共查询到20条相似文献,搜索用时 31 毫秒
1.
Bin Deng Fu Qiang Huang Donald E. Ellis Richard P. Van Duyne 《Journal of solid state chemistry》2007,180(2):759-764
The new compound NaLiCdS2 has been synthesized by the reaction of Cd and a Li2S/S/Na2S flux at 773 K. This compound, which has the Ce2O2S structure type, crystallizes with one formula unit in space group P3¯m1 of the trigonal system in a cell at T=153 K with a=4.1320(3) Å and c=6.8666(11) Å. The structure consists of two-dimensional layers stacked perpendicular to the [001] direction. The two-dimensional layers are formed by corner-sharing LiS4 or CdS4 tetrahedra. The Na atoms are between these layers. Li incorporation in the compound is confirmed by an SIMS chemical composition map and by ICP measurements. The Li and Cd atoms are disordered in the crystal structure. First-principles calculations show that the optical excitations arise primarily from S→Cd charge-transfer transitions at 1.0 eV (very weak) and 2.4 eV (strong). Calculations also indicate that Na contributions around the Fermi level are significant. Polarized single-crystal optical measurements indicate an indirect optical band gap of 2.37 eV for light perpendicular to the (001) crystal face, in good agreement with theory. The compound NaLiZnS2 has also been synthesized and is found to be isostructural with NaLiCdS2. 相似文献
2.
Ismail Ijjaali 《Journal of solid state chemistry》2003,172(2):257-260
The new quaternary lanthanum copper oxysulfide La3CuO2S3 has been synthesized by the reaction of La2S3 and CuO at 1223 K. This compound crystallizes in space group Pnma of the orthorhombic system with four formula units in a cell of dimensions at 153 K of a=14.0318(7) Å, b=3.9342(2) Å, and c=12.5212(6) Å. The structure of La3CuO2S3 consists of a three-dimensional framework of interconnected LaOnS8−n bicapped trigonal prisms and CuS4 tetrahedra. Optical absorption measurements on a La3CuO2S3 single crystal led to derived band gaps of 2.01 eV in both the [010] and [001] directions. 相似文献
3.
The compound NaAlF4 has been obtained in the form of thin fibrous crystals or fine colorless powder by condensation at 18 °C of vapors arising over chiolite Na5Al3F14 or NaCaAlF6, heated up to 800 °C. Thermal stability has been investigated by the methods of thermal analysis and high temperature X-ray diffraction. When heated in air, NaAlF4 is stable up to 390-400 °C, then there is an exothermal solid state decay into Na5Al3F14(s) and AlF3(s). At higher temperature Na5Al3F14(s) decays into Na3AlF6(s) and NaAlF4(g). The crystal structure (space group Cmcm, a=3.6124(1) Å, b=14.9469(7) Å, c=5.2617(3) Å, V=284.10 Å3) has been determined by X-ray powder diffraction method. In the crystal structure of NaAlF4 the octahedrons [AlF6] are joined through vertices and form corrugated layers, sodium ion layers being located between them. The distances between the atoms of Al-F are in the range 1.791-1.814 Å, and those for Na…F are in the range 2.297-2.439 Å. In spite of limited thermal stability of the crystal form, the compound NaAlF4 is the main component of the gas mixture over solid and molten salts in the ternary system NaF-AlF3-CaF2 and participates in chemical transformations between the phases at high temperature. 相似文献
4.
Ya.V Galadzhun Ya.M Kalychak A.P Pikul D Kaczorowski 《Journal of solid state chemistry》2004,177(1):17-25
A new compound Ce12Pt7In was synthesized and its crystal structure at 300 K has been determined from single crystal X-ray data. It is tetragonal, space group I4/mcm, Z=4, with the lattice parameters: a=12.102(1) Å and c=14.542(2) Å, wR2=0.1102, 842 F2 values, 33 variable parameters. The structure of Ce12Pt7In is a fully ordered ternary derivative of the Gd3Ga2-type. Isostructural compounds has been found to form with Pr (a=11.976(1) Å, c=14.478(2) Å), Nd (a=11.901(1) Å, c=14.471(2) Å), Gd (a=11.601(3) Å, c=14.472(4) Å), and Ho (a=11.369(1) Å, c=14.462(2) Å). Magnetic properties of Ce12Pt7In, Pr12Pt7In and Nd12Pt7In were studied down to 1.7 K. All three ternaries order magnetically at low temperatures with complex spin arrangements. The electrical resistivity of Ce12Pt7In and Nd12Pt7In is characteristic of rare-earth intermetallics. 相似文献
5.
Farshid Ramezanipour Shahab Derakhshan John E. Greedan Lachlan M.D. Cranswick 《Journal of solid state chemistry》2008,181(12):3366-3373
A new pillared perovskite compound La5Mo2.76(4)V1.25(4)O16, has been synthesized by solid-state reaction and its crystal structure has been characterized using powder X-ray and neutron diffraction. The magnetic properties of this compound have been investigated using SQUID magnetometry, and the magnetic structure has been studied using neutron diffraction data. A theoretical calculation of relative strengths of spin interactions among different magnetic ions and through different pathways has been performed using extended Hückel, spin dimer analysis. The crystal structure of this material contains perovskite-type layers that are connected through edge-sharing dimeric units of octahedra. The structure is described in space group C2/m with unit cell parameters a=7.931(2) Å, b=7.913(2) Å, c=10.346(5) Å and β=95.096(5)°. The material shows both short-range ferrimagnetic correlations from ∼200 to 110 K and long-range antiferromagnetic order below Tc∼100 K. The magnetic structure was investigated by neutron diffraction and is described by k=(0 0 ) as for other pillared perovskites. It consists of a ferrimagnetic arrangement of Mo and V within the layers that are coupled antiferromagnetically between layers. This is the first magnetic structure determination for any Mo-based pillared perovskite. 相似文献
6.
A tin(II) squarate Sn2O(C4O4)(H2O) was synthesized by hydrothermal technique. It crystallizes in the monoclinic system, space group C2/m (no. 12) with lattice parameters a=12.7380(9) Å, b=7.9000(3) Å, c=8.3490(5) Å, β=121.975(3)°, V=712.69(7) Å3, Z=4. The crystal structure determined with an R=0.042 factor, consists of [(Sn4O10)(H2O)2] units connected from one another in the [101] and [010] directions via squarate groups to form layers separated by Sn(II) lone pairs. This compound presents the same remarkable structural arrangement as observed in the tin-oxo-fluoride Sn2[Sn2O2F4] inorganic compound with Sn(II) lone pairs E(1) and E(2) concentrated in large rectangular-shape tunnels running along [001] direction. 相似文献
7.
Richard Becker Helmuth Berger Mladen Prester Marko Miljak 《Journal of solid state chemistry》2006,179(3):836-842
The crystal structures of the two new synthetic compounds Co2TeO3Cl2 and Co2TeO3Br2 are described together with their magnetic properties. Co2TeO3Cl2 crystallize in the monoclinic space group P21/m with unit cell parameters a=5.0472(6) Å, b=6.6325(9) Å, c=8.3452(10) Å, β=105.43(1)°, Z=2. Co2TeO3Br2 crystallize in the orthorhombic space group Pccn with unit cell parameters a=10.5180(7) Å, b=15.8629(9) Å, c=7.7732(5) Å, Z=8. The crystal structures were solved from single crystal data, R=0.0328 and 0.0412, respectively. Both compounds are layered with only weak interactions in between the layers. The compound Co2TeO3Cl2 has [CoO4Cl2] and [CoO3Cl3] octahedra while Co2TeO3Br2 has [CoO2Br2] tetrahedra and [CoO4Br2] octahedra. The Te(IV) atoms are tetrahedrally [TeO3E] coordinated in both compounds taking the 5s2 lone electron pair E into account. The magnetic properties of the compounds are characterized predominantly by long-range antiferromagnetic ordering below 30 K. 相似文献
8.
Hongwei Yu Shilie Pan Hongping Wu Xiaoyu Dong Zhongxiang Zhou 《Journal of solid state chemistry》2011,184(7):1644-1648
A new ternary borate oxide, K3CdB5O10, has been synthesized by solid-state reaction at 580 °C. The compound crystallizes in the monoclinic space group P21/n with a=7.6707 (7) Å, b=19.1765 (17) Å, c=7.8784 (6) Å, β=115.6083 (49)°, and Z=4. The crystal structure consists of a two-dimensional infinite [CdB5O10] layer, which forms by connecting isolated double ring [B5O10] groups and CdO4 tetrahedra. K atoms filling in the interlayer and intralayer link the layers together and balance charge. The IR spectrum has been studied and confirmed the presence of both BO3 and BO4 groups, and the UV-vis-IR diffuse reflectance spectrum exhibits a band gap of about 3.4 eV. The DSC analysis proves that K3CdB5O10 is a congruent melting compound. 相似文献
9.
Zuzana Hugonin Mats Johnsson Sven Lidin Dirk Wulferding Peter Lemmens Reinhard K. Kremer 《Journal of solid state chemistry》2008,181(10):2776-2782
We report the synthesis, crystal structure determination, magnetic and low-temperature structural properties of a new cobalt antimony oxo-bromide. CoSb2O3Br2 crystallizes in the triclinic crystal system, space group P−1, with the following lattice parameters: a=5.306(3) Å, b=7.812(4) Å, c=8.0626(10) Å, α=88.54(3)°, β=82.17(3)°, γ=80.32(4)°, and Z=2. The crystal structure was solved from single crystal X-ray data and refined on F2, R1=3.08. The structure consists of layers made up by three building blocks, [CoO4Br2], [SbO3Br], and [SbO3] that are connected via edge- and corner-sharing so that structural Co-Co dimers are formed. The layers have no net charge and are only weakly connected by van der Waals forces to adjacent layers. Above ∼25 K the magnetic susceptibility is independent of the magnetic field and can be very well described by a Curie-Weiss law. Below 25 K the susceptibility passes through a maximum and decreases again that is typical for the onset of long-range antiferromagnetic correlations. Long-range antiferromagnetic ordering is observed below TN∼9 K indicating substantial inter-dimer exchange coupling between Co-Co dimers within the layers. However, according to the heat capacity results only a minute fraction of the entropy is associated with the long-range ordering transition. The phonon anomalies observed for T<6 K in Raman scattering and an anomaly in the specific heat point to a structural instability leading to a loss of inversion symmetry at lowest temperatures. 相似文献
10.
Nicolas Guiblin Christine Martin Maryvonne Hervieu 《Journal of solid state chemistry》2004,177(10):3310-3315
Magnetic and crystal structures of the manganite Pr0.8Ca0.2MnO3 have been studied by neutron powder and single-crystal X-ray diffraction. Structure refinements using single crystal data [orthorhombic system, Pnma, (No. 62), aRT=5.5534(3) Å, bRT=7.6548(8) Å, cRT=5.4400(5) Å, Dx=6.422 g cm−3, RRT=0.029, RwRT=0.038] are consistent with a single domain sample. Structure and atomic displacement parameters exclude any electronic localization, even in a disordered way at 300 and 100 K. Low temperature electron diffraction observations do not show any trace of charge ordering.A Pr contribution to the magnetic structure has been shown with a maximum moment of 0.79 μB and spins alignments roughly along [101] orientations, at a lower temperature than the ferromagnetic transition observed at 130 K, due to Mn spins ordering. 相似文献
11.
Kjell Ove Kongshaug 《Journal of solid state chemistry》2004,177(6):1852-1857
The two organically pillared layered zinc hydroxides [Zn2(OH)2(ndc)], CPO-6, and [Zn3(OH)4(bpdc)], CPO-7, were obtained in hydrothermal reactions between 2,6-naphthalenedicarboxylic acid (ndc) and zinc nitrate (CPO-6) and 4,4′biphenyldicarboxylate (bpdc) and zinc nitrate (CPO-7), respectively. In CPO-6, the tetrahedral zinc atoms are connected by two μ2-OH groups and two carboxylate oxygen atoms, forming infinite layers extending parallel to the bc-plane. These layers are pillared by ndc to form a three-dimensional structure. In CPO-7, the zinc hydroxide layers are containing four-, five- and six coordinated zinc atoms, and the layers are built like stairways running along the [001] direction. Each step is composed of three infinite chains running in the [010] direction. Both crystal structures were solved from conventional single crystal data. Crystal data for CPO-6: Monoclinic space group P21/c (No. 14), a=11.9703(7), b=7.8154(5), c=6.2428(4) Å, β=90.816(2)°, V=583.97(6) Å3 and Z=4. Crystal data for CPO-7: Monoclinic space group C2/c (No. 15), a=35.220(4), b=6.2658(8), c=14.8888(17) Å, β=112.580(4)°, V=3033.8(6) Å3 and Z=8. The compounds were further characterized by thermogravimetric- and chemical analysis. 相似文献
12.
Marija Borna Alim Ormeci Ulrich Burkhardt Raul Cardoso-Gil 《Journal of solid state chemistry》2011,184(2):296-303
Application of high-pressure high-temperature conditions (3.5 GPa at 1673 K for 5 h) to mixtures of the elements (RE:B:S=1:3:6) yielded crystalline samples of the isotypic rare earth-thioborate-sulfides RE9[BS3]2[BS4]3S3, (RE=Dy-Lu), which crystallize in space group P63 (Z=2/3) and adopt the Ce6Al3.33S14 structure type. The crystal structures were refined from X-ray powder diffraction data by applying the Rietveld method. Dy: a=9.4044(2) Å, c=5.8855(3) Å; Ho: a=9.3703(1) Å, c=5.8826(1) Å; Er: a=9.3279(12) Å, c=5.8793(8) Å; Tm: a=9.2869(3) Å, c=5.8781(3) Å; Yb: a=9.2514(5) Å, c=5.8805(6) Å; Lu: a=9.2162(3) Å, c=5.8911(3) Å. The crystal structure is characterized by the presence of two isolated complex ions [BS3]3- and [BS4]5- as well as [□(S2-)3] units. 相似文献
13.
Ismail Ijjaali 《Journal of solid state chemistry》2003,172(1):127-131
The new quaternary sulfide La4MnCu6S10 has been synthesized by the reaction of La2S3, MnS, and CuS2 at 1223 K. This compound crystallizes in a new structure type in space group of the triclinic system with one formula unit in a cell of dimensions at 153 K of a=6.6076(3) Å, b=7.3247(3) Å, c=8.7844(4) Å, α=83.457(1)°, β=74.398(1)°, γ=89.996(1)°, and V=406.61(3) Å3. The structure of La4MnCu6S10 consists of a three-dimensional framework of interconnected LaS7 monocapped trigonal prisms, MnS6 octahedra, and CuS4 tetrahedra. Band gaps of 2.49 eV in the [100] direction and 2.53 eV in the [001] direction have been derived from optical absorption measurements on a La4MnCu6S10 single crystal. 相似文献
14.
Daniel E. Bugaris 《Journal of solid state chemistry》2009,182(5):1017-6666
The compound Cs2Hg2USe5 was obtained from the solid-state reaction of U, HgSe, Cs2Se3, Se, and CsI at 1123 K. This material crystallizes in a new structure type in space group P2/n of the monoclinic system with a cell of dimensions a=10.276(6) Å, b=4.299(2) Å, c=15.432(9) Å, β=101.857(6) Å, and V=667.2(6) Å3. The structure contains layers separated by Cs atoms. Within the layers are distorted HgSe4 tetrahedra and regular USe6 octahedra. In the temperature range of 25-300 K Cs2Hg2USe5 displays Curie-Weiss paramagnetism with μeff=3.71(2) μB. The compound exhibits semiconducting behavior in the [010] direction; the conductivity at 298 K is 3×10−3 S/cm. Formal oxidation states of Cs/Hg/U/Se may be assigned as +1/+2/+4/− 2, respectively. 相似文献
15.
Bi3Fe0.5Nb1.5O9 was synthesized using conventional solid state techniques and its crystal structure was refined by the Rietveld method using neutron powder diffraction data. The oxide adopts an Aurivillius-type structure with non-centrosymmetric space group symmetry A21am (a=5.47016(9) Å, b=5.43492(9) Å, c=25.4232(4) Å), analogous to other Aurivillius compounds that exhibit ferroelectricity. The Fe and Nb cations are disordered on the same crystallographic site. The [(Fe,Nb)O6] octahedra exhibit tilting and distortion to accommodate the bonding requirements of the Bi cations located in the perovskite double layers. Magnetic measurements indicate non-Curie-Weiss-type paramagnetic behavior from 300 to 6 K. Measurements of dielectric properties and electrical resistivity exhibited changes near 250-260 °C and are suggestive of a ferroelectric transition. 相似文献
16.
Crystals of a new potassium iron (III) diarsenate (KFeAs2O7) have been grown and characterized by single crystal X-ray diffraction. It crystallizes in the triclinic space group , with a=7.662(1) Å, b=8.402(2) Å, c=10.100(3) Å, α=90.42(3)°, β=89.74(2)°, γ=106.39(2)°, V=623.8(3) Å3 and Z=4. The final agreement factors are R=0.0342, wR=0.0889, S(F2)=1.01; the structural model is validated by bond valence sum (BVS) and charge distribution (CD) methods. The structure consists of corner-sharing FeO6 octahedra and As2O7 diarsenate groups, the three-dimensional framework delimits tunnels running along [0 1 0] direction where the potassium ions reside. The crystal structure of the title compound is different from that of the monoclinic KAlP2O7 type but structural relationships exist between the frameworks. Impedance measurements (frequency/temperature ranges: 5-13,000 Hz/526-668 K) show KFeAs2O7 an ionic conductor being the conductivity 2.76×10−7 S cm−1 at 568 K and Ea is 0.47 eV. The BVS model suggests that the most probable potassium conduction pathway is along b-direction. Magnetic measurements reveal the Curie—Weiss type paramagnetic behavior over the range 30-300 K and ferromagnetic below 29.3 K. 相似文献
17.
A. Migda?-Mikuli E. Mikuli I. Natkaniec K. Ho?derna-Natkaniec 《Journal of solid state chemistry》2003,174(2):357-364
Nuclear magnetic resonance (1H NMR and 19F NMR) measurements performed at 90-295 K, inelastic incoherent neutron scattering (IINS) spectra and neutron powder diffraction (NPD) patterns registered at 22-190 K, and X-ray powder diffraction (XRPD) measurements performed at 86-293 K, provided evidence that the crystal of [Zn(NH3)4](BF4)2 has four solid phases. The phase transitions occurring at: TC3=101 K, TC2=117 K and TC1=178 K, as were detected earlier by differential scanning calorimetry (DSC), were connected on one hand only with an insignificant change in the crystal structure and on the other hand with a drastic change in the speed of the anisotropic, uniaxial reorientational motions of the NH3 ligands and BF4− anions (at TC3 and at TC2) and with the dynamical orientational order-disorder process (“tumbling”) of tetrahedral [Zn(NH3)4]2+ and BF4− ions (at TC1). The crystal structure of [Zn(NH3)4](BF4)2 at room temperature was determined by XRPD as orthorhombic, space group Pnma (No. 62), a=10.523 Å, b=7.892 Å, c=13.354 Å and Z=4. Unfortunately, it was not possible to determine the structure of the intermediate and the low-temperature phase. However, we registered the change of the lattice parameters and unit cell volume as a function of temperature and we can observe only a small deviation from near linear dependence of these parameters upon temperature in the vicinity of the TC1 phase transition. 相似文献
18.
Robin T. Macaluso Richard E. Sykora Arthur Mar H. Lee Julia Y. Chan 《Journal of solid state chemistry》2004,177(1):293-298
The ternary antimonide CeNiSb3 has been prepared from an Sb flux or from reaction of Ce, NiSb, and Sb above 1123 K. It crystallizes in the orthorhombic space group Pbcm with Z=12 and lattice parameters a=12.6340(7) Å, b=6.2037(3) Å, and c=18.3698(9) Å at 193 K. Its structure consists of buckled square nets of Sb atoms and layers of highly distorted edge- and face-sharing NiSb6 octahedra. Located between the ∞2[Sb] and ∞2[NiSb2] layers are the Ce atoms, in monocapped square antiprismatic coordination. There is an extensive network of Sb-Sb bonding with distances varying between 3.0 and 3.4 Å. The structure is related to that of RECrSb3 but with a different stacking of the metal-centered octahedra. Resistivity measurements reveal a shallow minimum near 25 K that is suggestive of Kondo lattice behavior, followed by a sharp decrease below 6 K. 相似文献
19.
Ashok K. VishwakarmaPrasanna S. Ghalsasi Arulsamy NavamoneyYanhua Lan A.K. Powell 《Polyhedron》2011,30(9):1565-1570
Compounds of the general formula A2CuCl4, (where A = 4-fluoroanilinium (1) and 4-chloroanilinium (2)) were prepared, structurally characterized and their thermal and magnetic properties studied. These compounds have a layered structure, distorted perovskite, where layers of CuCl42− are sandwiched between a 4-haloanilinium cation bilayer. A single crystal X-ray diffraction study on (4-fluoroanilinium)2CuCl4, (1), shows that it crystallizes in the monoclinic P21/c space group with cell dimensions a = 15.5113(5) Å, b = 7.3788(2) Å, c = 7.0929(2) Å, β = 99.004(2)°, volume 801.81(4) Å3 at 150 K. Compound 2, (4-chloroanilinium)2CuCl4, crystallizes isostructurally to 1 at RT, but at 150 K it adopts the Pccn space group. This structural transition for 2 is reversible, and has been observed using Differential Scanning Calorimetric (DSC) measurements. The dc-magnetic studies using a SQUID magnetometer suggest that both compounds are soft ferromagnets and show an onset of long range magnetic ordering below 9 K. The ac-susceptibility measurements confirm the presence of this ferromagnetic ordering in both the compounds. 相似文献
20.
Alexei A. Belik Qingzhen Huang Jeffrey W. Lynn 《Journal of solid state chemistry》2008,181(9):2292-2297
The crystal and magnetic structures of SrFe2+2(PO4)2 have been determined by neutron powder diffraction data at low temperatures (space group P21/c (no. 14); Z=4; a=9.35417(13) Å, b=6.83808(10) Å, c=10.51899(15) Å, and β=109.5147(7)° at 15 K). Two magnetic phase transitions were found at T1=7.4 K (first-order phase transition) and T2=11.4 K (second-order phase transition). The transition at T2 was hardly detectable by dc and ac magnetization measurements, and a small anomaly was observed by specific heat measurements. At T1, strong anomalies were found by dc and ac magnetization and specific heat. The structure of SrFe2(PO4)2 consists of linear four-spin cluster units, Fe2-Fe1-Fe1-Fe2. Below T1, the propagation vector of the magnetic structure is k=[0,0,0]. The magnetic moments of the inner Fe1-Fe1 atoms of the four-spin cluster unit are ferromagnetically coupled. The magnetic moment of the outer Fe2 atom is also ferromagnetically coupled with that of the Fe1 atom but with spin canting. The four-spin cluster units form ferromagnetic layers parallel to the [−101] plane, while these layers are stacked antiferromagnetically in the [−101] direction. Spin canting of the outer Fe2 atoms provides a weak ferromagnetic moment of about 1 μB along the b-axis. The refined magnetic moments at 3.5 K are 4.09 μB for Fe1 and 4.07 μB for Fe2. Between T1 and T2, a few weak magnetic reflections were observed probably due to incommensurate magnetic order. 相似文献