The heat of formation of the ethyl radical

An examination of the results of measurements of the forward and reverse rate constants for the reaction\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm H} + {\rm C}_{\rm 2} {\rm H}_{\rm 6} \mathbin{\lower.3ex\hbox{$\buildrel\textstyle\rightarrow\over {\smash{\leftarrow}\vphantom{_{\vbox to.5ex{\vss}}}}$}} {\rm H}_{\rm 2} + {\rm C}_{\rm 2} {\rm H}_{\rm 5} $$\end{document}shows that agreement between the kinetics and the thermochemistry is achieved only through use of a value of ΔH f (C 2 H 5 ) = 28 kcal mol −1 . This system therefore provides further support for the recent measurement of this quantity.