共查询到20条相似文献,搜索用时 15 毫秒
1.
S. I. Pechenyuk L. F. Kuz'mich E. V. Kalinkina S. I. Matveenko 《Russian Chemical Bulletin》1998,47(4):560-565
The influence of the pH of precipitation (pH1) and the ionic medium on the sorption properties of as-precipitated samarium(III) oxohydroxides,i.e., the pH of zero charge point and the rate of heterogeneous hydrolysis of the IrCl6
2−, RhCl6
3−, and PtCl4
2− complexes, was studied. The composition of precipitates was studied by the drop titration of solutions of samarium nitrate
and thermography. It was found that as-predipitated samarium oxohydroxides are amorphous and the substitution of NO3
− ions by OH− is not complete even at pH1 11. Heterogeneous hydrolysis occurs on the surface of samarium oxohydroxide, and its rate increases with increasing pH1. The as-precipitated samarium oxohydroxides have much higher sorption activities than crystalline Sm2O3, and their activities are similar to those of ferrogels.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 583–588, April, 1998. 相似文献
2.
Genovaitė Valiulienė Albina Žielienė Birutė Šimkūnaitė Leonas Naruškevičius Loreta Tamašauskaitė Tamašiūnaitė Vidas Pakštas Algis Selskis 《Journal of Solid State Electrochemistry》2010,14(2):203-212
The electrochemical behavior of Bi2S3 coatings in Watts nickel plating electrolyte was investigated using the cyclic voltammetry, electrochemical quartz crystal
microbalance, X-ray diffraction, and energy dispersive X-ray analysis methods. During the bismuth sulfide coating reduction
in Watts background electrolyte in the potential region from −0.4 to −0.6 V, the Bi2S3 and Bi(III) oxygen compounds are reduced to metallic Bi, and the decrease in coating mass is related to the transfer of S2− ions from the electrode surface. When the bismuth sulfide coating is reduced in Watts nickel plating electrolyte, the observed
increase in coating mass in the potential region −0.1 to −0.4 V is conditioned by Ni2+ ions reduction before the bulk deposition of Ni, initiated by Bi2S3. In this potential region, the reduction of Bi(III) oxygen compounds can occur. After the treatment of as-deposited bismuth
sulfide coating in nickel plating electrolyte at E = −0.3 V, the sheet resistance of the layer decreases from 1013 to 500–700 Ω cm. A metal-rich mixed sulfide Ni3Bi2S2–parkerite is obtained when as-deposited bismuth sulfide coating is treated in Watts nickel plating electrolyte at a potential
close to the equilibrium potential of the Ni/Ni2+ system and then annealed at temperatures higher than 120 °C. 相似文献
3.
Joan Gregori David Gimenez-Romero Jose Juan Garcia-Jareño Francisco Vicente 《Journal of Solid State Electrochemistry》2006,10(11):920-928
A kinetic analysis of the electrochemical impedance spectra for nickel electrodissolution in an acid medium based on the characteristic points of the faradaic impedance function has been performed when chloride ions are present in the acid medium. Moreover, the obtained results are compared with the event when chloride ions are not present in the acid medium. Chloride ions cause a decrease in both Γ1 and Γ2 surface concentration assuming a two consecutive electron transfer mechanisms, Ni(0) → Ni(I) + e− → Ni(II) + e−, followed by a dissolution process, Ni(II) → Ni2+
aq. An increase of the pH favors the formation of a Ni(OH)2 passive layer that impedes to distinguish clearly between both electron transfers from electrochemical impedance results. 相似文献
4.
B. G. Ershov 《Russian Chemical Bulletin》2000,49(10):1715-1721
Radiation-chemical reduction of Ni2+ ions in aqueous solutions of Ni(ClO4)2 containing sodium formate or isopropyl alcohol was studied, γ-Irradiation of deaerated solutions in the presence of polyethyleneimine,
polyacrylate, or polyvinyl sulfate gives stable metal sols containing spherical particles 2–4 nm in diameter. The optical
absorption spectra of nickel nanoparticles exhibit a band with a maximum at 215±5 nm (ε215=4.7·103 L mol−1 cm−1) and a shoulder at 350 nm. A mechanism for the radiation-chemical reduction of Ni2+ ions by hydrated electrons and organic radicals (CO2- radical anions in the case of HCOONa and Me2C·OH radicals in the case of PriOH). The redox potentials of the Ni2+/Ni0 and Ni+/Ni0 pairs (Ni0 is a nickel atom) are approximately −2.2 and −1.7 V, respectively. The nanoparticles are readily oxidized by O2, H2O2, and other oxidants. The reactions of these species with silver ions yield relatively stable nanoaggregates containing both
nickel and silver in addition to silver nanoparticles.
Published inIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 10, pp. 1733–1739, October, 2000. 相似文献
5.
The overpotential of nickel ion electroreduction on the nickel and mercury electrodes is shown to increase in the following
sequence of anions: ClO4−,CH3SO3−, SO42−. On the nickel electrode, the overpotential of nickel evolution decreases as the pHv increases from 1.5 to 4. This is associated with the increase in pHs as the result of a parallel reaction of hydrogen evolution. It is shown that in contrast to mercury, the Tafel plots of the
nickel electrode demonstrate a bend corresponding to the change in their slope from −0.044 to −0.132 V. This is accompanied
by the lowering down of the reaction order in nickel ions from 2 to 1. A mechanism of nickel ion electroreduction that includes
two parallel routes is proposed and substantiated by a model. In the low overpotential range, the predominant process is the
electroreduction of nickel hydroxocomplexes, which is characterized by the strong dependence of the reaction rate on the potential
and the concentration of electroactive species. For high overpotentials, the predominant process is the direct discharge of
nickel aquacomplexes the rate of which depends weaker on the potential and the concentration of electroactive species. 相似文献
6.
M. M. Degtyarik A. S. Lyakhov O. A. Ivashkevich Yu. V. Grigoriev 《Russian Journal of Coordination Chemistry》2012,38(2):77-85
The reactions of Co(II), Ni(II), and Cu(II) chlorides and bromides and their metallic powders with tetrazol-1-yl-tris(hydroxymethyl)methane
(L) afforded new complexes ML2Hal2 · mH2O(M = Co(II) or Ni(II), Hal = Cl−; M = Cu(II), Hal = Cl− or Br−, m = 0; and M = Co(II) or Ni(II), Hal = Br−, m = 2), MLnCl2 (M = Co(II) or Ni(II), n = 2 or 4; M = Cu(II), n = 2), and MLnBr2 · mH2O (M = Ni(II), n = 2, m = 2; M = Cu(II), n = 2, m = 0). The compositions and structures of the synthesized complexes were determined by elemental analysis, IR spectroscopy
(50–4000 cm−1), and X-ray diffraction analysis. The introduction of a bulky substituent into position 1 of the tetrazole cycle was shown
to exert almost no effect on the coordination mode but affected the composition and structure of the complexes. 相似文献
7.
Pritha Talukder Shyamapada Shit Heinrich N?th Matthias Westerhausen Alexander Nikolai Kneifel Samiran Mitra 《Transition Metal Chemistry》2012,37(1):71-77
A heterobimetallic cyano-bridged 1D coordination polymer of the composition [Ni(baepn)(μ-NC)Fe(CN)3(NO)(μ-CN)]n·3H2O has been synthesized by the reaction of nickel(II) nitrate hexahydrate, baepn (baepn = N, N′-bis(2-aminoethyl)-1,3-propanediamine), and sodium nitroprusside dihydrate in a methanol–water mixture. The complex was characterized
by physicochemical and spectroscopic methods. The crystal structure was established by single-crystal X-ray diffraction analysis.
It reveals cyano-bridged heterometallic chains consisting of alternating arrays of Ni(II) and Fe(II) atoms, both being embedded
in distorted octahedral environments. Low-temperature susceptibility measurements show the presence of weak antiferromagnetic
exchange interactions between paramagnetic Ni(II) centers (J = −0.46 cm−1) through long diamagnetic [Fe(CN)5(NO)]2− bridges. Spin state of the iron atom was established by 57Fe M?ssbauer spectroscopy. 相似文献
8.
A study of the electrochemistry of uranium in LiF–BeF2 system important for molten salt reactor concept was conducted at W and Ni electrodes. Cyclic voltammetry and chronopotentiometry
methods were used. Two-step reduction mechanism for U4+ ions involving one electron exchange in soluble/soluble U4+/U3+ system and three electron exchange in the second step were found on W electrode. Both processes were identified as reversible
and diffusion-controlled. Based on voltammetric and chronopotentiometric measurements, the diffusion coefficient of U4+ ions at 813 K was calculated: D(U4+) = 1.26 × 10−6 cm2 s−1 and D(U4+) = 1.28 × 10−6 cm2 s−1, respectively. Formation of U–Ni alloys was observed on Ni electrode. 相似文献
9.
Predrag Djurdjevi? Ratomir Jeli? Ljubinka Joksovi? Mirjana Cvijovi? 《Monatshefte für Chemie / Chemical Monthly》2006,12(2):717-735
Solution equilibria between aluminium(III) ion and L-aspartic acid were studied by potentiometric, 27Al, 13C, and 1H NMR measurements. Glass electrode equilibrium potentiometric studies were performed on solutions with ligand to metal concentration
ratios 1:1, 3:1, and 5:1 with the total metal concentration ranging from 0.5 to 5.0 mmol/dm3 in 0.1 mol/dm3 LiCl ionic medium, at 298 K. The pH of the solutions was varied from ca. 2.0 to 5.0. The non-linear least squares treatment of the data performed with the aid of the Hyperquad program, indicated
the formation of the following complexes with the respective stability constants log βp,q,r given in parenthesis (p, q, r are stoichiometric indices for metal, ligand, and proton, respectively): Al(HAsp)2+ (log β1,1,1 = 11.90 ± 0.02); Al(Asp)+ (log β1,1,0 = 7.90 ± 0.03); Al(OH)Asp0 (log β1,1,−1 = 3.32 ± 0.04); Al(OH)2Asp− (log β1,1−2 = −1.74 ± 0.08), and Al2(OH) Asp3+ (log β2,1,−1 = 6.30 ± 0.04). 27Al NMR spectra of Al3+ + aspartic acid solutions (pH 3.85) indicate that sharp symmetric resonance at δ∼10 ppm can be assigned to (1, 1, 0) complex. This resonance increases
in intensity and slightly broadens upon further increasing the pH. In Al(Asp)+ complex the aspartate is bound tridentately to aluminum. The 1H and 13C NMR spectra of aluminium + aspartic acid solutions at pH 2.5 and 3.0 indicate that β-methylene group undergoes the most pronounced changes upon coordination of aluminum as well as
α-carboxylate group in 13C NMR spectrum. Thus, in Al(HAsp)2+ which is the main complex in this pH interval the aspartic acid acts as a bidentate ligand with –COO− and –NH2 donors closing a five-membered ring. 相似文献
10.
N. A. Sanina N. S. Emel’yanova A. N. Chekhlov A. F. Shestakov I. V. Sulimenkov S. M. Aldoshin 《Russian Chemical Bulletin》2010,59(6):1126-1136
Dinuclear iron tetranitrosyl complex with the composition [Fe2(SPh)2(NO)4] (1) was synthesized and its single crystals and polycrystals were studied by X-ray diffraction, IR spectroscopy, and elemental
analysis. The decomposition products of complex 1 were investigated by electrochemical method and mass spectrometry. The mass spectrum of a solution of complex 1 shows two groups of ions: the primary decomposition products of 1 in solution (the complex ions [Fe(SPh)(NO)2(NO2)]−, [Fe(SPh)2(NO)]−, and [Fe(SPh)2(NO)2]−) and a series of the ions [FeO2 + n(NO)]− and [FeO3 + n(NO)]− (n = 0–4), which are formed in secondary reactions. The structures of the complexes, which were formed through the Fe-NO bond
dissociation and the replacement of the NO ligand by aqua and oxygen ligands in complex 1, and the structure of the complex [FeO3]− were studied by quantum chemical modeling. 相似文献
11.
Predrag Djurdjević Ratomir Jelić Ljubinka Joksović Mirjana Cvijović 《Monatshefte für Chemie / Chemical Monthly》2006,137(6):717-735
Summary. Solution equilibria between aluminium(III) ion and L-aspartic acid were studied by potentiometric, 27Al, 13C, and 1H NMR measurements. Glass electrode equilibrium potentiometric studies were performed on solutions with ligand to metal concentration
ratios 1:1, 3:1, and 5:1 with the total metal concentration ranging from 0.5 to 5.0 mmol/dm3 in 0.1 mol/dm3 LiCl ionic medium, at 298 K. The pH of the solutions was varied from ca. 2.0 to 5.0. The non-linear least squares treatment of the data performed with the aid of the Hyperquad program, indicated
the formation of the following complexes with the respective stability constants log βp,q,r given in parenthesis (p, q, r are stoichiometric indices for metal, ligand, and proton, respectively): Al(HAsp)2+ (log β1,1,1 = 11.90 ± 0.02); Al(Asp)+ (log β1,1,0 = 7.90 ± 0.03); Al(OH)Asp0 (log β1,1,−1 = 3.32 ± 0.04); Al(OH)2Asp− (log β1,1−2 = −1.74 ± 0.08), and Al2(OH) Asp3+ (log β2,1,−1 = 6.30 ± 0.04). 27Al NMR spectra of Al3+ + aspartic acid solutions (pH 3.85) indicate that sharp symmetric resonance at δ∼10 ppm can be assigned to (1, 1, 0) complex. This resonance increases
in intensity and slightly broadens upon further increasing the pH. In Al(Asp)+ complex the aspartate is bound tridentately to aluminum. The 1H and 13C NMR spectra of aluminium + aspartic acid solutions at pH 2.5 and 3.0 indicate that β-methylene group undergoes the most pronounced changes upon coordination of aluminum as well as
α-carboxylate group in 13C NMR spectrum. Thus, in Al(HAsp)2+ which is the main complex in this pH interval the aspartic acid acts as a bidentate ligand with –COO− and –NH2 donors closing a five-membered ring. 相似文献
12.
M. V. Muftakhov R. V. Khatymov V. A. Mazunov V. N. Odinokov I. V. Galyautdinov 《Russian Chemical Bulletin》2000,49(4):713-716
The peculiarities of dissociative electron capture by 20-hydroxyecdysone molecules with the formation of fragment negative
ions were studied. In the region of high electron energies (5–10 eV), processes of skeleton bond rupture are accompanied by
the elimination of H2O and H2 molecules. In the region of thermal energies of electrons (≈0 eV), the mass spectrum is formed mainly by the [M−nH2O].− (n=1–3) and [M−H2−nH2O].− (n=0−3) ions that are generated exclusively by the rearrangement.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 709–712, April, 2000. 相似文献
13.
The kinetics of the oxidation of nickel (II) hexaaza and nickel (II) pentaaza macrocycles by the peroxydisulphate anion, S2O8
2−, were studied in aqueous media. Effect of pH on reaction rate was also studied. The rate increases with increase of S2O8
2− concentration. Rates are almost independent of acid betweenpH 4 and 2, giving overall a relatively simple second-order rate law followed by oxidation within the ion pair solvent shell.
Using rate =+1/2 d[Ni(L)3+]/dt =k[Ni(L)2+][S2O8
2−], oxidation rate constants were determined. 相似文献
14.
The heats of dissolution of tetramethyl-bis-carbamide (the pharmaceutical Mebicarum) in H2O and D2O were measured at 288.15, 298.15, and 318.15 K using a sealed microcalorimeter with an isothermal shell. The error of measurements
did not exceed 0.2%. The limiting molar enthalpies of dissolution Δsol
H
n
∞ and the H/D-isotope enthalpy effects of hydration δΔhydr
H
n
∞(H2O → D2O) were determined. Different effects of temperature on the pattern of variation of δΔ hydr
H
n
∞ were found: when T ≤ 315 K, this value is positive and decreases with T, while for T ≥ 315 K, hydration of tetramethyl-bis-carbamide upon replacement of H2O by D2O progressively becomes less endothermic.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 715–717, April, 2006. 相似文献
15.
Two two-dimensional coordination complexes, {[Cu4(BTM)6(OPA)4] · 4DMF · 3H2O}
n
(1) and {[Cu(BDTM)(OH)](ClO4) · 2H2O}
n
(2) (BTM = bis(1,2,4-triazol-1-yl)methane, BDTM = bis(3,5-dimethyl-1,2,4-triazol-1-yl)methane, OPA2− = ortho-phthalic dianion, DMF = N,N-dimethylformamide), were synthesized and structurally characterized. Each Cu(II) ion locates in a distorted square pyramidal
geometry in 1, in which OPA2− ligands bridge Cu2+ ions along a axis to form a magnetic transmission chain and BTM ligands act as flexible spacers to construct the two-dimensional layer
structure. In 2, each Cu2+ ion adopts tetra-coordination geometry to two hydroxyl groups and two triazolyl nitrogen atoms from two different BDTM ligands.
Two hydroxyl groups bridge two Cu2+ ions to form a rhombic diamond, and four BDTM ligands connect four diamonds to form a 36-membered macrocyclic structure with
large channels along a axis. Magnetic properties revealed that both OPA2− and OH− mediate anti-ferromagnetic interactions between Cu2+ ions with J = − 0.06(3) and −301.9(2) cm−1 for 1 and 2, respectively.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
16.
17.
N. V. Kosova E. T. Devyatkina V. V. Kaichev D. G. Kellerman 《Russian Journal of Electrochemistry》2008,44(5):543-549
The cathode materials of the composition LiNi1 − 2x
Co
x
Mn
x
O2 (x = 0.1, 0.2. 0.33) synthesized from the Ni, Co, Mn mixed hydroxides and LiOH by using mechanical activation method are studied.
It is shown that all synthesized compounds have layered structure described by the space group R-3m. With the decreasing of the nickel content the cell volume and the degree of structure disordering decrease. According to
XPS data, the electronic main state of d-ions at the prepared samples’ surfaces corresponds to Ni2+, Co3+, and Mn4+. An increase in the nickel content leads to the increase of the Ni2p
3/2 and Co2p
3/2 binding energy, which points to the change in the Me-O bond covalence. According to magnetic susceptibility measurements
data, the nickel ions in LiNi0.6Co0.2Mn0.2O2 exist in the two oxidation states: Ni2+ and Ni3+. It is shown that this sample has the highest specific discharge capacity (∼170 mAh/g). The positions of redox peaks in the
differential capacitance curves depend on the sample composition: with the increasing of nickel content they are shifted toward
lower voltages.
Based on the paper presented in the IX International Conference “Basic Problems of Energy Conversion in Lithium Electrochemical
Systems” (Ufa, 2006). 相似文献
18.
Electrochromic hydrated Ni-oxide films were prepared using a dip-coating technique from a nickel sulphate heptahydrate precursor
in combination with glycerol, formamide and polyvinyalcohol. In-situ monochromatic (λ=400 nm) spectroelectrochemical measurements
using a potential of −0.4 V to 0.8 V in 0.1M LiOH electrolyte revealed that the electrochromic efficiency was 23.5 cm2/C. The observed colouring/bleaching transmittance of a 100 nm thick film changed during potential cycling (20 cycles) by
45%. Ex-situ FT-IR absorption/reflection measurements performed at near-grazing incidence angle conditions (80°) confirmed
transformation of as-deposited α-Ni(OH)2 phase to β-Ni(OH)2 at cathodic (bleached state) and β-NiOOH at anodic (coloured state) potentials during extended cycling (200 cycles). Clear
evidence of the OH− ions insertion and release of SO
4
2−
ions from the as-deposited films when soaked (0.5 hour) in 0.1M LiOH are given. These processes are accompanied by the transformation of the residual COO− groups originating from the peptisation with glacial acetic acid into CO
3
2−
species residing in the films during extensive potential cycling. 相似文献
19.
Donald A. Palmer Pascale Bénézeth Caibin Xiao David J. Wesolowski Lawrence M. Anovitz 《Journal of solution chemistry》2011,40(4):680-702
Results of solubility experiments involving crystalline nickel oxide (bunsenite) in aqueous solutions are reported as functions
of temperature (0 to 350 °C) and pH at pressures slightly exceeding (with one exception) saturation vapor pressure. These
experiments were carried out in either flow-through reactors or a hydrogen-electrode concentration cell for mildly acidic
to near neutral pH solutions. The results were treated successfully with a thermodynamic model incorporating only the unhydrolyzed
aqueous nickel species (viz., Ni2+) and the neutrally charged hydrolyzed species (viz., Ni(OH)20)\mathrm{Ni(OH)}_{2}^{0}). The thermodynamic quantities obtained at 25 °C and infinite dilution are, with 2σ uncertainties:
log10Ks0o = (12.40 ±0.29),\varDeltarGmo = -(70. 8 ±1.7)\log_{10}K_{\mathrm{s0}}^{\mathrm{o}} = (12.40 \pm 0.29),\varDelta_{\mathrm{r}}G_{m}^{\mathrm{o}} = -(70. 8 \pm 1.7) kJ⋅mol−1;
\varDeltarHmo = -(105.6 ±1.3)\varDelta_{\mathrm{r}}H_{m}^{\mathrm{o}} = -(105.6 \pm 1.3) kJ⋅mol−1;
\varDeltarSmo = -(116.6 ±3.2)\varDelta_{\mathrm{r}}S_{m}^{\mathrm{o}} =-(116.6 \pm 3.2) J⋅K−1⋅mol−1;
\varDeltarCp,mo = (0 ±13)\varDelta_{\mathrm{r}}C_{p,m}^{\mathrm{o}} = (0 \pm 13) J⋅K−1⋅mol−1; and log10Ks2o = -(8.76 ±0.15)\log_{10}K_{\mathrm{s2}}^{\mathrm{o}} = -(8.76 \pm 0.15);
\varDeltarGmo = (50.0 ±1.7)\varDelta_{\mathrm{r}}G_{m}^{\mathrm{o}} = (50.0 \pm 1.7) kJ⋅mol−1;
\varDeltarHmo = (17.7 ±1.7)\varDelta_{\mathrm{r}}H_{m}^{\mathrm{o}} = (17.7 \pm 1.7) kJ⋅mol−1;
\varDeltarSmo = -(108±7)\varDelta_{\mathrm{r}}S_{m}^{\mathrm{o}} = -(108\pm 7) J⋅K−1⋅mol−1;
\varDeltarCp,mo = -(108 ±3)\varDelta_{\mathrm{r}}C_{p,m}^{\mathrm{o}} = -(108 \pm 3) J⋅K−1⋅mol−1. These results are internally consistent, but the latter set differs from those gleaned from previous studies recorded in
the literature. The corresponding thermodynamic quantities for the formation of Ni2+ and Ni(OH)20\mathrm{Ni(OH)}_{2}^{0} are also estimated. Moreover, the Ni(OH)3 -\mathrm{Ni(OH)}_{3}^{ -} anion was never observed, even in relatively strong basic solutions (mOH - = 0.1m_{\mathrm{OH}^{ -}} = 0.1 mol⋅kg−1), contrary to the conclusions drawn from all but one previous study. 相似文献
20.
Ding-Wa Zhang Zheng-Yin Yang Shi-Ping Zhang Ru-Dong Yang 《Transition Metal Chemistry》2006,31(3):333-336
A novel ligand (H2L), diethylenetriamine-N,N′,N′′-triacetylisoniazide N,N′′-bisacetic acid, and its four non-ion transition metal complexes,
ML · nH2O (M = Mn, n = 4; M = Co, Ni, n = 2; M = Cu, n = 1), have been synthesized and characterized on the basis of elemental analysis, molar conductivity, 1H-NMR, FAB-MS, TG-DTA analysis and IR spectrum. In addition, relaxivity (R1) of the complexes was determined, the relaxivity of MnL, CoL, NiL, CuL as well as Gd(DTPA)2− used as a control are 6.94, 2.79, 2.52, 1.59 and 4.34 l mmol−1 s−1, respectively. The relaxivity of MnL is larger than that of Gd(DTPA)2−. The results show that the complex of MnL may be a potential MRI contrast agent. 相似文献