Variable Magnetic Moments of Cobaltous Compounds

Abstract

IN the course of an investigation on the magnetism of cobalt compounds, we have found a notable difference between the magnetic moments of the blue and violet forms of bispyridylcobaltous chloride, (Co₂PyCl₂). The violet form, which is stable at room temperature, was first prepared in 1894 by Reitzenstein¹; the blue form was obtained in 1927 by Hantzsch and Schlegel² by dissolving the violet form in chloroform and precipitating the substance by dilution with ligroin. The blue form can also be prepared by heating the stable form to 120°; it is unstable at room temperature and reverts to the violet form in a few days. Much work has been done on the absorption spectra, molecular weight, and conductivity of these substances³.