User talk:Double sharp/Archive 22

I was wondering that, which of ²⁵⁰Cm, ²⁵⁴Cf, ^252-255Es can be produced in quantity at least of micrograms? I think ^253,254,255Es are available because they can be formed when ²⁵²Cf absorbs neutron; for the others, I don't think so. 14.52.231.91 (talk) 01:01, 16 August 2024 (UTC)

Seems to be just Es-253 and Es-254. Es-255 is shorter-lived...but I'm not sure it has ever been done even for Es-253 and Es-254. Double sharp (talk) 04:38, 16 August 2024 (UTC)

Thanks! At least we can have confidence with ²⁵³Es, as Wikipedia states explicitly that "Einsteinium is the element with the highest atomic number which has been observed in macroscopic quantities in its pure form as einsteinium-253". 14.52.231.91 (talk) 00:46, 19 August 2024 (UTC)

I think ²⁵⁴Es is also OK because it has been used in the nucleosynthesis of ununennium. As for ²⁵⁵Es, it has even longer half-life than ²⁵³Es... 14.52.231.91 (talk) 00:55, 19 August 2024 (UTC)

Back in that 1985 attempt, less than a microgram of ²⁵⁴Es was actually used – which was probably one of the reasons nobody saw anything. (Another is also probably that back then, the cross-section limit wasn't enough to see anything from ²⁴⁸Cm+⁴⁸Ca either.)

I actually have a significant worry that 119 will take a while to come after 120 (which has taken a long time already). That's because with the cross-sections likely to be the way they are, a ²⁴⁹Bk target might very well have significantly decayed by the time the first successful fusion occurs. And using ²⁴⁸Cm+⁵¹V gets the penalty of having the odd proton in the projectile instead of the target, while ²⁴³Am+⁵⁴Cr will likely have a smaller cross-section than ²⁴⁹Bk+⁵⁰Ti and leads to a more neutron-poor ER. But oh well, we've all waited fourteen years and counting for 120 in the first place. :) Double sharp (talk) 04:49, 19 August 2024 (UTC)

Either 119 or 120 coming first would be OK to me - we would be closer to finally finishing the periodic table up to n + l = 8 :) 14.52.231.91 (talk) 02:27, 20 August 2024 (UTC)

Haha, yes. The Janet table is great! But what I really want is to see the g-block. Hopefully, after that people will finally universally get group 3 correct (after Y comes Lu and Lr, certainly not asterisks or La-Ac). :) Double sharp (talk) 02:55, 20 August 2024 (UTC)

G-block would be a lot harder, and it's even worse that the first element with a 5g electron comes much later... 14.52.231.91 (talk) 07:00, 20 August 2024 (UTC)

Yeah, probably each change of projectile will mean things get one or two orders of magnitude worse. :( Probably already E121 has 5g low enough to participate in chemistry at least. But doing actual chemistry with the expected half-lives and low rate of production seems very far off. Still nobody has done Mt. (Okay, to some extent it's partly that Mt chemistry will probably be like Ir, making it hard to get into solution and also hard to find volatile compounds without using F₂.) Double sharp (talk) 10:00, 20 August 2024 (UTC)

What I also find curious is that only the lightest isotopes of Mt and Rg have been directly synthesized and no new hot fusion reactions have been attempted for those elements. ^Complex/_Rational 13:55, 20 August 2024 (UTC)

@ComplexRational: Considering the cross-section trend, wouldn't it be easier to fill them in from Mc, just like it's easier to produce Cn as an overshoot product from Fl? Though I have been hungering for ²³¹Pa+⁴⁸Ca for a while, especially now that ²³²Th+⁴⁸Ca has been successful. (And can someone please do ²⁴¹Am+⁴⁸Ca already? :D) Double sharp (talk) 14:57, 20 August 2024 (UTC)

Sadly it seems like no one cares about ²³¹Pa + ⁴⁸Ca, even the most recent reference about it was from 1981. :(

On the other hand, ²⁴¹Am + ⁴⁸Ca got a recent reference.^[1] In there, reactions involving ²⁴¹Am was even considered to create elements 119~122. :) Nucleus hydro elemon (talk) 16:01, 20 August 2024 (UTC)

@Nucleus hydro elemon: T_T Thanks for the papers! (Though I'd want to stick to ²⁴³Am for going beyond 118, at least at first. I wonder how close we are to the proton drip line in this region...) Double sharp (talk) 16:11, 20 August 2024 (UTC)

For cross sections, targeting Mc and observing its decay chains would certainly be more feasible based on experimental data. However, indirect synthesis is said not to be optimal for investigation of chemical properties.

And re below, the KTUY chart that I uploaded some time ago suggests that we are already very near the drip line for odd-Z superheavy elements, but the partial half-lives for alpha/SF are expected to be longer than those for proton emission, so I'm not sure if we'd even know. ^Complex/_Rational 18:50, 20 August 2024 (UTC)

@ComplexRational: Sure, though Cn and Nh were both investigated through indirect synthesis. So at least it's a possible option when the cross-section is likely to be worse for the lighter elements. :) Thanks for the answer on the drip line! Double sharp (talk) 02:55, 21 August 2024 (UTC)

@ComplexRational: Double sharp (talk) 10:09, 18 August 2024 (UTC)

I've come up with the calendar for civilizations living on Earth that use octal or nonary. I suppose that a week is still 7 days, because the number seems to be base-independent. I will use our seconds for comparison, even though a non-decimal civilization would have defined a second to be something else than 1/86400 of a day.

For people using nonary: Set a leap year in every 4₉ years, then eliminate one every 130₉ years, and add one back every 800₉ years.

This will make 184₉ leap years out of every 800₉ years, so a year would be 31638.3₉ seconds longer than a multiple of a day. The tropical year is 31631₉ seconds longer than that, so the difference is 7.3₉ seconds. A period of 800₉ years contains exactly 51337₉ weeks.

For people using octal, there are two choices. The more natural one would be to set a leap year in every 4₈ years, then eliminate one every 200₈ years. But we have to wait for 1600₈ years until the weekdays repeat themselves. Another choice with a period of 1600₈ years is to set a leap year in every 4₈ years, eliminate one every 160₈ years, then add one back every 1600₈ years.

In either case there will be 331₈ leap years out of every 1600₈ years, so a year would be 50675₈ seconds longer than a multiple of a day, which is only one second short compared to the tropical year!

In conclusion, the octal calendar wins by accuracy but the nonary one wins by a shorter period of weekdays (for comparison, our decimal calendar has yet lower accuracy but an even shorter weekday period). Still, it's amazing that the orbital period of the Earth can give a calendar in periods of a multiple of centuries which is accurate enough, for people using either decimal, octal or nonary :) 14.52.231.91 (talk) 06:51, 22 August 2024 (UTC)

By the way, my edit triggered filter 1321 when I tried to post all the paragraphs as a whole. But when I performed the edits in posting just some paragraphs at a time, the edits were OK. 14.52.231.91 (talk) 06:55, 22 August 2024 (UTC)

It seems that the edits were limited to 1280 characters. (Of course, since I did not mean to do any vandalism, my test stops here.) 14.52.231.91 (talk) 07:03, 22 August 2024 (UTC)

Very cool! The edit filter may not have appreciated these calendars, but I do! :) Double sharp (talk) 07:56, 22 August 2024 (UTC)

Thanks! :) 14.52.231.91 (talk) 00:49, 23 August 2024 (UTC)

This reference^[1] showed their bismuth target that contains ²¹¹At after irradiation (Fig. 1). Even better, the license is CC BY 4.0 and thus the picture can be used in Wikipedia. The problem is I'm not sure is the black stuff in that picture is real, visible ²¹¹At in nanogram quantities, or is it just burnt bismuth or anything else? If it is indeed real ²¹¹At then we might be able to use it in the infobox. :) --Nucleus hydro elemon (talk) 13:49, 24 August 2024 (UTC)

@Nucleus hydro elemon: I hate to give this answer, but it's just physically implausible that you're seeing At in any visible quantity. Still, it could be a good picture to illustrate astatine production, just not in the infobox. :) Double sharp (talk) 14:17, 24 August 2024 (UTC)

Hello Double Sharp! On the Wikipedia Page "Rectified truncated icosahedron" there are listed several related polyhedra, including their nets. Somehow two nets are missing, namely for the btI and mtI (in Conway notation). Is there any possibility for you to upload the last missing nets? This would be great. Kind regards, Sakura787 (talk) 16:06, 7 September 2024 (UTC)

@Sakura787: I'm terribly sorry, but my copy of the Stella software died with my previous computer. Since I no longer have the serial number, I'm no longer in a position to make such diagrams. :( Double sharp (talk) 16:47, 7 September 2024 (UTC)

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)

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)

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)

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)

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)

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)

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)

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)

Well, in that case all the elements might've been made in that universe's Big Bang, just as αβγ originally expected. :) Double sharp (talk) 04:40, 21 September 2024 (UTC)

(And considering a famous work by the γ in question, perhaps this discussion about living in universes with altered physical constants is apropos. ^_^) Double sharp (talk) 04:43, 23 September 2024 (UTC)

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)

For context, see Talk:Continuum hypothesis/Archive 2#CH is of particular interest. Double sharp (talk) 02:23, 27 January 2025 (UTC)

Reply to "Doesn't the existence of Vitali sets (a result of AC) already challenge intuition?": No, not at all in my opinion :) Anyway, why should ${\displaystyle \mathbb {R} }$ be so great that every subset is measurable? The existence of non-measurable sets rather than the non-existence is what looks more natural for me.

By the way, I love the reference you gave, thanks a lot :) 129.104.241.231 (talk) 21:33, 21 September 2024 (UTC)

I am neither a fan of CH nor a fan of ¬CH. I could have insisted that ${\displaystyle 2^{\aleph _{0}}=\aleph _{85}}$ because 85 is my favorite neutron number, but I really do have no opinion: both consequences of CH and of ¬CH are equally valid for me, and it is worthy to state them both. :) 129.104.241.231 (talk) 21:39, 21 September 2024 (UTC)

My personal take is basically: both consequences of CH and ¬CH are indeed equally valid. But the same holds for consequences of AC and ¬AC, despite the fact that mathematicians seem a lot happier to assume AC than otherwise. To that extent, I think it makes sense to ask which one conforms more with my intuitions about sets. So when I say "I'm a fan of CH", I suppose what I really mean is that my fuzzy ideas about how sets should behave are more consistent with the consequences of CH than with those of ¬CH. If we speak this way, about properly axiomatising intuitions, I think it makes sense to say that "CH is true of my sets" and simultaneously "¬CH is true of somebody else's".

With that said, Hamkins' presentation strongly persuades me that CH (actually, GCH) should be true of more people's sets. This is because I think hyperreals are in some sense the "natural" way to do analysis, and that epsilon-delta formulations are to some extent dancing around the intuition. It makes me think of, say, Cardano having to solve many types of cubics because he didn't like negatives. As such I think there's a strong argument that GCH "should" have the status AC currently enjoys among non-set-theorists (well, actually ZF+GCH implies AC, but you know what I mean).

Non-measurability was indeed a bit of a mind-blowing fact when I first encountered it in mathematical popularisations at about eight. :) I would find it intuitive now, but perhaps it has to do with von Neumann's dictum about getting used to things in mathematics. But I think Rodrigo Freire's answer to a MathOverflow question about V=L gets philosophically at the issue here. Though actually his argument persuades me towards V=L, because I would indeed take AC's attitude towards measurability as a "precedent" of sorts, which is why I reject Freiling's argument for ¬CH. BTW, Nik Weaver's answer on that page gets at something interesting: it seems quite plausible that we are in the current situation because non-set-theorists would have quite different intuitions about sets from set-theorists. The former would likely be a lot happier with V=L than the latter. Double sharp (talk) 03:55, 22 September 2024 (UTC)

P.S. Regarding another case of set-theorists and non-set-theorists having quite different intuitions, see this other paper by Joel David Hamkins (2012), where he gives a specific example of an axiom (${\displaystyle \kappa <\lambda \implies 2^{\kappa }<2^{\lambda }}$) that seems extremely natural to non-set-theorists and yet is generally rejected by set theorists. Double sharp (talk) 08:13, 22 September 2024 (UTC)

Most of the real analysis relies on DC, and it is written in the Wikipedia page "It is possible to generalize the axiom to produce transfinite sequences. If these are allowed to be arbitrarily long, then it becomes equivalent to the full axiom of choice", so I have no doubt on AC. That said, my attitude is that whenever ZF/AC_ω/DC is enough to prove a proposition, don't overuse the power of AC :)

Thanks for the link provided, and by the way, I just remembered this interesting implication of CH. 129.104.241.231 (talk) 14:22, 22 September 2024 (UTC)

Well, if you like interesting remarks on what's actually necessary to prove what, you might enjoy this MathOverflow question, regarding whether or not the infinitude of prime numbers is necessary to prove ${\displaystyle \pi }$ transcendental. (The Euler zeta product naturally makes it clear that the infinitude of the primes is related to the irrationality of ${\displaystyle \pi }$, because ${\displaystyle \zeta (2)={\frac {\pi ^{2}}{6}}}$. But this is about transcendence. Though there are some issues on whether you can even define ${\displaystyle \pi }$ properly in a setting where you cannot show that there are infinitely many primes...) :)

My philosophy is basically that the infinite should be like the finite when it comes to counting, on the grounds that ordinals seem to be the most obvious way to introduce "infinity" to children. So I have no issue with transfinite sequences indeed. If some funny things happen to measures, too bad. :)

I think "don't overuse the power of [just about anything really]" is sound advice. On the other hand, sometimes the proof that uses more firepower is the more intuitive one. So, maybe I'd say: do all the crazy stuff you want if it helps you get to the correct result. Then, after admiring your fireworks, step back and ask yourself how much of it was really needed. Double sharp (talk) 16:06, 22 September 2024 (UTC)

P.S. and thanks for that CH implication. :) Double sharp (talk) 04:47, 23 September 2024 (UTC)

P.S. another way CH makes NSA so much nicer. :) Double sharp (talk) 07:31, 25 September 2024 (UTC)

At the GA review of Radium, it was brought up that the infobox image may not actually be radium. I have no way to confirm or deny this but assuming it is what it says it is (radium electroplated on copper foil) it may be of use to provide a caption. I can't see any way to do that in the article or on Template:Infobox radium. Can you point me in the right direction on this? I see it's done for Template:Infobox protactinium. Reconrabbit 15:39, 9 October 2024 (UTC)

@Reconrabbit: I added the caption from the file page (File:Radium226.jpg) to {{Template:Infobox element/symbol-to-top-image/caption}}, so it should show up now. Double sharp (talk) 18:00, 9 October 2024 (UTC)

Manjunatha, H. C; Sowmya, N.; Manjunatha, N.; Gupta, P. S. Damodara; Seenappa, L.; Sridhar, K. N.; T, Ganesh; Nandi, T. (2020-12-08). "Entrance channel dependent hot fusion reactions for superheavy element synthesis". Physical Review C. 102 (6). American Physical Society (APS). doi:10.1103/physrevc.102.064605. ISSN 2469-9985.

This predicted many reactions with cross sections >1 nb. After removing those which don't make sense (such as using ²²³At as target), here are the reactions:

• ²⁵¹Cf(²⁵Mg,4n)²⁷²Ds
• ²⁵⁰Cm(³⁷Cl,4n)²⁸³Nh (if ²⁵⁰Cm is available...)
• ²⁴⁰Pu(⁴³Ca,3n)²⁸⁰Fl
• ²³⁶U(⁵¹V,3n)²⁸⁴Mc
• ²⁴⁸Bk(⁴⁸Ca,3n)²⁹³Ts (if ²⁴⁸Bk is available...)
• ²⁴⁴Pu(⁵²Cr,3n)²⁹³Og
• ²⁵⁰Cm(⁵⁰V,3n)²⁹⁷119 (if ²⁵⁰Cm is available...)
• ²⁴⁹Cf(⁴⁷Ti,n)²⁹⁵120
• ²⁴⁹Cf(⁵⁰Ti,n)²⁹⁸120 (the authors are probably too optimistic for this one.)
• ²⁴⁷Bk(⁶⁰Ni,n)³⁰⁵125 (if ²⁴⁷Bk is available...)
• ²³²Th(⁸²Kr,γ)³¹⁴126

Waiting for someone attempting any of these reactions, even if some products are neutron-poor. :) Nucleus hydro elemon (talk) 13:59, 12 October 2024 (UTC)

@Nucleus hydro elemon: Very cool! Double sharp (talk) 14:21, 12 October 2024 (UTC)

...has reportedly been found, fissioning with a half-life measured in nanoseconds, and is the first SHE isotope found with such a short half-life. There's no full-text or preprint source that I'm aware of, so I guess details must wait until the article gets published. But it's exciting news anyway. ^Complex/_Rational 04:11, 25 November 2024 (UTC)

@ComplexRational: Thanks for the info! Double sharp (talk) 06:25, 25 November 2024 (UTC)

Hello, Double sharp. You have new messages at Talk:Perpetual check.
Message added 22:37, 25 November 2024 (UTC). You can remove this notice at any time by removing the {{Talkback}} or {{Tb}} template.

Vanjagenije (talk) 22:37, 25 November 2024 (UTC)

Not everyone uses the word level to describe a tie. In America we don't. The article should reflect both usages. Briaboru (talk) 23:13, 1 December 2024 (UTC)

@Briaboru: Interesting, I didn't know this. Changed it to "tied", which to me as BrE user is also understandable. Double sharp (talk) 05:16, 2 December 2024 (UTC)

I mean a table of masses of bare nuclei, not of atoms.

By energy conservation we have nuclear mass + Z*electron mass - atomic mass = sum of ionization energies. For ⁴He, the left side is

${\displaystyle (4.001506179129+2\times 0.0005485799090441-4.002603254130)\times 931494103.72=79.00662\,\mathrm {eV} }$,

which is consistent with the sum 79.00514 eV of data given here.

In general, if we need to find nuclear mass, we must also know the data of ionization energies, which are in general incomplete and (more seriously) are suspected to vary for different isotopes of an element. (The calculation above works because the proportion of ³He in natural helium is much, much too tiny). Any idea? 169.155.234.214 (talk) 09:09, 26 December 2024 (UTC)

Currently away on holiday, so a search will have to wait. But indeed no idea off the top of my head. Double sharp (talk) 05:51, 27 December 2024 (UTC)

OK thanks :) 169.155.234.55 (talk) 11:18, 27 December 2024 (UTC)

Thank you! Szelma W (talk) 11:26, 3 January 2025 (UTC)

1. Does isolation means isolation of the element, or a compound is fine too? Fluorine uses the former while rare-earths use the latter.
2. Although no bulk francium has been made, there was a sample of 200000 francium atoms. So, does francium has an isolation date to be listed in the article?

Nucleus hydro elemon (talk) 09:39, 13 February 2025 (UTC)

@Nucleus hydro elemon: Off the top of my head, I think there was some confusion about it historically. In general it seems to me that often obtaining the oxide was considered the important thing, and the reduction to the pure metal (often difficult) was not considered necessary. But I'll need to check.

The question, I guess, would be whether any WP:RS consider that an isolation. I'm uncertain that isolation dates are commonly thought of as making sense for ephemeral elements that can't be made in bulk, but if you can find sources, sure! :D Double sharp (talk) 09:51, 13 February 2025 (UTC)

@Nucleus hydro elemon:I think isolation should mean obtaining the pure element (simple substance), as opposed to discovery which is a chemical proof that the element exists. Changed cerium accordingly. Burzuchius (talk) 12:24, 13 February 2025 (UTC)

I'm thinking about this definition too, but Fr is still a problem (that picture definitely shows pure francium). Nucleus hydro elemon (talk) 04:49, 14 February 2025 (UTC)

"Dale Corson, Kenneth Ross MacKenzie, and Emilio Segrè isolated the element [astatine] by its creation." (doi:10.1007/s10698-022-09452-9) I guess this source implies that synthetic elements have a different definition of "isolation". Nucleus hydro elemon (talk) 13:55, 13 February 2025 (UTC)

Sorry to have had to destroy a few hours work, but that's the risk of WP:BEBOLD.

I guess it might be just barely DUE to mention that symbols have been proposed for other astronomical bodies but have not gained acceptance, citing that paper. If only to save another editor from doing all the same work again.

BTW, wasn't it all a WP:COPYVIO anyway, unless the creator released them under CC-by-etc? 𝕁𝕄𝔽 (talk) 16:35, 14 March 2025 (UTC)

@JMF: Yeah, no worries. There's actually some discussion going at the talk, and I'd appreciate you chiming in for setting down a clearer line. :)

On his website the creator dedicated the symbols to the public domain. Double sharp (talk) 16:38, 14 March 2025 (UTC)

Simple geometric symbols can't be copyrighted, so we're okay regardless unless we use the actual images made by their creator. Moskowitz released SVG files of his fixed-width glyphs, retaining for himself only the variable-width glyphs, for which he's only released PNG files. — kwami (talk) 03:36, 20 March 2025 (UTC)

True enough but in the final analysis, it is wp:FRINGE and (essentially) WP:UGC with minimal recognition and no acceptance. So we shouldn't create a credence for it that it doesn't have in the real world. 𝕁𝕄𝔽 (talk) 11:40, 20 March 2025 (UTC)

I redid the DP stuff in the intros, since these two have density estimates above Grundy et al's limits. You might want to double check my summaries. — kwami (talk) 03:38, 20 March 2025 (UTC)

Moved salacia info to the body of the article — kwami (talk) 05:39, 20 March 2025 (UTC)

Looks good to me! Double sharp (talk) 13:12, 20 March 2025 (UTC)

Template:Extended periodic table (by Aufbau, 50 columns, period 8) has been nominated for deletion. You are invited to comment on the discussion at the entry on the Templates for discussion page. – Jonesey95 (talk) 16:34, 6 April 2025 (UTC)

A discussion is taking place as to whether the article Table of polyhedron dihedral angles, to which you have significantly contributed, is suitable for inclusion in Wikipedia according to Wikipedia's policies and guidelines or if it should be deleted.

The discussion will take place at Wikipedia:Articles for deletion/Table of polyhedron dihedral angles until a consensus is reached, and anyone, including you, is welcome to contribute to the discussion. Users may edit the article during the discussion, including to improve the article to address concerns raised in the discussion. However, do not remove the article-for-deletion notice from the top of the article.

To customise your preferences for automated AfD notifications for articles to which you've significantly contributed (or to opt-out entirely), please visit the configuration page. Delivered by SDZeroBot (talk) 01:03, 24 April 2025 (UTC)

Both articles have "Use British English" in their codes. But in the talk pages of the articles, the former article states it uses American English and the latter article states it uses Oxford spelling. So what spelling should be chosen for those articles? Burzuchius (talk) 20:06, 27 April 2025 (UTC)

I have nominated Dwarf planet for a featured article review here. Please join the discussion on whether this article meets the featured article criteria. Articles are typically reviewed for two weeks. If substantial concerns are not addressed during the review period, the article will be moved to the Featured Article Removal Candidates list for a further period, where editors may declare "Keep" or "Delist" in regards to the article's featured status. The instructions for the review process are here. Hog Farm _Talk 02:51, 3 June 2025 (UTC)

Would you be willing to administrate Tolkien Gateway - there really isn't anybody left at the moment? — Preceding unsigned comment added by IvarTheBoneless123 (talk • contribs) 04:35, 10 July 2025 (UTC)

@IvarTheBoneless123: Would seem a bit odd to administrate a wiki I've never edited, though. Also it does seem like a bunch of work. :) Double sharp (talk) 04:48, 10 July 2025 (UTC)

It does, but you're probably the most trustworthy, and experienced, editor I can think of. IvarTheBoneless123 (talk) 12:50, 12 July 2025 (UTC)

Who also happens to have an interest in Tolkien. IvarTheBoneless123 (talk) 12:51, 12 July 2025 (UTC)

@IvarTheBoneless123: Even so, I still wouldn't feel comfortable with it as an outsider because I've never edited TG. Maybe I'll have a different opinion if and when I actually do for long enough... Double sharp (talk) 14:47, 14 July 2025 (UTC)

Hey, Double sharp. I'd like to wish you a wonderful First Edit Day on behalf of the Wikipedia Birthday Committee! Have a great day! DaniloDaysOfOurLives (talk) 03:48, 7 August 2025 (UTC)

@DaniloDaysOfOurLives: Thank you! Double sharp (talk) 04:57, 7 August 2025 (UTC)

You recently made this edit to 10 Hygiea where you added this PDF as a citation, but I can't find anything related to Hygiea in there. I'm confused. Can you explain this? Nrco0e (talk • contribs) 19:03, 16 September 2025 (UTC)

@Nrco0e: I made a copy-paste mistake, should have referred to this PDF instead. Double sharp (talk) 03:38, 17 September 2025 (UTC)

Ahh, I see now! Nrco0e (talk • contribs) 03:39, 17 September 2025 (UTC)

...and I corrected it. :) Double sharp (talk) 04:33, 17 September 2025 (UTC)

Great! Nrco0e (talk • contribs) 05:11, 17 September 2025 (UTC)

	The Special Barnstar
	I love ur username! Fellow space/music theory fan spotted in the wild??? :O Shocksingularity (talk) 15:08, 22 September 2025 (UTC)

@Shocksingularity: Thank you for the barnstar! (And yes. :D) Double sharp (talk) 16:01, 22 September 2025 (UTC)

Hi double sharp, Europium has been in the midst of good article reassessment for a bit now and it doesn't look like you were notified since you have changed your name since that became a GA. It would probably be a lot of work to get it back up to standard but thought I would drop a note here. -- Reconrabbit 20:40, 27 October 2025 (UTC)

I have nominated Makemake for a featured article review here. Please join the discussion on whether this article meets the featured article criteria. Articles are typically reviewed for two weeks. If substantial concerns are not addressed during the review period, the article will be moved to the Featured Article Removal Candidates list for a further period, where editors may declare "Keep" or "Delist" in regards to the article's featured status. The instructions for the review process are here. Nrco0e (talk • contribs) 00:50, 7 November 2025 (UTC)

Iron has been nominated for a good article reassessment. If you are interested in the discussion, please participate by adding your comments to the reassessment page. If concerns are not addressed during the review period, the good article status may be removed from the article. Z1720 (talk) 01:12, 14 November 2025 (UTC)

The article Lithium atom has been proposed for deletion because of the following concern:

A separate page from Lithium does not make sense as the atom itself is not separately notable from the element, as is the case for Hydrogen atom or Helium atom which are themselves exceptions; every other element's atomic properties are treated on the element's page.

You may prevent the proposed deletion by removing the {{proposed deletion/dated}} notice, but please explain why in your edit summary or on the article's talk page.

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This is an automated notification. Please refer to the page's history for further information. DatBot (talk) 00:31, 17 December 2025 (UTC)