User talk:Double sharp

The page "List of nuclides"

I see you changing the split point 5 × 10⁸ years to 10⁸ years. But now, "Primordial radioactive nuclides (half-life > 10⁸ years)" looks inconsistent: A radionuclide having suffered 9 half-lives would be primordial, but certainly not one that has suffered 45... 103.166.228.86 (talk) 18:40, 15 September 2024 (UTC)

Well, current sensitivity is actually not that far off finding ²⁴⁴Pu (see the article): we're about an order of magnitude away. I won't be surprised if it really gets confirmed as primordial at some point (though maybe we need to wait another decade or two). Of course ¹⁴⁶Sm and ²⁴⁴Pu will still not be useful primordials, but it'd be fun to have them back (for a while we had ²⁴⁴Pu as primordial based on the 1971 result, that in retrospect cannot be right). :) Double sharp (talk) 04:29, 16 September 2024 (UTC)

I would indeed be happy to see ¹⁴⁶Sm be confirmed as primordial, for the sake of completeness - the hole of even-even nuclides between ¹⁴⁴Sm and ¹⁴⁸Sm is just unbearable... 129.104.241.231 (talk) 00:02, 18 September 2024 (UTC)

The N = 82 shell closure is a harsh mistress. :( Double sharp (talk) 06:01, 18 September 2024 (UTC)

The magic numbers only care about their own comfort and don't care about the lives of others :( 129.104.241.231 (talk) 11:20, 19 September 2024 (UTC)

The combo of Z = 82 and N = 126 is also harsh, killing Po~Ac with no mercy... :( Nucleus hydro elemon (talk) 15:12, 19 September 2024 (UTC)

But at least Ra gets enough beta-stable isotopes that it gets out of the killing zone of N = 126, with ²²⁶Ra (Z = 88, N = 138) able to have a respectable 1600-year half-life. :)

Unfortunately, as if making new superheavies wasn't hard enough already, the 5g row will probably head straight into the firing squad of N = 184 when it comes to doing Cf+Ni for 126. :( Double sharp (talk) 15:17, 19 September 2024 (UTC)

You guess what? My biggest wish is to live in my next life in a universe where the energy of the alpha nuclide is at least 5 MeV higher than in our universe :( 129.104.241.231 (talk) 15:29, 19 September 2024 (UTC)

Yeah but the cruelest enemy of superheavy elements is SF, not alpha decay... 129.104.241.231 (talk) 15:32, 19 September 2024 (UTC)

If nothing else, such a universe would probably not make the mistake of predicting astatine to be a black solid. That always got on my nerves from the time I realised what was wrong with it. Groups 13 to 16 eventually turn metallic, so why shouldn't groups 17 and 18!? (I'm still betting on oganesson turning out to be a full-fledged metal at STP, not just a semiconductor. But who really knows?) It would also be nice to know more about radon chemistry: the absence of chlorides is still a mystery, but the ionic-looking difluoride is really cool. And it would be nice to know if the destabilisation of 6p_3/2 is enough to make francium have oxidation states above +1. Ah well. Such forbidden mysteries. :(

That's true, but the shell closure strongly hinders SF, and is the only reason they're protected enough to be seen in the first place. When that protection gets lost, there's nothing holding back the terrible onslaught of fission. :(

P.S. the superheavy I would most like to see "stabilised" is copernicium. :D Double sharp (talk) 15:50, 19 September 2024 (UTC)

About ²²²Rn/²²²Fr

Hi! I have just noticed the mass excess of ²²²Rn given in NUBASE is 16372.0 ± 1.9 keV, while the mass excess of ²²²Fr is 16378 ± 7 keV, corresponding to an atomic mass of 222.0175825(75) for ²²²Fr. While the data are not decisive, ²²²Rn has lower energy if we ignore the error margin. So what do you think of the status of ²²²Rn? This will affect how we formulate in Isotopes of radon and Double beta decay. 129.104.241.231 (talk) 11:23, 19 September 2024 (UTC)

I think we should leave it open still, since Belli et al. explicitly predicted the single beta of this isotope and tried to find it. I'm naturally quite curious which way round it'll go. :) Double sharp (talk) 13:30, 19 September 2024 (UTC)

Thanks! I added the source to both page I mentioned. 129.104.241.231 (talk) 15:08, 19 September 2024 (UTC)