User talk:Double sharp

This user is busy in real life and may not respond swiftly to queries.

Archives

Archive 1 Archive 2 Archive 3 Archive 4 Archive 5 Archive 6 Archive 7 Archive 8 Archive 9 Archive 10 Archive 11 Archive 12 Archive 13 Archive 14 Archive 15 Archive 16 Archive 17 Archive 18 Archive 19 Archive 20 Archive 21 Archive 22

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)[reply]

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)[reply]

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)[reply]

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

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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

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)[reply]

Gd would have 9 naturally occuring isotopes, At would behave like Ta to occur mainly as ²¹⁵At and a small portion of ^214mAt, and there will perhaps be no more beta-decay mystery for ²²²Rn and ²⁴⁷Cm. What a fantastic world... 129.104.241.231 (talk) 18:19, 19 September 2024 (UTC)[reply]

Come to think of it, a world where Rn is stable immediately suggests an earlier discovery of noble gas chemistry. That would be fun. I wonder what the last natural element would be in this case. If the actinoid series can be completed (or nearly so), then perhaps a separate f-series could be recognised earlier: then Nd (maximum +4) vs U (maximum +6) somewhat brings to mind Fe (maximum +6 in bulk) vs Ru (maximum +8), and Cm–No will make a more extreme partner to Gd–Yb. The big drop in oxidation states near the end of the 5f series makes one think of the 4d series; I've thought for a while that if we had long-lived quasi-stable elements to the 6d series, then we wouldn't be having the La vs Lu argument, as it would be obvious that Lr is much more like a transition metal than Ac is. (Lu is also more like a transition metal than La, but not quite as obviously.) Ah well, I can dream about the chemical consequences while you dream of the nuclear-physics ones. ;) Double sharp (talk) 10:38, 20 September 2024 (UTC)[reply]

I dream about their geochemical properties then. :) I only guess up to Rg because Cn will be too weird, see below.

Tc probably lives together with Re, so do Rn with noble gases, Fr with Rb/Cs, Ra with Sr/Ba, and Pm, Ac, Am–Fm, Lr with rare-earth elements. Rf–Rg might be similar to their lighter congeners Hf–Au if the relativistic effects aren't too crazy.

I'm not sure do Pa, Np, Pu comes together with U or have its own ore. Md and No have stable +2 cations, not sure will this let them become closer to Ba than rare-earth elements. I don't know do Po behaves more similar to Bi or Te. Both At⁻ and At⁺ are stable, I'm not sure which one will dominate the geochemistry of At.

Cn probably have some noble gas character, and its predicted melting point and boiling point might cause a rain of Cn happen in that world. I don't want to live in a world with copernicium rain, it is just too dangerous. Nucleus hydro elemon (talk) 11:28, 20 September 2024 (UTC)[reply]

There would be no need to worry about copernicium rain - remind that this is a world full of ⁸Be :) 129.104.65.10 (talk) 12:07, 20 September 2024 (UTC)[reply]

I kind of suspect that in this world Be is like Al: useless to biology because it's insoluble at physiological pH, but tolerated because it's so common. Copernicium would be weird indeed. Still, I think it'd be quite rare like krypton and xenon already are in the real world. :) Double sharp (talk) 14:46, 20 September 2024 (UTC)[reply]

Before discussing implications for biology, we also have to consider how hypothetical beryllium burning would affect stellar evolution. A while back I had read a few interesting papers on the subject and written a bit about it (Beryllium-8#Hypothetical universes with stable 8Be). ^Complex/_Rational 16:18, 20 September 2024 (UTC)[reply]

If ⁸Be is stable because ⁴He is destabilized, then ⁵He and ⁵Li might be bound too. This will drastically change the Big Bang nucleosynthesis at that universe. Nucleus hydro elemon (talk) 04:36, 21 September 2024 (UTC)[reply]

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)[reply]

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)[reply]

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