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《The Journal of chemical thermodynamics》2007,39(6):888-892
Calcium titanofluoride CaTiF5(s) was prepared by solid-state reaction of CaF2(s) with TiF3(s) and characterized by X-ray diffraction method. The standard molar isobaric heat capacity of CaTiF5(s) was determined by a power compensated differential scanning calorimeter in the temperature from 230 K to 710 K. A solid-state galvanic cell with CaF2 as electrolyte was used to determine the standard molar Gibbs energy of formation of CaTiF5 in the temperature range from 803 K to 1005 K. The galvanic cell can be depicted as:The second law analysis of present data were carried out to derive the standard entropy and the enthalpy of formation and the values derived are 68.7 J · K−1 · mol−1 and −2848.4 kJ · mol−1, respectively. 相似文献
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Phase relations in the system (chromium + rhodium + oxygen) at T = 1273 K have been determined by examination of equilibrated samples by optical and scanning electron microscopy, powder X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS). Only one ternary oxide, CrRhO3 with rhombohedral structure (, a = 0.5031, and c = 1.3767 nm) has been identified. Alloys and the intermetallics along the (chromium + rhodium) binary were in equilibrium with Cr2O3. The thermodynamic properties of the CrRhO3 have been determined in the temperature range (900 to 1300) K by using a solid-state electrochemical cell incorporating calcia-stabilized zirconia as the electrolyte. For the reaction,where Cr2O3 has the corundum structure and Rh2O3 has the orthorhombic structure. Thermodynamic properties of CrRhO3 at T = 298.15 K have been evaluated. The compound decomposes on heating to a mixture of Cr2O3-rich sesquioxide solid solution, Rh, and O2. The calculated decomposition temperatures are T = 1567 ± 5 K in pure O2 and T = 1470 ± 5 K in air at a total pressure p° = 0.1 MPa. The temperature-composition phase diagrams for the system (chromium + rhodium + oxygen) at different partial pressures of oxygen and an oxygen potential diagram at T = 1273 K are calculated from the thermodynamic information. 相似文献
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Dioxygen affinities and catalytic oxidation performance of cobalt(Ⅱ) hydroxamates with benzo-15-crown-5 pendants 总被引:1,自引:0,他引:1
Hong Bo Li Chuan Qin Wen Bing Yang Xiao Ping Hu Sheng Ying Qin 《中国化学快报》2007,18(1):103-106
The oxygenation constants(Ko_2)of cobalt(Ⅱ)hydroxamates(CoL_2~1-CoL_2~3)with benzo-15-crown-5(B15C5)pendants were measured over the range of-5 to 20℃,and the values of thermodynamic parameters(ΔH~0 andΔS~0)were calculated based on these(No_2)values.Meanwhile,these crowned complexes were employed to the oxidation for p-xylene to p-toluic acid with air at 110Δunder normal atmospheric pressure.The effects of B15C5 pendant and the length of chain bonded to B15C5 in these complexes on the O_2-binding capabilities and oxidation for p-xylene were investigated with the comparison of crown-free analogues CoL_2~4. 相似文献
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