Differing colours and magnetic properties of coordination complexes
Many coordination complexes of transition metals are colored. As the table below shows, the colour of the complex depends on both the metal ion and the ligand.
Some coordination complexes of metal ions have unpaired electrons and thus weigh more in the presence of an magnetic field. The number of unpaired electrons also depends on both the metal ion and the ligand.
Co(NH3)63+
| different metal ions – same ligand | |
| V(H2O)62+ | |
| Cr(H2O)62+ | |
| Fe(H2O)62+ | |
| Ni(H2O)62+ | |
| Cu(H2O)62+ | CuCl42– |
| Zn(H2O)62+ | same metal ion different ligands |
Some coordination complexes of metal ions have unpaired electrons and thus weigh more in the presence of an magnetic field. The number of unpaired electrons also depends on both the metal ion and the ligand.
Co(NH3)63+
Crystal field theory enables chemists to rationalize the differing colors and magnetic properties on the basis of the d-electron configuration of the central metal atom.
We will apply crystal field theory only to octahedral complexes such as the cobalt complex shown at the right. In octahedral complexes the bonds to the ligands lie on the x,y,z coordinate axes.
We will apply crystal field theory only to octahedral complexes such as the cobalt complex shown at the right. In octahedral complexes the bonds to the ligands lie on the x,y,z coordinate axes.