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Table 3 Equilibrium constants for acetate and malonate complexes of Pb and Zn used in model calculations

From: Transport of Pb and Zn by carboxylate complexes in basinal ore fluids and related petroleum-field brines at 100 °C: the influence of pH and oxygen fugacity

Acetate (Ac- = CH3COO-)

Malonate (Ma2- = C3H2O42-)

Reaction

LogK

T/°C

Ref.a

Reaction

LogK

T/°C

Ref.a

H+ + Ac- → Hac

4.94

100

1

H+ + HMa- → H2Ma

3.02

100

5

    

H+ + Ma2- → HMa-

6.14

100

5

Pb2+ + Ac- → PbAc+

3.00

100

2

    

Pb2+ + 2Ac- → Pb(Ac)2

4.69

100

2

Pb2+ + Ma2+ → PbMa

2.79

25

6

Pb2+ + 3Ac- → Pb(Ac)3

3.66

100

3

Pb2+ + 2Ma2+ → Pb(Ma)22-

5.70

25

6

    

Pb2+ + HMa- → PbHMa+

2.40

25

6

Zn2+ + Ac- → ZnAc+

2.30

100

4

Pb2+ + 2HMa- → Pb(HMa)2

2.40

25

6

Zn2+ + 2Ac- → Zn(Ac)2

4.00

100

4

    

Zn2+ + 3Ac- → Zn(Ac)3

4.70

100

4

Zn2+ + Ma2- → ZnMa

3.84

25

7

    

Zn2+ + 2Ma2- → Zn(Ma)22-

5.40

25

7

    

Zn2+ + HMa+ → ZnHMa+

1.00

25

7

  1. a(1) Mesmer et al.[84] (2) Extrapolation based on 24 to 85°C data from Giordano[85] and Hennet et al.[50] (3) SOLMINEQ.88, Kharaka et al.[86] (4) Giordano and Drummond. (5) Kettler et al.[88] (6) Data from Hammam et al.[89] extrapolated to I = 0. (7) Evans and Monk.[90]