Summary table of Transition Metal Complex Ion colour in solution

Colour in aqueous solutIon Colour in aqueous NH3 / OH- (NaOH) Excess
// [M(H2O)6]M+ OR M+ added dropwise to solution NaOH Excess NH3




[Cu(NH3)4(H2O)2] - Deep/dark Blue
2+ 2+
Cu [Cu(H2O)6] - Pale Blue [Cu(OH)2(H2O)4] - Pale Blue precipitate INSOLUBLE solution, part ligand substitution


Fe2+ [Fe(H2O)6]2+ - Pale Green [Fe(OH)2(H2O)4] - Dark Green precipitate INSOLUBLE INSOLUBLE

[Fe(OH)3(H2O)3] - Orange-Brown Precipi-
3+ 3+
Fe [Fe(H2O)6] - Yellow tate INSOLUBLE INSOLUBLE

[Mn(OH)2(H2O)4] - Pale Brown precipi-
2+ 2+
Mn [Mn(H2O)6] - Pale Pink tate INSOLUBLE INSOLUBLE



[Cr(OH)6]3-
[Mn(H2O)6]3+ - Violet (heat/ - Dark
Impurities can make appear Green so- [Cr(NH3)6]3+ - Purple solution, full
Cr3+ green) [Cr(OH)3(H2O)3] - Green-Grey precipitate lution ligand substituion