transition elements colours

• Mn 2+


  pink/buff
• Cr 3+


  green
• Fe 2+


  green
• Fe 3+


  yellow
• Cu 2+


  pale blue
• Co 2+


  deep blue
• complex ion 


  when ligands form a dative covalent bond with a transition metal ion
• ligand


  atom/ion/molecule that can form a dative covalent bond by donating 2e- to a transition metal ion
• monodentate ligand 


  forms one dative covalent bond
• [Fe(H2O)6]2+ (aq) green solution


  Fe(H2O)4(OH)2 (s) green precipitate
• [Cu(H2O)6]2+ (aq) pale blue solution 


  Cu(H2O)4(OH)2 (s) pale blue precipitate
• [Mn(H2O)6]2+ (aq) pink solution


  Mn(H2O)4(OH)2 (s) pink/buff precipitate
• [Fe(H2O)6]3+ (aq) yellow solution


  [Fe(H2O)3(OH)3 (s) orange/brown precipitate
• bidentate ligand 


  forms 2 dative covalent bonds
• [Cr(H2O)6]3+ (aq) green solution 


  [Cr(H2O)3(OH)3 (s) grey green precipitate