- Complex Hydroxides of Chromium: Na9[Cr(OH)6]2(OH)3 ? 6 H2O and Na4[Cr(OH)6]X ? H2O (X = Cl, (S2)1/2) - Synthesis, Crystal Structure, and Thermal Behaviour
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Green plate-like crystals of Na9[Cr(OH)6]2(OH)3 · 6H2O (triclinic, P1?, a = 872.9(1) pm, b = 1142.0(1) pm, c = 1166.0(1) pm, α = 74.27(1)°, β = 87.54(1)°, γ = 70.69(1)°) are obtained upon slow cooling of a hot saturated solution of CrIII in cone. NaOH (50 wt%) at room temperature. In the presence of chloride or disulfide the reaction yields green prismatic crystals of Na4[Cr(OH)6]Cl · H2O (monoclinic, C2/c, a = 1138.8(2) pm, b = 1360.4(1) pm, c = 583.20(7) pm, β = 105.9(1)°) or green elongated plates of Na4[Cr(OH)6](S2)1/2 · H2O (monoclinic, P21/c, a = 580.8(1) pm, b = 1366.5(3) pm, c = 1115.0(2) pm, β = 103.71(2)°), respeclively. The latter compounds crystallize in related structures. All compounds can be described as distorted cubic closest packings of the anions and the crystal water molecules with the cations occupying octahedral sites in an ordered way. The thermal decomposition of the compounds was investigated by DSC/TG or DTA/TG and high temperature X-ray powder diffraction measurements. In all cases the final decomposition product is NaCrO2.
- Hinz, Dirk
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- Reactions of sulphides in molten cryolite
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The freezing point depression of cryolite (Na3AlF6) by the addition of Al2S3 and FeS was investigated. It was found that for contents of up to 10wt.% Al2S3, it brings into the melt three new species. X-ray analysis of solidified melts of the system Na3AlF6-Al2S3 showed that it contained chiolite, Na5Al3F14 and Na 2S. Chiolite originates from a reaction between Na 3AlF6 and AlF3. This suggests that the system Na3AlF6-Al2S3 is a part of the reciprocal system NaF, AlF3//Na2S, Al2S 3. The solubility of FeS in cryolite melt is so low that it cannot be determined by the thermal analysis. When FeO is added to the Na 3AlF6-Al2S3 melt, Fe2+ cations and S2- anions react under the formation of solid FeS. A similar reaction was observed for Ni2+ and S2- ions.
- Fellner,Korenko,Ambrová,Danielik,Thonstad
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- New strategy for designing promising mid-infrared nonlinear optical materials: narrowing the band gap for large nonlinear optical efficiencies and reducing the thermal effect for a high laser-induced damage threshold
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To circumvent the incompatibility between large nonlinear optical (NLO) efficiencies and high laser-induced damage thresholds (LIDTs) in mid-infrared NLO materials, a new strategy for designing materials with both excellent properties is proposed. This strategy involves narrowing the band gap for large NLO efficiencies and reducing the thermal effect for a high LIDT. To support these proposals, a series of isostructural chalcogenides with various tetrahedral center cations, Na2Ga2MQ6 (M = Ge, Sn; Q = S, Se), were synthesized and studied in detail. Compared with the benchmark AGS, these chalcogenides exhibit significantly narrower band gaps (1.56-1.73 eV, AGS: 2.62 eV) and high NLO efficiencies (1.6-3.9 times that of AGS at 1910 nm), and also outstanding LIDTs of 8.5-13.3 × those of AGS for potential high-power applications, which are contrary to the conventional band gap view but can be attributed to their small thermal expansion anisotropy, surmounting the NLO-LIDT incompatibility. These results shed light on the search for practical IR NLO materials with excellent performance not restricted by NLO-LIDT incompatibility.
- Li, Shu-Fang,Jiang, Xiao-Ming,Fan, Yu-Hang,Liu, Bin-Wen,Zeng, Hui-Yi,Guo, Guo-Cong
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- Na3+xMxP1?xS4 (M = Ge4+, Ti4+, Sn4+) enables high rate all-solid-state Na-ion batteries Na2+2δFe2?δ(SO4)3|Na3+xMxP1?xS4|Na2Ti3O7
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Electrolytes in current Na-ion batteries are mostly based on the same fundamental chemistry as those in Li-ion batteries-a mixture of flammable liquid cyclic and linear organic carbonates leading to the same safety concerns especially during fast charging. All-solid-state Na-ion rechargeable batteries utilizing non-flammable ceramic Na superionic conductor electrolytes are a promising alternative. Among the known sodium conducting electrolytes the cubic Na3PS4 phase has relatively high sodium ion conductivity exceeding 10?4 S cm?1 at room temperature. Here we systematically study the doping of Na3PS4 with Ge4+, Ti4+, Sn4+ and optimise the processing of these phases. A maximum ionic conductivity of 2.5 × 10?4 S cm?1 is achieved for Na3.1Sn0.1P0.9S4. Utilising this fast Na+ ion conductor, a new class of all-solid-state Na2+2δFe2?δ(SO4)3|Na3+xMxP1?xS4 (M = Ge4+, Ti4+, Sn4+) (x = 0, 0.1)|Na2Ti3O7 sodium-ion secondary batteries is demonstrated that is based on earth-abundant safe materials and features high rate capability even at room temperature. All-solid-state Na2+2δFe2?δ(SO4)3|Na3+xMxP1?xS4|Na2Ti3O7 cells with the newly prepared electrolyte exhibited charge-discharge cycles at room temperature between 1.5 V and 4.0 V. At low rates the initial capacity matches the theoretical capacity of ca. 113 mA h g?1. At 2C rate the first discharge capacity at room temperature is still 83 mA h per gram of Na2+2δFe2?δ(SO4)3 and at 80 °C it rises to 109 mA h per gram with 80% capacity retention over 100 cycles.
- Rao, Rayavarapu Prasada,Chen, Haomin,Wong, Lee Loong,Adams, Stefan
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- Mesolamellar thiogermanates [CnH2n + 1NH 3]4Ge4S10
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The mesostructured lamellar phases with the general formula [C nH2n + 1NH3]4Ge4S 10 (n = 12, 14, 16, 18) were synthesized by metathesis of alkyl ammonium chloride surfactants and Na4Ge4S10 in aqueous medium. The crystal structures of the phases with n = 12 and 14 were determined by single-crystal X-ray diffraction; [C12H 13NH3]4Ge4S10 crystallizes in monoclinic C2/c space group (a = 16.149(3), b = 46.576(9) c = 9.147(2) ?, β = 97.13(3)° and Z = 4) and [C14H 29NH3]4Ge4S10 in the triclinic P1? space group (a = 9.1280(6), b = 16.1992(1), c = 26.971(2) ?, α =73.370(1)°, β = 88.307(1)°, γ = 82.825(1)° and Z = 2). These compounds possess layers of adamantane [Ge 4S10]4- anions separated by layers of deeply interpenetrated long chain alkylammonium molecules. Strong hydrogen bonding is observed between the terminal sulfur atoms of the [Ge4S 10]4- clusters and H atoms of the NH3 groups of the surfactant molecules. Spectroscopic and thermal characterization of these compounds is reported.
- Rangan, Krishnaswamy K.,Kanatzidis, Mercouri G.
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- Aromatic hydrocarbon-catalyzed direct reaction of sulfur and sodium in a heterogeneous system: Selective and facile synthesis of sodium monosulfide and disulfide
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Sodium disulfide and monosulfide were selectively formed via the direct reaction of sulfur and an equimolar amount of sodium in 1,2-dimethoxyethane at 70 °C in the presence of a catalytic amount of aromatic hydrocarbons and ketone.
- Takata, Toshikazu,Saeki, Daisaku,Makita, Yoshimasa,Yamada, Nobuo,Kihara, Nobuhiro
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- An 57Fe Moessbauer Study of the Intermediates Formed in the Reduction of FeS2 in the Li/FeS2 Battery System
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57Fe Moessbauer spectroscopy has been used to study the intermediates formed at the FeS2 cathode during room-temperature discharge in the LiLiClO4-propylene carbonateFeS2 cell.Moessbauer spectra recorded at 4.2 K provided evidence for the formation of Li3Fe2S4 and another lithiated phase, similar to but not exactly the same as Li2FeS2.Small particles of superparamagnetic iron were also formed early in the discharge.When LiAsF6 was the electrolyte, no intermediates were detectable and rapid reduction to small particles of iron occured.Chemical lithiation of FeS2 with n-BuLi in hexane produced a mixture of reduction products similar to that observed for the LiLiClO4-propylene carbonateFeS2 cell.
- Jones, C. H. W.,Kovacs, P. E.,Sharma, R. D.,McMillan, R. S.
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- Preparation of alkali-metal hypothiophosphates in an alcoholic solution
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A procedure was developed for preparation of lithium and sodium hypothiophosphates from the corresponding alkali-metal and phosphorus sulfides in ethanol. The possibility was explored for preparation of tin(II) hypothiophosphate in an alcoholic solution by an exchange reaction between sodium hypothiophosphate and tin(II) chloride.
- Svirskaya,Lupeiko,Pakhomov,Medvedeva
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- Determination of structural, thermodynamic and phase properties in the Na2S-H2O system for application in a chemical heat pump
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Structural, thermodynamic and phase properties in the Na2S-H2O system for application in a chemical heat pump have been investigated using XRD, TG/DTA and melting point and vapour pressure determinations. Apart from the known crystalline phases Na2S·9H2O, Na2S·5H2O and Na2S a new phase Na2S·2H2O has been proven to exist. Na2S·1/2H2O is not a phase but a 3:1 mixture of Na2S and Na2S·2H2O, presumably stabilised by very slow dehydration kinetics. The vapour pressure-temperature equilibria of the sodium sulphide hydrates have been determined and a consistent set of thermodynamic functions for these compounds has been derived. XRD measurements indicate the topotactic character of the transitions between the hydration states.
- De Boer,Haije,Veldhuis
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- DETERMINATION OF GIBBS ENERGY OF THE EXCHANGE REACTION OF SULPHIDES USING BETA-ALUMINA SOLID ELECTROLYTE.
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EMF measurements of the cell Na(l)/ beta prime -alumina/Na//2S plus Ag//2S plus Ag were carried out in the temperature range 463. 4 to 843. 7 K. The results are represented by the equation E/V ( plus or minus 0. 00057) equals 1. 75793( plus or minus 0. 00
- Itoh, Mitsuru,Kozuka, Tetsuya Yamamoto Zensaku
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- Solvent-thermal preparation of nanocrystalline tin chalcogenide
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Nanocrystalline β-SnS2 has been successfully prepared by the reaction between SnCl4 and anhydrous Na2S using a solvent-thermal method at 150 °C, which is similar to the well-known hydrothermal process except that toluene is substituted for water. X-ray diffraction analysis indicates that the product is the β-SnS2 phase, and no Sn-O vibrations are found in the IR spectra. Transmission electron microscopy shows that the average particle size is about 12 nm.
- Qian,Zhang,Wang,Wang,Xie,Qian
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- Zinc Tin Chalcogenide Complexes and Their Evaluation as Molecular Precursors for Cu2ZnSnS4 (CZTS) and Cu2ZnSnSe4 (CZTSe)
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A series of five heteronuclear zinc tin chalcogenide complexes with the general formula [(tmeda)Zn(SnR2)2E3] (1-R, E = S; R = Me, Ph, tBu; 2-R, E = Se; R = Ph, tBu) have been synthesized and characterized by X-ray crystal structure analysis. In all cases, the six-membered ZnSn2E3 rings exhibit twist boat conformation. The presence of the molecular structures in solution is confirmed by 119Sn and 77Se NMR spectroscopy. Cothermolysis experiments using a mixture of complexes 1-R or 2-R and [(iPr3PCu)2(EC2H4E)]2 as a copper source were monitored by thermogravimetry and temperature dependent X-ray powder diffraction to examine the thermolysis reaction. According to Rietveld refinement, the solid residue consists of Cu2ZnSnS4 (up to 78 wt %) or Cu2ZnSnSe4 (up to 43 wt %) as the main product, respectively.
- Fuhrmann, Daniel,Dietrich, Stefan,Krautscheid, Harald
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- Topochemical anion metathesis routes to the Zr2N2S phases and the Na2S and ACL derivatives (A = Na, K, Rb)
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Anion metathesis reactions between ZrNCl and A2S (A = Na, K, Rb) in the solid state follow three different pathways depending on reaction temperature and reactant stoichiometry: (1) the reaction of ZrNCl with A2S in the 2:1 stoichiometry at 800 °C/72 h/in vacuo yields α-Zr2N2S with the expected layered structure of La2O2S. Above 850 °C, α-Zr2N2S (P3m1; a = 3.605(1) A, c = 6.421(3) A) neatly transforms to β-Zr2N2S (P63/mmc: a = 3.602(1) A, c = 12.817(1) A). The structures of the α- and β-forms are related by an a/2 shift of successive Zr2N2 layers. (2) The same reaction at low temperatures (300-400 °C) yields ACl intercalated phases of the formula AxZr2N2SClx (0 a ZrNCl-type structure. The S and Cl ions are disordered and the c lattice parameters are alkali dependent (R3m, a ～ 3.6 A, c ～ 28.4 (Na), 28.9 (K), and 30.5 A (Rb). AxZr2N2SClx phases are hygroscopic and reversibly absorb water to give monohydrates. (3) Reaction of ZrNCl with excess A2S at 400-1000 °C gives A2S intercalated phases of the formula A2xZr2N2S1+x (0 a ZrNCl type structure (R3m, a ～ 3.64 A, c ～ 29.48 A). Structural characterization of the new phases and implications of the results are described.
- Stoltz,Ramesha,Sirchio,Goenen,Eichhorn,Salamanca-Riba,Gopalakrishnan
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- Selective and Facile Synthesis of Sodium Sulfide and Sodium Disulfide Polymorphs
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Na2S and Na2S2 were selectively synthesized using a microwave-assisted thermal treatment of a Na+/S solution in tetraglyme between 100 and 200 °C, considerably lower than that of current routes. This novel synthetic pathway yields the Na2S phase in high purity and allows for good selectivity between the polymorphs of Na2S2 (α and β phases). These materials show promising electrochemical properties and are particularly interesting for the continued development of Na-S batteries.
- El-Shinawi, Hany,Cussen, Edmund J.,Corr, Serena A.
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- Lithium intercalation in open-ended TiS2 nanotubes
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Filling the gaps: A low-temperature solution route was employed to successfully prepare multiwalled TiS2 nanotubes with open-ended tips (see HRTEM image). The as-prepared nanotubes could be intercalated with lithium atoms by treating a solution of the TiS2 nanotubes with nBuLi. The resulting homogeneous intercalated phase of LiTiS2 exhibited a c-axis expansion of approximately 10.5% relative to the original TiS2 material.
- Chen, Jun,Tao, Zhan-Liang,Li, Suo-Long
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- Flux Synthesis of LiAuS and NaAuS: Chicken-Wire-Like Layer Formation by Interweaving of (AuS)nn- Threads. Comparison with α-HgS and AAuS (A = K, Rb)
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From the reaction of Au with alkali metal polysulfide liquids, LiAuS and NaAuS were discovered. Orange crystals of LiAuS crystallize in the monoclinic space group C2/c, (no. 15), with a = 8.994(2) ?, b = 8.956(2) ?, c = 7.201(3) ?, β= 128.68(1)°, and Z = 8. Light-yellow planks of NaAuS crystallize in the orthorhombic space group Ccca, (no. 68), with a = 14.658(5) ?, b = 21.043(7) ?, c = 7.118(4) ?, and Z = 32. Both compounds contain infinite one-dimensional (AuS)nn- chains, featuring alternating sulfide anions and linear coordinated Au centers. In LiAuS, the chains are zigzag and fully extended and they pack in two mutually perpendicular sets. In NaAuS, the same chains coil in an unusual fashion so that they become interwoven to form layers reminiscent of chicken-wire . This novel coiling mode allows Au-Au contacts to form, which help to stabilize the structure. The structural relationships between LiAuS, NaAuS, Na7Au5S6, AAuQ (A = K, Rb, Cs; Q = S, Se), and α-HgS are explored.
- Axtell III, Enos A.,Liao, Ju-Hsiou,Kanatzidis, Mercouri G.
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- Facile synthesis of thiophene/selenophene-fused acene and their optoelectronic properties
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Dibenzo thiophene- and selenophene are widely used in very different areas, ranging from biology to electronic engineering. However, their compounds require multiple synthetic steps. In this report, we introduce a two-step facile synthesis of a dibenzo thiophene/selenophene, namely diindeno[1,2-b:2′, 1′-d]thiophene-10, 11-dione (DITD) and diindeno[1,2-b:2′, 1′-d]selenophene-10, 11-dione (DISD). The compounds were further converted via a Knoevenagel condensation to dicyanovinylene derivatives. Their electronic and optoelectronic properties, backed by density functional theory (DFT) calculations are reported.
- Wei, Zitang,Li, Xiangchun,Wudl, Fred,Zheng, Yonghao
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- Kinetics and Mechanism of the Reaction of the Ammoniated Electron with Sodium Thiosulfate in Liquid Ammonia
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The reaction of sodium with thiosulfate in liquid ammonia was found to be second order, first order with respect to both the sodium and thiosulfate concentration.The sodium ion concentration was found to have a dominant influence on the net reaction rate, and a mechanism involving ion-paired species is proposed.The stoichiometry and reaction products were also determined.
- Lau, Nathanielo,Dewald, Robert R.
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- Synthesis in molten alkali metal polythiophosphate fluxes. The new quaternary bismuth and antimony thiophosphates ABiP2S7 (A = K, Rb), A3M(PS4)2 (A = K, Rb, Cs; M = Sb, Bi), Cs3Bi2(PS4)3, and Na0.16Bi1.28P2S6
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The molten alkali metal polychalcogenide flux method was used to prepare the new compounds ABiP2S7 (A = K, Rb), A3M(PS4)2 (A = K, Rb, Cs; M = Sb, Bi), Cs3Bi2 (PS4)3, and Na0.16Bi1.28P2S6. The structural diversity in this family of compounds ranges from the one-dimensional non-centrosymmetric chains of A3M(PS4)2 and the layered compounds, ABiP2S7 and Cs3Bi2 (PS4)2, to the dense three-dimensional framework of Na0.16Bi1.28P2S6. Their synthesis, structural characterization, optical absorption and thermal properties are reported.
- McCarthy,Kanatzidis
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- Multielectron, Cation and Anion Redox in Lithium-Rich Iron Sulfide Cathodes
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Conventional Li-ion cathodes store charge by reversible intercalation of Li coupled to metal cation redox. There has been increasing interest in new materials capable of accommodating more than one Li per transition-metal center, thereby yielding higher charge storage capacities. We demonstrate here that the lithium-rich layered iron sulfide Li2FeS2 as well as a new structural analogue, LiNaFeS2, reversibly store ≥1.5 electrons per formula unit and support extended cycling. Ex situ and operando structural and spectroscopic data indicate that delithiation results in reversible oxidation of Fe2+ concurrent with an increase in the covalency of the Fe-S interactions, followed by reversible anion redox: 2 S2-/(S2)2-. S K-edge spectroscopy unequivocally proves the contribution of the anions to the redox processes. The structural response to the oxidation processes is found to be different in Li2FeS2 in contrast to that in LiNaFeS2, which we suggest is the cause for capacity fade in the early cycles of LiNaFeS2. The materials presented here have the added benefit of avoiding resource-sensitive transition metals such as Co and Ni. In contrast to Li-rich oxide materials that have been the subject of so much recent study and that suffer capacity fade and electrolyte degradation issues, the materials presented here operate within the stable potential window of the electrolyte, permitting a clearer understanding of the underlying processes.
- Hansen, Charles J.,Zak, Joshua J.,Martinolich, Andrew J.,Ko, Jesse S.,Bashian, Nicholas H.,Kaboudvand, Farnaz,Van Der Ven, Anton,Melot, Brent C.,Nelson Weker, Johanna,See, Kimberly A.
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- Na2EuAs2S5, NaEuAsS4, and Na4Eu(AsS4)2: Controlling the valency of arsenic in polysulfide fluxes
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The reactivity of europium with As species in Lewis basic alkali-metal polysulfide fluxes was investigated along with compound formation and the As3+/As5+ interplay vis-a-vis changes in the flux basicity. The compound Na2EuAs2S5 containing trivalent As3+ is stabilized from an arsenic-rich polysulfide flux. It crystallizes in the monoclinic centrosymmetric space group P21/c. Na2EuAs2S5 has [As2S 5]4- units, built of corner sharing AsS3 pyramids, which are coordinated to Eu2+ ions to give a two-dimensional (2D) layered structure. A sodium polysulfide flux with comparatively less arsenic led to the As5+ containing compounds NaEuAsS4 (orthorhombic, Ama2) and Na4Eu(AsS 4)2 (triclinic, P1) depending on Na2S/S ratio. The NaEuAsS4 and Na4Eu(AsS4)2 have a three-dimensional (3D) structure built of [AsS4]3- tetrahedra coordinated to Eu2+ ions. All compounds are semiconductors with optical energy gaps of ～2 eV.
- Bera, Tarun K.,Kanatzidis, Mercouri G.
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- Na3SbS3: Single crystal X-ray diffraction, raman spectroscopy, and impedance measurements
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Na3SbS3 was prepared by the reaction of anhydrous Na2S, antimony, and sulfur in a ratio of 3:2:3 at 870 K. The pale yellow compound is air and moisture sensitive. A microcrystalline sample was obtained after annealing Na3SbS3 for two weeks at 720 K. The crystal structure of Na3SbS3 was determined by single-crystal X-ray diffraction at 123 K. Na3SbS3 crystallizes in the cubic space group P213 (No. 198) with a = 8.6420(1) A, V = 645.42(1) A3 and Z = 4. The structure refinement converged to R = 0.0099 (wR = 0.0181) for 592 independent reflections and 23 parameters. Na3SbS3 is isotypic with Na 3AsS3. Sodium atoms are located on three different sites, which show a strongly distorted octahedral coordination sphere of sulfur. The coordination polyhedra of equivalent sodium sites share common vertices, whereas those of different sodium sites share common faces. Antimony and sulfur form trigonal SbS3 pyramids, which coordinate sodium as a mono-, bi-, or tridentate ligand. Raman spectroscopic investigations result in stretching modes ν(Sb-S) at 334, 321, and 312 cm-1, respectively. Thermoanalytical studies do not show any additional thermal effects up to the melting point of 875 K. Impedance spectroscopy on Na3SbS3 in a range from 325 to 570 K shows a temperature dependent Na+ conductivity, which is 1.9 × 10-6 Ω-1·cm-1 at 570 K. Copyright
- Pompe, Constantin,Pfitzner, Arno
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- Thiolate Spin Population of Type I Copper in Azurin Derived from33S Hyperfine Coupling
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The electron transfer mediating properties of type I copper proteins stem from the intricate ligand coordination sphere of the Cu ion in their active site. These redox properties are in part due to unusual cysteine thiol coordination, which forms a highly covalent copper-sulfur (Cu-S) bond. The structure and electronic properties of type I copper have been the subject of many experimental and theoretical studies. The measurement of spin delocalization of the Cu(II) unpaired electron to neighboring ligands provides an elegant experimental way to probe the fine details of the electronic structure of type I copper. To date, the crucial parameter of electron delocalization to the sulfur atom of the cysteine ligand has not been directly determined experimentally. We have prepared33S-enriched azurin and carried out W-band (95 GHz) electron paramagnetic resonance (EPR) and electron-electron double resonance detected NMR (EDNMR) measurements and, for the first time, recorded the33S nuclear frequencies, from which the hyperfine coupling and the spin population on the sulfur of the thiolate ligand were derived. The overlapping33S and14N EDNMR signals were resolved using a recently introduced two-dimensional correlation technique, 2D-EDNMR. The33S hyperfine tensor was determined by simulations of the EDNMR spectra using33S hyperfine and quadrupolar tensors predicted by QM/MM DFT calculations as starting points for a manual spectral fit procedure. To reach a reasonable agreement with the experimental spectra, the33S hyperfine principal value, Az, and one of the corresponding Euler angles had to be modified. The final values obtained gave an experimentally determined sulfur spin population of 29.8 ± 0.7%,significantly improving the wide range of 29-62% reported in the literature. Our direct, experimentally derived value now provides an important constraint for further theoretical work aimed at unravelling the unique electronic properties of this site.
- Ramirez Cohen, Marie,Mendelman, Netanel,Radoul, Marina,Wilson, Tiffany D.,Savelieff, Masha G.,Zimmermann, Herbert,Kaminker, Ilia,Feintuch, Akiva,Lu, Yi,Goldfarb, Daniella
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- Quaternary Pavonites A1+xSn2-xBi5+xS10 (A+ = Li+, Na+): Site Occupancy Disorder Defines Electronic Structure
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The field of mineralogy represents an area of untapped potential for the synthetic chemist, as there are numerous structure types that can be utilized to form analogues of mineral structures with useful optoelectronic properties. In this work, we describe the synthesis and characterization of two novel quaternary sulfides A1+xSn2-xBi5+xS10 (A = Li+, Na+). Though not natural minerals themselves, both compounds adopt the pavonite structure, which crystallizes in the C2/m space group and consists of two connected, alternating defect rock-salt slabs of varying thicknesses to create a three-dimensional lattice. Despite their commonalities in structure, their crystallography is noticeably different, as both structures have a heavy degree of site occupancy disorder that affects the actual positions of the atoms. The differences in site occupancy alter their electronic structures, with band gap values of 0.31(2) eV and 0.07(2) eV for the lithium and sodium analogues, respectively. LiSn2Bi5S10 exhibits ultralow thermal conductivity of 0.62 W m-1 K-1 at 723 K, and this result is corroborated by phonon dispersion calculations. This structure type is a promising host candidate for future thermoelectric materials investigation, as these materials have narrow band gaps and intrinsically low thermal conductivities.
- Khoury, Jason F.,Hao, Shiqiang,Stoumpos, Constantinos C.,Yao, Zhenpeng,Malliakas, Christos D.,Aydemir, Umut,Slade, Tyler J.,Snyder, G. Jeffrey,Wolverton, Chris,Kanatzidis, Mercouri G.
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- Mixed thio/oxo orthovanadates Na3[VSxO4-x] (x = 2, 3): Synthesis - crystal structures - properties
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Mixed sodium thio/oxo orthovanadates(V), dark red Na3[VS 3O] and orange red Na3[VS2O2], were synthesized via reactions in the melt starting from V, Na, Na2S, Na2O and sulfur. The structure of the low temperature phase of Na3[VS3O] (space group Pnma, a = 589.5(3), b = 962.8(5), c = 1186.6(6) pm, Z = 4, R1 = 0.0494) contains anions [VS3O] 3- almost identical to those known from the high temperature form, β-Na3[VS3O] (space group Cmc21, a = 968.4(4), b = 1194.6(4), c = 590.5(2) pm, Z = 4, R1 = 0.0291). The second order phase transition between these two forms at 536°C was studied by temperature dependent powder diffraction and explained on the basis of a comparison of the anion packing in the two related structures. The packing of the dithiodioxovanadate anions in Na3[VS2O2] (space group Pbca, a = 1162.7(2), b = 592.71(12), c = 1766.7(4) pm, Z = 8, R1 = 0.0312) is also closely related. The chemical bonding in the anions [VS 3O]3- and [VS2O2]3- of approximately ideal C3v and C2v symmetry is discussed on the basis of FP-LAPW band structure calculations and force constants obtained from Raman spectroscopy. The decrease of the calculated band gaps with increasing S content x in Na3[VSxO4-x] is in accordance with the optical properties showing a gradually deepening of the crystal and solution colour. Discernible trends in the chemical bonding in this series of mixed thio-oxo anions also include the amount of π bonding of the V-O and V-S bonds and the corresponding variation of force constants and V-O/V-S distances.
- Schnabel, Simone,R?hr, Caroline
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- Neutral Mo6Q8-clusters with terminal phosphane ligands-a route to water-soluble molecular units of Chevrel phases
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Despite the numerous studies on Chevrel phases, their building blocks-molecular compounds containing the {Mo6Q8} cluster core-are hardly presented in the literature. Here we present rare examples of phosphane molybdenum chalcogenide clusters-[{Mo6Q8}(Ph2P
- Gassan, Alena D.,Ivanov, Anton A.,Novikova, Evgeniya D.,Shestopalov, Michael A.,Vorotnikov, Yuri A.
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p. 2218 - 2223
(2022/02/16)
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- An efficient method for synthesizing dimethylsulfonio-34S-propionate hydrochloride from 34S8
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Dimethylsulfoniopropionate (DMSP, (2-carboxyethyl)dimethylsulfonium) is a highly abundant compound in marine environments. As a precursor to the climatically active gas, dimethylsulfide (DMS), DMSP connects the marine and terrestrial sulfur cycles. However, the fate of DMSP in microbial biomass is not well understood as only a few studies have performed isotopic labeling experiments. A previously published method synthesized 34S-labeled DMSP from 34S8, but the efficiency was only 26% and required five separate reactions, expensive reagents, and purification of the products of each reaction. In this study, a method of synthesizing 34S-labeled DMSP from 34S8 is described. Improvements include elemental steps, inexpensive reagents, purification of only one intermediate, and less time to complete. The efficiency of this method is 65% and results in pure DMSP with more than 98% isotope enrichment as determined by 1H-nuclear magnetic resonance (NMR) and gas chromatography–mass spectrometry (GC–MS).
- Wirth, Joseph S.,Whitman, William B.
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- In situ TEM observing structural transitions of MoS2 upon sodium insertion and extraction
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In this study, the sodiation and desodiation processes of MoS2 were characterized by using an in situ TEM technique. The structural evolution of MoS2 and its performance in a coin-type cell are recognized. Our findings provide a fundamental understanding of the reaction mechanism of MoS2 as anode for Na ion batteries.
- Zhang, Liqiang,Tang, Yushu,Wang, Yuecun,Duan, Yongli,Xie, Degang,Wu, Chunyang,Cui, Lishan,Li, Yongfeng,Ning, Xiaohui,Shan, Zhiwei
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p. 96035 - 96038
(2016/10/25)
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- Half sandwich complexes of chalcogenated pyridine based bi-(N, S/Se) and terdentate (N, S/Se, N) ligands with (η6-benzene)ruthenium(ii): Synthesis, structure and catalysis of transfer hydrogenation of ketones and oxidation of alcohols
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The half sandwich complexes [(η6-C6H 6)Ru(L)Cl][PF6] (1-5) have been synthesized by the reactions of (2-arylchalcogenomethyl)pyridine [L = L1-L3] and bis(2-pyridylmethyl)chalcogenide [L = L4-L5] (chalcogen = S, Se; Ar = Ph/2-pyridyl for S, Ph for Se) with [(η6-C6H 6)RuCl2]2, at room temperature followed by treatment with NH4PF6. Their HR-MS, 1H, 13C{1H} and 77Se{1H} NMR spectra have been found characteristic. The single crystal structures of 1-5 have been established by X-ray crystallography. The Ru has pseudo-octahedral half sandwich "piano-stool" geometry. The complexes 1-5 have been found efficient for catalytic oxidation of alcohols with N-methylmorpholine-N-oxide (NMO) and transfer hydrogenation of ketones with 2-propanol (at moderate temperature 80 °C) as TON values are up to 9.9 × 103 and 9.8 × 103 respectively for the two catalytic reactions. On comparing the required catalyst loading for good conversions and reaction time for the present complexes with those reported in literature for other transfer hydrogenation/oxidation catalysts, it becomes apparent that 1-5 have good promise. The complexes of Se ligands have been found more efficient than their sulphur analogues. The complexes of bidentate ligands are more efficient than those of terdentate, due to difficult bond cleavage in the case of latter. These orders of efficiency are supported by DFT calculations. The calculated bond lengths/angles by DFT are generally consistent with the experimental ones.
- Prakash, Om,Sharma, Kamal Nayan,Joshi, Hemant,Gupta, Pancham Lal,Singh, Ajai K.
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p. 8736 - 8747
(2013/07/27)
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- Method for obtaining polysulphide monoorganoxysilanes
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The invention concerns the preparation of sulphur-containing organosilicic compounds of general formula (I) wherein, for example: R1═C1-C15 alkyl; R2 and R3═C1-C6 alkyl; in a mean number ranging from 1.5±0.1 to 5±0.1. Said preparation is carried out by performing successively the following steps (a), (b) and (c): (a) hydrosilylation of the type: R2R3HSi-Hal+CH2═CH—CH2-Hal}Hal-R2R3Si—(CH2)3Hal; (b) alcoholysis of the type: Hal-R2R3Si—(CH2)3-Hal+R1—OH}R′O—R2R3Si—(CH2)3Hal; (c) sulphidization of the type: R′O—R2R3Si—(CH2)3Hal+M2Sx} compound of formula (I); with Hal=a halogen atom and M=alkali metal.
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Page/Page column 9
(2011/05/08)
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- Soluble semiconductors AAsSe2 (A = Li, Na) with a direct-band-gap and strong second harmonic generation: A Combined experimental and theoretical study
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AAsSe2 (A = Li, Na) have been identified as a new class of polar direct-band gap semiconductors. These I - V - Vl2 ternary alkali-metal chalcoarsenates have infinite single chains of (1/∞)[AsQ 2] derived from corner-sharing pyramidal AsQ3 units with stereochemically active lone pairs of electrons on arsenic. The conformations and packing of the chains depend on the structure-directing alkali metals. This results in at least four different structural types for the Li1 xNaxAsSe2 stoichoimetry (α-LiAsSe 2, β-LiAsSe2, γ-NaAsSe2, and δ-NaAsSe2). Single-crystal X-ray diffraction studies showed an average cubic NaCI-type structure for (α-LiAsSe2, which was further demonstrated to be locally distorted by pair distribution function (PDF) analysis. The β and γ forms have polar structures built of different (1/∞)[AsSe2] chain conformations, whereas the δ form has nonpolar packing. A wide range of direct band gaps are observed, depending on composition: namely, 1.11 eV for (α-LiAsSe2, 1.60 eV for LiAsS2, 1.75 eV for γ-NaAsSe2, 2.23 eV for NaAsS2. The AAsQ2 materials are soluble in common solvents such as methanol, which makes them promising candidates for solution processing. Band structure calculations performed with the highly precise screenedexchange sX-LDA FLAPW method confirm the direct-gap nature and agree well with experiment. The polar y-NaAsSe2 shows very large nonlinear optical (NLO) second harmonic generation (SHG) response in the wavelength range of 600-950 nm. The theoretical studies confirm the experimental results and show that y-NaAsSe2 has the highest static SHG coefficient known to date, 337.9 pm/V, among materials with band gaps larger than 1.0 eV.
- Bera, Tarun K.,Jang, Joon I.,Song, Jung-Hwan,Malliakas, Christos D.,Freeman, Arthur J.,Ketterson, John B.,Kanatzidis, Mercouh G.
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p. 3484 - 3495
(2010/04/30)
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- Synthesis and properties of Na6[Pb(S2O 3)4] · 6H2O
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Conditions for the synthesis of the water-soluble lead thiosulfate complex Na6[Pb(S2O3)4] · 6H2O were determined. The complex synthesized was characterized by UV and IR spectroscopy and X-ray phase and thermal a
- Egorov
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p. 179 - 185
(2010/06/17)
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- Stages of thermal decomposition of sodium oxo-salts of sulphur
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Thermal behaviour of sodium oxo-salts of sulphur: Na2SO 4, Na2S2O7, Na2S 2O6, Na2SO3, Na2S 2O5, Na2S
- Jaszczak-Figiel, Beata,Gontarz
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p. 147 - 154
(2009/05/06)
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- PROCESS FOR THE RECOVERY OF MATERIALS FROM A DESULFURIZATION REACTION
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Disclosed herein is an improved method for regenerating materials from a desulfurization/demetallation reaction. The desulfurization/demetallation reaction preferably has products including one or more of an alkali sulfide, polysulfide or hydrosulfide, or alkali earth sulfide, polysulfide, or hydrosulfide. The method includes the steps of reacting the desulfurization/demetallation products with a halogen, liberating and removing sulfur from the product, and then electrolyzing the halogenated products to separate the halogen from the alkali metal or alkali earth metal.
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Page/Page column 5
(2010/02/13)
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- NaPdPS4 and RbPdPS4: Systems with infinite straight 1/∞ [PdPS4]- chains soluble in polar solvents and the structure of cubic RbPdPS4{Rb0.33P0.4S 2.23Ox}
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The synthesis, crystal structures, chemical and spectroscopic properties of NaPdPS4, RbPdPS4, and RbPdPS4{Rb 0.33P0.4S2.23Ox} are described. NaPdPS4, RbPdPS4, are isostructural and crystallize in the tetragonal system I4/mcm with cell parameters a=7.3074(8)A, c=12.2308(14)A and a=8.2954(3)A, c=12.2284(4)A respectively. RbPdPS4{Rb0.33P0.4S2.23O x} is cubic, space group Pm-3n and a=12.0042(2)A. All compounds contain the same 1∞[PdPS4]- chains made of alternating square planar Pd2+ cations and tetrahedral [PS 4]3- anions. RbPdPS4{Rb0.33P 0.4S2.23Ox} contains co-crystallized highly disordered molecular species encapsulated within [Rb8] cubic cavities. Spectroscopic solid state 31P NMR, infrared and Raman data as well as elemental analysis suggest that these species could be S n2- (n=3 or 4) anions and possibly cationic [P 4S6O]6+ fragments. NaPdPS4 and RbPdPS4 exhibit exfoliative dissolution in polar solvents giving rise to solutions that show signs of complex fluid behavior.
- Coste, Servane,Hanko, Jason,Bujoli-Doeuff, Martine,Louarn, Guy,Evain, Michel,Brec, Raymond,Alonso, Bruno,Jobic, Stephane,Kanatzidis, Mercouri G.
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p. 133 - 145
(2008/10/08)
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- Low-temperature precursor synthesis of crystalline nickel disulfide
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Pure, crystalline nickel disulfide is synthesized within seconds from the solid-state reaction between potassium hexafluoronickelate(IV) and sodium pentasulflde hydrate at ～65°C. The nickel disulfide product is isolated by simply washing away the byproduct salts. The reaction is influenced by the hydration and the sulfur content of the sulfiding agent and by the transition-metal precursor. Increasing the hydration of the sodium pentasulfide or lowering the oxidation state of the nickel in potassium hexafluoronickelate from Ni(IV) to Ni(III) favors a less crystalline product. Reactions containing sulfiding agents with lower sulfur content, such as sodium monosulfide or sodium disulfide, produce mixtures of nickel monosulfide and nickel disulfide. X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry results are presented.
- Bonneau, Philippe R.,Shibao, Robert K.,Kaner, Richard B.
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p. 2511 - 2514
(2008/10/08)
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- DISSOLUTION KINETICS OF SULFUR IN THE Ca(OH)2-H2O AND Ca(OH)2-H2O-Na2SO4 SYSTEMS.
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In this work a kinetic equation was derived for the reaction of sulfur with calcium hydroxide. Beside this, kinetic mechanisms were studied for the method of obtaining alkaline sulfide solution from lime and sodium sulfate. The test results show that in solution sulfur exists in the form of polysulfide and thiosulfate ions. The ratio of zero valent polysulfide and divalent monosulfide sulfur in the polysulfide is determined by the reagents ratio and is independent of temperature. The relationship of total concentration of the monosulfide and polysulfide sulfur in the polysulfide molecule to the concentration of monosulfide sulfur (polysulfidity) depends on the quantity of calcium hydroxide charge and reduces from 5. 0 to 4. 2 with increased usage of calcium hydroxide from 0. 47 to 0. 71 M. Some excess of the thiosulfate sulfur concentration with respect to the monosulfide resulted due to partial oxidation of sulfur with oxygen from air.
- Mukhnev,Rashkovskii,Emel'yanov
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p. 277 - 280
(2008/10/08)
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- Solvent free preparation of diarylthioethers
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A method for making diarylthioethers including thioetherbis(phthalic anhydrides) and thioetherbis(phthalimides) in the absence of a solvent medium by the interaction of sulfide compounds, including alkali metal sulfides and alkali metal hydrogen sulfides,
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