The weiss constant of paramagnetic ions in the S-state - Part I—Aqueous solutions of manganous salts
Recent theoretical studies by Van Vleck and others on the magnetic behaviour of paramagnetic ions in the S-state,et al., Mn++, predict that their susceptibilities should follow the simple Curie law of temperature dependence. The available experimental data for aqueous solutions of manganous salts, however, do not verify this result, the data conforming to the Weiss relationX=C (T−θ) whereθ, instead of being zero as required by theory, has a value as high as 22 to 28. The present paper gives an account of some fresh measurements on aqueous solutions of MnCl2, Mn(NO3)2 and MnSO4 of various concentrations, by a convenient form of Gouy’s method. The susceptibility data for the Mn++ ion obtained from these measurements do conform to the simple Curie law, as predicted by theory. Further the Curie constant of the Mn++ ion is found to be practically the same for all the solutions, being independent of the nature of the salt and of its concentration, and it corresponds to a magnetic moment of 29·3 to 29·4 Weiss magnetons, in agreement with the theoretical value for the6S5/2 state,viz., 29·4.