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1.
《Journal of solid state chemistry》1987,69(1):126-134
In the system Na3PO4Na2SO4, the high-temperature, cubic γ form of Na3PO4 forms an extensive range of solid solutions: Na3−x(P1−xSx)O4, 0 < x < (0.57 to 0.70, depending on temperature). For compositions in the range x = ca. 0.33 to 0.57, these γ solid solutions are thermodynamically stable at all temperatures. The conductivity of the γ solid solutions increases with increasing x and reaches a maximum at x = 0.5 to 0.6, with values of 2 × 10−5 ohm−1 cm−1 at 100°C, rising to 1.3 × 10−2 ohm−1 cm−1 by 300°C; this conductivity increase with x is attributed to an increase in the sodium ion vacancy concentration, associated with the solid solution mechanism Na + PS. The phase diagram for the system Na3PO4Na2SO4 is given together with lattice parameters of the γ solid solutions. 相似文献
2.
《Solid State Sciences》2000,2(4):489-493
The partial system Mg3(PO4)2Mg4Na(PO4)3Na4P2O7Mg2P2O7 in the ternary system MgONa2OP2O5 was investigated using thermal and X-ray diffraction analyses and microscopy, and its phase diagram has been determined. In this range of composition, two binary phosphates occur: Mg4Na(PO4)3 and Mg6Na8(P2O7)5. The former melts incongruently (at 1155°C) and the latter does congruently (at 808°C). In the partial system of interest, the two sections Mg4Na(PO4)3Mg2P2O7 and Mg4Na(PO4)3Mg6Na8(P2O7)5 are studied, and their phase diagrams are established. The partial system is divided into three partial ternary systems in which two ternary eutectics and one ternary peritectic occur. 相似文献
3.
《Fluid Phase Equilibria》1988,39(1):101-110
Bubble-point pressures of the H2COCO2 system were measured at temperatures from 253.15 to 303.15 K and pressures up to 9 MPa. Multiple bubble-points were observed within certain limits of hydrogen compositions. The data have been compared with the calculated results by the Redlich-Kwong and the Peng-Robinson equations of state. 相似文献
4.
《Journal of the Less Common Metals》1991,167(2):373-379
Thermodynamic measurements by the electromotive force method were made on the binary intermetallic phases URu3 and U3Ru5 and on the ternary carbides URu3C0.7 and U2RuC2 of the URu and the URuC systems between 950 and 1200 K using galvanic cells with CaF2 single crystal electrolytes: U, UF3¦CaF2¦UF3, URu3, Ru; U, UF3¦CaF2¦UF3, U3Ru5, URu3; Ru, URu3, UF3¦CaF2¦UF3, URu3C0.7, Ru, C; U, UF3¦CaF2¦UF3, URu3C0.7, U2RuC2, C. The Gibbs energies of formation of URu3, U3Ru5, URu3C0.7 and U2RuC2 were evaluated from the measured electromotive force which give fΔGo〈URu3〉 = −199 100 + 35.9 T J mol−1fΔGo〈U3Ru5〉 = −398 600 + 43.6 T J mol−1fΔGo〈URu3C0.7〉 = −192 600 + 2.5 T J mol−1fΔGo〈U2RuC2〉 = −380 200 + 52.5 T J mol−1 The implications of these thermodynamic data for the behaviour of the fission product ruthenium in irradiated carbide fuels are discussed. 相似文献
5.
NdFeB and corresponding MmFeB compounds were studied, the high field magnetization at 4.2 K, the a.c. susceptibility (4.2 < T < 300 K) and the anisotropy field were measured using the singular point detection technique (77 < T < 570 K). At room temperature the anisotropy field of the MmFeB is about 3T, whereas that of NdFeB compounds is about 7T. The MmFeB compounds showed effects due to the cerium (lowering the Curie temperature) as well as due to the neodymium (spin reorientation at low temperatures). 相似文献
6.
《Journal of solid state chemistry》1987,66(2):350-359
The activities of the components in the pseudo-binary NaK β-alumina system have been calculated from equilibrium ion-exchange data. Using data from exchanges with molten nitrate, chloride, and iodide salts, the results indicate that this system shows negative deviations from ideal mixing. A model involving preferential “ion pairing” of Na and K ions gives a good fit to the experimental data. Two maxima in the excess stabilities are found at compositions lying close to those which have been shown to exhibit the lowest ionic conductivities in the system. It is suggested that the “mixed-alkali” effect in NaK β-alumina is strongly related to the presence of cation order, and that the driving force for order results from reduction of nearest-neighbor cation repulsions. 相似文献
7.
《Journal of solid state chemistry》1987,69(2):274-279
The systems CaCl2SrCl2 and CaCl2EuCl2 were studied over the entire composition range by X-ray powder diffraction. The CaCl2XCl2 (X = Sr, Eu) systems behave similarly and exhibit two single-phase regions with corresponding adjacent two-phase regions. The first single-phase region exhibits the SrI2-type and the second the SrBr2-type structure. The cation distribution is probably random throughout the systems. 相似文献
8.
《Journal of solid state chemistry》1987,71(2):562-565
A hypothetical oxygen pressure-composition phase diagram and a projection of the oxygen pressure-temperature-composition diagram on the composition triangle were constructed from phase equilibria in the system MnCrO on the basis of the data available in literature. The temperature-composition phase equilibrium diagram of this same system in air was specified. Isomorphism of solid solutions with spinel and hausmannite structure and their intertransformation was studied. Two chemical compounds, MnCr2O4 and Cr4Mn28O48, are supposed to exist in the system. 相似文献
9.
10.
《Journal of solid state chemistry》1987,71(1):61-69
The first systematic survey of the BaOReRe2O7 phase diagram is reported, with emphasis on the reduced ternary oxides. At 800°C, the previously reported compounds Ba3Re2O9, Ba2ReO5, and Ba3ReO6 were observed, all of which contain Re(VI) in ReO6 octahedra. The stability of these phases is apparently due to ReO π-bonding in and between the octahedra. The previously unknown structure of Ba2ReO5 was determined by powder neutron diffraction and found to be isotypic with that of K2VO2F3 (space group Pnma), with a = 7.3233(2), b = 5.7745(1), and c = 11.4124(2), Å. ReO6 octahedra share adjacent corners to produce cis chains which are held together by 10 coordinated Ba atoms. 相似文献
11.
《Chemical physics》1987,115(3):325-337
The results of ab initio self-consistent field (SCF) and configuration interaction (CI) calculations on the hydrogen bonded N2HF, N2HCl, (HCN)2 and NH3HCN complexes, using basis sets that range from double-zeta plus polarization to triple-zeta plus double polarization, are reported. The primary objective of this work has been to calculate the changes in the dipole moments and the electric field gradients (EFGs) at the quadrupolar 14N, 2H and 35Cl nuclei that are induced by H-bonding. Since the interpretation of the H-bond induced shifts requires a knowledge of the molecular dynamics in weakly H-bonded molecular complexes such as those studied in the present work, we have taken into account the effects of vibrational averaging on both the EFGs and dipole moments utilizing harmonic intermolecular force fields that were generated using ab initio SCF methods. The results of these calculations are compared with the corresponding experimental quantities that are obtained from the microwave spectra of these complexes. 相似文献
12.
13.
R. V. Panin N. R. Khasanova A. M. Abakumov W. Schnelle J. Hadermann E. V. Antipov 《Russian Chemical Bulletin》2006,55(10):1717-1722
Sodium ruthenium(III,IV) oxide Na1−x
Ru2O4 was synthesized by the solid state reaction of Na2CO3 and RuO2 in inert atmosphere and characterized by X-ray powder diffraction, electron diffraction, and high-resolution transmission
electron microscopy. The compound crystallizes in the CaFe2O4-type structure (space group Pnma, Z = 4, a = 9.2641(7) Å, b = 2.8249(3) Å, c = 11.1496(7) Å). Double rutile-like chains of the RuO6 octahedra form a three-dimensional framework, whose tunnels contain sodium cations. The structure contains two crystallographically
independent sites of ruthenium atoms randomly occupied by the RuIII and RuIV cations. The superstructure with the doubled b parameter found for one of the samples under study using electron diffraction is caused, probably, by ordering of the Ru
cations in the rutile-like chains. The Na1− x
Ru2O4 compound exhibits temperature-independent paramagnetism with χ0 = 1.9·10−4 cm3 (mole of Ru−1).
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1655–1660, October, 2006. 相似文献
14.
L. Soliev 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2013,87(9):1442-1447
Phase equilibria of the Na,K,Mg,Na,K,Mg,Ca//SO4,Cl-H2O system are studied at 50°C via translation in the crystallization range of glaserite (3K2SO4 · Na2SO4). It is found that glaserite as the equilibrium phase of the investigated system at 50°C participates in the formation of 21 invariant points, 21 monovariant curves, and 34 divariant fields. A fragment of the phase equilibria diagram of the investigated system is constructed in the crystallization range of glaserite. 相似文献
15.
《Journal of solid state chemistry》1991,92(1):130-135
The ternary system YPO4Ca3(PO4)2Ca2P2O7 has been investigated by differential thermal analysis, powder X-ray diffraction, and microscopy in reflected light. Its phase diagram and isothermal section at room temperature have been determined. The system contains only one double phosphate which is formed at the 1:1 molar ratio YPO4:Ca3(PO4)2, i.e., Ca3Y(PO4)3. 相似文献
16.
《European Journal of Solid State and Inorganic Chemistry #》1998,35(8-9):591-594
It has been found experimentally that phase diagram for the system Bi2O3CaOSrOCuO in SrO-rich region at 850°C in the open air includes three elementary tetrahedra: CaOSrOSr6Bi2O11Sr2CuO3, CaOSr2CuO3Sr6Bi2O11Sr3,5Ca0,5Bi2O7 and Sr3Bi2O6Sr6Bi2O11Sr3,5Ca0,5Bi2O7 Sr2CuO3. In the considered interval of corresponding oxide concentrations quaternary oxides are not formed under the above conditions. 相似文献
17.
Interaction of salts in ionic melts of the ternary reciprocal systems Na,K‖BO2,MoO4 and Na,K‖BO2,WO4
The phase diagrams of the ternary reciprocal systems Na,K‖BO2,MoO4 and Na,K‖BO2,WO4 were studied for the first time by a calculation-experimental method and differential thermal analysis. The coordinates were determined for binary eutectics of the diagonal stable sections NaBO2-K2MoO4(K2WO4) and the ternary invariant points e(55 mol % NaBO2, 45 mol % K2MoO4, 740°C), e(55 mol % NaBO2, 45 mol % K2WO4, 730°C), E(4.5 mol % NaBO2, 78 mol % Na2MoO4, 17.5 mol % K2MoO4, 652°C), E(4.5 mol % NaBO2, 78 mol % Na2WO4, 17.5 mol % K2WO4, 643°C), P2(5 mol % NaBO2, 56 mol % Na2MoO4, 39 mol % K2MoO4, 673°C), P2(5 mol % NaBO2, 56 mol % Na2WO4, 39 mol % K2WO4, 671°C). Binary solid solutions based on sodium and potassium metaborates were shown to be stable. Analytical models of phase equilibrium states of the ternary reciprocal systems Na,K‖BO2,MoO4(WO4) were obtained, which enable one to calculate melting (crystallization) points and construct isotherms at any given composition. The specific heats of melting of samples of invariant compositions were found by quantitative differential thermal analysis. 相似文献
18.
《Journal of the Less Common Metals》1987,127(1):147-153
The CeFe binary system was investigated and an FeCe binary phase diagram was proposed. This system consists of
- 1.(i) two peritectic reactions, γ-Fe + L → Ce2Fe17 and Ce2Fe17 + L → CeFe2, occurring isothermally at 1063°C and 925°C respectively;
- 2.(ii) a eutectic reaction, L → CeFe2 + Ce, occurring isothermally at 592°C with eutectic containing 83.3 at.% Ce (92.6 wt.% Ce);
- 3.(iii) a peritectoid reaction, γ-Fe + Ce2Fe17 → α-Fe(Ce), occurring isothermally at 922 °C.
19.
C. Bhongale A. Ghule R. Murugan H. Chang 《Journal of Thermal Analysis and Calorimetry》2001,65(3):891-905
In this work, dehydration of sodium diphosphate decahydrate Na4P2O7⋅10H2O and phase transformations of Na4P2O7 in open air have been studied in detail by thermo-Raman spectroscopy. The spectra were measured continuously in a temperature
range from room temperature up to 600°C for the bands of P2O7
4- and H2O. The spectral variation showed one step of dehydration and four-phase transformations. The thermo-Raman intensity(TRI) and
differential thermo-Raman intensity (DTRI) curves calculated from the characteristic bands of H2O also showed one step of dehydration with the loss of all hydrated water in the temperature interval from 45 to 69°C. Thermogravimetric
measurements supported this result. The thermo-Raman investigation indicated the transformation of Na4P2O7 from low temperature phase to high temperature phase proceed through pre-transitional region from 75 to 410°C before the
major orientational disorder at 418°C and minor structural modifications at 511,540 and 560°C. The results from differential
scanning calorimetry and differential thermal analysis on Na4P2O7 showed endotherms at 407,517, 523, 548, 557°C and 426, 528, 534, 555, 565°C, respectively.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
20.
《Journal of the Less Common Metals》1989,146(1-2):213-219
The phase behavior of the AlIr system has been studied using differential thermal analysis, electron microprobe analysis, X-ray diffraction, chemical analysis and X-ray fluorescence. Our work confirms the existence of four compounds: Al9Ir2, Al3Ir, Al2.7Ir and AlIr. We also observed an additional intermetallic phase, with a stoichiometry corresponding to Al13Ir4; however, this compound exhibits a complex X-ray pattern and currently no structure has been determined.Peritectic temperatures were determined for Al9Ir2 (900 °C), Al13Ir4 (1015 °C) and Al3Ir (1450 °C). The Al2.7Ir phase is stable to above 1450 °C, and the congruent melting temperature of AlIr is 2120 ± 20 °C. The solubility of aluminum in iridium was measured between 1085 and 1850 °C, and the maximum solid solubility was extrapolated to 18 at.% at 2058 °C. The maximum solid solubility of iridium in aluminum was measured to be less than 0.1 at.%. A phase diagram for the AlIr system is presented. 相似文献