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1.
《Solid State Sciences》2001,3(1-2):121-132
The structures of the tetramethylammonium dichromate, [(CH3)4N]2Cr2O7 and trichromate, [(CH3)4N]2Cr3O10, were determined from single-crystal X-ray diffraction data. These compounds crystallize in the orthorhombic system (space group Pnma, with Z=4 and a=17.192(1) Å, b=8.55(1) Å, c=10.637(1) Å), for the dichromate and in the monoclinic system (space group P21/n, with Z=4 and a=11.366(2) Å, b=8.493(2) Å, c=20.187(4) Å, β=103.98(3)° for the trichromate. The structures consist of discrete dichromate anions (Cr2O7)2– or trichromate anions (Cr3O10)2–, respectively, stabilized by quaternary ammonium [(CH3)4N]+. Phase transitions in [(CH3)4N]2Cr2O7 have been evidenced by differential scanning calorimetry as well as a new allotropic variety of [(CH3)4N]2Cr2O7 which was characterized by X-ray powder diffraction. It crystallizes in an orthorhombic system with the unit cell parameters a=24.49(1) Å, b=8.85(1) Å, c=8.705(8) Å. 相似文献
2.
Subsolidus phase relations in Na2O–Fe2O3–Sb2Ox system (excluding Na-rich and Sb-rich corners) were studied using powder X-ray diffraction. Samples were prepared by conventional solid-state reactions at 980–1030 °C followed by quenching. Sb substitution for Fe stabilizes the low-temperature rhombohedral α form of NaFeO2 and enhances ionic conductivity: σ(300 °C) = 0.5 S/m, Ea = 0.38(3) eV, te < 0.01 for Na0.8Fe0.9Sb0.1O2 ceramics. Besides known orthorhombic Na2Fe3SbO8, three new compounds have been identified: trigonal Na4FeSbO6, a superlattice of α-NaFeO2 type, a = 5.4217(7) Å, c = 16.2715(1) Å, possible space group P3112; orthorhombic Na2FeSbO5, possibly related to brownmillerite, Pbcn, a = 10.8965(13) Å, b = 15.7178(13) Å, c = 5.3253(4) Å, and one more phase with empirical formula Na4Fe3SbO9, whose pattern could not be indexed. Ion-exchange reactions lead to a delafossite-type superlattice Ag3(NaFeSb)O6 (a = 5.4503(12) Å, c = 18.7747(20) Å, possible space group P3112). 相似文献
3.
《Journal of solid state chemistry》2004,177(4-5):1053-1059
Two new compounds, LaInS2O and La5In3S9O3 were synthesized in the La–In–S–O quaternary system. Both compounds crystallize in the orthorhombic system with lattice constants a=20.5421(6) Å, b=14.8490(4) Å, c=3.9829(1) Å for LaInS2O, and a=4.1018(1) Å, b=26.833(1) Å, c=16.023(1) Å for La5In3S9O3. The structure of La5In3S9O3 was solved from single-crystal X-ray data, in the space group Pbcm, with Z=4; it is built from three-atom-thick (100)NaCl layers interleaved with fluorite-type ribbons, and is closely related to the structures of the known lanthanum and indium compounds La10In6S17O6 and La4In5S13. Both compounds LaInS2O and La5In3S9O3 exhibit a yellow color; measurement of their optical gaps gave 2.73 and 2.60 eV, respectively. 相似文献
4.
The structures of tin(II)-oxalate, tin(IV)Na–EDTA and tin(IV)Na8-inositol hexaphosphate were investigated using XRD analysis. Samples were identified using the Mössbauer study, thermal analysis and FTIR spectrometry. The Mössbauer study determined two different oxidation states of tin atoms, and consequently two different tin surroundings in the end products. The tin oxalate was found to be orthorhombic with space group Pnma, a=9.2066(3) Å, b=9.7590(1) Å, c=13.1848(5) Å, V=1184.62 Å3 and Z=8. SnNa–EDTA was found to be monoclinic with space group P21/c1, a=10.7544(3) Å, b=10.1455(3) Å, c=16.5130(6) Å, β=98.59(2)°, V=1781.50(4) Å3 and Z=4. Sn(C6H6Na8O24P6) was found to be amorphous. 相似文献
5.
Single crystals of two new barium rhenate compositions, Ba16Re6O37 and Ba10Re3O16(OH)3, and of one new polymorph, orthorhombic Ba5Re2O12, were grown out of a barium hydroxide flux in sealed silver tubes. Ba16Re6O37 and Ba10Re3O16(OH)3 crystallize into the monoclinic C2/m system, with a = 20.577(4) Å, b = 5.8897(10) Å, c = 15.438 (3) Å, β = 92.255(10) ° and a = 1938342(9) Å, b = 5.8172(3) Å, c = 10.2925(5) Å, β = 91.7460(10) °, respectively. The orthorhombic polymorph of Ba5Re2O12 crystallizes in the space group Pnma, with a = 19.6728(10) Å, b = 5.8491(3) Å and c = 10.4648(5) Å. All the three crystal structures are related and consist of a framework of BaOx polyhedra (where x varies from six to twelve) with interpenetrating layers of ReO6 octahedra. 相似文献
6.
《Journal of solid state chemistry》2004,177(4-5):1437-1443
Na2CoP2O7 is found in two allotropic forms. The first one is rose and belongs to the triclinic crystallographic system. The second one is blue and described in the orthorhombic system, space group Pna21, No. 33, with cell parameters a=15.378(6) Å, b=10.271(4) Å, c=7.713(2) Å and Z=8. A recent work showed that the orthorhombic phase could be considered as tetragonal: space group P42/mnm, No. 136 with a=7.706(1) Å and b=10.301(2) Å and Z=4. The optical and magnetic properties, particularly the EPR spectrum, of the divalent cobalt ion and their phenomenological simulation were of considerable help to complement the study and allowed us to specify the real structure. 相似文献
7.
《Solid State Sciences》2007,9(5):380-384
Two complex oxides of osmium, Ba2Fe0.92Os1.08O6 and Ba2Co0.77Os1.23O6, have been prepared as single crystals from molten potassium hydroxide. Both oxides crystallize in the hexagonal space group P63mc with a = 5.7403(1) Å and c = 14.0771(6) Å and a = 5.7745(2) Å and c = 14.0946(7) Å for Ba2Fe0.92Os1.08O6 and Ba2Co0.77Os1.23O6, respectively. The structure of these compounds is related to the 6H–BaTiO3 structure but exhibit mixed occupancy of both metals on the three crystallographically independent metal sites. 相似文献
8.
The perovskite (Bi0.5Pb0.5)(Fe0.5Zr0.5)O3 was synthesized by solid-state reaction in an attempt to find magnetoelectric materials, in which ferroelectricity and ferromagnetism coexist. This complex perovskite has been studied by X-ray and neutron powder diffraction in combination with magnetic measurements. The compound crystallizes in the orthorhombic space group Pbam with a ~ √2ap, b ~ 2√2ap and c ~ 2ap (with ap ~ 4.057 Å). The field and temperature dependence of the magnetization combined with neutron diffraction data showed antiferromagnetic behavior with the Neel temperature, TN ~ 450 K. Rietveld refinements of neutron powder diffraction data collected at different temperatures, between 10 and 700 K, have been carried out in order to extract information about the thermal evolution of the nuclear and magnetic structures. A distorted orthorhombic perovskite structure was found within the whole temperature interval. The Bi/Pb and Fe/Zr ions were found to be partially ordered over the perovskite A-site and disordered over the B-site. The neutron diffraction patterns of the (Bi0.5Pb0.5)(Fe0.5Zr0.5)O3 sample showed evidence of a long-range magnetic ordering below TN with a propagation vector k = (0,0,0) and an antiferromagnetic arrangement of the magnetic moments of the Fe3+ cations in the B-site. This is consistent with an Ay-type magnetic structure. The factors governing the structural and magnetic properties of (1 ? x)BiFeO3–xPbZrO3 solid solutions are discussed and compared with those of pure BiFeO3 and PbZrO3. A solid solution strategy for developing magnetoelectric properties in BiFeO3-based compounds is described, with the aim of realizing both a spontaneous polarization and magnetization at room temperature. 相似文献
9.
Brahim Ayed 《Comptes Rendus Chimie》2012,15(7):603-608
Single crystals of a new phosphate AgCr2(PO4)(P2O7) have been prepared by the flux method and its structural and the infrared spectrum have been investigated. This compound crystallizes in the monoclinic system with the space group C2/c and the parameters are, a = 11.493 (3) Å, b = 8.486 (3) Å, c = 8.791 (2) Å, β = 114.56 (2)°, V = 779.8 (3) Å3and Z = 4. Its structure consists of CrO6 octahedra sharing corners with P2O7 units to form undulating chains extending infinitely along the [110] direction. These chains are connected by the phosphate tetrahedra giving rise to a 3D framework with six-sided tunnels parallel to the [101] direction, where the Ag+ ions are located. The infrared spectrum of this compound was interpreted on the basis of P2O74? and PO43? vibrations. The appearance of νsP–O–P in the spectrum suggests a bent P–O–P bridge for the P2O74? ions in the compound, which is in agreement with the X-ray data. The electrical measurements allow us to obtain the activation energy of (1.36 eV) and the conductivity measurements suggest that the charge carriers through the structure are the silver captions. 相似文献
10.
《Radiation Physics and Chemistry》2009,78(4):239-243
Using various methods different tin phosphate samples were prepared. One of them was amorphous, while the others were crystalline with monoclinic structure, having unit cell parameters as follows: a=4.586 Å, b=13.618 Å, c=5.818 Å, β=99.61° [Sn (H2PO4)2] and a=8.612 Å, b=4.964 Å, c=15.860 Å, β=98.87° [Sn(HPO4)2], respectively. The crystal water content and the method of thermal decomposition of the samples were determined. The chemical composition of the end products of preparations was determined by promt-gamma activation analysis and was found to be Sn:P=1:2 for all samples independent of their preparation method. The oxidation state of tin atoms in samples as determined by Mossbauer spectroscopy was mainly +2 in sample no. 2, while in some other samples it was +4. 相似文献
11.
《Solid State Sciences》2007,9(3-4):322-328
Electrochemical measurements demonstrate that magnesium surfaces can be protected by alkyl carboxylate. In a nearly neutral pH solution of sodium decanoate, the reduced corrosion rate and a passivation behaviour are attributed to the formation of Mg(C10H19O2)2(H2O)3 (Mg(C10)2) at the magnesium surface whereas heptanoate Mg(C7H13O2)2(H2O)3 (Mg(C7)2) is not efficient in such media. The crystal structures of the two metal carboxylates Mg(C7)2 and Mg(C10)2 are determined by X-ray diffraction. Single crystal data: Mg(C7)2, P21/a, a = 9.130(5) Å, b = 8.152(5) Å, c = 24.195(5) Å, β = 91.476(5)°, V = 1800.3(15) Å3, Dx = 1.242 g cm−3, Z = 4. Synchrotron powder data: Mg(C10)2, P21/a, a = 9.070(3) Å, b = 8.165(1) Å, c = 32.124(1) Å, β = 98.39(1)°, V = 2353.85(8) Å3, Dx = 1.188 g cm−3, Z = 4. Their layered structures are quite similar and differ mainly by the length of the hydrophobic chains. They consist of two planes of O-octahedra centred by Mg atoms, parallel to (001). The distorted octahedra are constituted by three oxygen atoms from carboxylate groups and by three oxygen atoms coming from water molecules. The layers are connected by hydrogen bonds. The carboxylate chains are located perpendicularly and on both sides of these planes. One carboxylate chain is bridging the Mg atom along [010] while the other is monodendate. The presence of structural water is confirmed by thermal analyses. 相似文献
12.
《Solid State Sciences》2007,9(1):16-20
A new molybdenum complex (C4H12N2)2[(MoV2O4)(MoVIO4)(C2O4)2]·2H2O, was solvothermally synthesized and characterized by single-crystal X-ray diffraction. The structure of the compound consists of oxalate acid-coordinated mixed-valent [MoV2O4][MoVIO4] helical chains and protonated piperazine cations. The helical chains are built up from the [MoV2O4] units and [MoVIO4] tetrahedral. The central axis about helical chain is a 2-fold screw axis. The compound crystallizes in the space group P21/n of monoclinic system with a = 11.396(2) Å, b = 14.107(3) Å, c = 15.805(3) Å, β = 102.09(3)°, V = 2484.6(9) Å3, Z = 4. Other characterizations by elemental analysis, IR, and thermal analysis for this compound are also given. 相似文献
13.
《Solid State Sciences》2007,9(6):459-464
The synthesis and crystal structure of the red transparent lithium boride Li6B18(Li2O)x (0 < x ≤ 1) is reported. The lattice constants are a = 8.21708(17) Å and c = 4.15893(16) Å for x = 0.26 (powder data), a = 8.223(4) Å and c = 4.160(2) Å for x = 0.7 (single crystal data), a = 8.21179(16) Å and c = 4.14485(13) Å for x = 0.9 (powder data). The compound crystallizes in the space group P6/mmm (no. 191). The crystal structure consists of B6 octahedra forming a 3-dimensional network with large open channels. This compound has remarkable topological similarities with hexagonal tungsten bronzes and zeolites and is only formed, when a template is present during the synthesis. 相似文献
14.
Rie Fredrickson Takagi Daisy Torino Hjelmqvist Mats Johnsson Sven Lidin 《Solid State Sciences》2009,11(1):13-17
The compounds CaCo2Te3O8Cl2, SrCo2Te3O8Cl2 and SrNi2Te3O8Cl2 were synthesized via solid–gas reactions and investigated using single-crystal X-ray diffraction. While the compound CaCo2Te3O8Cl2 formed large enough single crystals to allow for a detailed structural analysis, crystals of the Sr-containing compounds yielded evidence that they are isostructural. CaCo2Te3O8Cl2 crystallizes in the monoclinic system, space group P21/c, a = 6.537(2) Å, b = 9.088(2) Å, c = 19.500(9) Å, β = 113.36(4)°, Z = 4. It exhibits [CoO5Cl] helical chains along the [010] direction, connected by [CaO8] polyhedra, [TeO3E] tetrahedra and [TeO4E] trigonal bipyramids (the lone pair of electrons on TeIV is designated as E) to form a layer. The layers are held together only by weak van der Waals forces; the shortest interlayer distance is a Te?Cl contact of 3.432(4) Å. 相似文献
15.
Iran Sheikhshoaie Alireza Akbari S. Yousef Ebrahimipour 《Arabian Journal of Chemistry》2013,6(4):407-411
Treatment of the Schiff base 2-((E)-(2-hydroxy propylimino)methyl)phenol with MoO2(acac)2 in dry methanol gave the mononuclear complex (methanol{6-[(2-oxidopropyl)iminometh-yl]phenolato}dioxidomolybdenum(VI), which was characterized by X-ray crystal analysis, and it has monoclinic space group p21/c, and a = 10.330(17) Å, b = 9.397(15) Å, c = 13.695(2) Å, V = 1252.1(3) Å3, and Z = 4. B3LYP theoretical method with DZP basis sets calculations nicely reproduces the X-ray experimental geometry, molecular orbital levels and the other structural properties for this complex. 相似文献
16.
《Solid State Sciences》2007,9(7):619-627
Three new crystal structures, isotypic with β-Zr2O(PO4)2, have been resolved by the Rietveld method. All crystallize with an orthorhombic cell (S.G.: Cmca) with a = 7.1393(2) Å, b = 9.2641(2) Å, c = 12.5262(4) Å, V = 828.46(4) Å3 and Z = 8 for Th(OH)PO4; a = 7.0100(2) Å, b = 9.1200(2) Å, c = 12.3665(3) Å, V = 790.60(4) Å3 and Z = 8 for U(OH)PO4; a = 7.1691(3) Å, b = 9.2388(4) Å, c = 12.8204(7) Å, V = 849.15(7) Å3 and Z = 4 for Th2O(PO4)2. By heating, the M(OH)PO4 (M = Th, U) compounds condense topotactically into M2O(PO4)2, with a change of the environment of the tetravalent cation that lowers from 8 to 7 oxygen atoms. The lower stability of Th2O(PO4)2 compared to that of U2O(PO4)2 seems to result from this unusual environment for tetravalent thorium. 相似文献
17.
《Solid State Sciences》2007,9(5):370-375
A new two-dimensional lead(II) vanadate, Ba3PbV4O14 has been synthesized by standard solid state techniques using BaCO3, PbO, and V2O5 as reagents. The structure of Ba3PbV4O14 was determined by single-crystal X-ray diffraction. Ba3PbV4O14 crystallizes in the triclinic space group P-1 (no. 2), with a = 7.2997(15) (Å), b = 7.2932(15) (Å), c = 13.379(3) (Å), α = 93.68(3)°, β = 99.68(3)°, γ = 91.49(3)°, V = 700.2(2) (Å3) and Z = 2. Ba3PbV4O14 exhibits a novel two-dimensional layered structure consisting of corner shared VO4 tetrahedra that are linked by edge shared PbO7 polyhedra, in which the Ba2+ cations occupy the interlayer region. The Pb2+ cations are in asymmetric coordination environments attributable to its lone pair. Infrared, Raman, and UV–vis diffuse reflectance spectroscopy, thermogravimetric analysis, and dipole moment calculations are also presented. 相似文献
18.
F.Y. Bai X.T. Li G.S. Zhu Y.H. Xing 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,75(5):1388-1393
A new complex of oxovanadium(IV), V2O2[(HB(pz)3)2(pyrro)2 (1) and a dimer-dithio carboxyl compound (C5H8NS2)2 (2) have been synthesized by the reaction of VOSO4·nH2O with NaHB(pz)3 and pyrrolidine dithio carboxylic acid ammonium salt. They were characterized by element analysis, IR spectra, UV–vis spectra and X-ray diffraction. Structural analyses of 1 and 2 gave the following parameters: 1, triclinic, P-1, a = 7.732(4) Å, b = 14.285(8) Å, c = 17.802(9) Å, α = 101.314(8)°, β = 92.682(9)°, γ = 92.228(9)°, V = 1923.6(18) Å3, and Z = 4; 2, monoclinic, C2/c, a = 13.857(2) Å, b = 10.4213(18) Å, c = 9.436(2) Å, β = 97.099(2), V = 1352.1(4) Å3, and Z = 4. In complex 1, vanadium atom adopts a distorted tetragonal bipyramid structure, which is typical for oxovanadium(IV) complexes. Compound 2 is a dimer-dithio carboxyl compound with S–S bond. In addition, thermal analysis was performed for analyzing the stabilization of the complexes. 相似文献
19.
《Solid State Sciences》2007,9(2):137-143
Four new magnesium containing metal–organic hybrid compounds have been synthesized in an effort to prepare low-density materials for hydrogen storage. The compounds were prepared hydrothermally and characterized using single crystal X-ray diffraction. Three of these compounds are analogs of known transition metal structures with squarate (I, Pn-3n, a = 16.276(5) Å), diglycolate (II, P212121, a = 6.860(1) Å, b = 9.993(1) Å, c = 10.884(1) Å, R1 = 0.0341), and glutarate (III, R-3, a = 10.744(2) Å, c = 28.677(5) Å, R1 = 0.0554) ligands; the fourth is a novel structure using cyclobutanetetracarboxylate (IV, Pccn, a = 9.382(1) Å, b = 14.410(2) Å, c = 8.725(1) Å, R1 = 0.0465) which contains potassium as well as magnesium cations. 相似文献
20.
S. Kaoua P. Gravereau J.P. Chaminade S. Pechev S. Krimi A. El Jazouli 《Solid State Sciences》2009,11(3):628-634
We have extended our research interest on titanium oxyphosphates (MII(TiO)2(PO4)2, with MII = Mg, Fe, Co, Ni, Cu, Zn) to vanadium oxyphosphates MII(VIVO)2(PO4)2 (MII = Co, Ni). For each compound two phases, named α and β according to synthesis conditions, have been stabilized at room temperature, then characterized. The four crystal structures M(VO)2(PO4)2 (α and β for M = Co, Ni) have been determined in monoclinic P21/c space group using X-ray single crystals diffraction data. Structure of the α phase is derived from the Li(TiO)(PO4) (orthorhombic Pnma) and LiNi0.50(TiO)2(PO4)2 (monoclinic P21/c) types, with cell parameters: a = 6.310(1) Å, b = 7.273(1) Å, c = 7.432(1) Å, β = 90.43(1)° for M = Co, and a = 6.297(2) Å, b = 7.230(2) Å, c = 7.421(2) Å, β = 90.36(2)° for M = Ni. Structure of the β phase is derived from the Ni(TiO)2(PO4)2-type (monoclinic P21/c) with cell parameters: a = 7.2742(2) Å, b = 7.2802(2) Å, c = 7.4550(2) Å, β = 120.171(2)° for M = Co, and a = 7.2691(2) Å, b = 7.2366(2) Å, c = 7.4453(2) Å, β = 120.231(2)° for M = Ni. All these structures consist of a three dimensional (3D) framework built up of infinite chains of tilted corner-sharing [VO6] octahedra, cross-linked by corner-sharing [PO4] tetrahedra. The M2+ ion (M = Co, Ni) is located in a triangular based antiprism which shares faces with two [VO6] octahedra. Structural filiation is discussed based on a common structural unit, a sheet where divalent cations M2+ (M = Co, Ni) are inserted. A thermal study of the α ? β transition is also presented. 相似文献