Molecular susceptibility. The determination of molar Cotton-Mouton constants at infinite dilution in benzene or cyclohexane

Abstract

Reliable measurements of the small incremental Cotton-Mouton constants encountered at low solute concentrations with solutions in which the magnetic birefringences of solute and solvent do not differ widely cannot be made with equipment at present available. Five such systems are examined in this paper. It is shown that the larger incrementa easily observable among stronger solutions can be fitted to empirical equations containing ascending powers of the concentrations and hence estimates of ΔC/w₂ as w₂ approaches zero become accessible. Values of ∞(_mC₂) obtained by this device agree reasonably with others directly drawn from much weaker solutions of the same solutes in carbon tetrachloride or cyclohexane, i.e, in media for which C₁ = 0.