Bond Energies and Bond Distances of Hydrocarbons

Abstract

The relations between carbon‐carbon bond energies [B(CC)] and distances [R(CC)] and carbon‐hydrogen bond energies [B(CH)] and distances [R(CH)] are taken to be a parabola and a straight line, respectively, $$\mathrm{B(}\mathrm{CC}\text{)=1450.762–1644.151·R(}\mathrm{CC}\text{)+491.936·R(}\mathrm{CC}{)}^2$$ and $$\mathrm{B(}\mathrm{CH}\text{)=\hspace{0.17em}252.956−\hspace{0.17em}141.721·R(}\mathrm{CH}\mathrm{),}$$ yielding $$\mathrm{B(}\mathrm{CH}\text{)=\hspace{0.17em}\hspace{0.17em}98.104−\hspace{0.17em}\hspace{0.17em}0.075·B(}\mathrm{CC}\text{)+[3.196·B(}\mathrm{CC}{\text{)−246.048]}}^{\frac{1}{2}}$$ and $$\mathrm{R(}\mathrm{CH}\text{)=\hspace{0.17em}\hspace{0.17em}1.396−\hspace{0.17em}\hspace{0.17em}0.594·R(}\mathrm{CC}\text{)+0.261·R(}\mathrm{CC}{)}^2.$$ This system of equations is based on the assumption that the heat of sublimation of carbon L(C)=169.75 kcal. Similar relations with L(C)=124.3 and 135.8 kcal are also derived.