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1.
V. Ya. Kavun N. F. Uvarov I. A. Telin M. M. Polyantsev A. B. Podgorbunskii O. V. Brovkina B. K. Goncharuk 《Journal of Structural Chemistry》2016,57(2):330-337
The ionic mobility and conductivity in the crystalline phases of PbSnF4–xCaF2 systems (x = 2.5 mol.%, 5 mol.%, 7.5 mol.%, and 10 mol.%) in the temperature range of 150-500 K are studied by NMR and impedance spectroscopy. The parameters of 19F NMR spectra, types of ion motions, and ionic conductivity in the PbSnF4 compound doped with calcium fluoride are found to be determined by the temperature and concentration of calcium fluoride. The specific conductivity of the crystalline phases in the PbSnF4–CaF2 systems is rather high at room temperature, and hence, one cannot exclude the possibility to use them for the creation of functional materials with a high ionic (superionic) conductivity. 相似文献
2.
V. Ya. Kavun N. F. Uvarov L. A. Zemnukhova A. S. Ulikhin N. A. Didenko O. V. Brovkina V. I. Sergienko 《Russian Journal of Electrochemistry》2013,49(7):633-644
The ion mobility, phase transitions, and ionic conductivity in the crystal phases in the KF-NH4F-SbF3 system were studied by NMR, DTA, and impedance spectroscopy. An analysis of the 19F and 1H NMR spectra showed how the character of ionic motions in the fluoride and proton sublattices changed with temperature. The types and temperature ranges of ionic motions were determined. Diffusion of the fluoride and partially ammonium ions was found to be the dominant form of ionic motion in the high-temperature modifications formed as a result of phase transitions. According to the electrophysical data, the high-temperature K1 ? x (NH4) x SbF4 phases (0.05 ≤ x ≤ 0.75) are superionic, their conductivity reaching ~10?2–10?3 S/cm at 450–500 K. 相似文献
3.
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
4.
Electrical conductivity in the monoclinic Li2TiO3, cubic Li1.33Ti1.67O4, and in their mixture has been studied by impedance spectroscopy in the temperature range 20–730 °C. Li2TiO3 shows low lithium ion conductivity, σ300≈10–6 S/cm at 300 °C, whereas Li1.33Ti1.67O4 has 3×10–8 at 20 °C and 3×10–4 S/cm at 300 °C. Structural properties are used to discuss the observed conductivity features. The conductivity dependences
on temperature in the coordinates of 1000/T versus loge(σT) are not linear, as the conductivity mechanism changes. Extrinsic and intrinsic conductivity regions are observed. The change
in the conductivity mechanism in Li2TiO3 at around 500–600 °C is observed and considered as an effect of the first-order phase transition, not reported before. Formation
of solid solutions of Li2–
x
Ti1+
x
O3 above 900 °C significantly increases the conductivity. Irradiation by high-energy (5 MeV) electrons causes defects and the
conductivity in Li2TiO3 increases exponentially. A dose of 144 MGy yields an increase in conductivity of about 100 times at room temperature.
Electronic Publication 相似文献
5.
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
6.
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
7.
A. M. Potapova G. V. Zimina I. N. Smirnova F. M. Spiridonov P. P. Fedorov 《Russian Journal of Inorganic Chemistry》2011,56(9):1453-1457
The 950°C isothermal section of the InPO4-Na3PO4-Li3PO4 ternary system was studied and constructed; one-, two, and three-phase fields are outlined. Five solid-solution regions exist
in the system: solid solutions based on the complex phosphate LiNa5(PO4)2 (olympite structure), the indium ion stabilized high-temperature Na3PO4 phase (Na3(1 − x)In
x
(PO4); space group Fm
[`3]\bar 3
m), the complex phosphate Na3In2(PO4)3, and the α and β phases of the compound Li3In2(PO4)3. A narrow region of melt was found in the vicinity of eutectic equilibria. All the phases detected in the system are derivatives
of phases existing in the binary subsystems. Isovalent substitution of lithium for sodium in Na3In2(PO4)3 leads to a significant increase in the region of a NASICON-like solid solution. 相似文献
8.
Anna Blonska-Tabero 《Journal of Thermal Analysis and Calorimetry》2008,93(3):707-710
A new phase Cd4Fe7+xV9+xO37+4x, where −0.5<x<1.5, has been obtained in the solid-state in the FeVO4−Cd4V2O9 system. The temperature of incongruent melting and the unit cell volume of this phase decrease with decreasing the content
of cadmium. The IR spectrum and SEM image of the new phase are presented. 相似文献
9.
The present work deals with the composite system (CuI)
x
–(Ag2O–TeO2)100–
x
, where x=30, 35, 40, 45, 50, 55, 60, 65, 70 and 75 mol%, respectively, synthesized by a solid-state reaction route. Powder specimens
were analysed using differential scanning calorimetry, X-ray diffraction and Fourier transform infrared techniques. These
studies have revealed the formation of Cu3TeO6, AgI and/or other phases. The ambient temperature electrical conductivities obtained for the samples using a complex impedance
method were found to lie in the range 10–6–10–4 Scm–1, with low activation energies, thus indicating their superionic nature. The typical composition 35CuI–32.5Ag2O–32.5TeO2 was identified as the best conducting one, having an electrical conductivity of 6×10–4 Scm–1 at 296 K and an activation energy of 0.23 eV. Ion transport number measurements carried out using Wagner's polarization technique
as well as by an electromotive force method suggested that silver ions were responsible for the observed transport features
of the composite system.
Electronic Publication 相似文献
10.
M. Hartmanová V. Navrátil V. Buršíková F. Kundracik C. Mansilla 《Russian Journal of Electrochemistry》2011,47(5):505-516
Electrical conductivity, dielectric permittivity and mechanical hardness of the polycrystalline CeO2 + xSm2O3 (x = 0, 10.9–15.9 mol %) films prepared by Electron Beam Physical Vapour Deposition (EB-PVD) and Ionic Beam Assisted Deposition,
(IBAD), techniques were investigated in dependence on their structure and microstructure influenced by the deposition conditions,
namely composition, deposition temperature and Ar+ ion bombardment. The electrical conductivity of doped ceria prepared without Ar+ ion bombardment and investigated by the impedance spectroscopy, IS, was found to be predominantly ionic one under the oxidizing
atmosphere/low-temperature conditions and the higher amounts of Sm2O3 (>10 mol %) used. The bulk conductivity as a part of total measured conductivity was a subject of interest because the grain
boundary conductivity was found to be ∼3 orders of magnitude lower than the corresponding bulk conductivity. Ar+ ion bombardment acted as a reducer (Ce4+ → Ce3+) resulting in the development of electronic conductivity. Dielectric permittivity determined from the bulk parallel capacitance
measured at room temperature and the frequency of 1 MHz, similarly as the mechanical hardness measured by indentation (classical
Vickers and Depth Sensing Indentation-DSI) techniques were also found to be dependent on the deposition conditions. The approximative
value of hardness for the investigated films deposited on the substrate was estimated using a simple phenomenological model
described by the power function HV = HV
0 + aP
b
and compared with the so-called apparent hardness (substrate + investigated film) determined by the classical Vickers formula.
Results obtained are analyzed and discussed. 相似文献
11.
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
12.
V. A. Prituzhalov E. I. Ardashnikova V. A. Dolgikh A. M. Abakumov 《Russian Journal of Inorganic Chemistry》2011,56(3):313-324
Tysonite solid solutions Bi1−x
Ba
x
O
y
F3−x−2y
in the BiF3-BiOF-BaF2 system were obtained by solid-phase synthesis in sealed copper tubes in an argon atmosphere at 873 K with subsequent quenching.
The solid solutions were studied by X-ray diffraction, electron diffraction, and impedance spectroscopy. On the basis of X-ray
powder diffraction data, the homogeneity ranges of the tysonite solid solutions were determined and the scheme of their location
in the BiF3-BiOF-BaF2 system at 873 K was suggested. Aliovalent substitutions in both the cation and anion sublattices Ba2+ → Bi3+ and O2− → F− made it possible to vary the concentration of anion vacancies. It was found that, at a high concentration of anion defects
at 873 K, the hexagonal tysonite modification with space group P63/mmc is stable. With a decrease in the defect concentration, the trigonal tysonite modification with space group $
P\bar 3c1
$
P\bar 3c1
becomes stable. An ordered monoclinic tysonite-type modification BiO
y
F3 − 2y
(0.13 < y < 0.23) was revealed. For the homogeneity ranges of all tysonite phases, dependences of the unit cell parameters and conductivity
on the composition along the sections with a constant barium or oxygen content were reported. The most probable location of
oxygen anions and anion vacancies in the tysonite structure is discussed. 相似文献
13.
I. A. Sokolov I. V. Murin V. E. Kriyt A. A. Pronkin 《Russian Journal of Electrochemistry》2011,47(4):410-415
The influence of the SO42− ion on the temperature and concentration dependences of electric conductivity and the structure of sodium phosphate oxide
glasses was studied. The increased electric conductivity of sulfate-phosphate glasses was explained by the formation of mixed
sulfate-phosphate fragments with terminal SO42− ions in the structure of glasses in the Na2SO4-NaPO3 system. The dissociation energies of the sodium sulfate fragments are lower than those of pure oxide sodium phosphate structural
units. As a result, the number of dissociated sodium ions increases, the activation energy of electric conductivity falls,
and the conductivity (at 25°C) increases approximately 270-fold relative to the conductivity of NaPO3. The arrangement of SO42− ions in the structure was evaluated from the IR spectra of the glasses. 相似文献
14.
The effect of partial substitution of Zr4+ ions for Ge4+ ions in highly conducting lithium-cationic solid electrolyte Li3.75Ge0.75P0.25O4 is studied. It is found that the introduction of zirconium ions considerably raises the conductivity of basic electrolyte
in the high-temperature range. For the optimal composition, the conductivity is 2.82 × 10−1 S cm−1 at 400°C and 1.55 S cm−1 at 700°C. Possible reasons for the effects are discussed. 相似文献
15.
R. N. Pletnev É. I. Yurieva S. V. Verkhovskii G. V. Bazuev 《Journal of Structural Chemistry》2005,46(1):59-66
The 63Cu and 139La NMR spectra of the low-(δ = 0.25) and high-temperature (δ = 0) phases of lanthanum cuprate LACu0.81Ni0.19O2.5+δ have been obtained. Quantum chemical calculations of the electronic structure of the high-temperature phase have been performed. It is found that the observed metal-semiconductor phase transition is attended by changes in the degree of atomic ordering and in the character of electronic conductivity over certain types of “copper” centers. 相似文献
16.
Peter Klampfer Primož Benkič Maja Ponikvar Ana Rahten Antonija Lesar Adolf Jesih 《Monatshefte für Chemie / Chemical Monthly》2003,134(1):1-9
Summary. Hydrazinium(+2) fluoroarsenate(III) fluoride was prepared by the reaction of hydrazinium(+2) fluoride and liquid arsenic
trifluoride. N2H6AsF4F is stable at 273 K, but decomposes slowly at room temperature. N2H6AsF4F crystallizes in the orthorhombic space group Pnn2 with a = 774.0(2) pm, b = 1629.2(4) pm and c = 436.6(1) pm; V = 0.5506(3) nm3, Z = 4 and d
c
= 2.461 g cm−3. The structure consists of N2H6
2+ cations, AsF4
− anions, and F− anions and is interconnected by a hydrogen bonding network. Distorted trigonal-bipyramidal AsF4
− units are very weakly interconnected and form chains along the b axis. Bands in the Raman spectrum are assigned to the vibrations of N2H6
+2 cations and AsF4
− anions.
Corresponding author. E-mail: adolf.jesih@ijs.si
Received April 18, 2002; accepted July 15, 2002 相似文献
17.
K. Suryakala K. R. Marikkannu G. Paruthimal Kalaignan T. Vasudevan 《Journal of Solid State Electrochemistry》2007,11(12):1671-1677
LiMn2O4-based spinels are of great interest as positive electrode materials for lithium ion batteries. LiCo
x
Mn2−x
O4 (x = 0.0, 0.1, 0.2, 0.3, and 0.4) spinel phases have been synthesized by novel citric acid-modified microwave-assisted sol–gel
method. The structural properties of the synthesized products have been investigated by X-ray powder diffraction and scanning
electron microscopy. To improve the recharge capacity of Li/LiCo
x
Mn2−x
O4 cells, the electrochemical features of LiCo
x
Mn2−x
O4 compounds have been evaluated as positive electrode materials. The structural properties of Co-doped oxides are very similar
to LiMn2O4 electrode. Techniques like cyclic voltammetry, charge–discharge and cycle life are also used to characterize the LiCo
x
Mn2−x
O4 (x = 0.0, 0.1, 0.2, 0.3, and 0.4) electrodes. 相似文献
18.
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
19.
Temperature dependence of viscosity of title glasses (x=0, 2, 4, 6, 8, 10, abbreviated as M0, M2, M4, M6, M8, and M10, respectively) was measured by rotational viscometry (high
temperature region: 102−106.5 dPas) and thermomechanical analysis (low temperature region: 108.5−1011.5 dPas) and described by the Vogel-Fulcher-Tammann equation. The MgO/CaO equimolar substitution (i.e. the increasing x value) smoothly shifts the high temperature viscosity to higher values.
In the low temperature region the mixed alkali effect is demonstrated, and the highest viscosities are observed for the glasses
M0 and M10. In the low temperature range the activation energy of viscous flow linearly decreases with the increasing x value (E
act/kJ mol−1=479−9.0x). No significant dependence of activation energy on x was found in the high temperature range (E
act/kJ mol−1=238.1±4.2). The structural relaxation was measured by thermomechanical experiment and theoretically interpreted in the frame
of Tool-Narayanaswamy-Mazurin’s model. The broadening of the relaxation time spectrum was observed for the calcium-magnesium
glasses in comparison with the pure calcium or magnesium glasses. 相似文献
20.
T. Yoshida Y. Moriya T. Tojo H. Kawaji T. Atake Y. Kuroiwa 《Journal of Thermal Analysis and Calorimetry》2009,95(2):675-683
The heat capacity of PbMO3 (M=Ti, Zr and Hf) at constant pressure was measured using a differential scanning calorimeter (DSC) from room temperature up
to 870 K. Large anomalies were found in the heat capacity curves, corresponding to the ferroelectricparaelectric phase transition
in PbTiO3 (PT), the antiferroelectric-paraelectric phase transitions in PbZrO3 (PZ) and PbHfO3 (PH). The transition entropies were estimated as 7.3 J K−1 mol−1 (PT), 9.9 J K−1 mol−1 (PZ) and 9.3 J K−1 mol−1 (PH). These values of transition entropies are much larger than that of a typical displacive-type phase transition. 相似文献