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  • 11
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 290 (1981), S. 487-489 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Speciation models for lead in seawater (Table 1) alternatively predict: (1) that only lead carbonate complexes1 are important; (2) that lead carbonate species are unimportant and that lead chloride complexes are dominant2,3; (3) that lead hydroxide complexes are important4,5; and (4) that lead ...
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 219 (1968), S. 968-969 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Experiments were conducted with twelve ponies of both sexes (Equus caballus) from a wild herd living on Assateague Island, Virginia. The animals had previously been relatively isolated from human beings, had no known prior contact with other equine animals and lacked detectable serum neutralizing ...
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 11 (1982), S. 127-136 
    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
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 16 (1987), S. 555-566 
    ISSN: 1572-8927
    Keywords: Europium ; carbonate complexation ; carbonic acid dissociation ; tributy phosphate extraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The temperature dependencies of europium carbonate stability constants were examined at 15, 25, and 35°C in 0.68 molal Na+(ClO 4 − , HCO 3 − ) using a tributyl phosphate solvent extration technique. Our distribution data can be explained by the equilibria $$\begin{gathered} Eu^{3 + } + H_2 O + CO_2 (g)_ \leftarrow ^ \to EuCO_3^ + + 2H^ + \hfill \\ - log\beta _{12} = 9.607 + 496(t + 273.16)^{ - 1} \hfill \\ Eu^{3 + } + 2H_2 O + 2CO_2 (g)_ \leftarrow ^ \to Eu(CO_3 )_2^ - + 4H^ + \hfill \\ - log\beta _{24} = 21.951 + 670(t + 273.16)^{ - 1} \hfill \\ Eu^{3 + } + H_2 O + CO_2 (g)_ \leftarrow ^ \to EuHCO_3^{2 + } + H^ + \hfill \\ - log\beta _{11} = 1.688 + 1397(t + 273.16)^{ - 1} \hfill \\ \end{gathered}$$
    Type of Medium: Electronic Resource
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 22 (1993), S. 751-766 
    ISSN: 1572-8927
    Keywords: Rare earth elements ; fluoride complexation ; stability constant ; solvent exchange ; tributyl phosphate ; sodium perchlorate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Rare earth fluoride stability constants for Ce, Eu, Gd, Tb and Yb at 25°C have been determined by examining the influence of fluoride ions on the distribution of rare earths between tributyl phosphate (TBP) and 0.68M NaClO4. Our results indicate that rare earth mono and difluoro complexation constants show a steady increase as a function of atomic number from La to Tb but remain relatively constant after Dy. This behavior is similar to that which has been observed for dicarboxylic acids. Stepwise stability constant ratios, K2/K1, obtained in our work (where K1=[MF2+][M3+]−1[F−]−1 and K2=[MF 2 + ]−1[MF2+]−1[F−]−1) indicated that, for all rare earths, K2/K1=0.09±0.03.
    Type of Medium: Electronic Resource
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  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 10 (1981), S. 51-67 
    ISSN: 1572-8927
    Keywords: Hydrolysis ; ferric chloride ; ferric hydroxide ; UV spectroscopy ; complexes ; ion pairs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The equilibria among the species Fe3+, FeCl2+, FeCl2 +, FeOH2+ and Fe(OH)2 + have been examined by ultraviolet absorption spectroscopy. Our results indicate that previous workers have generally overestimated the stability constant of FeCl2+ and that the association of Fe3+ and Cl− is predominantly inner sphere. The formation constant of FeOH2+ obtained in 0.68 m NaCl is in good agreement with our earlier results obtained in 0.68 m NaClO4. Our results indicate that formation of FeOHCl+ is much less significant than has been previously reported. Molar absorptivities for the species Fe3+, FeCl2+, FeCl2 + and FeOH2+ are reported for wavelengths between 220 and 400 nanometers.
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 10 (1981), S. 243-251 
    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
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  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 12 (1983), S. 581-596 
    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
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  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 7 (1978), S. 373-383 
    ISSN: 1572-8927
    Keywords: Ferric ; hydrolysis ; ionic strength ; temperature ; enthalpy ; ferric hydroxide ; ultraviolet ; spectroscopic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Ultraviolet absorbance spectra of ferric ions in 0.68m NaClO4 were studied as a function of pH at 4.0, 14.9, and 25.0°C. The results provided an evaluation of the stability constant for the formation of FeOH2+ which is *β1=[FeOH +][H +]/[Fe 3+]. The enthalpy change for the reaction Fe3++H2O⇌ FeOH2++H+ was calculated as 10.0±0.3 kcal-mole−1. Increasing temperature was also found to promote the reaction Fe3++2H2O⇌ Fe(OH) 2 + +2H+. Our results were combined with the results of other to produce an expression describing the first hydrolysis equilibrium at ionic strengths between 0 and 3m and temperatures between 4.0 and 45.0°C at 1 atm total pressure. At 25°C and 0.68m the ionic strength *β1=1.90×10-3
    Type of Medium: Electronic Resource
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  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 27 (1998), S. 803-815 
    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
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