Potentiometric study of equilibriums in aqueous divalent metal orthophosphate solutions

Childs, CW

doi:10.1021/ic50093a017

Cited by 79 publications

(34 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The uses of the fourth section of the curve in Table 4 will be limited to preliminary and semiquantitative estimates of chemical properties. The reason for this indicated by the data of Tables 2 and 3 is poor electrode response in the potential region of 0.0 to -0.06 V. Although this disturbing result remains generally unrecognized, evidence of it has persisted in the literature for more than forty years (13,16,19,23,24,28,40,41). ago as 1935, Ellis and Kiehl found the problem to be greatest in pure water of low conductivity (41).…”

Section: Results and Discussion The Quality Of The Titration Curvementioning

confidence: 99%

“…Veith, for example, has used the inflection points in the pH titration curves of aluminum orthophosphate samples for determining the stoichiometric composition of precipitates (12). A rare and important precedent for the present AllI1 orthophosphate investigations is the work of Childs (13). He applied glass electrode measurements of H+ concentrations to the study of metal ion orthophosphate species in solution.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Potentiometric measurement of H⁺ concentrations for aluminum orthophosphate titration curves

Gamble¹

1980

Can. J. Chem.

View full text Add to dashboard Cite

A potentiometric titration method of measuring accurate H+ concentrations is demonstrated for aluminum orthophosphate solutions. A calibration procedure has been used which permitted the glass electrode to be used as a concentration probe instead of as a quasi-activity probe. The random error "background noise" has been reduced by the use of Fortran computing for chemical calculations, data handling and sorting, and averaging by least squares poly nomial fits. The distribution of experimental errors along the sample titration curve is indicated by estimates for its various regions.

show abstract

Section: Results and Discussion The Quality Of The Titration Curvementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Potentiometric measurement of H⁺ concentrations for aluminum orthophosphate titration curves

Gamble¹

1980

Can. J. Chem.

View full text Add to dashboard Cite

show abstract

“…Evidence has been given for ion-complexes of calcium and phosphate ions in solution (Gregory, Moreno & Brown, 1970;Childs, 1970). The very strong hydrogen bonding found in the crystal structure of Ca(HzPO4)z (Dickens, Prince, Schroeder & Brown, 1972) suggests that complexes involving more than one PO4 ion may sometimes be present in solution.…”

Section: Discussionmentioning

confidence: 99%

The crystal structure of CaKAsO4.8H2O

Dickens¹,

Brown²

1972

Acta Crystallogr B Struct Crystallogr Cryst Chem

View full text Add to dashboard Cite

“…In studies at 37 °C, Hacht and Berthon [87HBb] determined log 10 *K 1 = -8.378 in 0.15 molؒdm -3 NaCl and Childs [70CHc] determined a value of -9.03 in 0.15 molؒdm -3 KNO 3 . With the above assumptions about Δε(4), we calculate log 10 *K 1 = -8.93 ± 0.10 based on the value for I = 0 selected in this review (-8.62 ± 0.10 for 36 °C [62PEb]; Table A3-1); this result is consistent with that of Childs [70CHc].…”

Section: Formation Of Znoh +mentioning

confidence: 99%

Chemical speciation of environmentally significant metals with inorganic ligands. Part 5: The Zn²⁺ + OH^-, Cl^-, CO₃ ^2-, SO₄ ^2-, and PO₄ ^3- systems (IUPAC Technical Report)

Powell

Brown

Byrne

et al. 2013

Pure and Applied Chemistry

View full text Add to dashboard Cite

Abstract:The numerical modeling of Zn II speciation amongst the environmental inorganic ligands Cl -, OH -, CO 3 2-, SO 4 2-, and PO 4 3-requires reliable values for the relevant stability (formation) constants. This paper compiles and provides a critical review of these constants and related thermodynamic data. It recommends values of log 10 β p,q,r°v alid at I m = 0 molؒkg -1 and 25 °C (298.15 K), and reports the empirical reaction ion interaction coefficients, Δε, required to calculate log 10 β p,q,r values at higher ionic strengths using the Brønsted-Guggenheim-Scatchard specific ion interaction theory (SIT). Values for the corresponding reaction enthalpies, Δ r H, are reported where available. There is scope for additional high-quality measurements for the Zn 2+ + H + + CO 3 2-system and for the Zn 2+ + OH -and Zn 2+ + SO 4 2-systems at I > 0. In acidic and weakly alkaline fresh water systems (pH < 8), in the absence of organic ligands (e.g., humic substances), Zn II speciation is dominated by Zn 2+ (aq). In this respect, Zn II contrasts with Cu II and Pb II (the subjects of earlier reviews in this series) for which carbonato-and hydroxido-complex formation become important at pH > 7. The speciation of Zn II is dominated by ZnCO 3 (aq) only at pH > 8.4.In seawater systems, the speciation at pH = 8.2 is dominated by Zn 2+ (aq) with ZnCl + , Zn(Cl) 2 (aq), ZnCO 3 (aq), and ZnSO 4 (aq) as minor species. This behaviour contrasts with that for Cu II and Pb II for which at the pH of seawater in equilibrium with the atmosphere at 25 °C (log 10 {[H + ]/c°} ≈ 8.2) the MCO 3 (aq) complex dominates over the MCl n (2-n)+ species. The lower stability of the different complexes of Zn II compared with those of Cu II , Pb II , and Cd II is also illustrated by the percentage of uncomplexed M 2+ in seawater, which is ca. 55, 3, 2, and 3.3 % of [M II ] T , respectively.

show abstract

Potentiometric study of equilibriums in aqueous divalent metal orthophosphate solutions

Cited by 79 publications

References 0 publications

Potentiometric measurement of H⁺ concentrations for aluminum orthophosphate titration curves

Potentiometric measurement of H⁺ concentrations for aluminum orthophosphate titration curves

The crystal structure of CaKAsO4.8H2O

Chemical speciation of environmentally significant metals with inorganic ligands. Part 5: The Zn²⁺ + OH^-, Cl^-, CO₃ ^2-, SO₄ ^2-, and PO₄ ^3- systems (IUPAC Technical Report)

Contact Info

Product

Resources

About

Potentiometric study of equilibriums in aqueous divalent metal orthophosphate solutions

Cited by 79 publications

References 0 publications

Potentiometric measurement of H+ concentrations for aluminum orthophosphate titration curves

Potentiometric measurement of H+ concentrations for aluminum orthophosphate titration curves

The crystal structure of CaKAsO4.8H2O

Chemical speciation of environmentally significant metals with inorganic ligands. Part 5: The Zn2+ + OH-, Cl-, CO3 2-, SO4 2-, and PO4 3- systems (IUPAC Technical Report)

Contact Info

Product

Resources

About

Potentiometric measurement of H⁺ concentrations for aluminum orthophosphate titration curves

Potentiometric measurement of H⁺ concentrations for aluminum orthophosphate titration curves

Chemical speciation of environmentally significant metals with inorganic ligands. Part 5: The Zn²⁺ + OH^-, Cl^-, CO₃ ^2-, SO₄ ^2-, and PO₄ ^3- systems (IUPAC Technical Report)