Table 4 Equilibrium constants for thioarsenite species^a

As(OH)₃⁰ + HS^- + H⁺ ⇌ As(OH)₂(SH)⁰ + H₂O

8.69 ± 0.29 (n = 10)

As(OH)₃⁰ + HS^- ⇌ As(OH)₂S^- + H₂O

3.54 ± 0.36 (n = 8)

As(OH)₂S^- + HS^- ⇌ As(OH)S₂^2- + H₂O

5.06 ± 0.49 (n = 17)

As(OH)S₂^2- + HS^- + H⁺ ⇌ AsS₃H^2- + H₂O

11.78 ± 0.89 (n = 11)

As(OH)S₂^2- + HS_- ⇌ AsS₃^3- + H₂O

3.89 ± 0.41 (n = 6)

AsS₃H^2- + HS^- + 2H⁺ ⇌ As(SH)4^-

16.16 ± 0.29 (n = 6)