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1.
Yuko Ichiyanagi Yuki Moro Hikaru Katayanagi Shinji Kimura Daiki Shigeoka Tomoyuki Hiroki Toshiyuki Mashino 《Journal of Thermal Analysis and Calorimetry》2010,99(1):83-86
Magnetic nanoparticles were prepared by a wet chemical method. Precursors of MFe2O4 (M = Co, Mn, Zn) were prepared from a mixture of metal chloride and metasilicate nonahydrate aqueous solutions. The precipitates
obtained in the wet chemical method were calcined to obtain MFe2O4 nanoparticles encapsulated by amorphous SiO2. The blocking temperatures T
B’s were between 20 and 320 K, in this temperature range, the anisotropy energy of the particles decreased below their thermal
energy. T
B increased with the particle size. In order to clarify the nanoparticle formation process, differential thermal analysis and
thermogravimetric (TG-DTA) measurements were performed for the as-prepared samples. 相似文献
2.
N. G. Chernorukov A. V. Knyazev A. V. Ershova 《Russian Journal of Inorganic Chemistry》2007,52(8):1171-1174
Compounds with the composition Ba(M 2/3 III U1/3)O3 (MIII = Sc, Y, In, Nd-Lu) were synthesized by high-temperature solid-state reactions. The structures of the compounds were studied by X-ray diffraction analysis, including the high-temperature method, and IR spectroscopy. 相似文献
3.
A. M. Chernysheva P. A. Shelyganov I. V. Kazakov A. Y. Timoshkin 《Russian Journal of General Chemistry》2017,87(4):665-669
Structural, spectral, and thermodynamic characteristics of complex amidoboranes M2[M1(NH2BH3)4] (M1 = Al, Ga; M2 = Li, Na, K, Rb, Cs) were calculated by the B3LYP/def2-SVPD quantum-chemical method. The procedure for the synthesis of these compounds by reactions of alkali metal amidoboranes with aluminum and gallium chlorides was suggested and experimentally tested. Reaction products were characterized by the NMR and IR spectroscopy and X-ray phase analysis. 相似文献
4.
E. Tomaszewicz 《Journal of Thermal Analysis and Calorimetry》2008,93(3):711-715
Three new compounds MPr2W2O10 (M=Mn, Co, Cd) were prepared by the solid-state reaction. They are isostructural and crystallize in the orthorhombic system.
MPr2W2O10 (M=Mn or Co) melt incongruently above 1150°C and the solid product of melting is Pr2W2O9. The CdPr2W2O9 compound starts decomposing in the solid-state at 1156°C to Pr2W2O9 and CdO. 相似文献
5.
Calorimetric measurements
have been performed in glassy Se90M10
(M=In, Te, Sb) alloys to study the effect
of In, Te and Sb additives on the kinetics of glass transition and crystallization
in glassy Se90M10 system. Kinetic
parameters of glass transition and crystallization such as the activation
energy of glass transition (E
g),
the activation energy of crystallization (M
c),
the order parameter (n), the rate constant
(K), etc. have been determined using different
non-isothermal methods. The composition dependence of the activation energies
of glass transition and crystallization processes is also discussed. 相似文献
6.
P. Tabero 《Journal of Thermal Analysis and Calorimetry》2007,88(1):269-272
Studies on thermal expansion of the MNbO4
type phases where M=Al, Cr, Fe, Ga have
been carried out in the high-temperature X-ray diffraction attachment. In
the case of isotypic AlNbO4 and GaNbO4 compounds the
structure of which consists of the ReO3 type blocks,
the direction of minimal thermal expansion is consistent with the direction
in which these blocks spread to infinity. In the case of CrNbO4,
the maximal thermal expansion direction is consistent with the [001] direction
parallel to which the edge shared octahedra building its structure form infinite
chains. FeNbO4 has the highest coefficients of thermal
expansion in this group of compounds. 相似文献
7.
T. I. Chupakhina N. V. Mel’nikova E. A. Yakovleva Yu. A. Nikitina 《Russian Journal of Inorganic Chemistry》2018,63(2):141-148
New solid solutions La1.8Sr0.2Ni0.8M0.2O4 (M = Fe, Co, or Cu) have been prepared, and their crystal- chemical characteristics and electric properties studied. The studied materials have been shown to have activation-time conductivity. Structural distortions have been found to affect the dielectric properties of ceramic samples. La1.8Sr0.2Ni0.8M0.2O4 is observed to have the greatest distortion of АО9 coordination polyhedra and a higher dielectric constant. 相似文献
8.
LiHua Gan 《中国科学B辑(英文版)》2009,52(5):584-589
Based on the calculated findings that the sizes of encaged clusters determine the structures and the stability of C80-based trimetallic nitride fullerenes (TNFs), more extensive density functional theory calculations were performed on M3N@C68, M3N@C78 and M3N@C80 (M=Sc, Y and La). The calculated results demonstrated that the structures and stability undergo a transition with the increasing
of the sizes of the cages and clusters. Sc3N is planar inside the three considered cages, Y3N is slightly pyramidal inside C68-6140 and C78-5 and planar inside Ih C80-7, however, La3N is pyramidal inside all the three cages. Those cages with pyramidal clusters inside deformed considerably, compared with
their parent cages. In these cases, the bonding of metallic atoms toward the cages does not play an important role, and the
encaged cluster tends to be located inside the cages with the largest M-M and M-C distances so that the strain energy can
be released mostly. These calculations revealed the size effect of fullerene cages and encaged clusters, and can explain the
position priority of M3N inside fullerene cages and the differences in yield of M3N@C2n
.
Supported by the Southwest University, China (Grant No. SWNUB2005002) 相似文献
9.
Roman Zaremba Ute Ch. Rodewald Rainer Pöttgen 《Monatshefte für Chemie / Chemical Monthly》2007,138(9):819-822
Summary. The isotypic indides RE
5Pt2In4 (RE = Sc, Y, La–Nd, Sm, Gd–Tm, Lu) were synthesized by arc-melting of the elements and subsequent annealing. They were investigated
via X-ray powder diffraction. Small single crystals of Gd5Pt2In4 were grown via slow cooling and the structure was refined from X-ray single crystal diffractometer data: Pbam, a = 1819.2(9), b = 803.2(3), c = 367.6(2) pm, wR
2 = 0.089, 893 F
2 values and 36 parameters. The structure is an intergrowth variant of distorted trigonal and square prismatic slabs of compositions
GdPt and GdIn. Together the platinum and indium atoms build up one-dimensional [Pt2In4] networks (292–333 pm Pt–In and 328–368 pm In–In) in an AA stacking sequence along the c axis. The gadolinium atoms fill distorted square and pentagonal prismatic cages between these networks with strong bonding
to the platinum atoms. 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.
A. S. Ivanova 《Kinetics and Catalysis》2009,50(6):797-815
The effect of synthesis conditions, the nature of components, and the ratio between the components on the phase composition,
the texture, and the redox and catalytic properties of the Ce-Zr-O, Ce-Zr-M1-O (M1 = Mn, Ni, Cu, Y, La, Pr, or Nd), N/Ce-Zr-O (N = Rh, Pd, or Pt), and Pd/Ce-Zr-M2-O/Al2O3 (M2 = Mg, Ca, Sr, Ba, Y, La, Pr, Nd, or Sm) was considered. A cubic solid solution with the fluorite structure was formed on
the introduction of <50 mol % zirconium into CeO2, and the stability of this solid solution depended on preparation procedure and treatment conditions. The presence of transition
or rare earth elements in certain concentrations extended the range of compositions with the retained fluorite structure.
The texture of the Ce-Zr-O system mainly depended on treatment temperature. An increase in this temperature resulted in a
decrease in the specific surface area of the samples. The total pore volume varied over the range of 0.2–0.3 cm3/g and depended on the Ce/Zr ratio. The presence of transition or rare earth elements either increased the specific surface
area of the system or made it more stable to thermal treatment. The introduction of the isovalent cation Zr4+ into CeO2 increased the number of lattice defects both on the surface and in the bulk to increase the mobility of oxygen and facilitate
its diffusion in the Ce1 − x
Zr
x
O2 lattice. The catalytic properties of the Ce-Zr-M1-O or N/Ce-Zr-M2-O systems were due to the presence of anion vacancies and the easy transitions Ce4+ ai Ce3+, M12n+ ai M1
n+, and N
δ+ → N
0 in the case of noble metals. 相似文献
12.
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
13.
V. Berbenni C. Milanese G. Bruni A. Marini 《Journal of Thermal Analysis and Calorimetry》2005,82(2):401-407
The thermal decomposition of gallium nitrate hydrate (Ga(NO3)3·xH2O) to gallium oxide has been studied by TG/DTG and DSC measurements performed at different heating rates. It is concluded
that 8 water molecules are present in the hydrate compound. The anhydrous gallium nitrate does not form at any temperature
as the reaction consists of coupled dehydration/decomposition processes that occur with a mechanism dependent on heating rate.
TG measurements performed with isothermal steps (between 31 and 115°C) indicate that Ga(OH)2NO3 forms in the first stage of the reaction. Such a compound undergoes further decomposition to Ga(OH)3 and Ga(NO3)O, compounds that then decompose respectively to Ga(OH)O and finally to Ga2O3 and directly to Ga2O3. Diffuse reflectance Fourier transform IR spectroscopy (DRIFTIR) has been of help in assessing that the reaction consists
of parallel dehydration/decomposition processes. 相似文献
14.
The mono- and bisligands complexes formed by rare earth cation (Sc, Y) with pentazolato anion or cyclo-P5− anion, the all-nitrogen counterparts of metallocenes or the all-phosphorus counterparts of metallocenes, have been studied
at hybrid basis sets level with the DFT method. The geometric parameters, binding energy and the charge distributions of these
complexes were characterized. And their stable orders were obtained. Monoligand complexes incline to become bisligands complexes
due to their destabilization. The charge transferring between ligand and metallic cation has affinity with the stability of
complex. The possibility of forming stable [M(η
5-E5)2] (M = Sc, Y, E = N, P) complexes is predicted and they are viable synthetic targets theoretically, especially Sc(η
5-N5)2. 相似文献
15.
Monika Bosacka 《Journal of Thermal Analysis and Calorimetry》2007,88(1):43-46
It has been demonstrated that Co2V2O7
and InVO4 react with each other forming a new compound
of the Co2InV3O11
formula, when their molar ratio is equal to 1:1, or among CoCO3,
In2O3 and V2O5,
mixed at a molar ratio of 4:1:3. This compound melts incongruently at the
temperature of 960±5°C, depositing crystals of InVO4.
It crystallizes in the triclinic system and the unit cell parameters amount
to: a=0.6524(6) nm, b=0.6885(5)
nm, c=1.0290(4) nm, α=96.5°, β=104.1°,
γ=100.9°, Z=2. The phase equilibria
being established in the Co2V2O7–InVO4
system over the whole components concentration range up to the solidus line
were described. 相似文献
16.
L. Abbas L. Bih A. Nadiri Y. El Amraoui H. Khemakhem D. Mezzane 《Journal of Thermal Analysis and Calorimetry》2007,90(2):453-458
Thermal and chemical durability studies of the phosphate glasses belonging to the binary MoO3-P2O5 and the ternary K2O-MoO3-P2O5 systems are reported. The chemical resistant attack tests carried out on the free alkaline MoO3-P2O5 glasses show that the glass associated with the P/Mo ratio 2 has the high chemical durability. It shows also a high glass
transition temperature value. The above findings are interpreted in terms of the cross-link density of the glasses and the
strength of the M-O bonds (M=P, Mo).
The influence of K2O addition on the properties (density, T
g, durability) of this binary high water resistant glass is studied. It is found that the chemical durability along with the
other physical properties are reduced by the incroporation of K2O in the glass matrix. The results were explained by assuming the formation of non-bridging oxygens and weak bonds. The mechanism
of the dissolution of these glasses is proposed. 相似文献
17.
M. Boča V. Danielik Z. Ivanová E. Mikšíková B. Kubíková 《Journal of Thermal Analysis and Calorimetry》2007,90(1):159-165
The phase diagrams of the systems KF-K2TaF7 and KF-Ta2O5 were determined using the thermal analysis method. The phase diagrams were described by suitable thermodynamic model. In
the system KF-K2TaF7 eutectic points at x
KF=0.716 and t=725.4°C and at x
KF=0.214 and t=712.2°C has been calculated. It was suggested that K2TaF7 melts incongruently at around 743°C forming two immiscible liquids. The system KF-Ta2O5 have been measured up to 8 mol% of Ta2O5. The eutectic point was estimated to be at x
KF∼0.9 and t∼816°C. The formation of KTaO3 and K3TaO2F4 compounds has been observed in the solidified samples. 相似文献
18.
V. N. Krasil’nikov 《Russian Journal of Inorganic Chemistry》2007,52(3):419-423
Powder X-ray diffraction and microscopy have been used to study phase ratios of the M2O-V2O5-SO3 (M = Rb, Cs) systems, which model the active component of rubidium-vanadium and cesium-vanadium catalysts for sulfuric acid production at high sulfur dioxide conversions. We have stated that each system forms four compounds: M3VO2(SO4)2, MVO2SO4, M4V2O3(SO4)4, and MVO(SO4)2. The thermal properties of these compounds and their interaction with water vapor saturated at room temperature have been studied. The unit cell parameters have been determined for the compounds MVO2SO4 (M = K, Rb), MVO(SO4)2, and M[VO2(SO4)(H2O)2] · H2O (M = Rb, Tl). The reciprocal transformations of the components and phases of the M2O-V2O5-SO3 systems match the Lux-Flood ideas of the acid-base properties of oxide compounds. 相似文献
19.
Yu. A. Titov N. S. Slobodyanik V. V. Polubinskii V. V. Chumak 《Theoretical and Experimental Chemistry》2012,47(6):394-398
We have established and analyzed the sequences of phase transitions in synthesis of layered compounds in the AnBn–1O3n family (
\textA3\textII\textLnB3\textV\textO12 {\text{A}}_3^{\text{II}}{\text{LnB}}_3^{\text{V}}{{\text{O}}_{{12}}} (AII = Ba, Sr, Ln = La, Nd, BV = Nb, Ta) and La4Ti3O12 with n = 4) from coprecipitated hydroxocarbonate and hydroxide systems, including steps involving the formation, solid-phase
reaction, or structural rearrangement of intermediates. 相似文献
20.
V. M. Zainullina 《Russian Journal of Inorganic Chemistry》2009,54(1):100-114
The electronic structure of the Sn0.875M0.125O2 compounds (M = Cr, Mn, Co) with a rutile structure and magnetic moments of the transition metal atoms in them were calculated by the ab initio spin-polarized linear muffin-tin orbital method. The electron density and electron localization function maps for these compounds were constructed. Based on these data, the effect of the composition of these phases on the electronic spectrum, chemical bond, and magnetic and transport properties were analyzed. 相似文献