Revised Formula for Gradual Sum Even Way to Calculate Group Electronegativity

According to the principle of electronegativity equilibrium,we revised the formula for gradual sum even way to calculate electronegativities of groups,and calculated some often-used electronegativities of groups by the revised formula in this paper.The calculated results not only conform very much to the several scales of group electronegativities which are widely accepted,but also can distinguish electronegativities of symmetrical groups(-XY and-YX),indicating regular changes.