Talk:Mattauch isobar rule

Electron Capture

It might be mentioned that the rule is only valid if one includes electron-capture as a decay mode. It is hypothetically possible for the mass difference to be small enough that neither an electron in one, nor a positron in the other, can be created. That would enable two adjacent bare nuclei to be absolutely stable. That's the case for ⁷Li and ⁷Be. But once an electron is bound, to the nucleus, it appears that electron capture can occur if beta decay can't. — Preceding unsigned comment added by Johnm307 (talk • contribs) 17:57, 5 February 2021 (UTC)[reply]

247

247 also seems to be a violation, at least under the looser wording of this rule. ²⁴⁷Cm and ²⁴⁷Bk are of course both unstable, but neither has been observed to undergo beta decay. ²⁴⁷Cm should theoretically release energy with beta decay to ²⁴⁷Bk, but small decay energy and large spin difference inhibits it. Double sharp (talk) 05:13, 1 January 2022 (UTC)[reply]