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  • 1
    Electronic Resource
    Electronic Resource
    Mixed halide complexes of lead. A comparison with theoretical predictions (1982)
    Springer
    Journal of solution chemistry 11 (1982), S. 127-136 
    Details
    ISSN: 1572-8927
    Keywords: Lead ; lead bromide ; lead chloride ; mixed ligand ; complexation ; spectroscopic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Experimentally and theoretically derived formation constants of mixed lead halide complexes are compared at 25.0°C and one molar ionic strength. The formation constant of PbBrCl, β11=79±10, is somewhat larger than the theoretical results, β11=55, predicted using the formation constants of PbBr2 and PbCl2. The molar absorptivity of PbBrCl was observed to be intermediate in character between the molar absorptivities of PbBr2 and PbCl2. Determinations of the formation constants of PbBr2Cl− and PbBrCl2 − are in reasonable agreement with the predictions based on the formation constants of PbBr3 − and PbCl3 −. Mixed ligand species dominated the complexation scheme of Pb(II) in our test media.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01036380
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  • 2
    Electronic Resource
    Electronic Resource
    Evaluation of the CuCl+ stability constant and molar absorptivity in aqueous media (1983)
    Springer
    Journal of solution chemistry 12 (1983), S. 581-596 
    Details
    ISSN: 1572-8927
    Keywords: Copper ; molar absorptivity ; complexation ; spectroscopy ; copper and magnesium chloride
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Upper and lower bound estimates of the CuCl+ stability constants produced by various investigations have been quantitatively examined. Our analyses, including our own ultraviolet spectroscopic investigations, indicate that the CuCl+ stability constant in 1 molar HClO4 is β1=0.70±0.23. The CuCl+ molar absorptivity at a wavelength of 250 nm was determined as 1860 cm2-mol−1. Our analyses suggest the bound β 1 ′≤0.37 for the formation constant of MgCl+ at one molar ionic strength.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01150850
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  • 3
    Electronic Resource
    Electronic Resource
    The hydrolysis and fluoride complexation behavior of Fe(III) at 25°C and 0.68 molal ionic strength (1996)
    Springer
    Journal of solution chemistry 25 (1996), S. 773-785 
    Details
    ISSN: 1572-8927
    Keywords: Iron(III) ; ferric ; hydrolysis ; fluoride ; complexation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Fe(III) hydrolysis and fluoride complexation behavior was examined in 0.68 molal sodium perchlorate at 25°C. Our assessment of the complexation of Fe(III) by fluoride ions produced the following results: logFβ1 = 5.155, logFβ2 = 9.107, logFβ3 = 11.96, logFβ4 = 13.75, where logFβn = 5.155=[FeF n (3-n)+ ][Fe3+]−1[F−]−n. The stepwise fluoride complexation constants,FK n+1, obtained in our work (where logF K n+1 =logFβn) indicate that K n+1/K n =0.072±0.01. Formation constants for equilibria, Fe3++nH2O⇌Fe(OH) n (3−n)+ +nH+, expressed in the form β n * [Fe(OH) n (3-n)+ ][H+]n ,[Fe 3+]-1, were estimated as β 1 * = −2.754, and β 2 * ≤ −7. Our study indicates that the results of previous hydrolysis investigations include very large overestimates of Fe(OH) 2 + formation constants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00973784
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  • 4
    Electronic Resource
    Electronic Resource
    Ionic Strength Dependence of Rare Earth – NTA Stability Constants at 25°C (1997)
    Springer
    Aquatic geochemistry 3 (1997), S. 99-115 
    Details
    ISSN: 1573-1421
    Keywords: rare earth elements ; copper ; complexation ; ionic strength effects ; nitrilotriacetic acid ; lanthanide ; yttrium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Observations of competitive complexation of NTA by Cu2+ and rare earth element (REE) ions are used to determine REE-NTA stability constants at ionic strengths between 0.1 and 5.0 molar. Although REE stability constants change markedly with ionic strength, differences in the ionic strength dependence of REE-NTA stability constants across the rare earth element series are small. The ionic strength dependence of logβ1 for Y and REEs with NTA at 25 °C can be described as: logβ1(M) = logβ1(M)0 - 9.198 I1/2/(1+B I1/2)+C I + D I3/2, where β1(M) = [MNTA°][M3+]-1[NTA3-]-1, I is ionic strength, B = 1.732, C = 0.1596, D = 0.0816, and logβ1(M)° is the metal-NTA stability constant at zero ionic strength.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009643409154
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  • 5
    Electronic Resource
    Electronic Resource
    Comprehensive Investigation of Yttrium and Rare Earth Element Complexation by Carbonate Ions Using ICP–Mass Spectrometry (1998)
    Springer
    Journal of solution chemistry 27 (1998), S. 803-815 
    Details
    ISSN: 1572-8927
    Keywords: Rare earth ; complexation ; carbonate ; ICP–MS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Carbonate stability constants for yttrium and all rare earth elements have been determined at 25°C and 0.70 molal ionic strength by solvent exchange and inductively coupled plasma–mass spectrometry (ICP–MS). Measured stability constants for the formation of $${\text{MCO}}_3^ +$$ and $${\text{M}}\left( {{\text{CO}}_{\text{3}} } \right)_2^--$$ from M3+ are in good agreement with previous direct measurements, which involved the use of radio-chemical techniques and trivalent ions of Y, Ce, Eu, Gd, Tb, and Yb. Direct ICP–MS measurements of $${\text{MCO}}_3^ +$$ and $${\text{M}}\left( {{\text{CO}}_{\text{3}} } \right)_2^--$$ formation constants are also in general agreement with modeled stability constants for the metals La, Pr, Nd, Sm, Dy, Ho, Er, Tm, and Lu, based on linear-free energy relationship (LFER). The experimental procedures developed in this work can be used for assessing the complexation behavior of other geochemically important ligands such as phosphate, sulfate, and fluoride.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022677119835
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  • 6
    Electronic Resource
    Electronic Resource
    Lead chloride complexation using ultraviolet molar absorptivity characteristics (1981)
    Springer
    Journal of solution chemistry 10 (1981), S. 243-251 
    Details
    ISSN: 1572-8927
    Keywords: Lead chloride ; molar absorptivity ; complexation ; medium dependence ; ultraviolet ; spectroscopic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The molar absorptivities of Pb2+, PbCl+, PbCl2, and PbCl 3 − were obtained between 210 and 300 nm. Molar absorptivity data were used to determine lead speciation directly from Pb(II) absorbance characteristics in a variety of media including natural seawater. The absorbance characteristics of lead in a particular chloride medium reveal the lead chloride formation constants appropriate to that medium. Our analyses indicate that lead chloride formation constants are significantly smaller in MgCl2 media than in HCl at constant ionic strength.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00645013
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  • 7
    Electronic Resource
    Electronic Resource
    The solubility control of rare earth elements in natural terrestrial waters and the significance of PO 4 3− and CO 3 2− in limiting dissolved rare earth concentrations: A review of recent information (1995)
    Springer
    Aquatic geochemistry 1 (1995), S. 157-173 
    Details
    ISSN: 1573-1421
    Keywords: rare earth elements ; lakes ; groundwaters ; activity products ; solubility products ; solubility controls ; complexation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Rare earth element (REE) concentrations in alkaline lakes, circumneutral pH groundwaters, and an acidic freshwater lake were determined along with the free carbonate, free phosphate, and free sulfate ion concentrations. These parameters were used to evaluate the saturation state of these waters with respect to REE phosphate and carbonate precipitates. Our activity product estimates indicate that the alkaline lake waters and groundwaters are approximately saturated with respect to the REE phosphate precipitates but are significantly undersaturated with respect to REE carbonate and sulfate precipitates. On the other hand, the acidic lake waters are undersaturated with respect to REE sulfate, carbonate, and phosphate precipitates. Although carbonate complexes tend to dominate the speciation of the REEs in neutral and alkaline waters, our results indicate that REE phosphate precipitates are also important in controlling REE behavior. More specifically, elevated carbonate ion concentrations in neutral to alkaline natural waters tend to enhance dissolved REE concentrations through the formation of stable REE-carbonate complexes whereas phosphate ions tend to lead to the removal of the REEs from solution in these waters by the formation of REE-phosphate salts. Removal of REEs by precipitation as phosphate phases in the acid lake (pH=3.6) is inconsequential, however, due to extremely low [PO 4 3− ] F concentrations (i.e., ∼ 10−23 mol/kg).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00702889
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  • 8
    Electronic Resource
    Electronic Resource
    Interaction of B $$(OH)_3^0 $$ and $$HCO_3^ - $$ in Seawater: Formation of B $$(OH)_2 CO_3^ - $$ (1997)
    Springer
    Aquatic geochemistry 3 (1997), S. 345-356 
    Details
    ISSN: 1573-1421
    Keywords: boron ; boric acid ; carbonate ; CO2 system ; complexation ; spectrophotometric pH
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Boron is known to interact with a wide variety of protonated ligands(HL) creating complexes of the form B(OH)2L-.Investigation of the interaction of boric acid and bicarbonate in aqueoussolution can be interpreted in terms of the equilibrium $$B(OH)_3^0 + HCO_3^ - \rightleftharpoons B(OH)_2 CO_3^ - + H_2 O$$ The formation constant for this reaction at 25 °C and 0.7 molkg-1 ionic strength is $$K_{BC} = \left[ {B(OH)_2 CO_3^ - } \right]\left[ {B(OH)_3^0 } \right]^{ - 1} \left[ {HCO_3^ - } \right]^{ - 1} = 2.6 \pm 1.7$$ where brackets represent the total concentration of each indicatedspecies. This formation constant indicates that theB(OH)2 $$CO_3^ - $$ concentration inseawater at 25 °C is on the order of 2 μmol kg-1. Dueto the presence of B(OH)2 $$CO_3^ - $$ , theboric acid dissociation constant ( $$K\prime _B $$ ) in natural seawaterdiffers from $$K\prime _B $$ determined in the absence of bicarbonate byapproximately 0.5%. Similarly, the dissociation constants of carbonicacid and bicarbonate in natural seawater differ from dissociation constantsdetermined in the absence of boric acid by about 0.1%. Thesedifferences, although small, are systematic and exert observable influenceson equilibrium predictions relating CO2 fugacity, pH, totalcarbon and alkalinity in seawater.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009633804274
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