Dielectric-constant anomaly near the consolute point of a binary mixture: Nitrobenzene-isooctane

The static dielectric permittivity of a nitrobenzene-isooctane mixture shows, along its critical isochore, a 0.3% deviation from normal behavior at a temperature of 5×${10}^{-3\mathrm{}}$ K above $T_c$. Near the consolute point, no gravity effects resulting from composition gradients are detected. A free fit of the critical exponent $\theta$ yields a value of 0.855±0.035, in good agreement with the theoretical values.