The linear correlations of enthalpy of formation differences with electronegativity (covalent potential, V-x), published by Luo and Benson (LB), have been reexamined with inclusion of additional data for silicon and other group 14 organometallic compounds, While there is support for the idea that the covalent potential represents a good scale for such correlations, certain conclusions of LB are not supported. The correlations yield the following Delta H-f(0) values (kT mol(-1)): SiH3I, +8.6; Me3SiF, -586; Me3SiNH2, -291; Me3SiSH, -273, in close agreement with LB. However, there is no case for revision of Delta H-f(0)(Si2H6) = 80.0 kJ mol(-1) and our estimated Delta H-f(0) values (kJ mol(-1)), for MeGeH3 (42 +/-4) and MeSnH3 (118 +/- 4) do not fit the linear correlations previously proposed. It is shown that average hydrogen-for-methyl substitution enthalpies fit best a nonlinear correlation with V-x, just as shown earlier by Benson and co-workers for the same correlation with Pauling electronegativity.