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A low-temperature ionothermal method for the facile synthesis of the halide carbonate, Ba 3 Cl 4 CO 3 , in single-crystalline form has been developed. This has enabled the first determination of the crystal structure of this material to be carried out. Analysis of single-crystal X-ray diffraction data indicates that barium chloride carbonate crystallises in the orthorhombic space group Pnma ( Z =4), with a =8.4074(11), b= 9.5886(12), c =12.4833(15) A ( R w =0.0392). It exhibits a complex structure in which a three-dimensional network is formed from cross-linking of chains of anion-centred octahedra that share faces.

The synthesis and structural characterisation, carried out using a combination of single-crystal and powder X-ray diffraction, of the materials MGeTe (M = Co, Rh) are described. These phases adopt an ordered α-NiAs2 structure, which can be considered intermediate between those of pyrite and marcasite. Electrical resistivity and Seebeck coefficient measurements, carried out over the temperature range 77 ≤ T/K ≤ 325, indicate that these materials are n-type semiconductors.

Variable-temperature powder neutron diffraction data reveal that Co3Sn2S2 crystallizes in the shandite structure (space group R (3) over barm, a = 5.36855(3)angstrom, c = 13.1903(1) angstrom at 300 K). The structural relationship between Co3Sn2S2 and the intermetallic compound CoSn, both of which contain Kagome nets of cobalt atoms, is discussed. Resistivity and Seebeck coefficient measurements for Co3Sn2S2 are consistent with metallic behaviour. Magnetic susceptibility measurements indicate that Co3Sn2S2 orders ferromagnetically at 180(10) K, with a saturation moment of 0.29 mu(B) per cobalt atom at 5 K. The onset of magnetic ordering is accompanied by marked anomalies in the electrical transport properties. (c) 2008 Elsevier Masson SAS. All rights reserve

High-resolution powder neutron diffraction data collected for the skutterudites MGe1.5S1.5 (M=Co, Rh, Ir) reveal that these materials adopt an ordered skutterudite structure (space group R3¯), in which the anions are ordered in layers perpendicular to the [111] direction. In this ordered structure, the anions form two-crystallographically distinct four-membered rings, with stoichiometry Ge2S2, in which the Ge and S atoms are trans to each other. The transport properties of these materials, which are p-type semiconductors, are discussed in the light of the structural results. The effect of iron substitution in CoGe1.5S1.5 has been investigated. While doping of CoGe1.5S1.5 has a marked effect on both the electrical resistivity and the Seebeck coefficient, these ternary skutterudites exhibit significantly higher electrical resistivities than their binary counterparts.

International audience; Bulk polycrystalline samples in the series Ti1-xNbxS2 (0 ≤ x ≤ 0.075) were prepared using mechanical alloying synthesis and spark plasma sintering. X-ray diffraction analysis coupled with high resolution transmission electron microscopy indicates the formation of trigonal TiS2 by high energy ball-milling. The as-synthesized particles consist of pseudo-ordered TiS2 domains of around 20-50 nm, joined by bent atomic planes. This bottom-up approach leads, after spark plasma sintering, to homogeneous solid solutions, with a niobium solubility limit of x = 0.075. Microstructural observations evidence the formation of small crystallites in the bulk compounds with a high density of stacking faults. The large grain boundary concentration coupled with the presence of planar defects, leads to a substantial decrease in the thermal conductivity to 1.8 W/mK at 700 K. This enables the figure of merit to reach ZT = 0.3 at 700 K for x = 0.05, despite the lower electron mobility in mechanically alloyed samples due to small crystallite/grain size and structural defects. © 2015 Elsevier Ltd.

International audience; A family of phases, CoxTiS2 (0 ≤ x ≤ 0.75) has been prepared and characterised by powder X-ray and neutron diffraction, electrical and thermal transport property measurements, thermal analysis and SQUID magnetometry. With increasing cobalt content, the structure evolves from a disordered arrangement of cobalt ions in octahedral sites located in the van der Waals' gap (x ≤ 0.2), through three different ordered vacancy phases, to a second disordered phase at x ≥ 0.67. Powder neutron diffraction reveals that both octahedral and tetrahedral inter-layer sites are occupied in Co0.67TiS2. Charge transfer from the cobalt guest to the TiS2 host affords a systematic tuning of the electrical and thermal transport properties. At low levels of cobalt intercalation (x andlt; 0.1), the charge transfer increases the electrical conductivity sufficiently to offset the concomitant reduction in |S|. This, together with a reduction in the overall thermal conductivity leads to thermoelectric figures of merit that are 25% higher than that of TiS2, ZT reaching 0.30 at 573 K for CoxTiS2 with 0.04 ≤ x ≤ 0.08. Whilst the electrical conductivity is further increased at higher cobalt contents, the reduction in |S| is more marked due to the higher charge carrier concentration. Furthermore both the charge carrier and lattice contributions to the thermal conductivity are increased in the electrically conductive ordered-vacancy phases, with the result that the thermoelectric performance is significantly degraded. These results illustrate the competition between the effects of charge transfer from guest to host and the disorder generated when cobalt cations are incorporated in the inter-layer space. © The Royal Society of Chemistry 2016.

We describe the construction of a cell that enables the electrical resistance of a material to be measured simultaneously with the collection of powder neutron diffraction data at elevated temperatures. The cell has been used to investigate the origin of the anomalous electron-transport properties of the monosulphide, CrS. The data reveal that a decrease in electrical resistance above 573 K is associated with the disappearance of semiconducting monoclinic CrS and the concomitant growth of a disordered CdI 2 -type metallic phase.

The synthesis and crystal structure of four gallium sulphide open frameworks, built from supertetrahedral clusters, are described. The structures of [ C 4 NH 12 ] 6 [ Ga 10 S 18 ] (1) and [ C 4 NH 12 ] 12 [ Ga 20 S 35.5 ( S 3 ) 0.5 O ] (2) contain supertetrahedral T3 clusters, while in the isostructural compounds [ C 4 NH 12 ] 16 [ Ga 10 S 18 M 4 Ga 16 S 33 ] ( M = Co (3), Zn (4)), T3 and T4 clusters alternate. These materials exhibit three-dimensional frameworks, with topologies consisting of two interpenetrating diamond lattices, and contain over 50% of solvent accessible void space. UV–Vis diffuse reflectance measurements indicate that these compounds are semiconducting, with band gaps over the range 3.4–4.1 eV.

Bi2O2Te is prepared by solid state reaction of a stoichiometric mixture of Bi, Bi2O3, and Te (evacuated silica tubes, 873 K, 10 h; complex heating schedule).

A combination of structural, physical, and computational techniques including powder X-ray and neutron diffraction, SQUID magnetometry, electrical and thermal transport measurements, DFT calculations, and 119Sn Mossbauer and X-ray photoelectron spectroscopies has been applied to Co3Sn2–xInxS2 (0 ≤ x ≤ 2) in an effort to understand the relationship between metal-atom ordering and physical properties as the Fermi level is systematically varied. While solid solution behavior is found throughout the composition region, powder neutron diffraction reveals that indium preferentially occupies an interlayer site over an alternative kagome-like intralayer site. DFT calculations indicate that this ordering, which leads to a lowering of energy, is related to the differing bonding properties of tin and indium. Spectroscopic data suggest that throughout the composition range 0 ≤ x ≤ 2, all elements adopt oxidation states that are significantly reduced from expectations based on formal charges. Chemical substitution ena...

The skutterudite-related material CoGe1.5Te1.5 has been synthesised and structurally characterised by powder neutron diffraction. Analysis of the high-resolution powder neutron diffraction data indicates that the structure of CoGe1.5Te1.5 retains the a+a+a+ tilt system of the ideal skutterudite structure, while the anions are ordered in layers perpendicular to the [111] direction of the skutterudite unit cell. This anion ordering results in a lowering of the symmetry from cubic to rhombohedral (space group R 3 ¯ , a=12.3270(5) and c=15.102(1) A at 293 K). The electrical transport properties have been investigated using four-probe resistivity and Seebeck coefficient measurements. The temperature dependence of the electrical resistivity and the magnitude of the Seebeck coefficient indicate that CoGe1.5Te1.5 is an n-type semiconductor.

Two new main group metal sulphides, [C10N4H26]0.5[InS2] (1) and [C10N4H26]0.5[GaS2] (2) have been prepared solvothermally in the presence of 1,4-bis(3-aminopropyl)piperazine and their crystal structures determined by single-crystal X-ray diffraction. Both compounds are isostructural and crystallise in the monoclinic space group P21/n (Z=4), with a=6.5628(5), b=11.2008(9), c=12.6611(9) A and β=94.410(4)° (wR=0.035) for compound (1) and a=6.1094(5), b=11.2469(9), c=12.7064(10) A and β=94.313(4)° (wR=0.021) for compound (2). The structure of [C10N4H26]0.5[MS2] (M=In,Ga) consists of one-dimensional [MS2]− chains which run parallel to the crystallographic a axis and are separated by diprotonated amine molecules. These materials represent the first example of solvothermally prepared one-dimensional gallium and indium sulphides.

We present ferromagnetic resonance (FMR) and magnetic properties of single domain Y3Fe5O12 (YIG) nanoparticles with an average size of 60 nm. The saturation magnetization shows a diminution of practically 1/3 of the bulk magnetization due to the surface/volume contribution. The coercive force vs. temperature indicates that the particles are single magnetic domains in the blocked state. The FMR data, confirm this state below 350 K. Data of DC-magnetization, magnetic resonance field and linewidth of the FMR spectra are presented. Shape, surface and dipolar contributions to effective anisotropy are discussed. © 2004 Elsevier B.V. All rights reserved.

Two new antimony sulphides have been prepared solvothermally and characterised by single-crystal X-ray diffraction. [Co(en) 3 ][Sb 4 S 7 ] ( 1 ) was prepared at 140 °C from CoS, Sb 2 S 3 and S in the presence of ethylenediamine, whilst heating a mixture of Sb 2 S 3 , Co and S in tris(2-aminoethyl)amine, N(CH 2 CH 2 NH 2 ) 3 , at 180 °C results in the formation of [C 6 H 20 N 4 ][Sb 4 S 7 ] ( 2 ). Both materials contain [Sb 4 S 7 ] 2− chains formed from linkage of cyclic Sb 3 S 6 3− units by SbS 3 3− pyramids. In ( 1 ), the [Sb 4 S 7 ] 2− chains are linked by secondary Sb–S interactions to form sheets, between which the charge balancing [Co(en) 3 ] 2+ cations reside. The structure of ( 2 ) involves interconnection of pairs of [Sb 4 S 7 ] 2− chains through Sb 2 S 2 rings to form isolated [Sb 4 S 7 ] 2− double chains which are interleaved by protonated template molecules.

Ordered-defect phases of stoichiometry AB2S4 adopt a structure in which dichalcogenide slabs are separated by defective layers containing cations in 50% of the octahedral sites. The physical properties of such phases may be varied systematically by chemical substitution. This may be effected preferentially at sites in either the dichalcogenide or defective layers or at both sites simultaneously. The resulting cation distribution is related to the electronic properties of the constituent ions. In the series VxCr3-xS4 (0≤x≤1), there is an abrupt change in this distribution at x≥0.4, which drives the system into a semiconducting state, with a concomitant loss of long-range magnetic order. Substitution within the dichalcogenide slab in NiCr2-xVxS4 (0

The series of compounds V1+xMo2−xS4 (0 ≤ x ≤ 2) has been prepared and characterised by powder X-ray and neutron diffraction, thermogravimetry, SQUID magnetometry and electrical transport measurements. Materials with x ≤ 0.50 adopt a distorted variant of the Cr3S4 structure (space group Cca ≈ 11.8, b ≈ 6.5, c ≈ 12.8 A, β ≈ 114.8°) in which there are triangular clusters of cations within a dichalcogenide unit. At higher levels of vanadium incorporation, the phases crystallise in the space group C2/m (a ≈ 12.8, b ≈ 3.3, c ≈ 5.9 A, β ≈ 114.9°) and the cations within the dichalcogenide slab form zigzag chains, with an intrachain cation–cation separation of ca 2.8A. The change in the nature of the cation clustering occurs at a composition where there is a transition from semiconducting (x ≤ 0.50) to metallic (x > 0.50) behaviour. Magnetic measurements reveal that paramagnetism is observed over the whole composition range. The measured Curie constants suggest a magnetic moment associated with the cations in the ordered defect layer only and indicate a significant degree of electron delocalisation.

Two new silver-antimony sulfides, [C(2)H(9)N(2)][Ag(2)SbS(3)] (1) and [C(2)H(9)N(2)](2)[Ag(5)Sb(3)S(8)] (2), have been prepared solvothermally in the presence of ethylenediamine and characterized by single-crystal X-ray diffraction, thermogravimetry, and elemental analysis. Compound 1 crystallizes in the space group Pn (a = 6.1781(1) A, b =11.9491(3) A, c = 6.9239(2) A, beta =111.164(1) degrees ) and 2 in the space group Pm (a = 6.2215(2) A, b = 15.7707(7) A, c = 11.6478(5) A, beta = 92.645(2) degrees ). The structure of 1 consists of chains of fused five-membered Ag(2)SbS(2) rings linked to form layers, between which the template molecules reside. Compound 2 contains honeycomb-like sheets of fused silver-antimony-sulfide six-membered rings linked to form double layers. The idealized structure can be considered to be an ordered defect derivative of that of lithium bismuthide, Li(3)Bi, and represents a new solid-state structure type.

A new chromium-antimony-sulfide, [Cr(C6H18N4)(SbS3)], has been synthesised under solvothermal conditions from CrCl3. 6H(2)O, Sb2S3 and S in the presence of triethylenetetramine at 433 K and characterised by single-crystal X-ray diffraction, thermogravimetry, elemental analysis and SQUID magnetometry. The structure of [Cr(C6H18N4)(SbS3)] consists of neutral mononuclear chromium-centred complexes, in which the Cr3+ is chelated by one tetradentate triethylenetetramine molecule and a bidentate SbS33- ligand, yielding distorted octahedral coordination. Intermolecular hydrogen bonds link individual molecules into layers within the ac plane. Within a layer, molecules occur in pairs with each member related by a centre of inversion. The Cr...Cr separation within a pair is approximately 6.5 Angstrom. Magnetic susceptibility data reveal Curie-Weiss behaviour with mu(eff) = 3.819(3)/mu(B) and a negligible Weiss constant, indicative of non-interacting Cr3+ ions. (C) 2003 Elsevier Science Ltd. All rights reserved.

International audience; The purity and structural stability of the high thermoelectric performance Cu12Sb4S13 and Cu10.4Ni1.6Sb4S13 tetrahedrite phases, synthesized by solid-liquid-vapor reaction and Spark Plasma Sintering, were studied at high temperature by Rietveld refinement using high resolution X-ray powder diffraction data, DSC/TG measurements and high resolution transmission electron microscopy. In a complementary study, the crystal structure of Cu10.5Ni1.5Sb4S13 as a function of temperature was investigated by powder neutron diffraction. The temperature dependence of the structural stability of ternary Cu12Sb4S13 is markedly different to that of the nickel-substituted phases, providing clear evidence for the significant and beneficial role of nickel substitution on both sample purity and stability of the tetrahedrite phase. Moreover, kinetic effects on the phase stability/decomposition have been identified and discussed in order to determine the maximum operating temperature for thermoelectric applications. The thermoelectric properties of these compounds have been determined for high density samples (>98%) prepared by Spark Plasma Sintering and therefore can be used as reference values for tetrahedrite samples. The maximum ZT of 0.8 was found for Cu10.4Ni1.6Sb4S13 at 700 K. © 2015 Elsevier B.V.

Solutions of 4-methylphenylurethane of cellulose in N-vinyl pyrrolidinone have been investigated, and a cholesteric mesophase was found above a concentration of 35 wt % of polymer. The selective reflection of light from the cholesteric solutions lies in the visible region of the spectrum and moves from blue toward red with increasing temperature. After photopolymerization of these solutions, solid opalescent films, which conserve the cholesteric order of the lyotropic phase, can be prepared. The fine structure of these colored films has been investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). In the fractured surfaces of the films, a periodic lamellar structure, which may arise from the helically twisted structure of the cholesteric mesophase, is observed. The periodicity of the lamellar structure is in good agreement with the calculated value of half a pitch of the cholesteric helix.

A new copper−antimony sulfide, [C4H12N2]0.5[CuSb6S10], has been hydrothermally synthesized from binary metal sulfides in the presence of triethylenetetramine and characterized by single-crystal X-ray diffraction, thermogravimetry, elemental analysis, and SQUID magnetometry. The product (Mr = 1158.72) crystallizes in the monoclinic space group P21/n with a = 11.2578(4) A, b = 12.5259(5) A, c = 13.9390(7) A, β = 102.445(3)°, and V = 1919.4 A3. The structure consists of cyclic Sb3S63- units in a boatlike conformation, linked by Sb−S bonds to form a complex Sb6S126- building block. Sb−S bonds serve to link Sb6S126- units to four others in a herringbone array, forming a sheet of stoichiometry Sb6S102-, containing 24-membered rings of alternating Sb and S atoms. Pairs of edge-sharing CuS4 distorted tetrahedra form pillars which link Sb6S102- layers together. The interlayer space contains piperazine cations, formed by cyclization of the triethylenetetramine during synthesis. Bond-valence sums are consistent with...

Powder neutron diffraction data collected for AMo2S4 (A = V, Cr, Fe, Co) reveal that the materials crystallize in the space group Cc (a ≈ 11.8 A, b ≈ 6.5 A, c ≈ 13 A, β ≈ 114°). The structure consi...

The system VxCrS2 (0 < x ≤1) has been investigated by X-ray and neutron powder diffraction. Five single-phase regions have been identified. All single-phase materials adopt pseudolayered structures, in which octahedral sites between alternate pairs of close packed sulfide layers are fully and partially occupied by cations. With increasing vanadium content, rhombohedral M2S3, trigonal M2S3, monoclinic M3S4, trigonal 3C-M7S8, and hexagonal M1-xS structures are successively observed. All single-phase materials exhibit semiconducting behavior, consistent with a variable range hopping conduction mechanism. Magnetic properties show considerably greater variation. The phase with the lowest vanadium content (rhombohedral M2S3) exhibits ferrimagnetic ordering at 100(10) K. Phases with higher vanadium content also exhibit long-range magnetic ordering, with the exception of the monoclinic M3S4, which is a spin glass (Tg = 40(5) K).

A series of sulfides NiCr2-xVxS4 (0 < x < 2.0) has been synthesized at high temperatures. All products are isostructural with Cr3S4 (space group I2/m; a ≈ 5.9 A, b ≈ 3.4 A, c ≈11.1 A; β ≈ 91.8°) in...

Non-stoichiometric phases in the series Co1 − xNixCr2S4 (0 ≤ x

Variable-temperature powder neutron diffraction data demonstrate that FeV{sub 2}S{sub 4} undergoes a transition to a long-range magnetically ordered state at 135(7) K, in agreement with magnetic susceptibility data. High-resolution neutron diffraction data collected at 1.9 K reveal that magnetic ordering results in a doubling of the crystallographic unit-cell dimensions (I2/m a = 5.8303(2), b = 3.2761(1), c = 11.2398(4) {angstrom}, {beta} = 92.046(2){degree}) in the a and c directions and that the magnetic structure is described by a propagation vector of ({1/2}, 0, {1/2}). Cations in an ordered defect layer, 76% of which are Fe(II), possess an average ordered moment of 1.86(5) {mu}{sub B}, which is directed at an angle of 75{degree} to the layer. Cation-cation interactions reduce the average moment of cations in the MS{sub 2} unit to 0.17(4) {mu}{sub B}. The complex magnetic structure involves essentially collinear antiferromagnetic ordering between nearest-neighbor cations.

The synthesis and characterization of the first anions containing two gallium-sulfide supertetrahedra linked via an organic moiety are described.

A combination of time-of-flight powder neutron diffraction and powder X-ray diffraction has been used to investigate changes in the cation distribution in a series of isostructural (space group I2/m a≈5.9, b≈3.3 c≈11.3A, β≈92°) ternary vanadium sulfides, AV 2 S 4 (A=Ti, Cr, Fe, Ni). A progressive change from an inverse Cr 3 S 4 structure, when A is drawn from the left of the transition series, to a normal Cr 3 S 4 structure, when A is drawn from the right of the series, occurs. The magnetic susceptibility of all materials has a significant temperature-independent component and both spin-glass behaviour [A=Cr, T g =15(3) K] and long-range magnetic order [A=Fe, T N =135(3) K] are observed.

High temperature structural transformations in NiCr2S4 have been investigated by neutron powder diffraction in situ. At 835(5) °C, NiCr2S4 undergoes an order–disorder transition from the monoclinic Cr3S4 structure to a hexagonal cation-deficient NiAs structure. Above the transition temperature, cation vacancies, which at room temperature are ordered in every second cation layer, become statistically distributed between all cation layers. Prior to this structural transition, intralayer disordering of vacancies occurs within the half-occupied layer. This is not sufficiently complete to cause the change to trigonal symmetry which has been reported for binary sulfides.

An open-framework indium selenide, [C7H10N][In9Se14], has been prepared under solvothermal conditions in the presence of 3,5-dimethylpyridine and characterized by single-crystal X-ray diffraction, thermogravimetry, elemental analysis, Fourier tranform IR spectroscopy, and UV-vis diffuse reflectance. The crystal structure of [C7H10N][In9Se14] contains an unusual building unit, in which corner- and edge-linked InSe45- tetrahedra coexist. The presence of one-dimensional circular channels, of ca. 6 A diameter, results in approximately 25% of solvent-accessible void space.

A systematic study of the sol−gel technique for the synthesis of Y3Fe5O12 is presented, using two different complexing agents (citric acid and malonic acid) and adding two different alcohols (ethylene glycol and glycerol). The influence of the pH value of the initial solution on the final product is also studied. Yttrium−iron garnet YIG is obtained from the gels by heating above 650 °C in air atmosphere. Samples are characterized by X-ray powder diffraction and IR spectroscopy. The crystallite size and the lattice parameter are also determined, and their dependence on the synthesis conditions is studied.

We describe a new technique using microemulsions to produce ultrafine precursors of yttrium iron garnet. A coprecipitation of hydroxide or carbonate precursors was made in a W/O microemulsion medium. These precursors (ca. 3 nm in size), when heated above 700 °C, transformed to YIG phase. Once prepared, YIG nanoparticles were characterized by X-ray diffraction, transmission electron microscopy and dc magnetic measurements.

Yellow crystals of [NH4][InSe2] (I) are solvothermally synthesized from a mixture of In, Se, trans-1,4-diaminocyclohexane or concentrated NH3 solution, and water (autoclave, 200 °C, 5—10 d).

[H2dach][GaS2]2, [H2dach][Ga2Se3(Se2)], and [H2dach] [Ga2-xInxSe3(Se2)] (0 < x < 2) are solvothermally synthesized using gallium, indium, sulfur, selenium, and trans-1,4-diaminocyclohexane (dach) as starting materials, and 1,2-diaminocyclohexane, MeOH, and water as solvents (autoclave, 170 °C, 10 d).

Yttrium iron garnet (YIG) was synthesized from a citrate gel containing ethylene glycol. The conditions for obtaining the pure phase depending on the citric acid/ethylene glycol ratio were studied. The sizes of the obtained particles ranged from 20 to 500 nm with the annealing temperature. Particles exhibited a rounded surface morphology, without faceted borders.

Solvothermal synthesis affords access to the first truly three-dimensional antimony-sulfide framework which contains one-dimensional circular channels.

The temperature dependence of anion ordering in the skutterudites CoGe 1.5 Q 1.5 ( Q =S, Te) has been investigated by powder neutron diffraction. Both materials adopt a rhombohedral structure at room temperature (space group R 3 ¯ ) in which the anions are ordered trans to each other within Ge 2 Q 2 rings. In CoGe 1.5 S 1.5 , anion ordering is preserved up to the melting point of 950 °C. However, rhombohedral CoGe 1.5 Te 1.5 undergoes a phase transition at 610 °C involving a change to cubic symmetry (space group Im 3 ¯ ). In the high-temperature modification, there is a statistical distribution of anions over the available sites within the Ge 2 Te 2 rings. The structural transition involves a reduction in the degree of distortion of the Ge 2 Te 2 rings which progressively transform from a rhombus to a rectangular shape. The effect of this transition on the thermoelectric properties has been investigated.

The title compounds are synthesized by solid state reaction of stoichiometric mixtures of the elements (1173 K, 12 h followed by annealing at 873 K for 6 d).

[3,5-Me2PyH][In3Se5] (I) is solvothermally synthesized from a mixture of In, Se, and 3,5-dimethylpyridine (3,5-Me2Py) in a molar ratio of 1.46:2.5:66 (autoclave, 185 °C, 10 d).

A new layered indium selenide, [C(7)H(10)N][In(3)Se(5)] (1), has been prepared solvothermally using 3,5-dimethylpyridine as a solvent and structure-directing agent. This material, which was characterized by single-crystal and powder X-ray diffraction, thermogravimetric analysis, UV-vis diffuse-reflectance spectroscopy, IR spectroscopy, and elemental analysis, crystallizes in the monoclinic space group P2(1)/c [a = 3.9990(4) A, b = 16.7858(15) A, c = 23.930(2) A, and β = 94.728(4)°]. The crystal structure of 1 contains anionic layers of stoichiometry [In(3)Se(5)](-) in which indium atoms with octahedral and tetrahedral coordination coexist. The [In(3)Se(5)](-) layers are interspaced by monoprotonated 3,5-dimethylpyridinium cations. A closely related material, [C(7)H(10)N][In(3)Se(5)] (2), was obtained when using 2,6-dimethylpyridine instead of 3,5-dimethylpyridine.

The family of materials Yb x Fe2 Ni 2Sb12 (0 ≤ x ≤ 0.4) has been prepared by solid-state synthesis from the pure elements and characterized by powder X-ray diffraction. These materials crystallize in the skutterudite structure, with the framework voids partially filled with Yb atoms. Electrical resistivity, Seebeck coefficient and thermal conductivity measurements have been performed on hot-pressed samples, and indicate that the thermoelectric performance is significantly improved by increasing the Yb content. The decomposition of the compounds under oxidizing atmosphere at elevated temperatures has also been studied by thermogravimetric analysis. The physical properties and thermal stability of the new compounds are further discussed in comparison with those of the reported isostructural and isoelectronic Yb x Co4Sb12 (0 ≤ x ≤ 0.19).

Here we describe the first results from an interdisciplinary project that seeks to develop a skutterudite-based thermoelectric (TE) energy recovery system for a vehicle exhaust stream. Filled skutterudites have been prepared and characterised and their thermal stability evaluated. Thermoelements fabricated from these skutterudites have been used to evaluate the compatibility of materials required for the construction of TE modules. The results of modelling studies for the optimization of heat exchanger design and the creation of a component in the loop test facility are also described.

We report on SANS measurements carried out on the instrument SANS1 (V4) at the BENSC facility on solutions and composites of cellulose tricarbanilate (CTC). This cellulose derivative exhibits lyotropic behaviour in methylacrylate (MA). The SANS data indicate that in the isotropic liquid state (up to 25% wt CTC in MA) the CTC chains behave like rods of mass per unit length (M/L). In the liquid crystalline (LC) phase (at and above 35% wt CTC in MA), the Q dependence varies from Q-1 to Q-4, probably as a result of self-assembling of the CTC chains. The general aim of our work is to prepare molecular composites, i.e. miscible blends of rigid-rod and flexible-coil polymers, from CTC solutions in polymerizable media. To establish the degree of homogeneity of the composites, we performed SANS measurements on UV-cured CTC/MA solutions. Here, we compare the SANS data of CTC/monomer solutions with those of the corresponding composites.

The new title compound (III) crystallizes in the monoclinic space group C2/c with Z = 4 (single crystal XRD).

Single crystals of the new title compound are solvothermally synthesized from a mixture of Ga2S3, S, tryptamine, and sodium imidazolate in aqueous 3,5-dimethyl pyridine (autoclave, 200 °C, 10 d).

The charge-transfer complexation of TTF with paraquat and its oligomeric derivatives are described.

Tetrahedral chalcogenide clusters, with their well-defined molecular structures and interesting properties, are attractive building blocks for hybrid materials, in which porosity may be integrated with electronic or optical properties. Linkage of tetrahedral clusters often occurs through bridging chalcogenolate ligands, and results in extended structures of inorganic connectivity. However, linkage of tetrahedral clusters via organic ligands is also possible and a number of coordination polymers have already been reported. Recent advances on the synthesis and crystal structures of extended hybrid structures based on tetrahedral clusters are described here.

This highlight discusses recent trends in the search for new high-efficiency thermoelectric materials. Thermoelectric materials offer considerable attractions in the pursuit of a more efficient use of existing energy resources, as they may be used to construct power-generation devices that allow useful electrical power to be extracted from otherwise waste heat. Here, we focus on the significant enhancements in thermoelectric performance that have been achieved through nanostructuring. The principal factor behind the improved performance appears to be increased phonon scattering at interfaces. This results in a substantial reduction in the lattice contribution to thermal conductivity, a low value of which is a key requirement for improved thermoelectric performance.

A series of sulfides NiCr2-xVxS4 (0 < x < 2.0) has been synthesized at high temperatures. All products are isostructural with Cr3S4 (space group I2/m; a ≈ 5.9 A, b ≈ 3.4 A, c ≈11.1 A; β ≈ 91.8°) in...

A new copper−antimony sulfide, [C4H12N2]0.5[CuSb6S10], has been hydrothermally synthesized from binary metal sulfides in the presence of triethylenetetramine and characterized by single-crystal X-ray diffraction, thermogravimetry, elemental analysis, and SQUID magnetometry. The product (Mr = 1158.72) crystallizes in the monoclinic space group P21/n with a = 11.2578(4) A, b = 12.5259(5) A, c = 13.9390(7) A, β = 102.445(3)°, and V = 1919.4 A3. The structure consists of cyclic Sb3S63- units in a boatlike conformation, linked by Sb−S bonds to form a complex Sb6S126- building block. Sb−S bonds serve to link Sb6S126- units to four others in a herringbone array, forming a sheet of stoichiometry Sb6S102-, containing 24-membered rings of alternating Sb and S atoms. Pairs of edge-sharing CuS4 distorted tetrahedra form pillars which link Sb6S102- layers together. The interlayer space contains piperazine cations, formed by cyclization of the triethylenetetramine during synthesis. Bond-valence sums are consistent with...