The saturated carbons in NBD, NBN, and NDA exhibit a similar trend. That is, the flag C7 has smaller C1s energy than the bridge carbons (C1 and C4) of the compounds, except for PPL. The bridge carbons in NBA, NBN, NBD, and QC require larger energy to oxidize. This aligns with the stability study of norbornane radicals where 2-norbornayl > 7-norbornayl > 1-norbornayl . The calculated C1s CEBEs for NBD, NBN, and NBA exhibit the same trends as the C1s core energies estimated using core orbital energies in our earlier study , indicating that while relaxation energy and ionic states play a significant role, they do not alter the qualitative energy trend but result in a shift. and in Figure .