPS and photoluminescence spectroscopy methods. The chemical composition is (wt%, electron microprobe, H2O and CO2 determined by selective sorption of ignition products, CO2 confirmed by quantitative IR spectroscopic method, sulfate sulfur determined by wet chemical analysis): Na2O 19.28, K2O 0.12, CaO 5.13, Al2O3 27.01, SiO2 33.25, SO3 10.94, S 1.75, Cl 0.10, CO2 1.42, H2O 0.90, –O≡(Cl,HS) –0.03, total 99.87. The empirical formula is Na27.57Ca4.05 K0.11(Si24.52Al23.48O96)(SO4)6.06S2.420Cl0.12(CO2)1.43·2.21H2O where S2.420 is the total sulfide sulfur, mainly occurring as neutral S6 and subordinate S4 molecules, according to the structural data. XPS spectroscopy confirms the presence of sulfide sulfur in neutral form. The crystal structure was determined using single-crystal X-ray diffraction data and refined to R = 0.0428. Slyudyankaite is triclinic, space group P1, a = 9.0523(4) Å, b = 12.8806(6) Å, c = 25.681(1) Å, α = 89.988(2)°, β = 90.052(1)°, γ = 90.221(1)°, V = 2994.4(2) Å3, Z = 1. Slyudyankaite contains two kinds of sodalite cages occurring in the structure in a ratio of 3:1. Cages of the first kind are completely occupied by SO42− anions and extra-framework cations, whereas cages of the second type contain only neutral molecules (S6, CO2, H2O, and minor S4). The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 6.45 (11) (004, 112, 020), 3.716 (100) (204, 220, 116, 132), 2.878 (12) (136, 028, 044), 2.625 (23) (208, 240), 2.431 (6) (209), 2.275 (6) (048), 2.143 (12) (0.0.12, 336), 1.784 (7) (444, 1.1.14, 356, 172).

Positive regulation of osteogenesis on titanium surface by modification of nanosized Ca2+-exchanged EMT zeolites

Cell–titanium interactions are of great importance for the clinical success of dental implants, while traditional titanium surfaces are affected by inertness and have poor osteogenicity. In this study, for the purpose of enhanced osteoconductive and osteoinductive properties, titanium (Ti) substrates modified with calcium ion-exchanged nanosized EMT zeolites (Ca 2+ -EMT) were developed and the effect on cell viability, proliferation, osteo-differentiation, and mineralization of MC3T3-E1 cells was systematically and quantitatively examined. For this purpose, firstly, we synthesized and characterized the nanosized EMT zeolites fabricated using a Na 2 O-Al 2 O 3 -SiO 2 -H 2 O precursor system without the organic template. Then calcium ion was exchanged at different levels within nanosized EMT zeolites (Ca 2+ -EMT) and spin-coated onto the Ti surfaces (EMT@Ti, EMT-3@Ti, EMT-6@Ti, EMT-12@Ti, and EMT-18@Ti). Comprehensive characterization was conducted to study the physicochemical properties of as-synthesized specimens. To determine the osteogenic effects of Ti substrates functionalized with Ca 2+ -EMT, we investigated the biological behavior of MC3T3-E1 cells cultured on Ca 2+ -EMT surfaces in vitro with pure Ti and EMT@Ti serving as negative control and experimental control groups, respectively. The results showed that the Ca 2+ was successfully encapsulated in the sodalite cage of the EMT zeolite, while the overall microstructure was not compromised. Enhanced hydrophilicity and roughness were achieved by spin-coating the Ca 2+ -EMT to the surface of Ti specimens. In vitro biological experiments suggested that all Ca 2+ -EMT coated samples possess favorable osteogenicity, as evidenced by the in vitro osteogenic-related biological cell performance. Notably, a dose-dependent manner was detected, where the EMT-12@Ti group exhibited the greatest bone regenerative potential. Meanwhile, the mechanisms of promoting osteoblast differentiation by Ca 2+ regulation were discussed in depth.

Step-By-Step Modeling and Demetallation Experimental Study on the Porous Structure in Zeolites

The organization of microporous space in zeolites is discussed. A new step-by-step model is proposed that explains the principles of organizing the hierarchy of microporous space at the stage of assembling zeolites from elements of minimal size: a primary building unit, secondary building units, tertiary building units or building polyhedra, a sodalite cage, and a supercage. To illustrate the stepwise hierarchical porous structure of nanomaterials, the following zeolites with small and large micropores have been selected as the model objects: sodalite (SOD, the maximum diameter of a sphere that can enter the pores is 0.3 nm) and zeolites of type A (LTA, the maximum diameter of a sphere that can enter the pores is 0.41 nm), type X, Y (FAU, the maximum diameter of a sphere that can enter the pores is 0.75 nm), and type BETA (the maximum diameter of a sphere that can enter the pores is 0.67 nm). Two-dimensional and three-dimensional modeling in 3Ds Max software was used. We believe that such an approach will be useful for developing ways to create complex zeolite compositions for specific applications, such as catalysis, where the geometry of the pores determines the size of the molecules entering the voids and computer modeling can play an important predictive role. This work takes a look at specific aspects of using the heat desorption method to study mesoporous materials with a BETA zeolite as an example and presents the results of experimental research into the characteristics of the porous structure of hierarchically structured zeolite materials (specific surface area 180-380 m2/g, external surface area 120-200 m2/g, micropore volume 0.001-0.1 mL/g).

Computer simulation of the early stages of self-assembly and thermal decomposition of ZIF-8.

We employ all-atom well-tempered metadynamics simulations to study the mechanistic details of both the early stages of nucleation and crystal decomposition for the benchmark metal-organic framework (MOF) ZIF-8. To do so, we developed and validated a force field that reliably models the modes of coordination bonds via a Morse potential functional form and employs cationic and anionic dummy atoms to capture coordination symmetry. We also explored a set of physically relevant collective variables and carefully selected an appropriate subset for our problem at hand. After a rapid increase of the Zn-N connectivity, we observe the evaporation of small clusters in favor of a few large clusters, which leads to the formation of an amorphous highly connected aggregate. Zn(MIm)4 2- and Zn(MIm)3 - complexes are observed with lifetimes in the order of a few picoseconds, while larger structures, such as four-, five-, and six-membered rings, have substantially longer lifetimes of a few nanoseconds. The free ligands act as "templating agents" for the formation of sodalite cages. ZIF-8 crystal decomposition results in the formation of a vitreous phase. Our findings contribute to a fundamental understanding of MOF's synthesis that paves the way to controlling synthesis products. Furthermore, our developed force field and methodology can be applied to model solution processes that require coordination bond reactivity for other ZIFs besides ZIF-8.

Ammonia and water in zeolites: Effect of aluminum distribution on the heat of adsorption

We have investigated MOR, MFI, and FAU zeolites to acquire a better understanding of the aluminum T-position effect on the heat of adsorption of ammonia and water at a microscopic level. We performed Monte Carlo simulations using RASPA code to obtain the heats of adsorption of water and ammonia in zeolites with one Al-substitution. We show that the values of heats of adsorption of water and ammonia on MOR do not vary much for the T1, T2, and T4 positions being around 41 kJ/mol and 31 kJ/mol respectively. However, the T3 position shows a noticeable variation for both molecules. When aluminum is in the T3 position ammonia with zeolite have the strongest interaction, inversely water and zeolite have the weakest interaction compared to the other T-sites. MFI-type zeolite is also sensitive in terms of Al-position, and more significantly in the case of ammonia adsorption. In MFI all favorable/unfavorable for water T-sites of MFI were also favorable/unfavorable for ammonia respectively. The heats of adsorption of ammonia and water as a function of the position of aluminum substitution in FAU (super-cage, sodalite cage, or hexagonal prism) have almost constant values with 40.5 kJ/mol for water and 28.3 kJ/mol for ammonia. Thus, FAU zeolite has been shown to be insensitive with regard to T-positions which are crystallographically identical in a highly symmetric spherical cage topology.

Infrared spectroscopy as a tool for the analysis of framework topology and extra-framework components in microporous cancrinite- and sodalite-related aluminosilicates

The identification of the framework type in multilayer cancrinite- and sodalite-group minerals and synthetic compounds is predominantly based on the unit-cell dimensions determined from powder or single-crystal X-ray diffraction data, by analogy with previously characterized samples with known crystal structures. However, topological type of the framework cannot be reliably determined in this way because of the different possible ABC staking sequences and different sets of cages with the same number of layers in the repeat unit. To solve this problem, additional criteria are required. The use of infrared (IR) spectroscopy makes it possible to distinguish topologically different types with the same unit-cell parameters. The most important diagnostic range in the IR spectrum (the “finger-print region”, from 510 to 760 cm−1) corresponds to the O–T–O bending vibrations (T = Si, Al). The spectral bands at 705 ± 8, 528 ± 5, 547 ± 4, and 555 ± 3 cm−1 indicate the presence of the sodalite, Losod, liottite, and giuseppettite cages, respectively. The band at 528 ± 5 cm−1 shifts towards ∼518 cm−1 in the case when Losod cage hosts carbonate group. The IR spectrum in the “finger-print region” can be also used to identify a mineral species belonging to two-layer or three-layer minerals with different extra-framework compositions. The wavenumber of the antisymmetric stretching mode of the 12CO2 molecule, which is a common admixed extra-framework constituent in minerals belonging to the cancrinite and sodalite groups, depends on the kind of the host cage or channel: 2340–2343 cm−1 for the sodalite cage, 2338 cm−1 for the Losod cage, and 2351–2353 cm−1 for the liottite cage and wide channel in the cancrinite-type framework.