The susceptibility critical exponent for a nonaqueous ionic binary mixture near a consolute point

We report turbidity measurements of a nonaqueous ionic solution of triethyl n-hexylammonium triethyl n-hexylboride in diphenyl ether. A classical susceptibility critical exponent γ=1.01±0.01 is obtained over the reduced temperature range 10−4≤ t≤10−1. The best fits of the sample transmission had a standard deviation of 0.39% over this range. Ising and spherical model critical exponents are firmly excluded. The correlation length amplitude ξ0 from fitting is 1.0±0.2 nm which is much larger than values found in neutral fluids and some aqueous binary mixtures.