Simple mass relations of mirror nuclei

The Coulomb energy difference of mirror nuclei is parametrized in terms of charge radii with further consideration of deformation and shell effects, in addition to the odd-even effect originated from the pairing phenomenon between the last two protons. With only three parameters, we arrive at a very simple mass relations of mirror nuclei, with the root-mean-square deviation of only 63 keV for nuclei with proton number $Z>10$, without resorting to any statistical correlations. Predicted mass values of proton-rich nuclei (including some of the unbound systems) are tabulated as Supplemental Material of this paper.