THE CORRELATION OF EXCESS MOLAR REFRACTION AND EXCESS VOLUME FOR SOMEBINARY-SOLUTIONS - A NEW APPROACH

It nas long been Known that the molar refractions or solutions, R(v) = {(n(2) - 1)/(n(2) + 2}V-v(m), can be estimated from those of the sepa rated components using additivity relations, but deviations from such rules have been large enough to prevent practical application (such as the calculation of excess volumes from excess refractive index data, or vice versa). The present paper develops an empirical correction to additivity resulting from asymmetry in the concentration dependence of the dispersion energy, thus permitting practical application of addit ivity rules for R(v). With this new approach, it becomes possible to u se conveniently obtained continuous-dilution differential refractometr y data (c.d.d.r.) to yield both excess molar refractions and excess vo lumes over the entire concentration range. (C) 1996 Academic Press Lim ited