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  • 1
    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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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Aquatic geochemistry 3 (1997), S. 345-356 
    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
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