排序方式: 共有29条查询结果,搜索用时 31 毫秒
1.
2.
K.S. Weil 《Journal of solid state chemistry》2008,181(1):199-210
The thermal decomposition of a CrN precursor, hexaammine chromium(II) chloride, in ammonia has been investigated via a combination of thermogravimetric analysis, differential thermal analysis, Fourier transform infrared spectroscopy, and X-ray diffraction. Upon heating, [Cr(NH3)6]Cl2 sequentially loses ammonia ligands, ultimately forming CrCl2·NH3 at ∼400 °C. When heat-treated to 500 °C in ammonia, this compound ammonolyzes to form nanocrystalline CrN. 相似文献
3.
A. Stork C. Wessel A. Börger K.-D. Becker M. Lerch 《Journal of solid state chemistry》2010,183(9):2051-2058
The aim of our study was to modify the basis compound ß-TaON, which crystallizes in the monoclinic baddeleyite-type, by incorporation of appropriate dopant ions, in order to obtain anion-deficient cubic fluorite-type phases, which are of interest as solids with mobile nitrogen ions. For this purpose, scandium-doped tantalum oxide nitrides were prepared by ammonolysis of amorphous oxide precursors. An unexpected variety of phases with different structural features was observed: bixbyite-type phases of general composition ScxTa1−x(O,N)y with 0.33≤x≤1 and 1.7≤y≤1.9, yellow colored metastable anatase-type phases such as Sc0.1Ta0.9O1.2N0.8 or Sc0.15Ta0.85O1.3N0.7 and, additionally, anosovite-type phases ScxTa3−xO2xN5−2x with 0≤x≤1.05. Selected phases were investigated by UV/vis spectroscopy. Anatase- and anosovite-type compounds show brilliant colors. In the anatase-type phase, a possible anion ordering was examined by theoretical methods. Additionally, energy calculations on phase stability were performed for ScxTa1−xO1+2xN1−2x in the baddeleyite, rutile, and anatase structure types with varying amounts of dopants. 相似文献
4.
Giordano Paniconi Ronald I. Smith Bryan L. Gallagher 《Journal of solid state chemistry》2008,181(1):158-165
Zn3N2 powders were prepared by ammonolysis reactions at 600 °C and examined by thermogravimetric analysis, powder X-ray and neutron diffraction. The powders obtained in this way are unstable in an oxygen atmosphere above 450 °C. In an argon atmosphere, the powders are stable up to their decomposition point at around 700 °C. Structural models obtained from Rietveld refinements against the powder neutron diffraction data indicate that the Zn3N2 powders so-prepared have the anti-bixbyite structure and are almost certainly stoichiometric with no compelling evidence of nitrogen vacancies. Further, no evidence was found for aliovalent oxygen substitution at the nitrogen sites. The calculated bond valence sums imply that Zn3N2 cannot be described as a 100% ionic compound. The structural findings are supported by photoluminescence measurements that reveal a band gap of approximately 0.9 eV. 相似文献
5.
In the quest for novel PPARα/γ dual agonists as putative drugs for the treatment of type 2 diabetes and dyslipidemia,we designed and synthesized a series of urea acetates as potential PPARα/γ dual agonists.The structure of the target compounds,intermediates were characterized by 1H NMR,HRMS. 相似文献
6.
The Courses of the Ammonolyses of the Ammonium Hexafluorometalates of Aluminum, Gallium, and Indium, (NH4)3MF6 (M = Al, Ga, In) The courses of the ammonolysis reactions of the ammonium hexafluorometalates (NH4)3MF6 (M = Al, Ga, In) were investigated with the aid of in‐situ powder diffractometry and differential thermal analysis. Under these conditions, the reaction of (NH4)3AlF6 with gaseous ammonia yields at about 360 °C AlF3 via the intermediates NH4AlF4, Al(NH3)2F3 and Al(NH3)F3. The ammonolysis of (NH4)3GaF6 produces GaN at about 400 °C. Depending upon the actual reaction conditions, the intermediates NH4GaF4 and Ga(NH3)F3 as well as their ammonia adducts NH4GaF4 · NH3 and Ga(NH3)2F3 and the amide‐ammoniate Ga(NH3)(NH2)F2 are observed. In the case of (NH4)3InF6 the intermediates (NH4)3InF6 · NH3 and In(NH3)F3 may exist; there are also indications for the reduction of In(III) to In(I) and for the existence of In(NH3)2F and InF as products of the ammonolysis of (NH4)3InF6. 相似文献
7.
Highly crystalline niobium- and tantalum-based oxynitride perovskite nanoparticles were obtained from hydrothermally synthesized oxide precursors by thermal ammonolysis at different temperatures. The samples were studied with respect to their morphological, optical and thermal properties as well as their photocatalytic activity in the decomposition of methyl orange. Phase pure oxynitrides were obtained at rather low ammonolysis temperatures between 740 °C (CaNbO2N) and 1000 °C (BaTaO2N). Particle sizes were found to be in the range 27 nm–146 nm and large specific surface areas up to 37 m2 g−1 were observed. High photocatalytic activities were found for CaNbO2N and SrNbO2N prepared at low ammonolysis temperatures. CoOx as co-catalyst was loaded on the oxynitride particles resulting in a strong increase of the photocatalytic activities up to 30% methyl orange degradation within 3 h for SrNbO2N:CoOx. 相似文献
8.
《Journal of Coordination Chemistry》2012,65(2):71-75
Abstract Crystals of the adduct titanium tetrachloride-ethylcyanoformate (1–1) are monoclinic a =9.06 Å, b =18.36 Å, c =13.83 Å, β =113°.2, space group C2/c, Z =8. The structure was solved by application of X-Ray diffraction techniques at room temperature. Atomic positions were refined by a full-matrix least-squares method to a final R of 0.049 using 829 non-zero independent reflections. This compound is dimeric with a double chlorine bridge between titanium atoms. Titanium is octahedrally coordinated to five chlorine atoms and to the nitrogen atom of the nitrile group and not to the oxygen atom of the carbonyl group. Thus in this complex the nitrogen atom is a better donor than the carbonyl oxygen. 相似文献
9.
10.
Jinwang Li Dmytro Dzivenko Andreas Zerr Claudia Fasel Yanping Zhou Ralf Riedel 《无机化学与普通化学杂志》2005,631(8):1449-1455
A simple process to synthesize Zr3N4 and nitrogen‐rich Hf3N4 powders via ammonolysis of metal dialkylamides, i.e. Zr(NEt2)4 and Hf(NEt2)4, at temperatures below 700 °C is presented. The obtained nitrides have a rhombohedrally distorted NaCl‐type structure, which has previously been reported only for nitrogen‐rich films of these nitrides. Regardless of the atmosphere (N2 and He), the Zr3N4 starts to decompose above about ~ 650 °C and achieves the highest decomposition rate at about 900 °C, finally yielding the mononitride ZrN. Both Zr3N4 and Hf3N4 powders are nanocrystalline with the crystal size of about 2 nm. 相似文献