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1.
S. Ledain M. M. Borel A. Leclaire J. Provost B. Raveau 《Journal of solid state chemistry》1995,120(2)
A lithium Mo(V) diphosphate LiMoOP2O7 has been synthesized for the first time. It crystallizes in the space group P 21/n with a = 16.046(4) Å, b = 11.951(2) Å, c = 9.937(2) Å, β = 104.62(2)°. Its original structure is built up from P2O7 groups and MoO6 octahedra forming intersecting tunnels, where the Li+ cations are located with a tetrahedral coordination. This phase belongs to the IB class of Mo(V) phosphates defined by Costentin et al. The [MoP2O8] framework indeed consists of MoP2O11 units built up from one P2O7 group sharing two apices with the same MoO6 octahedron; the MoP2O11 units share their apices forming [MoP2O10]∞ chains running along a and b and the [
04] direction. This phase exhibits a classical paramagnetic behavior, with 0 = -9.8 K and μ = 1.58 μB. 相似文献
2.
Compounds Ce2TiO5, Ce2Ti2O7, and Ce4Ti9O24 were prepared by heating appropriate mixtures of solids containing Ce4+ and Ti3+ or Ti which were placed in a platinum-silica-ampoule combination at T = 1250°C (3d) under vacuum. The new compounds were characterized by powder patterns. We obtained Ce2TiO5 which is isotypic to La2TiO5 and crystallizes in the Y2TiO5-type (space group Pnma) with a = 10.877(6) Å, b = 3.893(1) Å, c = 11.389(8) Å, Z = 4. Ce2Ti2O7 is isotypic to La2Ti2O7 and crystallizes in the monoclinic Ca2Nb2O7 type (space group P 21) with a = 7.776(6) Å, b = 5.515(4) Å, c = 12.999(6) Å, β = 98.36(5), Z = 4. The compound Ce4Ti9O24 crystallizes orthorhombic with a = 14.082(4) Å, b = 35.419(8) Å, c = 14.516(4) Å, Z = 16. The new cerium titanate Ce4Ti9O24 is isotypic to Nd4Ti9O24 (space group Fddd (No. 70)) which represents a novel type of structure. 相似文献
3.
Single crystals of Ln5Ru2O12 (Ln=Pr, Nd, Sm-Tb) were grown out of either NaOH or KOH fluxes in sealed silver tubes. The crystals of all the phases were observed to be twinned as confirmed by TEM studies. The series crystallize in the C2/m monoclinic system with lattice parameters, a=12.4049(4)-12.7621(6) Å, b=5.8414(2)-5.9488(3) Å, c=7.3489(2)-7.6424(4) Å, β=107.425(3)-107.432(2)° and Z=2. The crystal structure is isotypic with the defect/disorder model of Ln5Re2O12 (Ln = Y, Gd) and consists of one dimensional edge shared RuO6 octahedral chains separated by a two dimensional LnOx polyhedral framework. Magnetic measurements indicate paramagnetic and antiferromagnetic behavior for Ln=Nd, Sm-Gd and Ln=Tb, respectively. 相似文献
4.
The crystal structures of two new oxides, BiReO4 and BiRe2O6, have been determined by single-crystal X-ray methods using an Enraf-Nonius CAD-4F diffractometer. BiReO4 crystallizes as red metallic needles in the space group Cmcm, cell dimensions a = 3.839(1) Å, b = 14.914(2) Å, c = 5.534(1) Å, Z = 4. The structure consists of sheets of corner-shared octahedra (composition ReO4) linked by Bi atoms (R = 2.55%). BiRe2O6 crystallizes as black metallic plates in the space group C2/m, cell dimensions a = 5.516(1) Å, b = 4.906(1) Å, c = 8.384(1) Å, β = 106.71(1)°, Z =2. The structure consists of layers containing Re2O10 units linked together by corner sharing of the octahedra, alternating with layers of Bi atoms (R = 2.61%). The structure is disordered due to the random stacking of the Re layers. The Re---Re distance of 2.5 Å in the Re2O10 unit is comparable to that found in similar compounds. Both compounds exhibit stereochemically active lone pairs. 相似文献
5.
A novel Mo(V) diphosphate Sr(MoO)2P2O7 has been synthesized. It crystallizes in the space group P21/n with a=7.925(1) Å, b=7.739(1) Å, c=9.485(1) Å and β=91.05(1)°. Its original framework consists of MoP2O11 units built up of one P2O7 group sharing two apices with one MoO6 octahedron. The MoP2O11 units share corners, forming [MoP2O10]∞ chains running along [101]. The assemblage of these chains forms the [Mo2P4O16]∞ intersecting tunnel framework. The Sr2+ cations are located at the tunnel intersection, showing a distorted cubic coordination. This structure is compared to those of Ba(MoO)2P2O7 and LiMoOP2O7, which are also built up of MoP2O11 units forming [MoP2O10]∞ chains, but with different configurations. 相似文献
6.
A mixed-valent molybdenotungstophosphate, Nax(Mo, W)2O3(PO4)2 (x 0.75) has been isolated for the first time. It crystallizes in the space group P 21/m with a = 7.200(1) Å, b = 6.369(1) Å, c = 9.123(1) Å, and β = 106.29(1)°. Its structure consists of M2PO13 units built up of two M O6 octahedra (M = Mo, W) and one PO4 tetrahedron sharing their apices as already observed in several molybdenum phosphates. These units share their apices with PO4 tetrahedra forming [M2P2O15]∞ chains running along
. The host lattice [(Mo, W)2P2O11]∞ can be described by the assemblage of such chains or by the assemblage of [MPO8]∞ chains running along
, in which one PO4 tetrahedron alternates with one MO6 octahedron. The tridimensional framework [Mo, WP2O11]∞ delimits tunnels running along
, occupied by sodium with two kinds of coordination, 6 and 5. The distribution of the different species, in the octahedral sites according to the formulation Na0.75(MoVI0.42WVI0.58)M1 (MoV0.75WVI0.25)2O3(PO4)2, is discussed. 相似文献
7.
Synthesis, structure and magnetic properties of the S=1/2, one-dimensional antiferromagnet, Y5Re2O12
Lisheng Chi 《Journal of solid state chemistry》2003,172(2):451-457
Single crystals of Y5Re2O12 have been grown, and the crystal structure has been determined by X-ray diffraction. This compound crystallizes in space group C2/m with cell dimensions of a=12.4081(10) Å b=5.6604(5)Å, c=7.4951(6) Å, β=107.837(3)°, Z=2. The final refinement led to R1=0.0238, WR2=0.0459 for 1053 observed reflections with F>4σ(F0). Edge-sharing ReO6 octahedra form infinite linear [ReO2O4/2]n chains along the b direction with alternating short and long Re-Re distances. Three crystallographically independent yttrium atoms surround O2 to form OY4 tetrahedra, which share edges and corners in the ab plane to form a two-dimensional Y5O4 network which separates the [ReO2O4/2]n magnetic chains. This compound is therefore isostructural with the series Ln5Re2O12Ln=Gd-Lu, which have been known since 1969. The average Re oxidation state is +4.5 in the chains and a reasonable, if qualitative MO scheme results in one unpaired electron per Re dimer. Consistent with this, magnetic susceptibility data can be fitted to the one-dimensional antiferromagnetic Heisenberg model with S=1/2 and parameters Jintra/k=−89(1)K, g=2.15(4) and χ(TIP)=5(1)×10−4 emu/mol. There is no sign of long-range magnetic order down to 2 K. These results are contrasted with those for the isostructural Y5Mo2O12. 相似文献
8.
Hong Zhang Yangguang Li Liying Duan Yang Lan Enbo Wang Changwen Hu Yuangen Yao Jiutong Chen Song Gao 《Journal of solid state chemistry》2003,170(2):232-236
A new mixed Mo/Ni/Ti heteropoly compound [C5H5NH]5 [(NiOH)2Mo10O36(PO4)Ti2] has been hydrothermally synthesized and structurally determined by the single-crystal X-ray diffraction. Black prismatic crystals crystallize in the monoclinic system, space group P2(1)/n, a=11.2075(2), b=37.8328(5) c=13.0888(1) Å, β=101.4580(10)°, M=2276.13, V=5439.19(13) Å3, Z=4. Data were collected on a Siemens SMART CCD diffractometer at 293(2) K in the range of 1.68<θ<25.09° using the ω-scan technique (λ=0.71073 Å R(F)=0.0872 for 9621 reflections). The title compound contains a trimetal heteropolyanion polymer and “trans-titanium”-bridging pseudo-Keggin fragments linked to a chain. 相似文献
9.
The crystal structure of K2Cu3(As2O6)2 was determined from single-crystal X-ray data by a direct method strategy and Fourier summations [a = 10.359(4) Å, B = 5.388(2)Å, C = 11.234(4) Å, β = 110.48(2)°; space group C2/m; Z = 2; Rw = 0.025 for 1199 reflections up to sin /λ = 0.81 Å−1]. In detail, the structure consists of As(V)O4 tetrahedra and As(III)O3 pyramids linked by a common O corner atom to [As(V)As(III)O6]4− groups with symmetry m. The bridging bonds As(V)---O [1.749(3) Å] and As(III)---O [1.838(2) Å] are definitely longer than the other As(V)---O bonds [mean 1.669 Å] and As(III)---O bonds [1.764(2) Å, 2×]. The angle As(V)---O---As(III) is 123.0(1)°. The Cu atoms are [4 + 2]- and [4 + 1]-, and the K atom is [9]-coordinated to oxygen atoms. The As2O6 groups and the Cu coordination polyhedra are linked to sheets parallel to (001). These sheets are connected by the K atoms. Single crystals of K2Cu3(As2O6)2 suitable for X-ray work were synthesized under hydrothermal conditions. 相似文献
10.
Yttrium molybdate (Y2Mo3O12) has been prepared by non-hydrolytic sol–gel chemistry. The phase evolution upon heating was investigated using in situ and ex situ heat treatments combined with powder X-ray diffraction. This method has led to the isolation of two orthorhombic phases with different atomic connectivity. Yttrium adopts 6- and 7-coordinate sites in the Pbcn and Pba2 structures, respectively. Cocrystallization of both phases was observed in a narrow temperature range, suggesting that crystallization kinetics play a major role in phase formation. It was found that the Pba2 phase is the stable polymorph below 550 °C, and converts to Pbcn at higher temperatures. 相似文献
11.
The crystal structure of BaNd2Ti3O10 has been determined by electron diffraction and high-resolution electron microscopy. The unit cell is monoclinic with P21/m as the most probable space group and not orthorhombic as previously found by X-ray diffraction. However, the structure has an orthorhomic pseudosymmetry, but due to the small Nd3+ cations the octahedra are titled and the structure is monoclinic. The cell dimensions based on X-ray data are: am = 7.7310 ± 0.0006 Å; bm = 7.6661 ± 0.0007 Å; cm = 14.210 ± 0.002 Å; βm = 97.82 ± 0.01°. 相似文献
12.
The new compound Hg2FeF5(OH)2 · H2O was prepared by evaporation of an aqueous 40% HF solution containing HgO and FeF3 in the stoichiometric ratio. The material is orthorhombic, space group Cmmm, with a = 7.505(1) Å, b = 11.823(3) Å, c = 3.941(2)Å, and Z = 2. The crystal structure was determined from single crystal intensity data obtained by means of an automated four-circle diffractometer and refined to the conventional values R = 0.0621 and Rw = 0.0566 for 451 observed reflections. The structure is characterized by infinite straight chains of FeF6 octahedra sharing trans F atoms in the direction [001]. These chains are linked by rutile-type chains of HgF4(OH)2 octahedra also running along [001]. Water molecules are statistically distributed on half of the 4i positions; they are off-centered in the channels parallel to [001] allowing O---H ··· F bonding. The structure is compared to that of HgFeF5 · 2H2O and to that of the hexagonal tungsten bronze. 相似文献
13.
A new series of vanadates with the general formula M Ba2V3O11, where M may be Bi, In, or a rare earth, has been synthesized and structurally characterized by single crystal X-ray diffraction and powder X-ray diffraction. The general formula may be rewritten as M Ba2(VO4)(V2O7) to emphasize that there is one orthovanadate group and one pyrovanadate group in each formula unit. Up to one-third of the vanadium may be replaced by phosphorous, leading to the general formula M Ba2V2PO11. However, phosphorous shows no preference between the ortho and pyro groups. Both M Ba2V3O11 and M Ba2V2PO11 crystallize in the monoclinic system with the space group P21/c and Z = 4. The cell parameters from single crystal X-ray data of BiBa2V3O11 are a = 12.332(4) Å, b = 7.750(4) Å, c = 11.279(4) Å, β = 103.22(3)°, V = 1049(1) Å3; and for BiBa2PO11 are a = 12.266(2) Å, b = 7.615(2) Å, c = 11.312(2) Å, β = 103.32(2)°, V = 1028.2(2) Å3. The Bi atom coordinates to six oxygen atoms forming a distorted octahedron, and the edge sharing of BiO6 octahedra results in a BiO4 chain along the b axis. There are two types of Ba atoms with coordination numbers of 10 and 11. There are three types of tetrahedral (T) atoms in these structures. The nonequivalent T atoms of the pyro group give T-O-T angles of 167 and 171° in BiBa2V3O11 and BiBa2V2PO11, respectively. Isostructural M Ba2V3O11 compounds were prepared in which M is In, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, or Lu. 相似文献
14.
E. A. Juarez-Arellano L. Bucio J. A Hernandez E. Camarillo R. E. Carbonio E. Orozco 《Journal of solid state chemistry》2003,170(2):735-423
A new indium terbium germanate InTbGe2O7, which is a member of the thortveitite family, was prepared as a polycrystalline powder material by high-temperature solid-state reaction. This new compound crystallizes in the monoclinic system, space group C2/c (No. 15), with unit cell parameters a=6.8818(2) Å, b=8.8774(3) Å, c=9.7892(4) Å, β=101.401(1)°, V=586.25(4) Å3 and Z=4. Its structure was characterized by Rietveld refinement of powder laboratory X-ray diffraction data. It consists of octahedral sheets that are held together by sheets of isolated Ge2O7 diorthogroups composed of two tetrahedra sharing a common vertex. It contains only one octahedral site occupied by In3+ and Tb+3 cations. The characteristic mirror plane in the thortveitite (Sc2Si2O7) space group (C2/m, No. 12) is not present in this new compound. Besides, in InTbGe2O7, the Ge–O–Ge angle bridging two diorthogroups is 156.8(2)° as compared to the one in thortveitite, which is 180°. On the other hand, luminescent properties were observed when it is excited with 376.5 nm wavelength. The luminescence spectrum shows typical transitions from the 5D4 multiplet belonging to the trivalent terbium ion. 相似文献
15.
The complex oxide Na3Fe2Mo5O16 has been synthesized, and its crystal structure was determined by single-crystal X-ray diffraction (space group (SG) P-3m1; a=5.7366(6) Å, c=22.038(3) Å; Z=2). The compound can be considered as a new structure type containing Mo3O13 cluster units, which can be derived from the Na2In2Mo5O16 structure model by doubling of the cell along the c-axis. Na3Fe2Mo5O16 crystallizes in centrosymmetric SG (P-3m1) and the positions of the sodium atoms are fully occupied in contrast to the proposed Na2In2Mo5O16 model SG (P3m1). Magnetic properties of Na3Fe2Mo5O16 were studied by superconducting quantum interference device measurements, revealing antiferromagnetic ordering below Tχmax=10(1) K. Thermal stability in air was investigated by in situ high-temperature X-ray powder diffraction. Structural relationships to Na2In2Mo5O16 and NaFe(MoO4)2 are discussed. 相似文献
16.
[C4H9)4N]2[Mo2O7] reacts with a variety of organic species containing α-diketone groups to give tetranuclear complexes of general composition [RMo4O15X]3−. The complexes [(C4H9)4N]3[(C9H4O)Mo4O15(OCH3)] (I), [(C4H9)4N]3[(C14H10)Mo4O15(C6H5CO2)] (11) and [(C4H9)4N]3[(C14H8)Mo4O15(OH)] (III) were synthesized from the reactions of dimolybdate with ninhydrin, benzil and phenanthraquinone, respectively. Complex II may also be prepared from dimolybdate and benzoin in acetonitrile-methanol solution, from which it co-crystallizes with the binuclear species [(C4H9)4N]2[Mo2O5(C6H5C(O)C(O)C6H5)2] · CH3CN · CH3OH (IV). Complexes I–III exhibit the tetranuclear core, previously described for the α-glyoxal derivatives [(C4H9)4N]3[(HCCH)Mo4O15X], where X = F− or HCO2−. The ligands may be formally described as diketals, formed by insertion of ligand carbonyl subunits into molybdenum-oxygen bonds. The structures I–III differ most dramatically in the identity and coordination mode of the anionic ligand X− which occupies a position opposite the diketal moiety relative to the [Mo4O11]2+ central cage. Thus, I exhibits a doubly bridging methoxy group in this position, while II possesses a benzoate ligand with an unusual μ3-O,O′coordination mode. Complex III presents a hydroxy-group unsymmetrically bonded to three of the molybdenum centres. The stereochemical consequences of the various coordination modes are discussed. Crystal data: Compound I, monoclinic space group Pc, a = 24.888(2), b = 12.897(3), c = 24.900(3) Å, β = 101.94(2)°, Dcalc = 1.28 g cm−1 for Z = 4. Structure solution and refinement based on 8695 reflections with Fo 6σ(Fo) (Mo-Kα, λ = 0.71073 Å) converged at a conventional discrepancy factor of 0.060. Compound II, orthorhombic space group Pbca, a = 20.426(6), b = 26.916(6), c = 32.147(7) Å, V = 17673.2(20) Å3, Dcalc = 1.33 g cm−3 for Z = 8; 5224 reflections, R = 0.076. Compound III, tetragonal space group I41/a, a = b = 48.129(6), c = 13.057(2) Å, V = 30246.2(12) Å3, Dcalc = 1.35 g cm−3 for Z = 16; 5554 reflections, R = 0.053. Compound IV, orthorhombic space group Pnca, a = 16.097(4), b = 16.755(4), c = 25.986(7) Å, V = 7008.1(13) Å3, Z = 4, Dcalc = 1.18 g cm−3 ; 2944 reflections, R = 0.061. 相似文献
17.
Xuean Chen Fangping Song Xinan Chang Hegui Zang Weiqiang Xiao 《Journal of solid state chemistry》2009,182(11):3091-3097
Two oxoborates, (Pb3O)2(BO3)2MO4 (M=Cr, Mo), have been prepared by solid-state reactions below 700 °C. Single-crystal XRD analyses showed that the Cr compound crystallizes in the orthorhombic group Pnma with a=6.4160(13) Å, b=11.635(2) Å, c=18.164(4) Å, Z=4 and the Mo analog in the group Cmcm with a=18.446(4) Å, b=6.3557(13) Å, c=11.657(2) Å, Z=4. Both compounds are characterized by one-dimensional chains formed by corner-sharing OPb4 tetrahedra. BO3 and CrO4 (MoO4) groups are located around the chains to hold them together via Pb–O bonds. The IR spectra further confirmed the presence of BO3 groups in both structures and UV–vis diffuse reflectance spectra showed band gaps of about 1.8 and 2.9 eV for the Cr and Mo compounds, respectively. Band structure calculations indicated that (Pb3O)2(BO3)2MoO4 is a direct semiconductor with the calculated energy gap of about 2.4 eV. 相似文献
18.
D. M. De Leeuw C. A. H. A. Mutsaers G. P. J. Geelen C. Langereis 《Journal of solid state chemistry》1989,80(2)
The subsolidus phase diagram of the system La2O3---SrO---CuO at 950°C under 1 bar of pure oxygen has been investigated and a new ternary compound, La1+xSr2−xCu2O5.5+δ with 0.05 ≤ x ≤ 0.15, was isolated. This compound crystallizes in an orthorhombic unit cell with lattice constants related to the lattice constant of the perovskite cubic unit cell, ap, by a = 3.80 Å ap, B = 11.48 Å 3ap, and c = 20.23 Å 5ap. The structure is isotypical to that of LnSr2Cu2O5.5+δ with Ln = Sm, Eu, or Gd. Reported data on the crystal chemistry of the equilibrium compounds in the system La2O3---SrO---CuO have been summarized and compared with the present data. The structure of all compounds is built up of a La---O rock-salt layer separated by a number of LaCuO3 perovskite layers. The general formula is (La---O)(LaCuO3)n where La can be replaced either partly or completely by Sr. Compounds are found for n = 1, 2, and ∞. The structures of the compounds show different types of oxygen vacancy ordering. 相似文献
19.
The new compounds K12Ta6Se35 and KTaTe3 have been synthesized through the reaction of Ta metal with a K2Qn(Q = Se, Te) flux. K12Ta6Se35, crystallizes with 4 formula units in space group Pbcn of the orthorhombic system in a cell of dimensions a = 8.3390(17) Å, b = 13.259(3) Å, c = 56.023(11) Å (t = −120 °C). KTaTe3 crystallizes with 20 formula units (or 4 formula units of K5Ta5Te15) in the monoclinic space group P21/c in a cell of dimension a = 7.7177(15) Å, b= 13.826(3) Å, c = 30.981(6) Å, and β = 90.11(3)° (t = −120 °C). Each structure consists of infinite anionic chains of Ta-containing polyhedra well separated by K+ cations. In K12Ta6Se35 there are Ta2Se11 units formed by the face sharing of two TaSe7 elongated bipyramids. These Ta2Se11 units are in turn interconnected by Se2 and Se3 units to form α1[Ta6Se3Se3512−]infinite chains. In KTaTe3, the α1[TaTe3−] infinite chains arise from the face sharing of distorted TaTe6 octahedra. 相似文献
20.
J. T. Vaughey William T. A. Harrison Allan J. Jacobson 《Journal of solid state chemistry》1994,110(2)
Two new potassium vanadium phosphates have been prepared and their structures have been determined from analysis of single crystal X-ray data. The two compounds, K3(VO)(V2O3) (PO4)2(HPO4) and K3(VO)(HV2O3)(PO4)2(HPO4), are isostructural, except for the incorporation of an extra hydrogen atom into the nearly identical frameworks. The structures consist of a three-dimensional network of [VO]n chains connected through phosphate groups to a [V2O3] moiety. Magnetic susceptibility experiments indicate that in the case of the di-hydrogen compound, there are no significant magnetic interactions between the three independent vanadium (IV) centers. Crystal data: for K3(VO)(V2O3)(PO4)2 (HPO4), Mr = 620.02, orthorhombic space group Pnma (No. 62), a = 7.023(4) Å, b = 13.309(7) Å, c = 14.294(7) Å, V = 1336(2) Å3, Z = 4, R = 5.02%, and Rw = 5.24% for 1238 observed reflections [I > 3σ(I)]; for K3(VO)(HV2O3)(PO4)2(HPO4), Mr = 621.04, orthorhombic space group Pnma (No. 62), a = 6.975(3) Å, b = 13.559(7) Å, c = 14.130(7) Å, V = 1336(1) Å3, Z = 4, R = 6.02%, and Rw = 6.34% for 1465 observed reflections [I > 3σ(I)]. 相似文献