共查询到20条相似文献,搜索用时 11 毫秒
1.
Francesco Malatesta 《Journal of solution chemistry》2002,31(7):547-558
Activity coefficients of [Co(en)3](NO3)3 and [Co(en)3](ClO4)3, to be compared with [Co(en)3]Cl3 and the corresponding lanthanum salts previously studied, are determined. [Co(en)3]Cl3 data are revised. Ion interaction strengths vary in the same order found for La3+, i.e., as if nitrate and perchlorate ions were of smaller and larger size, respectively, than chloride ions; however, the differences are much smaller than in lanthanum salts. Tris(ethylenediamine)cobalt III and lanthanum nitrate, chloride, and perchlorate—like the corresponding hexacyanoferrate(III) and hexacyanocobaltate(III) salts, but contrary to sulfate salts—behave as if [Co(en)3]3+ were smaller in size than La3+. In the dilute regions, [Co(en)3](NO3)3 displays negative deviations from the limiting slope, a kind of behavior typical for 2:2, 2:3, 3:2, and 3:3 electrolytes, but unnoticed earlier for 3:1 or 1:3 electrolytes. Pitzer's equation parameters able to provide accurate activity and osmotic coefficients for [Co(en)3](NO3)3, [Co(en)3](ClO4)3, and, revised, [Co(en)3]Cl3 are reported. 相似文献
2.
Francesco Malatesta Laura Carbonaro Nicolangelo Fanelli Simone Ferrini Ambrogio Giacomelli 《Journal of solution chemistry》1999,28(5):593-619
The activity coefficients of CdSO4 CoSO4, and NiSO4 are determined from the emf of liquid-membrane cells, like those described in the papers I–VI of this series. The activity coefficients of the auxiliary salts Co(ClO4)2, Ni(ClO4)2, and K2SO4, needed to eliminate the problem of extrapolation to infinite dilution of the 2–2 salts, are also measured. CdSO4 CoSO4 and NiSO4 in the dilute region deviate downward from the limiting law by a larger extent than believed in the past, thus creating the need for the activity coefficients to be recalculated and systematically lowered by 8–16%. The activity coefficients of Co(ClO4)2 and Ni(ClO4)2, too, need to be corrected by around –3%. For K2SO4, the original values, although scattered, were substantially correct. Pitzer's theory best-fit parameter, able to provide the activity and osmotic coefficients of the salts considered, are reported. 相似文献
3.
Francesco Malatesta Ambrogio Giacomelli Roberto Zamboni 《Journal of solution chemistry》1994,23(1):11-36
The activity coefficients of LaCl3, K3Fe(CN)6, and LaFe(CN)6 were measured down to about 1×10–4, 3×10–5, and 2×10–5 mol-kg–1 respectively, by means of cells with ion-exchange liquid membranes. In the diluted region, the trend of lanthanum chloride agrees with the Debye-Huckel theory and corroborates earlier findings in the literature relevant to more concentrated solutions, with minor systematic corrections of the ± values. K3Fe(CN)6 attains (rather than tends to attain) the Debye-Huckel limiting slope at1×10–3 mol-kg–1, and lanthanum ferricyanide in the diluted region shows negative deviations from the limiting law, similar to the ones predicted for large-sized, highly-charged ions in the diluted region by Bjerrum's, IPBE, and Mayer's theories. The behavior of LaCl3 in the concentrated solutions proves that lanthanum ion drags along with it into the membrane many molecules of water which were then found to be twelve. Pitzer's theory best-fit coefficients that meet the experimental curves to be reproduced satisfactorily are reported. 相似文献
4.
Activity coefficients of K2C2O4 and Na2ds, ds2– = 1,5-naphthalenedisulfonate anion, which were previously unavailable, are examined at 25.0°C using liquid membrane cells. The results for both salts are approximated satisfactorily by the primitive model in spite of the fact that ds2–, a planar ion with electric charges distant from one another, does not resemble a charged hard sphere. Data are compared with those of K2SO4 and bivalent metal perchlorates. The Pitzer ion-interaction parameters are reported. 相似文献
5.
A new electrochemical cell is described, in which two permselective liquid membranes, one anionic the other cationic, are
interposed between the subsidiary electrodes and the solution of the electrolyte under examination By means of this kind of
cell it is possible to measure activity coefficients of salts of cations and anions for which reversible electrodes are not
available, with great accuracy even at high dilutions never accessible before (down to ≊10−4 mol-dm−3). The cell performance has been tested by measuring the activity coefficients of KCl for which accurate data are available
in literature. 相似文献
6.
Francesco Malatesta Giacomo Carrara Maria Perla Colombini Ambrogio Giacomelli 《Journal of solution chemistry》1993,22(8):733-749
The activity coefficients of Co(en)3Cl3 and K2SO4 were measured by means of a cell with ion-exchange liquid membranes following the method described in paper I. The results prove that this method is even more valuable with multicharged salts than with 1-1 electrolytes. The values obtained are precise and reliable down to dilution limits never before accessible, e.g., 4×10–5 mol-kg–1 in Co(en)3Cl3. High dilution levels are of particular importance when dealing with highly charged electrolytes since the trend at higher concentrations often leads to errors both in extrapolation to infinite dilution and in the absolute activity coefficients. As an application, the activity coefficients of [Co(en)3]2(SO4)3-suspected to be wrongly evaluated in past literature-were measured, and their values at low concentrations were actually lower than those quoted before. 相似文献
7.
Francesco Malatesta Ambrogio Giacomelli Roberto Zamboni 《Journal of solution chemistry》1996,25(1):61-73
The relative mean activity coefficients of the M3[Fe(CN)6]2 salts, M=Mg, Ca, Sr, Ba, are measured down to about 5×10–6 mol-kg–1 using the liquid membrane cell method. In the dilute region these salts display negative instead of positive deviations from the limiting law, contrary to Debye-Hückel's theory predictions. An indirect method based on auxiliary emf measurements in MCl2, K3Fe(CN)6 and KCl, rather than a theory-assisted direct extrapolation to zero of the relative activity coefficients, is used to identify the actual values of the activity coefficients. The data are compared with Mayer's theory, ion-pair theory and numerical integration of the Poisson-Boltzmann equation. Best-fit coefficients of Pitzer's equation which meet the activity coefficients of the M3[Fe(CN)6]2 salts to be reproduced, are reported. 相似文献
8.
Francesco Malatesta 《Journal of solution chemistry》1995,24(3):241-252
Lanthanum ferricyanide is so far the only 3–3 electrolyte whose activity coefficients have been studied carefully; however, the results have been acknowledged to be inconsistent below 1×10–4 mol-kg–1. New measurements have been made with an improved cell, proving that the wrong trend was due to chemical interference in the original cell. The new cell makes it possible to reach dilution levels of the order of 4×10–6 mol-kg–1. The salt behaves radically unlike Debye-Hückel's predictions, but agrees with other more refined treatments of the hard sphere models without needing any further hypotheses, such as e.g., association. The revised values of the activity coefficients are reported. 相似文献
9.
The activity coefficients of ZnSO4, MgSO4, CaSO4, and SrSO4 are measured by means of cells with ion-exchange liquid membranes similar to those described in the previous papers of this
series. Negative deviations from the limiting law are observed in the dilute region. These deviations are, for ZnSO4, appreciably more important than recent literature has indicated, and the corresponding activity coefficients need to be
corrected by about 12%. Pitzer’s theory best-fit coefficients have accordingly been recalculated. The osmotic coefficients
are also derived. Accessory information on the hydration state for zinc, magnesium, and sulfate ions, is presented. 相似文献
10.
On the Crystal Structures of the Cyano Complexes [Co(NH3)6][Fe(CN)6], [Co(NH3)6]2[Ni(CN)4]3 · 2 H2O, and [Cu(en)2][Ni(CN)4] Of the three title compounds X‐ray structure determinations were performed with single crystals. [Co(NH3)6][Fe(CN)6] (a = 1098.6(6), c = 1084.6(6) pm, R3, Z = 3) crystallizes with the CsCl‐like [Co(NH3)6][Co(CN)6] type structure. [Co(NH3)6]2[Ni(CN)4]3 · 2 H2O (a = 805.7(5), b = 855.7(5), c = 1205.3(7) pm, α = 86.32(3), β = 100.13(3), γ = 90.54(3)°, P1, Z = 1) exhibits a related cation lattice, the one cavity of which is occupied by one anion and 2 H2O, whereas the other contains two anions parallel to each other with distance Ni…Ni: 423,3 pm. For [Cu(en)2][Ni(CN)4] (a = 650.5(3), b = 729.0(3), c = 796.5(4) pm, α = 106.67(2), β = 91.46(3), γ = 106.96(2)°, P1, Z = 1) the results of a structure determination published earlier have been confirmed. The compound is weakly paramagnetic and obeys the Curie‐Weiss law in the range T < 100 K. The distances within the complex ions of the compounds investigated (Co–N: 195.7 and 196.4 pm, Ni–C: 186.4 and 186.9 pm, resp.) and their hydrogen bridge relations are discussed. 相似文献
11.
《Journal of Coordination Chemistry》2012,65(24):3997-4008
4-Methyl-2-(2-hydroxyphenyl)imidazo[4,5-f][1,10]phenanthroline) (MHPIP) and its complexes [Co(bpy)2MHPIP]3+ (1) (bpy = 2,2′-bipyridine), [Co(dmb)2MHPIP]3+ (2) (dmb = 4,4′-dimethyl-2,2′-bipyridine), and [Co(phen)2MHPIP]3+ (3) (phen = 1,10-phenanthroline) have been synthesized and characterized by UV/VIS, IR, EA, 1H, 13C-NMR, and mass spectra. The binding of the three complexes with calf-thymus-DNA (CT-DNA) has been investigated by absorption and emission spectroscopy, DNA-melting techniques, viscosity measurements, and DNA cleavage assay. The spectroscopic data and viscosity results indicate that these complexes bind to CT-DNA via an intercalative mode. The complexes also promote photocleavage of plasmid pBR322 DNA and were screened for antimicrobial activity. 相似文献
12.
《Journal of Coordination Chemistry》2012,65(9):1570-1581
Three ligands, 2-(3-(carboxymethyl)-1,10-phenanthroline-[5,6-d]imidazole-1-yl)acetate (CPIA), 2-(benzo[d][1,3]dioxol-4-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (BIP), and 2-(9H-carbazol-3-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (CIP), and their complexes, [Co(phen)2(CPIA)]3+ (1) (phen = 1,10-phenanthroline), [Co(phen)2(BIP)]3+ (2), and [Co(phen)2(CIP)]3+ (3), have been synthesized and characterized. Binding of the three complexes with calf thymus DNA (CT-DNA) has been investigated by spectroscopic methods, cyclic voltammetry, and viscosity measurements. The three complexes bind to DNA through an intercalative mode, and the size and shape of the intercalative ligands have significant effects on the binding affinity of complexes to CT-DNA. 相似文献
13.
Ralf Eßmann Guido Kreiner Anke Niemann Dirk Rechenbach Axel Schmieding Thomas Sichla Uwe Zachwieja Herbert Jacobs 《无机化学与普通化学杂志》1996,622(7):1161-1166
The Structures of some Hexaammine Metal(II) Halides of 3 d Metals: [V(NH3)6]I2, [Cr(NH3)6]I2, [Mn(NH3)6]Cl2, [Fe(NH3)6]Cl2, [Fe(NH3)6]Br2, [Co(NH3)6]Br2 and [Ni(NH3)6]Cl2 Crystals of yellow [V(NH3)6]I2 and green [Cr(NH3)6]I2 were obtained by the reaction of VI2 and CrI2 with liquid ammonia at room temperature. Colourless crystals of [Mn(NH3)6]Cl2 were obtained from Mn and NH4Cl in supercritical ammonia. Colourless transparent crystals of [Fe(NH3)6]Cl2 and [Fe(NH3)6]Br2 were obtained by the reaction of FeCl2 and FeBr2 with supercritical ammonia at 400°C. Under the same conditions orange crystals of [Co(NH3)6]Br2 were obtained from [Co2(NH2)3(NH3)6]Br3. Purple crystals of [Ni(NH3)6]Cl2 were obtained by the reaction of NiCl2 · 6H2O and NH4Cl with aqueous NH3 solution. The structures of the isotypic compounds (Fm3 m, Z = 4) were determined from single crystal diffractometer data (see “Inhaltsübersicht”). All compounds crystallize in the K2[PtCl6] structure type. In these compounds the metal ions have high-spin configuration. The orientation of the dynamically disordered hydrogen atoms of the ammonia ligands is discussed. 相似文献
14.
Mariano Velázquez-Rivera Donald A. Palmer Richard M. Kettler 《Journal of solution chemistry》2006,35(12):1699-1730
This study measures the osmotic coefficients of {xH2SO4 + (1−x)Fe2(SO4)3}(aq) solutions at 298.15 and 323.15 K that have ionic strengths as great as 19.3 mol,kg−1, using the isopiestic method. Experiments utilized both aqueous NaCl and H2SO4 as reference solutions. Equilibrium values of the osmotic coefficient obtained using the two different reference solutions
were in satisfactory internal agreement. The solutions follow generally the Zdanovskii empirical linear relationship and yield
values of a
w for the Fe2(SO4)3–H2O binary system at 298.15 K that are in good agreement with recent work and are consistent with other M2(SO4)3–H2O binary systems. 相似文献
15.
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
16.
The alkali dicyanamides M[N(CN)2] (M=K, Rb) were synthesized through ion exchange, and the corresponding tricyanomelaminates M3[C6N9] were obtained by heating the respective dicyanamides. The thermal behavior of the dicyanamides and their reaction to form the tricyanomelaminates were investigated by temperature-dependent X-ray powder diffractometry and thermoanalytical measurements. Potassium dicyanamide K[N(CN)2] was found to undergo four phase transitions: At 136 degrees C the low-temperature modification alpha-K[N(CN)2] transforms to beta-K[N(CN)2], and at 187degrees C the latter transforms to the high-temperature modification gamma-K[N(CN)2], which melts at 232 degrees C. Above 310 degrees C the dicyanamide ions [N(CN)2]- trimerize and the resulting tricyanomelaminate K3[C6N9] solidifies. Two modifications of rubidium dicyanamide have been identified: Even at -25 degrees C, the a form slowly transforms to beta-Rb[N(CN)2] within weeks. Rb[N(CN)2] has a melting point of 190 degrees C. Above 260 degrees C the dicyanamide ions [N(CN)2]- of the rubidium salt trimerize in the melt and the tricyanomelaminate Rb3[C6N9] solidifies. The crystal structures of all phases were determined by powder diffraction methods and were refined by the Rietveld method. alpha-K[N(CN)2] (Pbcm, a = 836.52(1), b = 46.90(1), c =7 21.27(1) pm, Z = 4), gamma-K[N(CN)2] (Pnma, a = 855.40(3), b = 387.80(1), 1252.73(4) pm, Z = 4), and Rb[N(CN)2] (C2/c, a = 1381.56(2), b = 1000.02(1), c = 1443.28(2) pm, 116.8963(6) degrees, Z = 16) represent new structure types. The crystal structure of beta-K[N(CN)2] (P2(1/n), a = -726.92(1), b 1596.34(2), c = 387.037(5) pm, 111.8782(6) degrees, Z = 4) is similar but not isotypic to the structure of alpha Na[N(CN)2]. alpha-Rb[N(CN)2] (Pbcm, a = 856.09(1), b = 661.711(7), c = 765.067(9) pm, Z = 4) is isotypic with alpha-K[N(CN)2]. The alkali dicyanamides contain the bent planar anion [N(CN)2]- of approximate symmetry C2, (average bond lengths: C-N(bridge) 133, C-N(term) 113 pm; average angles N-C-N 170 degrees, C-N-C 120 degrees). K3[C6N9] (P2(1/c), a = 373.82(1), b = 1192.48(5), c = 2500.4(1) pm, beta = 101.406(3) degrees, Z = 4) and Rb,[C6N9] (P2(1/c), a = 389.93(2), b = 1226.06(6), c = 2547.5(1) pm, 98.741(5) degrees, Z=4) are isotypic and they contain the planar cyclic anion [C6N9]3-. Although structurally related, Na3[C6N9] is not isotypic with the tricyanomelaminates M3[C6N9] (M = K, Rb). 相似文献
17.
Synthesis and Structure of Tetrafluoroaurates(III), TlF2[AuF4], M2F[AuF4]5 (M = Y, La, Bi), Sm[AuF4]3 with an Appendix on Sm[AuF4]2 In the system MF3/AuF3 the structures of several yellow Tetrafluoroaurates(III) have been determinated. TlF2[AuF4] crystallizes tetragonal, space group P41212 – D (Nr. 92) with a = 573.17(4) pm, c = 2780.4(3) pm, Z = 8; M2F[AuF4]5 (M = Bi, La) tetragonal, space group P41212 – D (Nr. 92) with a = 822.89(5) pm, c = 2557.1(3) pm, Z = 4 (Bi); with a = 836.80(3) pm, c = 2602.2(2) pm, Z = 4 (La); Y2F[AuF4]5 monoclin, space group P2/n – C (Nr. 13) with a = 1188.9(3) pm, b = 797.4(2) pm, c = 895.7(3) pm, β = 89.18(3), Z = 4 and Sm[AuF4]3 trigonal, space group R3c – D (Nr. 167) with a = 1034.5(1) pm, c = 1614.1(3) pm, Z = 6. All these yellow crystals have been obtained by solid state reactions in autoclaves or sealed goldtubes. 相似文献
18.
19.
Synthesis, properties, and structure of dimethylgold(III) complexes [(CH3)2AuI]2 and (CH3)2AuS2CN(C2H5)2 总被引:1,自引:0,他引:1
Volatile diethyldithiocarbamate of dimethylgold(III) was prepared by the interaction of dimethylgold(III) iodide with sodium diethyldithiocarbamate. The complex is examined by the elemental analysis, DTA, IR and electronic spectroscopy. The starting dimeric complex [(CH3)2AuI]2 and a novel monomeric volatile gold(III) complex (CH3)2AuS2CN(C2H5)2 with the AuC2S2 coordination core were investigated by single crystal X-ray diffraction for the first time. 相似文献
20.
Two novel one‐ and two‐dimensional network structure bismuth(III) complexes with N, N‐di(2‐hydroxylethyl)‐aminodithiocarboxylate, {Bi[S2CN(C2H4OH)2]2[1, 10‐Phen]2(NO3)}·3H2O (1) and (Bi[S2CN(C2H4OH)2]3)2 (2) were synthesized. Their crystal and molecular structures were determined by X‐ray single crystal diffraction analysis. The crystal 1 belongs to monoclinic system with space group C2/c, a=1.6431(7) nm, b=2.4323(10) nm, c= 1.2646(5) nm, β=126. 237(5), Z=4, V=4.076(3) nm3, Dc=1.757 Mg/m3, μ=4.598 mm?1, F(000)=2156, R= 0.0211, wR=0.0369. The structure shows a distorted square antiprism configuration with eight‐coordination for the central Bi atom. The one‐dimensional chain structure was formed by H‐bonding interaction between hydroxyl group of N, N‐di(2‐hydroxylethyl)aminodithiocarboxylate ligands and crystal water. The crystal 2 belongs to monoclinic system with space group p2(1)/c, a= 1.1149(4) nm, b=2.1274(8) nrn, c=2.2107(8) nm, β=98.325(8)°, 2=4, V=5. 188(3) nm3, Dc=1.920 Mg/m3, μ=7.315 mm?1, F(000)=2944, R=0.0565, wR=0.0772. The structure shows a distorted square antiprism configuration with eight‐coordination for the central Bi atoms. The two‐dimensional network structure was formed by H‐bonding interaction between adjacent molecules. 相似文献