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The size and morphology of metal nanoparticles (NPs) often play a critical role in defining the catalytic performance of supported metal nanocatalysts. However, common synthetic methods struggle to produce metal NPs of appropriate size and morphological control. Thus, facile synthetic methods that offer controlled catalytic functions are highly desired. Here we have identified a new pathway to synthesize supported Rh nanocatalysts with finely tuned spatial dimensions and controlled morphology using a doping-segregation method. We have analyzed their structure evolutions during both the segregation process and catalytic reaction using a variety of in situ spectroscopic and microscopic techniques. A correlation between the catalytic functional sites and activity in CO2 hydrogenation over supported Rh nanocatalysts is then established. This study demonstrates a facile strategy to design and synthesize nanocatalysts with desired catalytic functions.

The adsorption mechanism of ethane, ethylene, and acetylene (C2Hn; n = 2, 4, 6) on two microporous metal organic frameworks (MOFs) is described here that is consistent with observations from single crystal and powder X-ray diffraction, calorimetric measurements, and gas adsorption isotherm measurements. Two calcium-based MOFs, designated as SBMOF-1 and SBMOF-2 (SB: Stony Brook), form three-dimensional frameworks with one-dimensional open channels. As determined from single crystal diffraction experiments, channel geometries of both SBMOF-1 and SBMOF-2 provide multiple adsorption sites for hydrocarbon molecules through C–H···π and C–H···O interactions, similarly to interactions in the molecular and protein crystals. Both materials selectively adsorb C2 hydrocarbon gases over methane as determined with IAST and breakthrough calculations as well as experimental breakthrough measurements, with C2H6/CH4 selectivity as high as 74 in SBMOF-1.

SrRuO3 (SRO) has been studied extensively at the bulk and thin film scales for a variety of applications, such as multilayer devices, field-effect devices, multiferroics, and even ferroelectric random access memory (FeRAM). Conversely, the exploration of SRO nanoscale and submicrometer scale structures in terms of both synthesis and applications has been significantly limited. Herein, we are the first to report on the synthesis of SRO submicrometer-sized particles via a molten-salt method. We have accomplished this by systematically probing experimental parameters such as precursors, type of salt, annealing time, annealing temperature, surfactant, cooling rate, and reaction atmosphere in an effort to predictably control the resulting size, shape, and morphology of the SRO product particles. In particular, by quenching the reaction at a cooling rate of 100 °C/min, we can produce rounded SRO particles averaging 149 ± 100 nm in size. Moreover, with the addition of a mixture of mineral oil in Triton X-100, th...

Chromium(III) (oxy)hydroxide and mixed Cr(III)−Fe(III) (oxy)hydroxides are environmentally important compounds for controlling chromium speciation and bioaccessibility in soils and aquatic systems and are also industrially important as precursors for materials and catalyst synthesis. However, direct characterization of the atomic arrangements of these materials is complicated because of their amorphous X-ray properties. This study involves synthesis of the complete Cr(III)−Fe(III) (oxy)hydroxide compositional series, and the use of complementary thermal, microscopic, spectroscopic, and scattering techniques for the evaluation of their structural properties. Thermal analysis results show that the Cr end member has a higher hydration state than the Fe end member, likely associated with the difference in water exchange rates in the first hydration spheres of Cr(III) and Fe(III). Three stages of weight loss are observed and are likely related to the loss of surface/structural water and hydroxyl groups. As com...

Amorphous calcium carbonate (ACC) is an important phase involved in calcification by a wide variety of invertebrate organisms and is of technological interest in the development of functional materials. Despite widespread scientific interest in this phase a full characterization of structure is lacking. This is mainly due to its metastability and difficulties in evaluating structure using conventional structure determination methods. Here we present new findings from the application of two techniques, pair distribution function analysis and nuclear magnetic resonance spectroscopy, which provide new insight to structural aspects of synthetic ACC. Several important results have emerged from this study of ACC formed in vitro using two common preparation methods: (1) ACC exhibits no structural coherence over distances > 15 A and is truly amorphous; (2) most of the hydrogen in ACC is present as structural H2O, about half of which undergoes restricted motion on the millisecond time scale near room temperature; ...

Two new metal−organic framework compounds were synthesized under solvothermal conditions using Zn2+ ion, 1,2,4-triazole (TRZ), and 1,4- and 2,6-naphthalenedicarboxylic acids (NDC): Zn4(TRZ)4(1,4-NDC)2·2DMF·2H2O (1) and Zn4(TRZ)4(2,6-NDC)2·2DMF·4H2O (2). Their crystal structures were characterized by single-crystal X-ray diffraction. Structure 1 crystallizes in the P21/n space group with a = 13.609(2) A, b = 27.181(5) A, c = 13.617(3) A, β = 92.46(1) °, V = 5032.4(16) A3, and Z = 4. Structure 2 crystallizes in orthorhombic Pna21 space group with a = 30.978(6) A, b = 12.620(3) A, c = 13.339(3) A, V = 5215(2) A3, and Z = 4. Both structures are analogues of the previously reported Zn4(TRZ)4(1,4-BDC)2·16H2O where the layers of Zn−triazole moieties are pillared by aromatic dicarboxylates to create 3-D open frameworks. Nitrogen sorption studies revealed that these structures have Brunaer−Emmett−Teller (BET) surface areas of 362.1−584.1 m2/g. Hydrogen sorption experiments showed they can store 0.84−1.09 wt % of ...

Iron(III) hydroxides are abundant in near-surface natural environments and play an important role in geochemical processes and the fate of contaminants. The issue of the structure of the common nanophase material ferrihydrite (ferric hydroxide) is controversial and has been debated in the literature for many years without definitive resolution. At least two types of ferrihydrite, the 2-line and 6-line forms, are conventionally recognized. It has been suggested that these forms possess different structures built up by different mixtures of distinct nanophase components. However, traditional crystallographic methods provide depictions of structure that are most sensitive either to short-range order (X-ray absorption) or long-range periodicity (X-ray diffraction or electron diffraction). We used high-energy X-ray total scattering for pair distribution function analysis to observe both the short- and intermediate-range ordering (exceeding similar to 15 angstrom) of synthetic ferrihydrite with three distinct average domain sizes of 2, 3, and 6 nm. We show that there are no significant differences in the underlying structures of these materials and that the differences in the diffraction patterns can be entirely interpreted by variations in the average size of the coherent scattering domains. The average crystallite sizes inferred from the PDF analysis are in good agreement with direct observation by high-resolution transmission electron microscopy.

A new member of the CaCu 3 B 2 B' 2 O 12 perovskite family, CaCu 3 Cr 2 Ru 2 O 12 , has been synthesized at 12 GPa and 1150 °C. Rietveld refinement using powder X-ray diffraction data reveals that this oxide crystallizes in space group Im3 where cations are disordered over the octahedral B site. Measurements of magnetic susceptibility exhibit a temperature independent Pauli paramagnetic behavior. There is no indication of magnetic ordering, in contrast to the ferrimagnetic behavior associated with the superexchange between Cu(II) and Cr(III) in CaCu 3 Cr 2 Sb 2 O 12 . Although itinerant electron behavior is similar to that observed for the isostructural CaCu 3 Ga 2 Ru 2 O 12 , Cu(II)-O-Ru(V) ↔ Cu(III)-O-Ru(IV) charge transfer is not expected. Rather, a delocalization mechanism involving both CrO 6 and RuO 6 octahedral sublattices is proposed, as is typical for double perovskites. The pure paramagnetic behaviors of CaCu 3 Ga 2 B' 2 O 12 (B' = Nb, Sb, and Ta) perovskites, which contrast with the antiferromagnetic CaCu 3 Ti 4 O 12 , indicate that the electronic coupling within the A sublattice is strongly influenced by the electronic structure of the B sublattice.

Recent studies exploring the role of metal sulfides as (photo)catalysts in prebiotic synthesis reactions provide the impetus for finding carbon-free synthesis methods for metal sulfides. The decomposition of organosulfur and organometallic precursor compounds is often the protocol for synthesizing bulk metal chalcogenides, such as manganese sulfide (MnS). Here we report a hydrothermal synthesis method for the formation of MnS in which a MnCl2 solution is injected into a preheated sulfide solution. By varying the temperature of injection and subsequent aging time, we can control the specific crystal phase of the product. Three MnS polymorphs are known, and two of these, α-MnS and γ-MnS, form as pure phases in aqueous systems. The initial precipitate formed upon mixing of aqueous solutions of Mn2+ and S2- at ambient temperature is nanocrystalline and is composed of a mixture of γ-MnS (wurtzite structure) and β-MnS (zinc blende structure). β-MnS has not previously been identified as forming under aqueous con...

Three new metal−organic coordination polymers were synthesized hydrothermally using Zn2+ ion, 1,2,4-triazole, and 1,4-benzenedicarboxylic acid (BDC): Zn5(H2O)2(C2H2N3)4(C8H4O4)3·3.9H2O (1), Zn2(C2H2N3)2(C2H3N3)(C8H4O4)·2.5H2O (2), and Zn4(H2O)2(C2H2N3)4(C8H4O4)2·14H2O (3). Their crystal structures were determined by single-crystal X-ray diffraction. Their thermal properties were examined by thermogravimetric analysis. Structure 1 crystallizes in the monoclinic P21/n space group with a = 10.192(2) A, b = 17.764(4) A, c = 24.437(5) A, β = 91.19(3)°, and V = 4423.3(15) A3. Structure 2 crystallizes in the triclinic P1 space group with a = 7.797(2) A, b = 10.047(2) A, c = 13.577(3) A, α = 110.18(3)°, β = 105.46(3)°, γ = 93.90(3)°, and V = 947.0(3) A3. Structure 3 crystallizes in monoclinic P21/n space group with a = 13.475(3) A, b = 26.949(5) A, c = 13.509(3) A, β = 95.18(3)°, and V = 4885.7(17) A3. In structure 1, the units of the triazole−Zn polyhedra are linked by BDC in a zigzag fashion to create the sta...

A new perovskite-type oxide, CaCu 3 Cr 2 Sb 2 O 1 2 , has been synthesized at 10 GPa and 1100 °C. This compound crystallizes in space group Pn3 and shows simultaneous cation ordering on both A and B sites. Magnetization measurements indicate that an interaction between A-site Cu(II) and B-site Cr(III) cations dominates over possible antiferromagnetic couplings between Cu(II)-Cu(II) ions or Cr(III)-Cr(III) ions and induces net spontaneous magnetic moment below ∼160 K. The lack of significant hysteresis in the isothermal magnetization curves suggests that CaCu 3 Cr 2 Sb 2 O 1 2 is a soft ferrimagnet, which is consistent with the thermomagnetic irreversibility and magnetic susceptibility behavior. Interestingly, the experimentally determined effective magnetic moment of ∼1.4 μ B at 5 K is significantly smaller than the expected value of 3 μ B estimated assuming an antiparallel alignment of the spins of Cu(II) and Cr(III). Significant spin canting may account for the small magnetic moment. Such an anomalously small magnetization is similar to that of CuCr 2 O 4 spinel showing a non-unidirectional spin canting behavior.

Titanium silicate (TS) with sitinakite topology and composition Na2Ti2O3SiO4·2H2O has received considerable attention because of its high ion-exchange selectivity toward cesium and strontium. In this paper we report the results of the studies of the crystallization process of TS with a combination of ex and in situ experiments. The effects of various parameters, such as gel composition, time, and temperature of the synthesis, on crystallinity and composition of the final product have been investigated. In situ X-ray powder diffraction studies carried out during the synthesis of TS revealed that the process begins with the formation of layered sodium nonatitanate (SNT) with chemical composition Na4Ti9O20·xH2O, which is also an excellent ion exchanger, selective for strontium and actinides. The pathway of transformation of SNT to the final product is sensitive to alkalinity of the starting gels. At high hydroxide concentration the reaction resulted in the formation of sodium titanium oxide silicate, Na2TiSi...

We report the synthesis and structure solution of [Li-Si-O]-MFI (a = 19.793(4) A, b = 19.766(4) A, c = 13.266(3) A, space group P2 12 12 1), a framework zeolite related to ZSM-5 (silicalite) with a Li/Si ratio of 4:92. Single-crystal synchrotron X-ray diffraction data, 29Si NMR, and infrared spectroscopy indicate that the Li is randomly distributed over the framework sites. In addition, Li occupies ordered positions on extraframework sites that are occluded in voids outlined by the double five- or six-membered rings. The strong interaction between the extraframework Li cations and the negatively charged framework may be responsible for the distortion of the lattice from Pnma, the usual symmetry associated with as-synthesized members of the MFI-family, to its subgroup symmetry P2 12 12 1. Variable-temperature 7Li and 1H MAS NMR experiments show that the extraframework Li cations are not directly accessible to gas molecules, but that the protons formed on calcination are accessible.

Time-resolved in situ synchrotron X-ray powder diffraction (XRPD) was used to study ion-exchange mechanisms and pathways in K+ and Na+ forms of an aluminogermanate with the zeolite gismondine topology (AlGe−GIS). The Na+ and K+ forms differ in their distribution of extraframework cations with the Na+ ions ordered in the C-centered monoclinic Na−AlGe−GIS of unit-cell dimensions a = 14.490(3) A, b = 9.3840(2) A, c = 23.530(5) A, and β = 105.90(3)° and K+ ions disordered in the I-centered monoclinic K−AlGe−GIS of unit-cell dimensions a = 10.311(2) A, b = 9.749(1) A, c = 10.238(1) A, and β = 90.000(2)°. Rietveld structure refinements indicate K+ first occupies sites K2, K4, and K6 in the [101] channel of the Na−AlGe−GIS structure. After 10% (±2%) K+ exchange into the [101] channel, the I2/a unit cell forms and subsequent replacement of Na+ is consistent with site independent exchange along the [101] and [201] channels. Ion exchange proceeded to approximately 90% (±1%) substitution of K+ into Na−AlGe−GIS wi...

Three new perovskites, CaCu3Ga2Sb2O12, CaCu3Ga2Ta2O12, and CaCu3Ga2Nb2O12, have been synthesized at 12∼12.5 GPa and 1100 °C using the uniaxial split sphere anvil type press (USSA-2000) and recovered to ambient conditions, where they have been structurally characterized using X-ray and neutron powder diffraction. The large differences in the size and bonding preferences of Ca2+ and Cu2+ stabilize a large a+a+a+ octahedral tilting distortion in all three compounds. This distortion creates a 12-coordinate icosahedral site for Ca2+ and a 4-coordinate square-planar site for Cu2+. In addition to this A-site cation ordering, CaCu3Ga2Sb2O12 and CaCu3Ga2Ta2O12 also exhibit a rock salt ordering of the octahedral B-site cations. The B-site cation order decreases from 98% in CaCu3Ga2Sb2O12 to 70% in CaCu3Ga2Ta2O12 to effectively no long range order in CaCu3Ga2Nb2O12. These materials represent the first examples in which both A-site cation order and rock salt B-site cation order have been observed simultaneously. The ...

The recent expansion of zeolitic synthesis toward mixed geometry frameworks reflects their potential applications in shape-selective catalysis and absorption. Four scandium phosphates with three-dimensional frameworks have been hydrothermally synthesized. All structures were solved from single-crystal X-ray diffraction and were supported by 31P MAS NMR and infrared spectroscopy. Structure 1 ((C2N2H10)8Sc8(ScO2)4(PO4)4(HPO4)12·12H2O) consists of a novel framework with 14-membered rings (MRs) and 10-MR channels along the a and c axes, respectively. Ethylenediamine and water reside in the resulting supercage. Structure 2 ((C2N2H10)2Sc4(HPO4)8) consists of a framework built from the corner-sharing of ScO6 octahedra with HPO4 tetrahedra whose connection results in a 8-MR channel down the a axis, where hydrolyzed cyclam resides. This compound is isostructural to a number of existing synthetic materials including a scandium phosphate, an indium phosphate, and an iron phosphate. Structure 3 (Sc4(HPO4)8·4(H3O)) is...

The influence of pressure, temperature, and composition on the crystal structure of Li-exchanged zeolite RHO with an aluminogermanate framework was investigated using synchrotron X-ray powder diffraction. At ambient conditions, aluminogermanate RHO adopts either a rhombohedral (R3) or cubic (I23) symmetry depending on the Li-exchange level. Under hydrostatic conditions mediated by an alcohol and water mixture in a diamond-anvil cell, the rhombohedral 68% Li−AlGe−RHO transforms to a cubic structure near 3 GPa, whereas the cubic 57% Li−AlGe−RHO first transforms to a rhombohedral phase near 0.4 GPa and then back to a cubic structure near 3 GPa. The rhombohedral distortion angle, an order parameter of the low-symmetry structure, increases continuously with pressure while approaching the transition to the cubic form, where it decreases abruptly to the equivalent cubic angle. All of these materials show progressive volume contraction under increasing pressure and the calculated bulk moduli suggests that the rho...

A new microporous lithozincosilicate (Cs 12 Li 13 [Li 3 Zn 8 Si 37 O 96 ].4H 2 O), an analogue of pollucite (CsAlSi 2 O 6 ) and analcime (NaAlSi 2 O 6 ), contains lithium in both framework and nonframework sites. This represents the first example of the incorporation of lithium into the ANA framework structure type. The analysis of the crystal structure used X-ray and neutron powder diffraction techniques, which reveal partially ordered sites in the framework occupied by Li, Zn, and Si atoms. The framework sites are occupied in a manner to distribute the low valent cations as far apart as possible. The pore system of the material consists of large cuboctahedra, occupied by Cs and water molecules, and smaller vacancies available for siting of nonframework Li bounded by six- and eight-membered rings of framework tetrahedra.

PrAlO3 is shown to undergo a rhombohedral (R3c) to orthorhombic (Imma) phase transition upon application of pressures of up to 9.1 GPa. The structures in both phases have been refined from high-re...

The local and long-range structures of LiZnxMn2-xO4 (x = 0.1, 0.2, 0.3, 0.5) have been studied by using 6Li magic-angle spinning (MAS) NMR spectroscopy and X-ray and neutron powder diffraction. For all the samples, a 6Li resonance at approximately 2000 ppm is observed due to the presence of Li in the octahedral sites of the spinel structure, indicating that Zn substitutes for lithium in the tetrahedral sites. For low doping levels (x = 0.1 and 0.2), several resonances at 500−700 ppm are seen, which are assigned to lithium cations in tetrahedral sites with local environments such as Li(OMn3.5+)12-y(OMn4+)y, Mn3.5+ indicating a Mn ion with an average oxidation state of 3.5. The x = 0.3 sample is not obtained as a single phase; instead, two phases with Zn-doping levels corresponding to x = 0.2 and 0.5 are observed. Different cation-ordering schemes are observed for the x = 0.5 sample, depending on the condition of synthesis: slow cooling from 700 °C to room temperature results in cation ordering in both tet...

Two new aluminogermanates, K-AlGe-GIS (K 8 Al 8 Ge 8 O 32 .8H 2 O) and Na-AlGe-GIS (Na 24 Al 24 Ge 24 O 96 40H 2 O), with the zeolite gismondine (GIS) type framework topology have been synthesized hydrothermally and characterized using single-crystal X-ray diffraction. K-AlGe-GIS crystallizes in the monoclinic space group I2/a with a = 10.311(2)A, b = 9.749-(1)A, c = 10.225(6)A, β = 90.000(2)°, and Z = 8. Na-AlGe-GIS crystallizes in the monoclinic space group C2/c with a = 14.490(3)A, b = 9.940(2)A, c = 23.530(5)A, β = 105.90(3)°, and Z = 8. Strict alternation of Ge and Al atoms over the framework sites lowers the symmetry of these aluminogermanates from their topological framework symmetry of I4 1 1amd to the real symmetry I2 /a. Both structures consist of twisted double-crankshaft chains running along the a and c axes. In K-AlGe-GIS, potassium and water statistically occupy extraframework sites along the perpendicular eight-ring channels. In Na-AlGe-GIS, all three sodium sites are fully occupied and only three out of seven sites containing water are statistically occupied. A zigzag-ordered arrangement of Na sites in Na-AlGe-GIS results in unit cell symmetry hitherto unobserved for GIS. The synthesis of Na-AlGe-GIS requires the presence of organic bases, while K-AlGe-GIS can be synthesized from gels with or without organic bases. Time-resolved synchrotron X-ray powder diffraction patterns obtained as a function of temperature for Na-AlGe-GIS show a gradual disappearance of the C-centered cell between 150 and 180 °C with a simultaneous appearance of an I-centered monoclinic phase. Calculated powder diffraction patterns indicate that this phase change results from disordering of Na sites in the eight-ring channels. Results of a single-crystal diffraction study for a 50% Na-exchanged K-AlGe-GIS (K 4 Na 4 Al 8 Ge 8 O 32 8H 2 O) shows that the space group I2/a is retained with a 0.3% increase in the unit cell volume. Both the AlGe frameworks retain the GIS topology until ca. 750 °C after dehydration. The average Al-O-Ge (T-O-T) bond angle of 135.75° in K-AlGe-GIS and 135.29° in Na-AlGe-GIS is smaller than the average Al-O-Si bond angle of 145° in aluminosilicates.

The potassium gallosilicate TsG-1, K10Ga10Si22O64·5H2O, when contacted with a Sr2+:Na+ = 1:5 solution, exhibited a preference for Sr2+ as determined from ion-exchange studies using ion chromatography. A structural model for the strontium-exchanged material, Sr-TsG-1, Sr5Ga10Si22O64·19H2O, was obtained using Rietveld analysis and high-resolution synchrotron X-ray powder diffraction data. The space group, Pnma, of the as-synthesized material is retained in Sr-TsG-1, which has a = 8.6826(1), b = 13.8828(1), c = 16.2484(1) A. The buckled 8-ring site, consisting of interpenetrated double 6-ring (iD6R) arrays in the CGS topology adopted by TsG-1, is half-occupied by Sr2+ to form a distorted tetrahedral coordination with four framework oxygen atoms. The elliptical 8-ring and s-shaped 10-ring, generated by cross-linking the iD6R arrays along the b and a axis, respectively, also provide environments suitable for Sr2+. An in-situ synchrotron X-ray powder diffraction study confirmed b axis contraction upon Sr2+ upta...

The influence of lithium substitution on the structure of aluminosilicate (AlSi) and aluminogermanate (AlGe) materials with the zeolite RHO topology has been examined. The exchanged materials were dehydrated and structurally characterized via Rietveld refinement using neutron powder diffraction data. Li−AlSi-rho crystallizes in the space group I43m with a = 14.2609(3) A, whereas Li−AlGe−rho adopts the space group I23 with a = 14.2926(5) A. The extraframework cations reside in their expected positions in Li−AlSi-rho: cesium is found in the double eight ring (D8R) and lithium is observed only in the single six ring (S6R). In Li−AlGe-rho, lithium resides in both the single six ring and the single eight rings (S8R) while cesium is located exclusively in the S6R. Although these cation positions are unusual for materials with the RHO topology, they are a response to the framework distortions introduced by ion exchange and dehydration. The extraframework cation positions correspond to those that best satisfy t...

The compound Bi1/2Ag1/2TiO3 has been synthesized, for the first time, at 14−14.5 GPa and 1000 °C using the uniaxial split sphere anvil type press (USSA-2000). The structure of the quenched powder s...

The mechanism by which K+ ions exchange into zeolite Na-low silica X (LSX) (Na96Al96Si96O384·nH2O) has been determined by studying structures of the Na-LSX and K-LSX end members in the Na−K LSX solid solution series as well as samples exchanged at the 20%, 42% and 80% K+ levels. A preliminary investigation using 29Si MAS NMR spectroscopy revealed a two-phase region in the solid solution near 80% K+ exchange. Rietveld analysis of the powder diffraction data collected from hydrated samples showed that, up to 42% of K+ exchange, K+ ions were located preferentially at site I‘, just outside the double 6-ring (D6R) in the sodalite cage, and at site II, above the single 6-ring (S6R) in the supercage. Introduction of K+ ions into site I‘ repositioned Na+ ions into site I, at the center of the D6R. An abrupt change in the cubic lattice parameter from 25.0389(5) to 25.2086(5) A marked the formation of a second phase at the 80% K+-exchange level as K+ ions began to occupy site I. No coexistence of phases was observe...

The program POTATO, which was developed to model distorted perovskite structures, has been used to assess the stability of hypothetical compositions and guide the synthesis of new materials at high pressures and high temperatures. The initial result of this effort is the synthesis of two new perovskites, Ca2NdAgTi4O12 and NdAgTi2O6, which were synthesized at 14−14.5 GPa and 1000 °C using the uniaxial split sphere anvil type press (USSA-2000). Both compounds are perovskites distorted from the ideal cubic structure by octahedral tilting distortions. Ca2NdAgTi4O12 contains a random distribution of Ca2+/Nd3+/Ag+ ions on the A-site, whereas NdAgTi2O6 has a partially ordered distribution of Nd3+/Ag+ ions. Ca2NdAgTi4O12 adopts the GdFeO3 structure (Glazer tilt system b-a+b-), space group Pnma, with a = 5.44883(4), b = 7.68915(6), and c = 5.42290(3) A. NdAgTi2O6 belongs to the tetragonal space group P4/nbm, with a = 5.45337(3) and c = 7.72934(6) A. This structure can be derived from the simple cubic perovskite st...

The structure of QUI-MnGS-1 has been determined from single-crystal X-ray diffraction on a ∼0.03 × 0.03 × 0.02 mm sample using synchrotron radiation. This material [(C7H13N)Mn0.25Ge1.75S4·H2O] crys...

Single crystals of Dabco−MnGS−SB1 (MnGe4S10·(C6H14N2)·3H2O) were synthesized hydrothermally in the presence of Dabco (1,4-diazabicyclo[2.2.2]octane). This material (Pna21, a = 18.367(2), b = 14.184(2), and c = 9.410(1) A) contains [Ge4S10]4- adamantine clusters corner-linked through distorted Mn2+ centers. The alternating Mn2+ centers and [Ge4S10]4- clusters lie at the nodes of a distorted Li-A(BW) net containing elliptical 8-rings. Channels defined by these 8-rings contain the template and water molecules. The distortion of S−Mn−S from the ideal tetrahedral angles is a result of the strain associated with ring system of the framework.

A novel antimony sulfide, [C4H10N]2[Sb8S13]·0.15H2O, was synthesized hydrothermally, and its structure was determined from data collected using a synchrotron/imaging plate system. The new compound consists of centrosymmetric Sb16S264- planar clusters. Each cluster is connected to four others through two edge-sharing and two corner-sharing SbS3 pyramids, forming an extended sheet. The protonated pyrrolidine molecules reside between the parallel stacked sheets. The structure is triclinic (space group P1) with a = 6.929(2) A, b = 16.747(2) A, c = 17.976(4) A, α = 94.84(1°), β = 95.41(1)°, and γ = 125.28(1)°.

Hydrothermal synthesis at 200 °C produced a new open antimony sulfide framework, [C2H8N]2[Sb8S12(S2)], designated DMA-SbS-SB8. The structure (Cmca, a = 9.9704(7), b = 11.652(2), and c = 25.979(3) A), determined from data collected on a small single crystal (20 × 30 × 40 μm in size) utilizing the synchrotron/imaging plate system installed at the X3A1 beamline of the NSLS, consists of [Sb8S12(S2)]2- double chains formed from Sb4S72- single chains joined through S−S bridges. The double chains contain 18-membered Sb8S10 rings and are interlocked to form sheets perpendicular to the b axis. Dimethylammonium ions, assumed to be protonated to charge balance the anionic [Sb8S12(S2)]2- framework, reside within 18-membered rings. The structural building units of the new open framework are similar to those described previously in other members of the antimony sulfide system. Experiments carried out at different temperatures and reaction times show that DMA-SbS-SB8 is formed from a distinct poorly crystallized phase (...

The structure of a zeolite ZSM-5 complex with ca. 4 molecules/unit cell of bithiophene was determined by high-resolution synchrotron X-ray powder diffraction. It adopts monoclinic symmetry in space group P21/n (a unique) between room temperature and 25 K, with refined lattice parameters at 25 K of a = 20.0614(4), b = 19.8251(4), c = 13.3623(4) A, and α = 90.848(2)°. Structural modeling and Rietveld refinements showed that there are two crystallographically unique bithiophene molecules, each with an occupancy factor of ca. 0.5. One bithiophene is localized at the center of the straight channels with one of the rings residing at the intersection with the sinusoidal channels. The other molecule lies in the sinusoidal channels and projects partially into the straight channels. The relationship between polythiophene chain length and the formation of conducting polythiophene molecular wires in the ZSM-5 framework is discussed.

Single crystals of TMA-CuGS-2, [C4H12N]6[(Cu0.44Ge0.56S2.23)4(Ge4S8)3], were synthesized hydrothermally, and the structure was determined using data collected from sealed-tube and synchrotron X-ray sources. This compound consists of Ge4S104- adamantine clusters, corner-sharing with MSx units (M = Cu, Ge; x = 3 or 4), forming an open framework with tetramethylammonium cations residing within four intersecting channels. Disorder in the M sites causes the composition of the framework to deviate from the ideal stoichiometry, Ge0.71M0.24S2, realized when M = Cu and x = 4. This is consistent with results obtained from electron-probe microanalysis. The structure refinements were carried out in space group I43d with cell parameter a = 20.629 (1) A. Fourteen unique weak reflections of the type hhl, 2h + l = 4n + 2, forbidden in I43d, were detected only in the synchrotron/imaging plate experiment. Trial refinements in space groups R3 and I213 suggest their origin in either weak ordering or multiple scattering eff...

When certain salts, R{sup +}AlF{sub 4}{sup -} are heated in flowing nitrogen, the equivalent of R{sub +}F{sup -} is lost at temperatures

We report the first example of a layered ternary lithium nitride in which the lithium can be deintercalated and reintercalated. This ternary nitride, LiMoN2, has been synthesized by the reaction of two different precursors, Li2Mo(NtBu)4 and Li2MoO4, with ammonia gas. The structure was refined using a combination of X-ray and neutron powder diffraction data in the space group R3 and the lattice parameters are (A) a=2.8672(3) and c=15.813(3) which were obtained from the neutron data. The ideal structure consists of MoN2 layers with Mo in trigonal prismatic holes and Li in octahedral holes between the MoN2 layers. The diffraction studies indicate the presence of cation anti-site defects; the structure is best described as Solid State Nitrides Li batteries Crystal Structure Magnetic and Electrical Properties (Li0.84Mo0.16) oct(Mo0.84Li0.16)tpN2. LiMoN2 is metallic and Pauliparamagnetic with Xo = 0.59 x 10(6) emu g-1. We have employed a variety of different oxidizing agents for the deintercalation of the lithium from LiMoN2 and have been able to deintercalate up to 64% of the lithium. This deintercalated species can be reintercalated with n-butyllithium (in hexane) at room temperature. Electrochemical studies show a large hysteresis in charge-discharge cycles.

The synthetic gallosilicate TsG-1 with the CGS framework topology has been synthesized under hydrothermal conditions and characterized via single-crystal synchrotron X-ray diffraction. Unlike the cobalt−gallium phosphate analogue, this material shows the ideal topological symmetry of Pnma (a = 8.613(2) A, b = 13.813(3) A, c = 16.330(3) A), and extraframework cations are distributed over the buckled 8-ring sites of the interpenetrated double 6-rings as well as along the channels of the s-shaped 10-rings and elliptical 8-rings.

Three aluminogermanate materials have been synthesized at temperatures below 100 °C and identified as analogues of RHO, GIS and NAT type zeolites. In addition, microwave heating has yielded phase-pure Ge-X after only 10 s, and Ge-RHO is the dominant product after several days reaction at ambient temperature. This demonstrates the relative ease of formation of aluminogermanate zeolites, provided a suitable starting stoichiometry is chosen.

Hydrothermal treatment of elemental indium and sulfur in the presence of the organic structure directing agent dimethylamine yields the novel open framework material DMA-InS-SB1. This material contains [In10S20]10- supertetrahedra that corner link to form an interpenetrating “double-diamond” lattice.

A novel aurate, CaAu{sub 2}O{sub 4}, after synthesis under high-pressure conditions was recovered to room temperature by quenching. The structure, determined with synchrotron powder X-ray diffraction and single-crystal X-ray data by model building, was refined using the Rietveld techniques. It contains corner-shared AuO{sub 4} square planes and CaO{sub 8} dodecahedra. 25 refs., 2 figs., 1 tab.