共查询到20条相似文献,搜索用时 62 毫秒
1.
V. I. Pet’kov I. A. Shchelokov E. A. Asabina V. S. Kurazhkovskaya D. A. Rusakov K. V. Pokholok B. I. Lazoryak 《Russian Journal of Inorganic Chemistry》2006,51(12):1855-1863
New complex phosphates of titanium, iron, and alkaline-earth metals have been synthesized. X-ray powder diffraction, differential thermal analysis (DTA), and IR spectroscopy are used to study phase formation in the series of M0.5(1+x)FexTi2?x (PO4)3 (M = Mg, Ca, Sr, Ba) phosphates. Individual compounds and solid solutions are found to crystallize in the NaZr2(PO4)3 and K2Mg2(SO4)3 structure types. Their crystal parameters are calculated. CaFeTi(PO4)3 is studied using Mössbauer spectroscopy. Its structure is refined by the Rietveld method: space group $R\bar 3$ c, Z = 6, a = 8.5172(1), Å, c = 21.7739(4) Å, V = 1367.91(4) Å3. 相似文献
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L. S. Aladko 《Russian Journal of General Chemistry》2014,84(6):1065-1068
The phase diagram of the binary system tetramethylammonium bromide-water was studied by the differential thermal analysis. In the stable region two phases, ice and the salt itself, were detected, and in the metastable region, three tetramethylammonium bromide hydrates (bromide-water, 1 : 4, mp 68.8°C, 1 : 5, mp 36.0°C, 1 : 7.5, mp ?19.5°C) were found. Formation of (C x H2x+1)4NBr·nH2O (x = 1–3, n = 4, 5, 7.5) hydrates was revealed. 相似文献
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V. I. Pet’kov I. A. Shchelokov V. S. Kurazhkovskaya N. V. Orekhova M. M. Ermilova G. F. Tereshchenko 《Russian Journal of Inorganic Chemistry》2008,53(7):993-999
Complex phosphates of titanium, chromium, and metals(2+) of the general formula M0.5(1 + x )Cr x Ti2 ? x (PO4)3 (M = Mg, Ca, Mn, Ni, Sr, Ba, and Pb) were synthesized. Their phase formation was studied by means of X-ray powder diffraction, electron probe microanalysis, differential thermal analysis, and IR spectroscopy. Individual phases and solid solutions crystallizing in kosnarite and langbeinite structure types were identified; their crystallographic parameters were calculated. The catalytic properties of phosphates Ca0.5(1 + x )Cr x Ti2 ? x (PO4)3 in methanol conversion were studied. 相似文献
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Villafuerte-Castrejón ME García-Guaderrama M Fuentes L Prado-Gonjal J González AM de la Rubia MÁ García-Hernández M Morán E 《Inorganic chemistry》2011,50(17):8340-8347
In this work, the sol-gel synthesis, structural characterization, and transport properties of a new solid solution of the general formula La(x)Bi(1-x)Fe(0.5)Cr(0.5)O(3) (0.4 ≤ x ≤ 1) are presented. The solubility limit x has been determined and variation of the lattice parameters measured through profile fitting. The cell parameters, space group, and atomic positions, as obtained by the Rietveld refinement of X-ray diffraction data, are reported. This analysis and electron diffraction studies as well do not reveal any evidence of Fe/Cr ordering. Regarding the transport properties, magnetic and electric characterizations are described. The electrical response with the temperature and frequency has been studied, and a "positive temperature coefficient" for the resistivity has been found for temperatures between 270 and 400 °C. The magnetic behavior is striking because, for all materials studied, zero-field-cooling curves appear above field-cooling ones, an anomalous feature that is interpreted as being due to complex ferromagnetic/antiferromagnetic interactions in the B perovskite sublattice. 相似文献
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V. N. Krasil’nikov O. I. Gyrdasova I. V. Baklanova L. Yu. Buldakova M. Yu. Yanchenko R. F. Samigullina O. V. Koryakova 《Russian Journal of Inorganic Chemistry》2013,58(2):120-126
Quasi-one-dimensional (1D) solid solutions Ti1 ? x Fe x (OCH2CH2O)2 ? x/2 (0 < x ≤ 0.1) with the structure of anatase were prepared by heating the glycolate Ti1 ? x Fe x (OCH2CH2O)2 ? x/2 in an atmosphere of air at a temperature of >450°C. The conditions of formation and the properties of the new glycolate Ti3Fe2(OCH2CH2O)9 were described. It was found that the synthesized Ti1 ? x Fe x O2 ? 2x/2 solid solutions exhibit photocatalytic activity in the reaction of hydroquinone oxidation in an aqueous solution on irradiation with UV light. A correlation between the rate of oxidation of hydroquinone and the concentration of iron in the catalyst was established. A procedure for the preparation of titanium dioxide with the structure of anatase doped with iron and carbon (Ti1 ? x Fe x O(2 ? x/2) ? yCy) and also composites on its basis, which contain an excess amount of carbon, was proposed. 相似文献
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Hoel CA Amores JM Morán E Alario-Franco MA Gaillard JF Poeppelmeier KR 《Journal of the American Chemical Society》2010,132(46):16479-16487
The corundum-type In(2-2x)Zn(x)Sn(x)O(3) solid solution (cor-ZITO, x ≤ 0.7) was synthesized at 1000 °C under a high pressure of 70 kbar. cor-ZITO is a high-pressure polymorph of the transparent conducting oxide bixbyite-In(2-2x)Zn(x)Sn(x)O(3) (x ≤ 0.4). Analysis of the extended X-ray absorption fine structure suggests that significant face-sharing of Zn and Sn octahedra occurs, as expected for the corundum structure type. In contrast to the ideal corundum structure, however, Zn and Sn are displaced and form oxygen bonds with lengths that are similar to those observed in high-pressure ZnSnO(3). Powder X-ray diffraction patterns of cor-ZITO showed the expected unit cell contraction with increased cosubstitution, but no evidence for ilmenite-type ordering of the substituted Zn and Sn. A qualitative second harmonic generation measurement, for the solid solution x = 0.6 and using 1064 nm radiation, showed that Zn and Sn adopt a polar LiNbO(3)-type arrangement. 相似文献
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《分子科学学报》2020,(3)
采用B3LYP和BP86方法,对铁羰基衍生物Fe(CO)_3(PR_3)_2和Fe(CO)_2(PR_3)_3(R=Cy,OPh和Ph)的几何和电子结构、成键特点以及热力学稳定性等进行了理论研究.计算结果表明,Fe(CO)_3(PR_3)_2的基态结构都为三角双锥的轴向双取代;对于Fe(CO)_2(PR_3)_3来说,三角双锥的腰部三取代(D_(3h))和腰部+轴向双取代(C_(2v))结构能量差别非常小.自然键轨道(NBO)分析显示,膦配体向羰基铁基团存在电荷转移,使得Fe—CO之间的共价作用有效增强.含膦配体铁羰基化合物Fe(CO)_3(PR_3)_2的第一膦配体解离能比第一羰基解离能低,预示Fe(CO)_3(PR_3)_2的反应活性比Fe(CO)_5有明显提高. 相似文献
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O. G. Shakirova L. G. Lavrenova Yu. G. Shvedenkov V. N. Ikorskii V. A. Varnek L. A. Sheludyakova V. L. Varand T. A. Krieger S. V. Larionov 《Journal of Structural Chemistry》2000,41(5):790-797
The reaction of Fe(NO
3
)
2
, trz, and atrz in ethanol–water gave solid Fe(trz)
3x
(atrz)
3-3x
(NO
3
)
2
·H
2
O
(x = 0.1, 0.2, 0.4, 0.8). The solids were investigated by magnetic chemistry, X-ray diffraction, photoelectron (DRS), IR, and Mössbauer spectroscopy methods. The individual Fe(trz)3(NO3)2 and Fe(atrz)3(NO3)2 as well as the solid phases exhibit a reversible spin crossover 1
, whose temperature and character depend on the phase composition. Due to this, T
c
may be changed by introducing another ligand into the complex exhibiting a spin crossover effect. 相似文献
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采用水热法制备了系列富锂尖晶石型正极材料Li2+4xMn0.6+2xNi0.6-6xCr0.8O4(x=1/30,1/20,1/15,1/12),通过X射线衍射(XRD)、电感耦合等离子体-原子发射光谱(ICP-AES)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、傅里叶变换红外光谱(FTIR)、拉曼光谱、循环伏安(CV)和充放电测试等手段对其结构及电化学性能进行表征.结果表明,所制备的系列材料为富锂型高电压尖晶石结构正极材料,该系列样品在4.7 V左右有放电平台.x=1/15和x=1/12时,样品中的Cr为+3价,没有观测到Cr6+.随着x值的增大,样品中Li离子与过渡金属离子的混排减小,样品的充放电比容量逐渐增大,且2.7 V处的放电平台容量也增加.当x=1/12时,样品具有较好的充放电比容量和倍率特性,首次放电比容量为107.3 mA·h/g,20次循环后容量保持率为84.9%. 相似文献
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在pH 2~3的溶液中,低浓度Fe^2+与K3[Fe(CN)6]反应产生的蓝色沉淀为近似真溶液,最大吸收波长为710 nm.形成的近似真溶液吸光度随静置时间变化而逐渐变大,30 min后吸光度变化缓慢.K3[Fe(CN)6]过量时,Fe^2+浓度与吸光度呈很好的线性关系.Fe^2+浓度较大时,易形成絮状沉淀.在pH 2~3的Fe^3+-K3[Fe(CN)6]体系中,加入Vc能将Fe^3+还原成Fe^2+,进而与K3[Fe(CN)6]反应,30 min后测定蓝色拟真溶液的吸光度,Vc的量与溶液的吸光度同样有很好的线性关系,线性相关系数R〉0.999,检出限为0.94μg. 相似文献
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Takao M. Kojima Nobuo Kobayashi Yozaburo Kaneko 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1992,23(2):181-185
The formation of cluster ions when hydrogen molecular ions H 2 + and H 3 + are injected into a drift tube filled with helium gas at 4.4 K has been investigated. When H 2 + ions are injected, cluster ions HHe x + (x≦14) are produced. No production of H2He x + ions is observed. When H 3 + ions are injected, cluster ions HHe x + (x≦14) are produced as well as H3He x + (x≦13), and very small signals corresponding to H2He x + (3≦x≦10) are observed. Information on the stability of HHe x + and H3He x + is derived from the drift field dependence of the cluster size distributions. The cluster sizex=13 is found to be a magic number for HHe x + , and for H3He x + ,x=10 and 11. 相似文献
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Pet’kov V. I. Shipilov A. S. Fukina D. G. Stenina I. A. Yaroslavtsev A. B. 《Russian Journal of Electrochemistry》2021,57(4):388-394
Russian Journal of Electrochemistry - Vanadate phosphates LiZr2(VO4)x(PO4)3 – x are synthesized by the sol-gel technique with subsequent annealing and studied using X-ray diffraction... 相似文献
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利用喷雾干燥法合成了富锂三元正极材料Li1.2Mn0.4+xNixCr0.4-2xO2(x=0,0.05,0.10,0.15,0.20,以下简称为SD1~SD5),并利用XRD,XPS,ICP,TEM,SEM等手段对材料进行结构,元素价态,形貌及电化学性能等方面的表征。SD1~SD5系列样品都具有层状结构,其所含的Cr元素为Cr6+和Cr3+共存,而Ni元素价态为+2.5价,Mn元素为+4价。SD1~SD4样品中由于存在非晶态的Li2CrO4,导致样品表现出强烈的吸湿性。这个问题可通过水洗处理来解决,且水洗处理对于改善该系列材料的电化学性能有明显的效果。SD1~SD5系列样品中,SD1与SD4样品电化学性能较好,以20 mA.g-1的放电电流密度,在4.8~2.0 V电压区间内,首次放电比容量分别为247和220 mA.h.g-1,经过20次充放电循环后,容量保持率分别为73%和78%。高温条件下SD1和SD4样品的首次放电比容量分别增大为256和237 mA.h.g-1,经过20次充放电循环后容量保持率分别为83%和99%。将充放电电压扩展为5.0~2.0 V时,SD4样品首次放电比容量可以达到307 mA.h.g-1。 相似文献
17.
Inhibitory effect of H_(3 + x)PMo_(12-x)V_xO_(40)-Ton the self-polymerization of methyl methacrylate
Yan-Bing Yin Hui-Song Wang Yu-Lin Yang Rui-Qing Fan Guo-Hua Dong Li-Guo Wei 《中国化学快报》2016,27(4):613-618
In this work,a series of molybdovanadophosphoric heteropoly acid quaternary ammonium salts H_(3+x)PMo_(12 -x)V_xO40-T were synthesized and employed as a reaction inhibitor in the selfpolymerization of methyl methacrylate(MMA).The polymerization inhibition effect of H_(3+x)PMoPMo_(12 -x)V_xO40-T)with different number of vanadium atoms and reaction dosages was investigated using differential scanning calorimetry(DSC).It shows that the inhibitory effect was improved with the increasing dosages of H_(3+x)PMoPMo_(12 -x)V_xO40-T),and the polymerization inhibition was also affected by the number of vanadium atoms in the H_(3+x)PMo_(12 -x)V_xO40-T .Furthermore,cyclic voltammograms(CV)was used to probe the mechanism of the inhibition reaction with H3+xPMo12xVxO40-T.The result of CV indicates that the inhibition reaction is an oxidation–reduction reaction.H_(3+x)PMo_(12 -x)V_xO40-T can react directly with the MMA monomer radicals,which eliminated the MMA monomers,and therefore the self-polymerization of the MMA can be effectively inhibited by H_(3+x)PMo_(12 -x)V_xO40-T. 相似文献
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