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71.
72.
M. Valkeapää Y. Katsumata T. Motohashi R.S. Liu H. Yamauchi 《Journal of solid state chemistry》2007,180(5):1608-1615
A comparative study on the oxidation and charge compensation in the AxCoO2−δ systems, A=Na (x=0.75, 0.47, 0.36, 0.12) and Li (x=1, 0.49, 0.05), using X-ray absorption spectroscopy at O 1s and Co 2p edges is reported. Both the O 1s and Co 2p XANES results show that upon removal of alkali metal from AxCoO2−δ the valence of cobalt increases more in LixCoO2−δ than in NaxCoO2−δ. In addition, the data of O 1s XANES indicate that charge compensation by oxygen is more pronounced in NaxCoO2−δ than in LixCoO2−δ. 相似文献
73.
Cássia Maria L. da Silva 《Talanta》2007,73(4):613-620
In this work, a flow injection system with spectrophotometric detection was developed for the determination of lithium in pharmaceutical formulations used in the treatment of bipolar disorder. Reaction between Quinizarine (1,4-dihydroxyanthraquinone) and Li(I) ion in alkaline medium containing dimethylsulfoxide (DMSO) was explored for this purpose. The flow system was optimized regarding to its chemical (DMSO, Quinizarine and NaOH concentrations and sample pH) and physical parameters (sample loop volume, carrier flow rate and reactor length) in order to establish better conditions in terms of sensitivity and sampling frequency. The results obtained showed that the concentration of DMSO in the reagent solution presents remarkable influence on the magnitude of analytical signal. Chemical species that could be found in the formulations such as Na(I), K(I), Mg(II), Ca(II), Ti(IV), Cl−, CO32− e sodium dodecylsulfate were tested as possible interfering ions. Among them, only non-monovalent cations presented noticeable interference on lithium signal. However, they were not found in concentrations high enough to cause interference in the determination of lithium in the samples. Sample preparation was performed by sonicating a slurry prepared by dispersing 100 mg of powdered sample in 15 mL of 0.10 mol L−1 HCl solution. Results obtained by developed methodology were not statistically different from those obtained by flame emission spectrometry. In the optimized conditions the method presented a linear range of 5-40 mg L−1 and a relative standard deviation of 3.6% at 5 mg L−1 Li concentration. Detection and quantification limits were 0.54 and 1.8 mg L−1, respectively. Sampling frequency, calculated as the time interval passed between two consecutive injections, was 60 samples per hour. The methodology was successfully applied in the determination of lithium in three commercial samples. 相似文献
74.
75.
J. Doménech E. Brillas J. A. Garrido R. M. Rodríguez 《Monatshefte für Chemie / Chemical Monthly》1987,118(2):197-202
Viscosities and densities of lithium perchlorate solutions in different ethylene glycol-water compositions have been measured at 25.0 and 35.0 °C. From these data, the correspondingB-coefficients of theJones-Dole equation have been determined. TheB-value depends on the solvent composition and it reaches a maximum in the water-rich region. This behaviour is analysed in terms of ionic solvation and solvent structure.
Viskositäts-B-Koeffizienten für Lösungen von Lithiumperchlorat in Ethylenglykol-Wasser-Mischungen
Zusammenfassung Es wurden die Dichten und Viskositäten für Lösungen von Lithiumperchlorat in verschieden zusammengesetzten Ethylenglykol-Wasser-Mischungen bei 25 °C und 35 °C gemessen. Auf Grund der erhaltenen Daten wurden dieB-Koeffizienten in den entsprechendenJones-Dole-Gleichungen für die relative Viskosität bestimmt. DieB-Werte hängen von der Zusammensetzung des Lösungsmittels ab und erreichen im wasserreichen Konzentrationsgebiet ein Maximum. Dieses Verhalten wird in Hinblick auf die Ionensolvatation und die Struktur des Lösungsmittels analysiert.相似文献
76.
The reduction of prochiral ketones using chiral reducing reagents, prepared from lithium aluminum hydride and (-)-(1R, 2S, 3S, 5R)-10-anilinopinanediol (5) and (-)-(1R, 2S, 3S, 5R)-10-N-methylanilinopinanediol (6), affords chiral secondary alcohols in useful chemical yields (70 ~ 93%) but in low optical purity (8 ~ 33% ee). Modifiers 5 and 6 are synthesized from (lR)-(-)-β-pinene in three steps. 相似文献
77.
Debprasad Patra Poulami Pattanayak Jahar Lal Pratihar Surajit Chattopadhyay 《Polyhedron》2007,26(18):5484-5490
The reactions of HL 1 [where HL is 1N-(2-pyridyl-2-methyl)-2-arylazoaniline and is formulated as ArN = NC6H4N(H)(CH2C5H4N); Ar = C6H5 (for HL1) or p-MeC6H4 (for HL2) or p-ClC6H4 (for HL3)] with K2PtCl4 and Co(ClO4)3 · 6H2O afforded the (L)PtCl and [(L)2Co]ClO4 complexes, respectively. The HL ligands bind the platinum(II) and cobalt(III) centres in a tridentate (N,N,N) fashion, forming new diazoketiminato chelates upon dissociating the amino proton. The X-ray structures of (L3)PtCl and [(L3)2Co]ClO4 were determined. Redox properties of the new complexes have been examined. 相似文献
78.
J. L. Gautier E. Meza E. Silva C. Lamas C. Silva 《Journal of Solid State Electrochemistry》1997,1(2):126-133
The electrochemical insertion of lithium in the spinel-type manganite with the formula ZnNi
y
Mn2–
y
O4 has been studied. The galvanostatic discharge curves show that the best performance is obtained for y = 0.25, where a tetragonal to cubic structural transformation occurs. The thermodynamics and kinetics of the process of insertion
of the lithium into the tetragonal spinel Li
x
ZnNi0.25Mn1.75O4 (x = 0.05–1.3) have been studied. The molar thermodynamic quantities, such as enthalpy, entropy and free energy determined by
EMF-T measurements, varied with the lithium concentration in the oxide structure, and a major variation was observed around
x = 0.8. The chemical diffusion coefficient of lithium in these spinels was also determined. Structural analysis, degree of
oxidation and magnetic susceptibility measurements were carried out for the lithiated oxides in order to obtain the cationic
distribution as a function of x. It has been possible to demonstrate that, upon lithium insertion, Mn4+ ions on B sites are reduced to Mn3+ and then to Mn2+. A cooperative Jahn-Teller effect is present in these spinel manganese-nickel oxides.
Received: 4 February 1997 / Accepted: 11 April 1997 相似文献
79.
F. Schaller W. Schwarz H.-D. Hausen K. W. Klinkhammer J. Weidlein 《无机化学与普通化学杂志》1997,623(9):1455-1466
Base-free Tris(trimethylsilyl)methyl Derivatives of Lithium, Aluminium, Gallium, and Indium Base-free LiR* (R*=-C(SiMe3)3) has been prepared from R*Cl and Li-metal in toluene at 85?90°C and used to synthesize the metallanes R*MMe2 with M = Al, Ga and In, respectively. The NMR (1H, 13C, 29Si) and the vibrational spectra of these trisyl compounds have been discussed. AlCl3 and LiR*(ratio 1 : 1) forms the metallate metallate Li[R*AlCl3]. The triclinic unit cell (space group P1 ) consists of a centrosymmetric assoziate, formed by four Li[R*AlCl3]- units with Al? Cl…?Li bridges, two pairs of Li-atoms differing in their chlorine-coordination and two disordered toluene molecules, inserted in the crystal lattice (R1wR2 =0,0444/0,1072). The reaction of GaCl3 with LiR* (I :1) gives the unusual sesquichloride (R*Ga(Cl1,33)Me0,67)3 in moderate yield. The X-ray structure determination shows a Ga3Cl3-skeleton with chairconformation and disordered, terminal gallium ligands (R1/wR2= 0,0646/0,2270). 相似文献
80.
稀土高氯酸盐开环冠醚三缩乙二醇(EO_3)[La(C_6H_(14)O_4)_3(H_2O)](ClO_4)_3·H_2O,单斜晶系,P2_1/c空间群。晶胞参数为:a=15.474(2),b=11.386(1),c=20.841(4),β=99.82(1)°,V=3618(1),MoKα,Z=4,D_c=1.718g/cm3,μ=1.499mm ̄(-1)。全矩阵最小二乘精细修正,结构因子R=0.056,R_w=0.083。中心原子La与开环冠醚醚链上的O(1)~O(9)及一个水分子形成10配位双帽四方反棱柱结构。弱配体高氯酸根不参加配位。 相似文献