begin mathsize 48px style X subscript M equals open parentheses I E space plus thin space E A close parentheses divided by 2 end style

XM =Electronegativity of an element ; IE = Ionization Energy ; EA =Electron Affinity 

begin mathsize 36px style X subscript A minus X subscript B equals 0.102 square root of E subscript A B end subscript minus left parenthesis E subscript A A end subscript. E subscript B B end subscript right parenthesis to the power of 1 half end exponent end root end style

XA , XB = Electronegativity of element A and B , such that XA > XBEAA =Bond energy of the A-A bond; EBB =Bond energy of the B-B bond;

EAB =Bond energy of the A-B bond;