Abstract
The investigation of the magnetic properties of chromium bi-nuclear complex compounds was made. The results of the magnetic susceptibility measurements were analyzed on the assumption that their magnetic behaviours are determined mainly by the superexchange interaction between two Cr+3 ions in the same complex unit. The coefficient of the superexchange interaction J was estimated to be about −30 k in the cases of [(NH3)5Cr–OH–Cr(NH3)5]+5 and [(NH3)5Cr–OH–Cr(NH3)4OH]+4 complex ions. In the case of [(NH3)5Cr–O–Cr(NH3)5]+4, the susceptibility is very small below room temperature, hence a large absolute value of J is required to account for the experimental result. The susceptibility of [Cr(NH3)5Cl]Cl2 which is a usual mononuclear complex salt, was measured for the sake of comparison with the above mentioned bi-nuclear complex salts. The susceptibility obeys in this case the Curie-Weiss law in the range between 2.5°K and room temperature. The Weiss constant Θ is −0.8°K±0.1°K and the Curie constant C is 1.82. The X-ray powder patterns of these complexes were taken and examined in comparison with the magnetic properties.
