Paramagnetic Resonance in some Complex Cyanides of the Iron Group I: Experimental Results

The results are described of paramagnetic resonance experiments on some complex cyanides of the iron group. The form of the spin Hamiltonian is found and the values of the parameters are measured. Potassium chromi-cyanide and potassium vanadocyanide (configuration 3d3), diluted with the isomorphous diamagnetic salts, have effective spin 3/2 with an electronic splitting of rhombic symmetry. The g-value is closely isotropic at 1.992, and the hyperfine structure is also isotropic. Potassium ferricyanide and potassium manganicyanide (configuration 3d5), diluted with the isomorphous diamagnetic salt, have effective spin ½ with anisotropic g-values between 0.6 and 2.6. The manganicyanide also exhibits an anisotropic hyperfine structure. The behaviour of undiluted potassium chromicyanide and potassium ferricyanide suggests that there is appreciable exchange interaction between neighbouring paramagnetic complexes.