Effect of Pressure on the Spectra of Certain Transition Metal Complexes

The effect of pressure (to 130 000 atmospheres) has been measured on the splitting of the 3d levels of the nickel and chromium ions complexed with water and ammonia. Data have also been obtained on CoSO4· 7H2O and K3Fe(CN)6. In general, the effect of pressure is to increase the effect of the ligand field and to increase the splitting of the levels. This is interpreted in terms of the change in ligand-metal distance. A phase transition was noted in [Ni(H2O)6]SO4 at 65 000 atmospheres. A charge transfer band was also observed in [NiNH3)6]Cl2. The effect of pressure is to increase the intensity with no apparent change in the location of the maximum.