Over the past decade, many Sb-based organohalides have been synthesized and analyzed due to their intriguing optical and electronic properties. They form low-dimensional (0D, 1D, and 2D) metal halide frameworks due to the 3+ oxidation state of antimony (Sb3+). The low-dimensional perovskite derivatives commonly have good moisture stability which makes them attractive for replacing the lead-containing halide perovskites. We focus on the A3Sb2X9 compositions since the band gap tunability of the compounds is noteworthy. Cs3Sb2I9 is known to form both 0D and 2D octahedral networks at room temperature. The A-site in A3Sb2X9 is crucial in determining the configuration of the metal halide framework. Within the hybrid A3Sb2X9 systems, the azetidinium cation (Az+, [(CH2)3NH2]+) has rarely been studied as a potential A-site candidate. We confirm that the polycrystalline powders and thin films of (Az)3Sb2I9 exhibit a 0D dimer structure, while (Az)3Sb2Br9 and (Az)3Sb2Cl9 adopt a 2D corrugated layer structure at the molecular level. (Az)3Sb2I9 and (Az)3Sb2Cl9 exhibit phase transitions at low temperatures, as shown by differential scanning calorimetry. Thin films grow with a strongly preferred (00l) orientation perpendicular to glass substrates. The Tauc plot analysis from diffuse reflectance spectra exhibits a band edge at 2.11 eV in (Az)3Sb2I9, at 2.63 eV in (Az)3Sb2Br9, and at 3.26 eV in (Az)3Sb2Cl9. A weak excitonic band is identified in the absorption spectrum of the (Az)3Sb2I9 thin film. Interestingly, there is a severe morphological difference in the thin films, depending on the solvent used, resulting in a band edge shift. The temperature dependence of the (Az)3Sb2I9 thin-film XRD data indicates the existence of an intermediate phase.

Eight calcined ZSM-48-type materials, selected for their diversity, have been examined crystallographically to determine whether they can be described in the same way as can RUB-58 (framework type RFE), with blocks of a single framework structure separated by shear planes. In RUB-58, only one framework structure is present, but it can adopt either of two origins related by exactly one-half of a unit cell along the channel direction. The framework blocks can connect to one another seamlessly along well-defined shear planes. The eight materials were synthesized in two different laboratories using seven different organic structure-directing agents under a variety of conditions. At first glance, their diffraction patterns are similar, but the reflection intensities and peak shapes differ. Analysis of the eight structures revealed that indeed all can be refined using the RUB-58 structural model. Only the amount of the shifted framework and the peak widths (arising primarily from different crystallite sizes) differ. Comparison of the diffraction patterns generated from several series of disorder models (using two polymorphs) with the measured ones shows that those from the RUB-58 single-framework model yield the best matches. Geometric optimization, simulations of different shear planes and the morphology suggest that the shear plane along (110) is the most likely one. These results indicate that the disorder (involving different polymorphs), which has been assumed for ZSM-48-type materials for nearly 40 years, probably does not exist.

Bi-based halide perovskites have been considered as alternatives to Pb-based perovskites with the intention of avoiding the use of lead in the field of photovoltaics. Over the last few years, novel Bi-based halide perovskites have shown potential in reaching good photovoltaic performance, as suggested by their similar electronic structure to Pb-based perovskites. Nevertheless, their lower dimensionality entails poor charge carrier transport. It has been consistently stated that the role of the A-site should be further studied. To explore this proposition, we have synthesized three different Bi-based halides with substitution on the A-site by azetidinium cations. In this contribution we report fundamental observations of azetidinium bismuth halides, [(CH2)3NH2]3Bi2I9, [(CH2)3NH2]3Bi2Br9, and [(CH2)3NH2]3Bi2Cl9 with prospects in optoelectronics and photovoltaics. These new materials exhibit 0D and 2D crystal structures at a molecular level and the optical feature of an excitonic band state.

Organic–inorganic hybrid halide perovskites have attracted attention in optoelectronics and photovoltaics. However, the Pb-content in the crystal structure and instability issues have raised questions about the industrialization of these materials. Bi and Sb are widely considered as an alternative on the B-site due to their isoelectronic configuration with the Pb divalent cation. Herein, we report four novel Pb-free azetidinium metal halides and present their fundamental material properties: [(CH2)3NH2]2AgBiBr6, [(CH2)3NH2]3Bi2I9, [(CH2)3NH2]3Bi2Br9, and [(CH2)3NH2]3Bi2Cl9. Our materials have a low-dimensional perovskite-like structure from 0 to 2D, where the replacement on the B-site is based on Ag+/Bi3+ and Bi3+. As a potential light absorber, four different azetidinium metal halides were successfully synthesized via evaporation. The polycrystalline powders and thin films of the azetidinium metal halides present low dimensionalities from 0 to 2D.

The discovery of new zeolite framework types plays an important role in producing new porous materials for applications such as adsorption, catalysis, separation, etc.

The structure of HPM-3, a layered aluminophosphate prepared using 1,2,3-trimethylimidazolium (123TMI) as an organic structure-directing agent by the fluoride route, has been solved by continuous rotation electron diffraction (cRED), and Rietveld refined against synchrotron powder X-ray diffraction data. Charge balance of the occluded cation is achieved through F- anions and dangling Al(OP)3OH groups. Half of the Al is pentacoordinated in negatively charged Al(OP)4-F-Al(OP)4 pairs. The layers in HPM-3, denoted as jsn, are observed in the fully connected metalloaluminophosphate molecular sieves with JSN topology. Thus, HPM-3 can be a precursor to a JSN metal-free aluminophosphate if a topotactic condensation can be reached, which proved to be difficult but feasible. Treatments under different conditions resulted in a number of known (PST-27 and AlPO4-5 by a disruptive transformation) or new phases (through mild thermal treatments). Among the latter, a layered phase with a shorter interlayer space, denoted as HPM-3S, contains half the amount of organic as HPM-3. This is afforded by the capability of 123TMI compounds to sublimate at relatively low temperatures. HPM-3S still contains the same jsn layers. Therefore, the transformation of HPM-3 into HPM-3S is topotactic but without reaching condensation. Among the phases appearing under calcination conditions at relatively low temperature (<350 degrees C), we observed solids compatible with the JSN topology, but with poor crystallinity. This is attributed to a wrong alignment in HPM-3 of the dangling Al(OP)3OH and P(OAl)3=O that should connect adjacent layers in a topotactic condensation, which favors 1-dimensional stacking disorder by random shifts of layers during the thermal treatments. However, detemplation at a much lower temperature (175 degrees C) using O3 finally afforded an aluminophosphate molecular sieve with JSN topology with only moderate stacking disorder. This is just the third reported 2D-to-3D topotactic condensations in aluminophosphates.

The preparation of renewable isoprene from biomass-derivable feedstocks is extremely desirable for the sustainable rubber/latex/pharmaceutical industries. We report here a novel tandem route to efficiently produce isoprene via bio-sourced methanol and isobutene over Mo-Fe-O+meso-Cu/MgO composite catalysts. High isoprene selectivity of 85 % was achieved at methanol conversion of 91 % under optimal conditions. Adding Cu into mesoporous MgO finely tunes the basicity and acidity balance, thereby promoting isoprene selectivity. It shows good recycle capability, with isoprene selectivity remaining 85 % after five successive regeneration cycles. In-situ DRIFTS of methanol and isobutene adsorption suggest the possible reaction pathways involve methanol oxidation to formaldehyde on Mo-Fe oxide, followed by Prins condensation between formaldehyde and isobutene to isoprenol, and final conversion to isoprene on meso-Cu/MgO. This work not only represents a great advance in industrial large-scale producing isoprene, but provides an efficient strategy for developing methanol as in-situ precursor of formaldehyde to participate in many reactions.

C48H200N8O104Si32, monoclinic, C2/m (no. 12), a = 16.2532(14) Å, b = 13.3020(7) Å, c = 16.7771(14) Å, β = 96.476(10)°, V = 3604.07(3) Å3, Z = 1, R(F) = 0.031, χ 2 = 2.44, Rgt (F) = , wRref (F 2) = , T = 293 K.

Hydrated H-Apophyllite (HH-Apo) and H-carletonite (H-Car) were synthesized at 0 °C by leaching an apophyllite and a carletonite single crystal in a large surplus of 1.2 molar hydrochloric acid. The XRD powder patterns of HH-Apo and H-Car were indexed with space group symmetries of P4/ncc and I4/mcm and lattice parameters of a = 8.4872(2) Å, c = 16.8684(8) Å and a = 13.8972(3) Å, c = 20.4677(21) Å, respectively. The crystal structures were solved based on model building of the structures of the precursors and a physico-chemical characterization. Rietveld structure refinements confirmed the structure models. HH-Apo and H-Car are among the very few crystalline silicic acids whose structures have been determined and confirmed based on a structure refinement. The structure of HH-Apo contains thin silicate monolayers that can be regarded as constructed by rings of interconnected [SiO3OH] tetrahedra which form a puckered silicate layer. A sheet of water molecules is intercalated between the silicate layers. There are no direct hydrogen bonds between the silanol groups, but there are hydrogen bonds of different strengths between the terminal O atoms of the silicate layers and the intercalated water molecules. The 1H MAS NMR spectrum presents a strong signal at 4.9 ppm related to the aforementioned bonds and interactions between the water molecules, as well as a small signal at 22.5 ppm corresponding to an extremely strong hydrogen bond with d(O...O) ≈ 2.2 Å. The structure of H-Car is free of structural water and consists exclusively of microporous silicate double-layers with 4-connected [SiO4] and 3-connected [SiO3OH] tetrahedra in a ratio of 1:1 and a thickness of 9.2 Å. Neighboring layers are connected to each other by medium–strong hydrogen bonds with O...O distances of 2.56 Å. The structure of HH-Apo decays within several hours while H-Car is stable. A topotactic condensation reaction applied to H-Car forms an irregularly condensed silicate which still contains the layers in a distorted form as building blocks.

In the last decade, organic-inorganic hybrid halide perovskite materials have developed into a very large research area in photovoltaics and optoelectronics as promising light harvesters. Lead-free double perovskites have recently been investigated as an environmentally friendly alternative to the lead-containing compositions. However, lead-free organic-inorganic hybrid halide double perovskites have so far rarely been produced due to a certain complexity in their synthesis. A number of small molecular cations have been investigated, but compositions containing azetidinium, which is a 4-membered heterocyclic molecular ring, on the A-site have hardly been considered. This study investigates the potential of [(CH2)(3)NH2](2)AgBiBr6 as an optical absorber in photovoltaics or optoelectronics. The use of this alternative cation changes the crystal symmetry significantly. Columns of alternating metal cation form which are separated by the organic ions. While crystal symmetry is rather different from the perovskites, the overall properties as an absorber are similar. It is thus worthwhile to further investigate alternate hybrid compositions which form into other symmetries than the perovskite base structure.

A silica zeolite (RWZ-1) with a very high framework density (FD) was synthesized from highly crystalline natural layered silicate magadiite, bridging the gap between the two research areas of zeolites and dense silica polymorphs. Magadiite was topotactically converted into a 3D framework through two-step heat treatment. The resulting structure had a 1D micropore system of channel-like cavities with an FD of 22.1 Si atoms/1000 & ANGS;3. This value is higher than those of all other silica zeolites reported so far, approaching those of silica polymorphs (tridymite (22.6) and & alpha;-quartz (26.5)). RWZ-1 is a slight negative thermal expansion material with thermal properties approaching those of dense silica polymorphs. It contributes to the creation of a new field on microporous high-density silica/silicates. Synergistic interactions are expected between the micropores with molecular sieving properties and the dense layer-like building units with different topologies which provide thermal and mechanical stabilities. Between zeolite and silica: A silica zeolite RWZ-1 with a very high framework density (FD) was synthesized through topotactic condensation of natural layered silicate magadiite. Based on the viewpoint of its FD and thermal expansion behavior, RWZ-1 is regarded as a truly intermediate silica material between zeolites and dense silica polymorphs, which can be applicable as a unique catalyst and adsorbent.image

Volcanic tuffs and sandstones have been used as natural building stones in the construction of monuments and buildings over the millennia of human history. Progressive weathering over time (e.g., temperature fluctuations, moisture uptake, variations in humidity, precipitation, the input of modern-day pollutants or salt crystallization) lead to damages in the internal structure of the stone. Scaling and layer-parallel flaking of rock fragments result from these types of damage-causing processes, especially when swellable clay minerals are present that lead to the generation of stresses in the rock fabric. Tuff and sandstone samples that exemplify these types of damages are investigated in this study, which were used in the construction of cultural heritage sites in Armenia, Mexico, Germany and Switzerland. Comparisons are made between these rock types considering that they show strong variations in fabric heterogeneity, grain sizes, mineralogical composition (e.g., swellable clay- and zeolite-bearing minerals), and visible macroscopic features such as depositional layering. Comprehensive investigations have been carried out that include detailed petrographic analyses, XRD analyses for the determination of the swellable and non-swellable clay fraction and minerals of the zeolite group, the cation exchange capacity (CEC), detailed SEM surveys for determining the type and localization of clays and zeolites in the rock fabric, as well as defining the petrophysical properties (e.g., porosity, capillary water uptake, water absorption, hydric expansion and mechanical properties). Moreover, this study explores the possible interaction between swellable clay minerals and zeolites (mordenite, heulandite/clinoptilolite) by conducting swelling experiments with salts and solvents and fluid-exchange experiments with and without the presence of zeolites. To explain the damages caused by the expansion in the tuffs and sandstones, two principle modes of moisture expansion are discussed when swellable clay minerals are present in the rock. These are dominantly inner or intracrystalline swelling, and secondarily, intercrystalline or osmotic swelling. When no swellable clay minerals are present, the study explains the damages in tuffs and sandstones as the result of disjoining pressure, where a high percentage of microporosity plays a pivotal role.

O24Si12, tetragonal, P4(3)2(1)2 (no. 96), a = 7.4462(1) angstrom, c = 8.5838(4) angstrom, V = 475.93(3) angstrom(3), Z = 1, R(F) = 0.037, T = 293 K.

A robust catalystthat can continuously and effectively producemethanol from methane is exceedingly desired. Cu-containing zeolitecatalysts were widely used in direct oxidative methane to methanolreactions, and the local structure of the Cu species was one of thekey factors to influence the reaction performance. It has been consideredthat dicopper was a highly active species, and its implementationwas thoroughly dependent on the Al pairs in the zeolite framework.Therefore, to obtain a highly effective Cu-exchanged AEI zeolite catalyst,the synthesis of the AEI zeolite with a high proportion of Al pairswas an important premise. Herein, AEI zeolite was successfully synthesizedfrom ferrierite (FER) zeolite via the interzeolite conversion (IZC)method. The use of FER zeolite realized a high proportion of Al pairs,leading to the fabrication of abundant dicopper-containing AEI. Inaddition, the high thermal stability of the AEI zeolite enabled usto adjust the framework Al distribution and the acidic propertiesby postcalcination. Thus, the prepared Cu/AEI zeolite with plentifuldicopper species exhibited a distinctive catalytic performance inthe continuous conversion of methane to methanol at 350 & DEG;C; astate-of-the-art methanol productivity of 40.8 & mu;mol & BULL;g(-1)& BULL;min(-1) (2448 & mu;mol & BULL;g(-1)& BULL;h(-1)) with a 45% selectivityand long-term reaction stability was achieved.

The new zeolite, COE-11, was synthesized at 155 °C to 168 °C by hydrothermal synthesis from a reaction mixture of SiO2/tetraethylammonium hydroxide/H3BO3/NaOH/H2O. Because tetraethylammonium is an unspecific structure directing agent, COE-11 crystallizes in all cases together with at least one impurity phase from a selection of phases: zeolite types *BEA, CHA, FER, MFI, MOR, MTW; the layered silicates magadiite and kenyaite; and searlsite and silica polymorph quartz. The crystal structure was solved from 3D electron diffraction (3D ED) data. Subsequent structure refinements of X-ray powder diffraction (PXRD) data and single crystal electron diffraction data converged to residual values of RF = 0.039, chi2 = 3.6 (PXRD) and RF = 21.81% (3D ED) confirming the structure model. COE-11 crystallizes in space group C2 with unit cell dimensions of a0 = 17.3494(11) Å, b0 = 17.3409(11) Å, c0 = 14.2789(4) Å and β = 113.762(2) °. The structure of COE-11 is characterized by a microporous borosilicate framework with intersecting, highly elliptical 12-ring channels running parallel (110) and (1–10) and forming a two-dimensional pore system. The Rietveld refinement provided a hint that boron partly substitutes silicon on three specific T sites of the framework. The idealized chemical composition of as-made COE-11 is [(CH3CH2)4N]4[B4Si62O132] per unit cell. Physico-chemical characterization using solid-state NMR spectroscopy, SEM, TG-DTA, and ATR-FTIR spectroscopy confirmed that COE-11 is a microporous borosilicate zeolite. COE-11 is structurally closely related to zeolite beta polymorph B but differs concerning the dimensionality of the pore system, which is 2D instead of 3D.

C 48 H 96 B 6 N 6 O 108 Si 48 , trigonal, R 3 ‾ m $R\overline{3}m$ (no. 166), a = 12.8892(1) Å, c = 22.3058(2) Å, V = 3209.23(4) Å 3 , Z = 1, density = 2.02(2) g·cm −3 , R ( F ) = 0.038, Chi 2 = 2.86, T = 293 K.

A large number of lepidolites K(LixAl3−x)[Si2xAl4−2xO10](OH)yF2−y and Li-muscovites K(LixAl2-x/3□1-2x/3)[Si3AlO10](OH)yF2−y were synthesised by a gelling method in combination with hydrothermal syntheses at a pressure of 2 kbar and a temperature of 873 K. The nominal composition ranged between 0.0≤x≤2.0 and 0.0≤y≤2.0, i.e. from polylithionite K[Li2.0Al][Si4.0O10](OH)yF2−y over trilithionite K[Li1.5Al1.5][AlSi3.0O10](OH)yF2−y to muscovite K[Al2.0□][AlSi3.0O10](OH)yF2−y. 1H, 19F, 29Si and 27Al magic-angle spinning nuclear magnetic resonance (MAS NMR) and 27Al multiple-quantum magic-angle spinning (MQMAS) NMR spectroscopy has been performed to investigate the order and/or disorder state of Si and Al in the tetrahedral layers and of Li, Al, OH and F in the octahedral layer. The synthetic mica crystals are very small, ranging from 0.1 to 5 µm. With increasing Al content, the crystal sizes decrease. Rietveld structure analyses on 12 samples showed that nearly all samples consist of two mica polytypes (1M and 2M1) of varying proportions. In the case of lepidolites, the 1M / 2M1 ratio depends on the Li/Al ratio of the reaction mixture. The refinement of the occupancy factors of octahedral sites shows that lepidolites (1.5≤x≤2.0) represent a solid solution series with polylithionite and trilithionite as the endmembers. In the case of the Li-muscovites (0.0≤x≤1.5), the 1M / 2M1 ratio depends on the number of impurity phases like eucryptite or sanidine depleting the reaction mixture of Li or Al. There is no solid solution between trilithionite and muscovite; instead, the Li-muscovite crystals consist of domains differing in the relative proportions of muscovite and trilithionite. The overall composition of the synthesised micas which consist of two polytypes can be characterised by 29Si, 1H and 19F MAS NMR spectroscopy. The Si/Al ratio in the tetrahedral layers and thus the content of [4]Al were calculated by analysing the signal intensities of the 29Si MAS NMR experiments. The Li content xest was calculated from the measured tetrahedral Si/Al ratio of the 29Si MAS NMR signals. The calculated Li contents xest of samples between polylithionite and trilithionite agree with the expected values. The F-rich samples show slightly increased values and the OH samples lower values. Lepidolites with only F (x = 1.5 to 2.0, y = 0.0), but not lepidolites with only OH (x = 1.5 to 2.0 and y = 2.0), were observed after synthesis. With decreasing Li content, x≤1.2, Li-muscovites containing mostly hydroxyl (y>1.0) are formed. It was possible to synthesise fluorine containing micas with a Li content as low as 0.3 and y = 0.2 to 1.8. The 19F and 1H MAS NMR experiments reveal that F and OH are not distributed statistically but local structural preferences exist. F is attracted by Li-rich and OH by Al-rich environments. The quadrupolar coupling constant which represents the anisotropy of the Al coordination is low for polylithionite with CQ=1.5 MHz and increases to CQ=3.8 MHz for trilithionite. For tetrahedral Al a smaller increase of CQ from 1.7 to 2.8 MHz is observed. Advancing from trilithionite to muscovite both quadrupolar coupling constants decrease to 2.5 MHz for octahedral and 1.5 MHz for tetrahedral Al. In polylithionite there is the most isotropic environment for octahedral Al; there are only Li2Al sites coordinated by F in the octahedral sheets and O from the tetrahedral sheets which are regular, containing only Si. The distortion and anisotropy for Al in tetrahedral as well as octahedral sheets increases with rising Al content. The most anisotropic environment can be found in trilithionite, especially for octahedral Al.

ZSM-48 describes a family of disordered high-silica zeolites with a one-dimensional pore system of straight 10-ring channels. Although many different synthesis procedures and various organic structure-directing agents have been tried, all ZSM-48-type materials produced to date have proven to be highly disordered. A few structural models were proposed by Schlenker et al. (Zeolites 1985, 5, 355-358) and by Lobo and van Koningsveld (J. Am. Chem. Soc. 2002, 124, 13222-12230) to describe the framework topology and the disorder of the real structure, but it has not been possible to refine the structure of a ZSM-48-type material using experimental diffraction data. RUB-58 was synthesized under hydrothermal conditions at 160 to 200 degrees C in the system SiO2/H2O/ethylenediamine/pyridine. The product consists of spherelike aggregates of small, needlelike, colorless crystals and has an X-ray powder diffraction (XPD) pattern similar to those published for ZSM-48-type materials. The pattern, however, contains a much larger number of sharp reflections indicative of a more ordered, crystalline material. The reflections could be indexed with the unit cell parameters a = 14.2095(3) angstrom, b = 20.0874(5) angstrom, c = 8.3752(2) angstrom in the space group Pna21, a sub subgroup of Imma, which is the highest possible symmetry of the ordered ZSM-48 polymorph A (see the Database of Disordered Zeolite Structures). The structure analysis was performed in successive steps: (I) analysis of the average structure, which showed that the framework structure of RUB-58 can be described in terms of polymorph A and that the pyridine molecules occupy defined positions in the elliptical 10-ring channels; (II) refinement of a faulted structure using two separate, but identical polymorph A-type framework structures, with one shifted by exactly 0.5 of the unit cell along the channel direction (volume ratio: 92/8); (III) analysis of the structure of guest-free RUB-58 to examine the geometry of the channels in the empty framework (elliptical cross section nearly identical to that of the as-made material); and (IV) development of convincing disordered models to describe the real structure of RUB-58.