- Reactions of oxides of some 3d elements with ammonium hydrogen difluoride
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Reactions of iron, manganese(II), manganese(IV), copper, and zinc oxides with ammonium hydrogen difluoride were studied by thermogravimetry, X-ray phase analysis, IR spectrometry, and chemical analysis.
- Kalinnikov,Nesterov,Makarov,Steshin,Tikhomirova
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- The first oligomeric anions of fluoro-litho metallates with octahedra sandwich motive: Cs4K{[F3MIIIF3]Li[F 3MIIIF3]}, MIII = Ga, Fe
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Colourless single crystals of Cs4K{Li[Ga2F12]} (A) and Cs4K{Li[Fe2F12]} (B) have been obtained by solid state reaction from intimate mixtures of the corresponding binary fluorides (Pt-tube, 750°C, 40 d). The trigonal unit cells with (A) a = 631,3(1) pm; c = 3059,9(6) pm and (B) a = 635,0(1) pm; c = 3089,2(7) pm, respectively (Z = 3, Guinier-Simon data, Cu-Kα1), are confirmed by single crystal investigations. The compounds crystalize isostructural in the space group R3m (No. 166). The structures were determined using four-circle diffractometer data (Siemens AED 2) with (A) R = 2.95%, 3627 Io and (B) R = 1.86%, 4179 Io, respectively (SHELX-76), and are characterized by triplets of facesharing octahedra parallel [00.1] with the cation-sequence MIII-Li-MIII, six of which are connected by [KF6]-octahedra via common corners and each triplet is surrounded by six different [KF6]-octahedra. The structure is completed by Cs+ filling the cavities. The Madelung Part of Lattice Energy (MAPLE), Mean Fictive Ionic Radii (MEFIR) and Effective Coordination Numbers (ECoN) are calculated and compared. The classification as lithometallate could be verified by a new MAPLE concept. The Charge Distribution (CHARDI) was calculated and compared with the results according to 'bond length-bond strength'. Johann Ambrosius Barth 1996.
- Bork,Hoppe
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- Moessbauer spectroscopy and magnetic properties of Ba5Feiii3-xMii19-x (M = Fe, Cu)
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The Moessbauer spectra of three phases of the tetragonal solid solution Ba5FeIII3-xMIIxF 19-x (M = Fe, Cu) obtained by substitution of Fe3+ by M2+ ions, have been studied, as well as their magnetic properties. A mechanism of substitution of the Fe3+ cations is proposed according to the Moessbauer data. These compounds are paramagnetic until 4.2 K, with very weak antiferromagnetic interactions below 30-40 K.
- Gredin, Patrick,De Kozak, Ariel,Pierrard, Angelique,Calage, Yvon
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- Enhancing cycling performance of FeF3 cathode by introducing a lightweight high conductive adsorbable interlayer
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Iron fluorides, as a kind of high specific capacity conversion-type cathode materials for lithium rechargeable batteries, are attracting an increasing number of researchers. However, their practical applications are hindered by the poor electrical conductivity and the volume effect during cycling. In this work, a lightweight porous hollow carbon nanofiber (PHCNF) interlayer is proposed to coat on the original FeF3 cathode to solve these problems. This interlayer is synthesized through a facile carbonizing-activating process using polypyrrole (PPy) as raw material, and plays a difunctional role in trapping the escaped FeF3 particles and improving the electrical conductivity of electrode. By introducing the high conductive coating layer, an extremely high specific capacity of 217 mAh g?1 for 40 cycles in the 2–4.5 V region is achieved, which is close to the theoretical specific capacity of 237 mAh g?1 for FeF3. Also, a superior power capability is retained delivering a reversible specific capacity of 193 mAh g?1 at 200 mA g?1 and 101 mAh g?1 even at 1000 mA g?1.
- Zhou, Xiangyang,Sun, Hongxu,Zhou, Haochen,Xu, Zhanglin,Yang, Juan
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- Structure and electrochemical performance of FeF3/V2O5 composite cathode material for lithium-ion battery
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Orthorhombic structure FeF3 was synthesized by a liquid-phase method using FeCl3, NaOH and HF solution as starting materials, and the FeF3/V2O5 composites were prepared by milling the mixture of as-pr
- Wu, Wen,Wang, Ying,Wang, Xianyou,Chen, Quanqi,Wang, Xin,Yang, Shunyi,Liu, Xiuming,Guo, Jia,Yang, Zhenhua
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- MOSSBAUER SPECTROSCOPY STUDY OF CRYSTALLIZATION OF AMORPHOUS IRON (III) FLUORIDES: INFLUENCE OF EXPERIMENTAL CONDITIONS.
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Isothermal and non-isothermal treatments were performed on amorphous fluorides vapor-deposited FeF//2 and FeF//3, xHF (0. 4 less than x less than 1. 0) obtained by a soft chemistry reaction. They crystallize in rhombohedral and/or hexagonal tungsten bronze type phases, evidenced by Mossbauer spectroscopy and X-ray diffraction. The influence of the experimental parameters is discussed: heating modes and pressure. It is concluded that the 'ideal' amorphous FeF//3 crystallizes in the rhombohedral form.
- Greneche, J. M.,Varret, F.,Leblanc, M.,Ferey, G.
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- Synthesis and thermal decomposition of (NH4)2[MIIIF5(H2O)] (M = Al, Fe and Cr)
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Ammonium pentafluorometallate monohydrates were prepared by different methods and characterized by chemical analysis, IR spectrometry and X-ray diffraction. Unit cell parameters were determined for the Fe and Cr compounds, which were found to be isostruct
- Bentrup. U.,Kolditz, L.
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- mer-Triammine trifluorido iron(III), mer-[FeF3(NH 3)3]
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Metal fluorides are scarcely soluble in liquid ammonia, and their ammine complexes are rare. The synthesis and crystal structure of the first ammine complex of an iron fluoride, the mer-triammine trifluorido iron(III), mer-[FeF3(NH3)3], is presented. The compound crystallizes in the form of colorless, needle-shaped single crystals in the monoclinic space group P21/n with Z = 4. The molecules are interconnected by strong N-H?F hydrogen bonds.
- Kraus, Florian,Baer, Sebastian A.
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- Characterization of an Amorphous Change of FeF3: Thermal, Magnetic and Mossbauer Study.
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Amorphous FeF//3 has been prepared by fast vaporization of the bulk material and condensation. It has been characterized by X-ray diffraction and differential thermal analysis. Strong antiferromagnetic interactions, but low spin-freezing temperature, are
- Ferey,Leclerc,de Pape,Mariot,Varret
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- An electron diffraction and crystal chemical investigation of oxygen/flourine ordering in rutile-type iron oxyflouride, FeOF
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Rutile-type iron oxyfluoride, FeOF, has been synthesized by the reaction of FeF3 with Fe2O3 in a sealed platinum tube at 950°C. The compound was previously believed to have a random distribution of oxygen and fluorine anions surrounding each of the Fe3+ cations. In this work, electron diffraction experiments have revealed the presence of a characteristic diffuse intensity distribution in the form of continuous rods of diffuse intensity running along both the [110]* and [110]* directions of reciprocal space through the (h+k+l) = odd parent rutile reflections. Fe3+ shifts induced by local O/F ordering are shown to be responsible for the characteristic reciprocal space intensity distribution of this observed diffuse scattering. The continuous 〈110〉* rods of diffuse intensity require the existence of orthogonal {110} planes within the parent rutile structure which exhibit long-range, two-dimensional, oxygen/fluorine ordering, but with no correlation from one {110} plane to the next. A crystal chemical explanation is proposed to support this argument.
- Brink, Frank J.,Withers, Ray L.,Thompson, John G.
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- Magnetic structure and properties of Pb8FeIIFe2IIIF24: A 1-D ferrimagnetic chain compound exhibiting a spin-flop transition
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The magnetic structure of Pb8FeIIFe2IIIF24 was solved starting from its neutron diffraction powder pattern obtained at 1.4 K and its magnetic properties were characterized using the data recorded on a SQUID magnetometer and on a magneto-susceptometer. Pb8FeIIFe2IIIF24 is triclinic, space group P1; its crystal structure was previously solved on a single crystal. The magnetic structure of this fluoride is built up from ferrimagnetic chains antiferromagnetically coupled approximately along the c-axis of the cell, making up layers parallel to the (b,c) plane. Two successive layers exhibit different orientations of the magnetic moments. The net magnetic moment of Pb8FeIIFe2IIIF24 is equal to zero in agreement with an antiferromagnetic structure. This magnetic structure does not evolve in the temperature range: 1.4-20 K. Thus, only one magnetic phase occurs below TN≈21 K. Under a sufficiently strong magnetic field (H>5000 Oe), Pb8FeIIFe2IIIF24 exhibits a spin-flop transition.
- Pierrard,Gredin,Dupont,De Kozak,Bouree-Vigneron,Andre,Rosenman
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- On the crystal structure of pyrochlores: Moessbauer spectra of orthorhombic CsFe2F6 and X-ray single crystal studies of the cubic compounds CsMgGaF6, CsMIIVIIIF 6 (MII = Mn, Zn), CsMIIFeIIIF 6 (MII = Mn, Cu, Zn), and Cs4Cu 5V3O ...
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Title full: On the crystal structure of pyrochlores: Moessbauer spectra of orthorhombic CsFe2F6 and X-ray single crystal studies of the cubic compounds CsMgGaF6, CsMIIVIIIF 6 (MII = Mn, Zn), CsMIIFeIIIF 6 (MII = Mn, Cu, Zn), and Cs4Cu 5V3O2F19. Orthorhombic CsFe2F6 (a = 749.1(3), b = 723.8(3), c = 1043.1(6) pm; V = 565.6(9) A3, Z = 4, Imma?) was prepared with strongly 57Fe doped FeF3 and its Moessbauer spectra measured. It is in accordance with the spectra of a natural 57Fe abundance sample, also with respect to the intensity ratio Fe II:FeIII = 1:1. For the formation of an ordered pyrochlore structure in spite of quenching thus an electronically induced phase transition should be responsible, explaining the MII/MIII order observed in all mixed valence pyrochlores AIMIIM IIIF6. By contrast, single crystals of CsMgGaF6 (a = 1021.6(1) pm), CsMnVF6 (a = 1058.9(1) pm), CsMnFeF6 (a = 1054.6(1) pm), CsZnVF6 (a = 1041.5(1) pm, CsZnFeF6 (a = 1042.1(1) pm) and CsCuFeF6 (a = 1037.7(2) pm), obtained by solid state reaction and slow cooling, all exhibit the cubic pyrochlore structure of the RbNiCrF6 type (Z = 8, Fd3m), in which the cations M II/MIII are disordered in position (16c). An oxidfluoride of approximate composition Cs4Cu5V3O 2F19 (a = 1022.2(1) pm) has the same structure, but in addition it shows a disordered occupation of the position (48f) by lack of about 1/8 of anions. Structural relations and distances for the cubic crystal structures refined (R between 0.02 and 0.06) are discussed.
- Baum, Elke,Dahlke, Patrik,Kaiser, Volker,Molinier, Michel,Schmidt, Roland E.,Pebler, Juergen,Massa, Werner,Babel, Dietrich
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p. 2244 - 2250
(2008/10/09)
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- Pyrohydrolysis of FeF2 and FeF3
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The pyrohydrolysis of iron di- and trifluoride has been studied. Intermediates have been separated out and analyzed. The rate constants and apparent activation energies for reactions involved have been calculated. Preparation conditions for pure FeF2 are reported. The heating behavior of this compound in an oxygen stream and in steam fed with an argon or air stream has been studied; reactions involved are described.
- Mel'nichenko,Krysenko,Epov
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p. 1399 - 1404
(2008/10/08)
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- (H2O)[V2III F6] and Pyr-VF3:Hydrothermal synthesis, structure determination, and magnetic characterization of new fluorides with the pyrochlore type
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Small green triangular crystals of a new tridimensional hydrated vanadium(III) fluoride have been hydrothermally prepared in a simple way by heating a mixture of V:HF:H2O in the molar ratio 1:1:50 at 200°C for 3 days. Its structure was solved by X-ray diffraction in the cubic space group Fd3m (No. 227) with a = 10.4636(2)A. (H2O)[V2IIIF6] presents the structure of the well-known pyrochlore type. The cavities contain water molecules which are lost by heating (T 3 (Pyr-VF3) with the pyrochlore structure is compared to that of the already known Pyr-FeF3 (1). The magnetic behavior of Pyr-VF3 is described.
- Barthelet, Karin,Marrot, Jerome,Riou, Didier,Ferey, Gerard
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p. 266 - 269
(2008/10/08)
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- Structural and magnetochemical studies of Ba5Mn3F19 and related compounds AII5MIII3F19
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Single crystal structure determinations by X-ray methods were performed at the following compounds, crystallizing tetragonally body-centred (Z = 4): Sr5V3F19 (a = 1423.4(2), c = 728.9(1) pm), Sr5Cr3F19 (a = 1423.5(2), c = 728.1(1) pm), Ba5Mn3F19 (a =1468.9(1), c =770.3(1) pm, Ba5Fe3F19 (a =1483.5(1), c =766.7 (1) pm), and Ba5Ga3F19 (a = 1466.0(2), c = 760.1(2) pm). Only Ba5Mn3F19 was refined in space group I4cm (mean distances for elongated octahedra Mn1-F: 185/207pm equatorial/axial; for compressed octahedra Mn2-F: 199/182 pm), the remaining compounds in space group I4/m. In all cases the octahedral ligand spheres of the M1 atoms showed disorder, the [M1F6] octahedra being connected into chains in one part of the compounds and into dimers in the other. The magnetic properties of the V, Cr and Mn compounds named above and of Pb5Mn3F19 and Sr5Fe3F19 as well were studied; the results are discussed in context with the in part problematic structures.
- Dahlke,Graulich,Welsch,Pebler,Babel
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p. 1255 - 1263
(2008/10/08)
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- On X-ray single crystal studies of Na2FeAlF7, Na2MIIGaF7 (MII = Ni, Zn), and Na2ZnFeF7 and the Structural Chemistry of Weberites
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At single crystals of the orthorhombic weberite Na2NiGaF7 (a = 716.1, b = 1021.6, c = 740.9 pm; Imma, Z = 4) and of the monoclinic variants (C2/c, Z = 16) Na2FeAlF7 (a = 1242.6, b = 727.8, c = 2420.6 pm, β = 99.99°), Na2ZnGaF7 (a = 1251.9, b = 730.3, c = 2435.3 pm, β = 99.74°) and Na2ZnFeF7 (a = 1261.0, b = 7.359, c = 2453.8 pm, β = 99.70°) complete X-ray structure determinations were performed. The results and the influence of radii on the bridge angles MII-F-MII and MII-F-MIII are discussed in connection with general features within the structural chemistry of 28 weberites.
- Dahlke,Peschel,Babel
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p. 1003 - 1010
(2008/10/09)
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- Thermal dehydration of the fluoride hydrates FeMIIIF5·7H2O (MIII = Al, Fe, V, Cr)
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The thermal dehydration of the fluoride hydrates FeAlF5·7H2O, Fe2F5·7H2O, FeVF5·7H2O and FeCrF5·7H2O has been investigated by thermoanalytical, X-ray and i.
- Bentrup
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p. 397 - 406
(2008/10/09)
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- The Crystal Structure of LiPdGaF6, RbPdAlF6 and K1.06Pd0.95Fe1.05F6
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Single crystals of LiPdGaF6 (blue; trigonal, P3-1C-D(2)3d (No. 163), a=505.72(2), c=923.7(2) pm; LiCaAlF6-Type [1]), RbPdAlF6 (violet; orthorhombic, PNMA-D(16)2h (No. 62), a=729.0(1), b=711.1(1), c=1006.5(2) pm; CsAgFeF6-Type [2]) and K1.06Pd0.95Fe1.05F6 (greenish-blue; tetragonal, P42/MBC-D(13)4h (No.135), a=1279.07(7), c-800.2(1) pm; K1.08MnFeF6-Type [3]; four cycle diffractometer data, Siemens AED2) are obtained by heating the binary fluorides in sealed Pd-tubes under dry argon [solid state reaction, T~650, t~ 19 d) (39 d, 24 d)].
- Mueller, Markus,Mueller, Bernd G.
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- The Crystal Structure of Pb8Fe(II)Fe(III)2F24: an ordered Fluorite-like Compound
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Pb8Fe(II)Fe(III)2F24 is triclinic: a=20.118(3) A, b=5.597(1) A, c=9.440(2) A, α=89.75(2)°, β=105.79(2)°, γ=89.38(2)°, Z=2. The structure is solved in the unconventional space group C1-, from X-ray single crystal data using 1641 independent reflections (R=0.048, Rw=0.051). It is built up from the stacking of two subnetworks along the a axis: fluorite-like [Pb8F10](6n+)n layers and infinite dimetallic [Fe(II)Fe(III)2F14](6n-)n double-chains of corner-sharing octahedra running along the b axis.
- Pierrard, Angelique,de Kozak, Ariel,Gredin, Patrick,Renaudin, Jean
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- A Mass-Spectrometric Study of Iron Trifluoride Decomposition
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Mass spectrometry was used to study iron trifluoride decomposition at 980-1100 K.It was found that iron trifluoride evaporated in a platinum cell without decomposition.The presence of a reducing agent in the sample leads to the decomposition of iron trifluoride to produce FeF2(s) and fluorine atoms; decomposition of the iron trifluoride can occur without direct contact between FeF3(s) and the reducing agent when fluorine atoms are transported from decomposition zone to the reducing agent.The decomposition rate of iron trifluoride obeys general relations governing thermal decomposition of solids and depends on the properties of the reducing agent and on the rate of fluorine atom removal from the decomposition zone.
- Chilingarov, N. S.,Skokan, E. V.,Rau, D. V.,Sidorov, L. N.
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p. 1068 - 1073
(2007/10/02)
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- Thermochemical quantities for gas-phase iron, uranium, and molybdenum fluorides, and their negative ions
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Ion-to-molecule equilibria among gaseous iron, uranium, and molybdenum fluorides, and their negative ions, have been studied by Knudsen-cell mass spectrometry with the help of a combined ion source.On the basis of thermochemical quantities, derived by third-law analysis and from the literature for enthalpies of formation of gaseous species, electron affinities have been calculated for a number of molecules: FeF3, (349 +/- 13) kJ*mol-1; UF5, (361 +/- 21) kJ*mol-1; UF6, (488 +/- 19) kJ*mol-1; MoF5, (335 +/- 17) kJ*mol-1; MoF6, (369 +/- 18) kJ*mol-1; Mo2F9, (350 +/- 40) kJ*mol-1; and Mo2F10, (363 +/- 25) kJ*mol-1.
- Borshchevskii, A. Ya.,Boltalina, O. V.,Sorokin, I. D.,Sidorov, L. N.
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p. 523 - 538
(2007/10/02)
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- On the Knowledge of LiSrFeF6
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Hitherto unknown LiSrFeF6 was obtained by heating mixtures of binary fluorides under argon as a colourless powder or colourless single crystals.LiSrFeF6 crystallizes monoclinicly in P21/c-C52h with a = 5.2972(4), b = 8.7989(8), c = 10.2257(7) Angstroem, β = 92.212(8) deg, Z = 4; droe = 3.69 and dpyk = 3.66 g*cm-3, positions are given in the text, R = 9.16percent (Rw = 6.83percent) for hkl (Mo-Kα, 4-circle diffractometer data). - Keywords: Hexafluoroferrate(III), Structure
- Fleischer, Th.,Hoppe, R.
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p. 981 - 987
(2007/10/02)
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