Table 2 Forms of existing cations of transition metals as a function of the medium acidity and chemical composition of buffer solution
Ion | pH | ||||
|---|---|---|---|---|---|
pH 1.0 HCl | pH 2.5 acetic acid | pH 5.0 acetate buffer | Distilled water | pH 8.0 ammonium acetate buffer | |
Zn(II) | [Zn(H2O)6]2+ [ZnCl4]2− | [Zn(CH3COO)2(H2O)2]2− [Zn(H2O)6]2+ | [Zn(CH3COO)2(H2O)2]2− [Zn(H2O)6]2+ | [Zn(H2O)6]2+ | [Zn(CH3COO)2(H2O)2]2− [Zn(NH3)4]2+ [Zn(NH3)2(CH3COO)2] |
Cu(II) | [Cu(H2O)6]2+ [CuCl4]2− | [Cu2(CH3COO)2(H2O)2]2+ [Cu(H2O)6]2+ | [Cu2(CH3COO)2(H2O)2]2+ [Cu(H2O)6]2+ | [Cu(H2O)6]2+ | [Cu2(CH3COO)2(H2O)2]2+ [Cu(NH3)2(H2O)4]2+ [Cu(NH3)4(H2O)2]2+ |
Cd(II) | [Cd(H2O)4]2+ [CdCl4]2− [CdCl3]− | [Cd(CH3COO)4]2− [Cd(H2O)4]2+ | [Cd(CH3COO)4]2− [Cd(H2O)4]2+ | [Cd(H2O)4]2+ | [Cd(NH3)4]2+ [Cd(CH3COO)4]2− [Cd(NH3)(CH3COO)3] – |
Pb(II) | [PbCl4]2− [PbCl3]− | [Pb(H2O)6]2+ [Pb(OH)(H2O)2(CH3COO)] 2- | [Pb(H2O)6]2+ [Pb(OH)(H2O)2(CH3COO)] 2- | [Pb(H2O)6]2+ | [Pb(OH)(H2O)3]+ [Pb(OH)(H2O)2(CH3COO)] 2- |
Fe(III) | [Fe(H2O)6]3+ [FeCl2]+ [FeCl4]− | [Fe(H2O)6]3+ [Fe3O(CH3COO)6](CH3COO)2 | [Fe(H2O)6]3+ [Fe3O(CH3COO)6](CH3COO)2 | [Fe(H2O)6]3+ [Fe(H2O)5(OH)]2+ [Fe(H2O)4(OH)2]+ | [Fe3O(CH3COO)6](CH3COO)2 [Fe(NH3)6]3+ |