Density and Compressibility of Oxygen in the Critical Region

Density-versus-height profiles have been measured in the critical region of oxygen by means of capacitance techniques. Results are given for the liquid and vapor densities at coexistence, for compressibilities along the coexistence curve to within $t\equiv \frac{(T-T_c)}{T_c}=-6\mathrm{}\times {10}^{-5\mathrm{}}$, for compressibilities along the critical isotherm to within $\frac{(\rho -{\rho }_c)}{{\rho }_c}=5\mathrm{}\times {10}^{-2\mathrm{}}$, and for compressibilities along the critical isochore to within $t=2\mathrm{}\times {10}^{-4\mathrm{}}$. The data are analyzed in terms of power-law descriptions and are shown to be in excellent agreement with recent scaling-law analyses of data for other fluids.