Thorough analysis of theUsvs.Upprincipal Hugoniot data for liquidCCl4shows that our values along with all the data reported by other groups except the low pressure results of Dick can be described by the single smooth function proposed by Woolfolk et al. with the following coefficients:Us/C0=(2.08±0.07)+(1.34±0.04)Up/C0−(1.08±0.07)exp((−1.2±0.2)Up/C0).This satisfies the boundary conditionUs=C0=926&hthinsp;m/satUp=0and gives the same asymptotic linear relationship as the best-fit expression reported by Dick at shock pressures above ∼16 GPa. On-Hugoniot temperatures calculated using the EOS of Cowperthwaite and Shaw and the revisedUsvs.Upare in good agreement with the results of our infrared (IR) measurements and reported optical pyrometry data. The maximum discrepancy does not exceed 5&percent; in the 3.3 to 7 GPa and 10 to 15 GPa shock pressure ranges and is less than 10&percent; for other pressures below 20 GPa. Within the accuracy of our data, the behavior of single-shockedCCl4does not contradict to the predictions of the constant(∂P/∂T)vmodel, at least between 3.3 and 7 GPa. All reliable experimental results suggest only two singularities along the principal Hugoniot ofCCl4:the threshold of chemical reactions at 7 GPa and complete decomposition at 20 GPa. ©2000 American Institute of Physics.