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1.
The complex impedance method in the temperature range of 291–660 K was used to study conductivity of oxofluoride BiO0.1F2.8 belonging to the tysonite structural type (LaF3). Bismuth oxofluoride was synthesized using a solid-phase method at 770–870 K for 1–2 h in an argon atmosphere. Heterovalent
substitution of fluoride ions F− by oxygen ions O2− in the anionic BiF3 matrix sublattice results in high ionic conductivity (∼0.1 S/cm at 660 K) of BiO0.1F2.8 ceramic samples. 相似文献
2.
Petra Šulcová Jan Večeřa Pavel Bystrzycki 《Journal of Thermal Analysis and Calorimetry》2012,108(2):525-529
New environmentally inorganic pigments based on Bi2O3 doped by metal ions, such as Zr4+ and Dy3+ have been developed and characterized using the methods thermal analysis, X-ray powder diffraction, and spectral reflectance
data. The compounds having formula Bi2−x
Dy
x/2Zr3x/8O3 (x = 0.2, 0.6, 1.0, and 1.2) were prepared by the solid state reaction. Methods of thermal analysis were used for determination
of the temperature region of the pigment formation and thermal stability of compounds. The incorporation of doped ions in
Bi2O3 changes the color from yellow to orange and also contributes to a growth of their thermal stability. This property gives
a direction for coloring ceramic glazes. 相似文献
3.
From recent rate constant data for the recombination reaction 2CF3• → C2F6 ($
k_{(CF_3 )_2 }^M
$
k_{(CF_3 )_2 }^M
) in the high-pressure limit and from experimental data obtained at intermediate pressures of buffer gases M (M = He, Ar,
N2, CF3I), analytical expressions for $
k_{(CF_3 )_2 }^M
$
k_{(CF_3 )_2 }^M
(in Lindemann’s formulation) are derived for the temperature range of 300–1300 K and intermediate pressures of the buffer
gases. 相似文献
4.
I. E. Animitsa E. N. Dogodaeva S. S. Nokhrin O. A. Kosareva A. Ya. Neiman 《Russian Journal of Electrochemistry》2010,46(7):734-740
Perovskite phases Ba3In2ZrO8 and Ba4In2Zr2O11 with the nominal concentration of structural oxygen vacancies 1/9 and 1/12, respectively, were synthesized by solid-phase
and solution methods. X-ray diffraction showed cubic symmetry of both phases with the unit cell parameter a = 0.4193(2) and 0.4204(3) nm, respectively. The absence of superstructural lines resulted in the conclusion on statistical
arrangement of oxygen vacancies. Thermogravimetry and mass spectrometry proved that both phases can reversibly absorb water
from gas phase (pH2O = 2 × 10−2 atm) with observed correlation between the concentration of oxygen vacancies and amount of absorbed water. The total water
amount was up to 0.9 mol per formula unit or, if recalculated for perovskite unit ABO3, 0.3 and 0.23 mol H2O, respectively. The temperature curves of coductivity in the atmosphere with various partial water vapor pressures (pH2O = 3 × 10−5 and 2 × 10−2 atm) showed significantly higher conductivity and lower activation energy (0.52 eV) in humid atmosphere due to proton transfer.
The proton conductivity is up to 5 × 10−4 Ohm−1 cm−1 at 300°C for Ba3In2ZrO8 specimen. IR spectrometry showed that protons in the structure exist primarily in OH-groups. 相似文献
5.
Danielle M. Chisholm J. Scott McIndoe Gabriella Bodizs Wee Han Ang Rosario Scopelliti Paul J. Dyson 《Journal of Cluster Science》2007,18(1):303-318
Reaction of [Ru6C(CO)16]2− with an excess of AgX (X = Cl, Br or I) affords heteronuclear clusters of formula [{Ru6C(CO)16Ag2X}2]2− in 80% yield, which for X = I and X = Br/Cl were crystallographically characterised. The formation of the cluster was followed
in solution using electrospray ionisation mass spectrometry (ESI-MS), which revealed the presence of a wide range of clusters
with the general formula [{Ru6C(CO)16}
x
Ag
y
X
z
](2x−y+z)− where x = 1 or 2, y = 1, 2, 3 or 4 and z = 0, 1 or 2. The high yield of the product despite the evident complicated solution speciation is attributed to selective
crystallisation of the observed compound driving the equilibrium toward this product. 相似文献
6.
L. F. Brum Malta Marta Eloisa Medeiros 《Journal of Thermal Analysis and Calorimetry》2007,87(3):883-886
This work reports the study of Bi4V2–xBaxO11–1.5x (0.02≤x≤0.50)
series, which is a potential source of solid electrolytes to apply in oxygen
sensors. X-ray powder diffraction was used to point out the formation of major
ionic conductive phases and minor ones. The modifications of vanadate substructure
were probed, at short range, by Fourier-transform infrared spectroscopy. Differential
scanning calorimetry evidenced the formation of tetragonal γ phase, which
can be ionic conductive, for x=0.14. 相似文献
7.
K. N. Zolotova I. V. Kolbanev E. I. Ardashnikova A. M. Abakumov V. A. Dolgikh 《Russian Journal of Inorganic Chemistry》2011,56(10):1625-1633
Isothermal anneals (at 873 K) and powder X-ray diffraction were used to study isothermal sections of phase diagrams of the
NdF3-Nd2O3-MF2 (M = Ba, Sr) systems. In studying the NdF3-Nd2O3-BaF2 system, classical solid-phase synthesis was supplemented with mechanochemical activation of feedstock mixtures or BaF2 activated with gaseous hydrogen fluoride was used. In both systems, a solid solution with the fluorite structure based on
MF2 and NdOF phases, a solid solution with the tysonite structure based on NdF3, and an ordered fluorite-related phase Ba4Nd3F17 were found. The NdOF-based solid solutions were shown to have polymorphism: βtrig ai αcub at ≈800 K; a new trigonal phase of these solid solutions has been discovered. The effect of a dimensional factor $\left( {R_{Ba^{2 + } } > R_{Sr^{2 + } } } \right)$\left( {R_{Ba^{2 + } } > R_{Sr^{2 + } } } \right) on phase formation and unit cell parameters of the solid solutions was traced. 相似文献
8.
Shangyun Ye Yongyao Xia Pingwei Zhang Zhiyu Qiao 《Journal of Solid State Electrochemistry》2007,11(6):805-810
A series of the mixed transition metal compounds, Li[(Ni1/3Co1/3Mn1/3)1–x-y
Al
x
B
y
]O2-z
F
z
(x = 0, 0.02, y = 0, 0.02, z = 0, 0.02), were synthesized via coprecipitation followed by a high-temperature heat-treatment. XRD patterns revealed that
this material has a typical α-NaFeO2 type layered structure with R3-
m space group. Rietveld refinement explained that cation mixing within the Li(Ni1/3Co1/3Mn1/3)O2 could be absolutely diminished by Al-doping. Al, B and F doped compounds showed both improved physical and electrochemical
properties, high tap-density, and delivered a reversible capacity of 190 mAh/g with excellent capacity retention even when
the electrodes were cycled between 3.0 and 4.7 V. 相似文献
9.
The effect of fluorine doping on the electrochemical performance of LiFePO4/C cathode material is investigated. The stoichiometric proportion of LiFe(PO4)1−x
F3x
/C (x = 0.01, 0.05, 0.1, 0.2) materials was synthesized by a solid-state carbothermal reduction route at 650 °C using NH4F as dopant. X-ray diffraction, scanning electron microscope, energy-dispersive X-ray, and X-ray photoelectron spectroscopy
analyses demonstrate that fluorine can be incorporated into LiFePO4/C without altering the olivine structure, but slightly changing the lattice parameters and having little effect on the particle
sizes. However, heavy fluorine doping can bring in impurities. Fluorine doping in LiFePO4/C results in good reversible capacity and rate capability. LiFe(PO4)0.95 F0.15/C exhibits highest initial capacity and best rate performance. Its discharge capacities at 0.1 and 5 C rates are 156.1 and
119.1 mAh g−1, respectively. LiFe(PO4)0.95 F0.15/C also presents an obviously better cycle life than the other samples. We attribute the improvement of the electrochemical
performance to the smaller charge transfer resistance (R
ct) and influence of fluorine on the PO43− polyanion in LiFePO4/C. 相似文献
10.
E. Yu. Pikalova V. G. Bamburov A. A. Murashkina A. D. Neuimin A. K. Demin S. V. Plaksin 《Russian Journal of Electrochemistry》2011,47(6):690-696
CeO2-based solid solutions with a fluorite structure are promising materials as electrolytes of medium-temperature electrochemical
devices: electrolytic cells, oxygen sensors, and solid oxide fuel cells. In this work, studies are presented of the effect
of the dopant cation radius and its concentration on the physico-chemical properties of the Ce1 − x
Ln
x
O2 − δ solid solutions (x = 0–0.20; Ln = La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb) and also of multicomponent solid solutions of Ce1 − x
Ln
x/2Ln′
x/2O2 − δ (x = 0–0.20; Ln = Sm, La, Gd and Ln′ = Dy, Nd, Y) and Ce1 − x − y
Sm
x
M
y
O2 − δ (M = Ca, Sr, Ba) obtained using the solid-phase synthesis technique. Electric properties of the samples were studied in the
temperature range of 623–1173 K and in the oxygen partial pressure range of 0.01–10−22 MPa. The values of oxygen critical pressure ( pO2 * )\left( {p_{O_2 }^* } \right) are presented, at which the ionic and electron conductivity values are equal. The values were calculated on the basis of
experimental dependences at 1023 K at the assumption that the ionic conductivity value is determined only by the dopant concentration
and its effective ionic radius and is independent of the oxygen partial pressure. 相似文献
11.
The anion-excess ordered fluorite-related phase Ba4Bi3F17 has been synthesized by a solid state reaction of BaF2 and BiF3 at 873 K. The crystal structure of Ba4Bi3F17 has been studied using electron diffraction and X-ray powder diffraction (a=11.2300(2) Å, c=20.7766(5) Å, S.G. , RI=0.020, RP=0.036). Interstitial fluorine atoms in the Ba4Bi3F17 structure are considered to form isolated cuboctahedral 8 : 12 : 1 clusters. The structural relationship between Ba4Bi3F17 and similar rare-earth-based phases is discussed. 相似文献
12.
V. A. Prituzhalov R. Ya. Zakirov E. I. Ardashnikova V. A. Dolgikh 《Russian Journal of Inorganic Chemistry》2008,53(1):129-135
Tysonite solid solutions Bi1 ? x M x (O, F)3 ? d (M = Na, Sr, or Nd) based on α-BiO y F3 ? 2y were prepared by solid-state synthesis at 873 K with subsequent quenching to ice-cold water. Aliovalent substitutions in both the cation and anion sublattices (M n+ → Bi3+ and O2? → F?) made it possible to vary the anion-vacancy density. The solid solutions were characterized by X-ray diffraction and impedance spectroscopy. The homogeneity regions for the tysonite solid solution were determined; triangulation schemes at 873 K were suggested for the systems BiF3-BiOF-NaBiF4 and BiF3-BiOF-SrF2, and a scheme of the subsolidus phase diagram for the system BiO0.1F2.8-NdF3 was suggested. In the system BiO0.1F2.8-NdF3, the transition temperature from the low-symmetry tysonite phase (phase II, space group P \(\overline 3 \) c1, Z = 6) to the high-symmetry one (phase I, space group P63/mmc, Z = 2) decreases with increasing anion-vacancy density. Conductivity measurements were performed in the temperature range 300–523 K and the frequency range from 5 to 1 × 106 Hz. The conductivity of samples in the system BiO0.1F2.8-NdF3 increases with increasing bismuth-ion and anion-vacancy concentrations. 相似文献
13.
Thermal behaviour of the glass series (100-x)[50ZnO-10B2O3-40P2O5]·xSb2O3 (x=0-42 mol%) and (100-y)[60ZnO-10B2O3-30P2O5]·ySb2O3 (y=0-28 mol%) was investigated by DSC and TMA. The addition of Sb2O3 results in a decrease of the glass transition temperature and crystallization temperature in both compositional series. All
glasses crystallize on heating in the temperature range of 522–632°C. Thermal expansion coefficient of the glasses monotonously
increases with increasing Sb2O3 content in both series and varies within the range of 6.6–11.7 ppm °C−1. From changes of thermal capacity within the glass transition region it was concluded that with increasing Sb2O3 content the ‘fragility’ of the studied glasses increases. 相似文献
14.
Elizabeth A. Turner Harald Rösner Yining Huang John F. Corrigan 《Journal of Cluster Science》2007,18(3):764-771
Mercury-selenosulfide (HgSe
x
S
1-x
) nanoparticles have been synthesized using the single-source reagent Me3Si–SeS–SiMe3. The reagent distributes Se2− and S2− to the metal core as the reaction between Me3Si–SeS–SiMe3 and mercury acetate occurs via a redox pathway, ultimately giving rise to Se–S bond cleavage. Particles are characterized
by EDX, TEM and powder X-ray diffraction analysis in conjunction with UV–Visible absorption spectroscopy.
Dedicated to Prof. Dr. Dieter Fenske on the occasion of his 65th birthday. 相似文献
15.
M. G. Zuev 《Russian Journal of Inorganic Chemistry》2010,55(1):93-95
Solid-phase interactions in the V2O5-Ta2O5-MoO3 system were studied. The formation of com- pounds TaVO5 and VTa9O25 in the V2O5-Ta2O5 binary system was verified. Tetragonal VTa9O25-base solid solutions of the general formula Ta5 + 4x
V5 − 4x
O25 (x = 0.25–1) and TaVO5-base solid solutions of the general formula Ta
x
Mo1 − x
V2 − x
O8 − 3x
(x = 0.625–1) were found to form. Subsolidus phase equilibria in the V2O5-Ta2O5-MoO3 were determined. 相似文献
16.
S. V. Kuznetsov P. P. Fedorov V. V. Voronov K. S. Samarina R. P. Ermakov V. V. Osiko 《Russian Journal of Inorganic Chemistry》2010,55(4):484-493
Single-phase samples of Ba4R3F17 · nH2O (R = La, Ce, Pr, Nd, Eu, Gd, Y, Er, or Yb; n = 2.5−3.2) were prepared by coprecipitation from nitrate solutions using hydrofluoric acid. The phases crystallize in a fluorite-type
face-centered cubic lattice. The dried precipitates are transparent. Scanning electron and atomic-force microscopy and X-ray
diffraction line broadening show a hierarchic structure in the samples: primary nanoparticles join into agglomerates with
characteristic sizes of about 150–200 nm, these agglomerates being self-packed into parallel layers with a thickness on the
order of 500 nm. 相似文献
17.
T. I. Krasnenko M. V. Rotermel’ S. A. Petrova R. G. Zakharov O. V. Sivtsova A. N. Chvanova 《Russian Journal of Inorganic Chemistry》2008,53(10):1641-1647
Phase relations in the Zn2V2O7-Cu2V2O7 system were studied by high-temperature X-ray diffraction and differential thermal analysis. The major phase constituents
of the system are solid solutions based on Zn2V2O7 and Cu2V2O7 polymorphs and their coexistence regions. The generation of α-Zn2 − 2x
Cu2x
V2O7 solid solution, where 0 ≤ x ≤ 0.30, leaves almost unchanged the stabilization temperature of the high-temperature zinc pyrovanadate phase. The α-Cu2 − 2x
Zn2x
V2O7 homogeneity range is 5 mol % Zn2V2O7. In the range 0.050 ≤ x ≤ 0.09 from 20 to ∼ 620°C, there is the two-phase field of α-Cu2V2O7 and β-Cu2V2O7 base solid solutions. At still higher temperatures, β-Zn2 − 2x
Cu2x
V2O7 and α-Cu2 − 2x
Zn2x
V2O7 coexist in the mixed-phase region. β-Zn2 − 2x
Cu2x
V2O7 solid solution, where 0 ≤ x ≤ 0.30, exists above 610 ± 5°C. The extent of the β′-Cu2V2O7-base solid solution is 9 to 65 mol % Zn2V2O7 at 615 ± 5°C, expanding to 0 mol % Zn2V2O7 with rising temperature.
Original Russian Text ¢ T.I. Krasnenko, M.V. Rotermel’, S.A. Petrova, R.G. Zakharov, O.V. Sivtsova, A.N. Chvanova, 2008, published
in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 10, pp. 1755–1762. 相似文献
18.
Perovskite Bi1−x
Y
x
FeO3 (0.0 ≤ x ≤ 0.1) oxides were prepared by a citrate-gel method. The crystal structure examined by X-ray powder diffraction indicates
that the samples were single-phase and crystallize in a rhombohedral (space group, R-3c no. 161) structure. The structural phase transition from rhombohedral to orthorhombic phase was observed at x = 0.10. Increase in magnetization was observed as a result of Y doping. The optical band-gap of (Bi, Y)FeO3 materials were determined. The observed increase in magnetization and low band-gap of (Bi, Y)FeO3 ceramics position them for potential magenotoelectric and photocatalytic applications, respectively. 相似文献
19.
Electrocatalytic oxygen reduction was studied on a RuxFeySez(CO)n cluster catalyst with Vulcan carbon powder dispersed into a Nafion film coated on a glassy carbon electrode. The synthesis
of the electrocatalyst as a mixture of crystallites and amorphous nanoparticles was carried out by refluxing the transition
metal carbonyl compounds in an organic solvent. Electrocatalysis by the cluster compound is discussed, based on the results
of rotating disc electrode measurements in a 0.5 M H2SO4. A Tafel slope of −80.00±4.72 mV dec−1 and an exchange current density of 1.1±0.17×10−6 mA cm−2 was calculated from the mass transfer-corrected curve. It was found that the electrochemical reduction reaction follows the
kinetics of a multielectronic (n=4e−) charge transfer process producing water, i.e. O2+4H++4e−→2H2O.
Electronic Publication 相似文献
20.
Matthias Weil Franz Werner Frank Kubel 《Monatshefte für Chemie / Chemical Monthly》2002,133(3):267-275
Summary. Single crystals of MgAl2F8(H2O)2 have been obtained under hydrothermal conditions (250°C, 14 d) from a starting mixture of AlF3 and MgAlF5(H2O)2 in a 5% (w/w) HF solution. The crystal structure has been determined and refined from single crystal data (Fmmm (#69), Z = 4, a = 7.2691(7), b = 7.0954(16), c = 12.452(2) ?, 281 structure factors, 27 parameters, R(F
2 > 2σ (F
2)) = 0.0282, wR(F
2 all) = 0.0885). The obtained crystals were systematically twinned according to (010/100/001) as twinning matrix, reflecting
the pseudo-tetragonal metric. The crystal structure is composed of perowskite-type layers built of corner sharing AlF6 octahedra with an overall composition of AlF4
− which are connected via common fluorine atoms of [MgF4/2(H2O)2/1] octahedra. Group-subgroup relations of MgAl2F8(H2O)2 to WO3(H2O)0.33 and to other M(II)M(III)2 F8(H2O)2 structures are briefly discussed. Above 570°C, MgAl2F8(H2O)2 decomposes under elimination of water into α-AlF3, β-AlF3, and MgF2.
Received October 29, 2001. Accepted (revised) December 6, 2001 相似文献