Pauling's electronegativity is based on

Pauling scale is a numerical scale of electronegativities based on bond-energy calculations for different elements joined by covalent bonds.

${\mathrm{X}}_{\mathrm{A}}-{\mathrm{X}}_{\mathrm{B}}=0.208{\left[{\mathrm{E}}_{\mathrm{A}-\mathrm{B}}-({\mathrm{E}}_{\mathrm{A}-\mathrm{A}}\times {\mathrm{E}}_{\mathrm{B}-\mathrm{B}})1/2\right]}^{1/2}$

Where X_A and X_B are EN of atom A and B , E_A−A,E_B−B and E_A−B are bond eneriges of molecules of A₂,B₂ and AB.