排序方式: 共有36条查询结果,搜索用时 15 毫秒
31.
L. Bencivenni A. Farina B. Martini S.Nunziante Cesaro R. Teghil M. Spoliti 《Journal of Molecular Structure》1980
IR and Raman spectra of gaseous and solid CpGeX3 species (Cp C5H5 and X = Cl, Br, I) are reported. The results are compared with those obtained previously for CpTiCl3. Internal rotation barriers and thermodynamic functions are reported. 相似文献
32.
E. Traversa G. Montesperelli P. Nunziante G. Chiozzini 《Journal of Thermal Analysis and Calorimetry》1992,38(12):2583-2592
The thermal behaviour of hydroxide mixtures, precursors to the synthesis of MgFe2O4 spinel powders, was investigated.The mixtures of hydroxides were prepared by coprecipitation reaction from nitrate solutions with an Mg/Fe atomic ratio of 12. The results were related to the thermal behaviour of separately precipitated components of the hydroxide mixtures. Samples prepared by mechanically mixing the separately precipitated hydroxides were also studied.The spinel formation temperature was identified by performing XRD analysis on powder samples heated to different temperatures. The presence of spinel from the thermal decomposition of coprecipitated mixtures was detected at a temperature as low as 380°C. The separate formation of MgO and Fe2O3 from the thermal decomposition of mechanical mixtures was observed; nevertheless the formation of MgFe2O4 through a solid state reaction between the oxides was noted at a temperature as low as 500°C.The Authors wish to thank Dr. L. Petrilli and Mr. F. Dianetti for carrying out the elemental chemical analyses at the Microanalysis Service of the C. N. R. laboratories of the Area della Ricerca di Roma. 相似文献
33.
Vibrational frequencies, force constants and geometrical parameters of the oxides of group VIB elements in rare gas matrices are compared with those in the gas phase. Bonding in these species is discussed. 相似文献
34.
Germanium monocarbonyl has been prepared by high-temperature vaporization of Ge with excess carbon powder or CO co-condensation and trapped in various matrices at 12 K. Fourier transform infrared spectra, ab initio (MP2 and CISD) and density function (Becke3LYP) calculations suggested a linear species with the formula GeCO. A weak feature appearing only in annealed N2 and CO matrices containing GeCO has tentatively been assigned to germanium dicarbonyl on grounds of isotopic substitution and theoretical calculations. SCF and CI methods predict a bent structure for this complex. 相似文献
35.
M. Maltese G. Zennaro B. Martini R. Croce S. Nunziante Cesaro M. Spoliti 《Journal of Molecular Structure》1980
The IR spectra (300–4000 cm?1) of bis-(N,N-diethyldithiocarbamato)-nickel(II) as N2 matrix and oriented polycrystalline layer are reported. All the observed bands are assigned and classified on the grounds of their polarisation in the symmetry classes of D2h, the highest possible molecular symmetry.Remarkably, polarisation of the absorptions around 1000 cm?1 rules out the assignment to any C-S stretching, in contrast with previous assignments. The room temperature crystal spectra do not show evidence for crystal splitting. The matrix spectrum shows features related to the existence of rotamers around the H2C-N bond, which give useful assistance in the assignment. 相似文献
36.