Table 1:

Core-valence correlation energies for hydrocarbons calculated by the CBS extrapolation of the CCSD(T)/cc-pwCVNZ ($\mathrm{N}=\mathrm{T},\mathrm{Q}$) energies

Name	$\frac{-\Delta E_{\mathrm{CV}}}{\mathrm{kJ}\cdot {\mathrm{mol}}^{-1}}$	$\frac{-\Delta E_{\mathrm{CV}}/n_{\text{C}}}{\mathrm{kJ}\cdot {\mathrm{mol}}^{-1}}$
ethane	314.42	157.21
propane	471.46	157.15
butane	628.52	157.13
2-methylpropane	628.55	157.14
cyclohexane	942.38	157.06
ethylene	314.21	157.11
propene	471.49	157.16
2-methylpropene	628.68	157.17
acetylene	314.55	157.28
benzene	943.15	157.19
Average:		157.16 ± 0.12