Abstract: According to the relationship between gravitational potential and electrostatic potential, and the physical meaning of the mass-to-electricity (mass of per unit electricity) Sr, the variation of ionic radius r with Sr and the phase difference factor of ion were studied. For positive ions, configuration the r varied directly with lgSr and the phase difference factor, and for negative ions with stable electronic configuration, the r varied quantitatively with as Sr and the phase difference factor. Calculating formulas for the positive ionic radius with stable and unstable electronic configurations, and the negative ionic radius with stable electronic configuration were obtained. The correlation coefficient R and test of significance (F) showed that r was closely relative to Sr and the phase difference factor. 138 radii of positive ions that contained 96 elements were fitted. The average absolute error of the 138 radii of positive ions was 2.0 pm compared with the representative radii of ions, and the relative error was 2.5%. 30 positive ionic radii of rare gases et al. were calculated by the formulas, and the calculated values were relatively reasonable. That was a new path of calculating the radi of ions, including complex ions.

Key words: Ionic radius, Mass-to-electricity, Factor of phase difference, Calculating formula, Ion