Talk:Noble gas

What color does radon glow in an electric discharge tube? Did someone get rid of it, or am I mistaken? 2600:1008:B11F:5DF9:2099:8782:E2A8:765E (talk) 21:11, 30 August 2023 (UTC)

Nobody ever tried it experimentally, I think. Probably it glows violet-blue. Double sharp (talk) 04:22, 25 December 2023 (UTC)

I've seen sources conflicting on this matter. Some say it glows green, others say it glows red. Its use is very limited by its radioactivity, making it impractical for commercial purposes. I suppose it has only been experimental. 174.103.211.175 (talk) 16:09, 5 July 2024 (UTC)

Rutherford and Royds wrote in 1908: Pure emanation, corresponding to the equilibrium amount from 130 mg. of radium, was condensed by liquid air in an exhausted spectrum tube of about 50 cubic millimetres capacity, provided with thin platinum electrodes. Two photographs were immediately taken, one giving about thirty of the more intense lines, and the other, with much longer exposure, showing more than one hundred lines. For a comparison spectrum a helium tube was used. The colour of the discharge in the tube was bluish. So I guess it really is blue. Double sharp (talk) 16:57, 22 October 2024 (UTC)

Thanks! I was wondering! 174.103.211.175 (talk) 14:33, 7 December 2024 (UTC)

Thank you for prompting me to look it up! I was really surprised myself that it had actually been tried experimentally. It seems Rn is the most radioactive element that has been seen as a pure sample: given what we know now of the health hazards, I doubt these pioneering 1900s experiments will ever be repeated. Double sharp (talk) 09:23, 8 December 2024 (UTC)

Sadly, I could not find any new progresses on radon chemistry. Even if they exist, they are likely get flooded by radon removal and computational chemistry articles. :( Nucleus hydro elemon (talk) 14:21, 9 December 2024 (UTC)

I wish someone would finally solve the mystery of how to get to the higher oxidation states +4 and +6. :( Double sharp (talk) 14:22, 9 December 2024 (UTC)

RnF₄ and RnF₆ looks hopeful, but 10.1016/j.jenvrad.2023.107259 claims there are no polonium fluorides due to ¹⁹F(α,n)²²Na reaction. This nuclear reaction might make the path to RnF₄ and RnF₆ even more dangerous. Nucleus hydro elemon (talk) 14:36, 9 December 2024 (UTC)

You're welcome! 174.103.211.175 (talk) 21:04, 16 December 2024 (UTC)

The section "Discharge color" has no content about noble gases other than the table. The spectra in that table are no discussed or sourced and are not useful in this article. I proposed to delete the section and put the table removed in this edit by Off and running with the edit summary All images in the table are duplicated by the table in the section Noble gas#Discharge color. The duplication would be removed by deleting the other of the two copies. Johnjbarton (talk) 16:06, 23 February 2026 (UTC)

I'm not clear about your proposal

1. Are you saying that the table better belongs in the lead rather than in its own section?
2. Are you saying that the images of the spectral lines are not useful?

Off and running (talk) 17:08, 23 February 2026 (UTC)

I am saying

1. The Discharge color section should be deleted as off topic. It says nothing about noble gases beyond the image in the table which are not explained in any case.
2. The images of the spectral lines are not useful. They are not used in this article to discuss anything about "noble gas". A comparison of the spectral lines across the noble gases might be an encyclopedic topic if sourced as such, but I guess such a discussion would belong in a subtopic article. Otherwise the spectra might be used in individual element pages, but I have a hard time imagining why.
3. The colorful table of discharge colors across the noble gases can be used as a introductory image in the spirit of so many articles. Neon lighting is widely known and the image provides a point of contact for interesting reader in the broader topic.

Johnjbarton (talk) 23:44, 23 February 2026 (UTC)

1. I agree that the table of colors is not about "noble gases" as a topic, unless we had cited content about the whole set (trends, special features of noble-gases vs other-gases, etc.). The effect of impurities and glass materials is certainly useful, but again not specific to any of these specific gases or this set of elements. Maybe it could find a home in the glow discharge or emission spectrum articles.
2. In addition to my (1) response, I note for your last thought: emission spectra of each element are standard in every element page.
3. Agree. This article isn't an essoteric topic itself, even though it has lots of deep details, so a lay-reader hook is nice. The topic isn't limited to glow-discharge emission and there are other lay applications that could be a hook as well. Maybe a picture of a blimp?

DMacks (talk) 05:53, 24 February 2026 (UTC)

I agree.

Spectral lines are the chemical fingerprints of the elements. Therefore, in an article about a group of elements, it is worthwhile to display the spectral lines of the different elements for comparison. This is especially true for this article because the section above the section that Johnjbarton proposes to delete is titled "Analysis of noble gases" and it discusses spectrometry as a method of analysis. Off and running (talk) 16:52, 24 February 2026 (UTC)

You wrote "I agree" but what you're saying contradicts what Johnjbarton wrote (and that I somewhat agreed with). The first part of your response sounds like WP:SYNTH unless there is a reference that actually discusses the relationships within this group. DMacks (talk) 17:39, 24 February 2026 (UTC)

Sorry for the confusion.

I agree that "the topic isn't limited to glow-discharge emission". Spectral lines are just one aspect. Off and running (talk) 17:50, 24 February 2026 (UTC)

When DMacks said "the topic isn't limited to glow-discharge emission" I understood: the topic of noble gases could be represented by many other introductory images. While true, the previous image set seemed ok to me. Johnjbarton (talk) 04:11, 25 February 2026 (UTC)

I assume that when you say "previous image set" you mean the images as they appeared in the Lead section prior to my removal for duplication. Those images are exactly the same images that appear in the section that you think should be deleted. The only difference is that in the section that you propose to delete, the table also contains images of the spectral line.

I therefore don't see

1. why do you think we should remove the images of the spectral lines but leave the images of the glow
2. why do you think the images are better suited for the lead than in a section of their own

Since the section above the section in question discusses spectroscopy as a method of analysis for noble gasses, it seems like it would be natural to present spectral lines in a section immediately below the section titled "Analysis of noble gases". Off and running (talk) 00:08, 27 February 2026 (UTC)

In my opinion the unexplained spectral lines are not encyclopedic information about the topic "noble gases". If we had sources that compared the spectral lines across the group of elements then it would make since to include these. (Even then I have my doubts about the suitability of this kind of technical detail in this level of article). But simply adding the spectral lines because they pertain to one member of the set does not inform the read about the article topic. Please see Wikipedia:Coatrack articles.

This article should summarize sources about "noble gases" not about any other topic, including Neon, Krypton, or, individually, any member of the set. I've seen the mess this makes of articles, they grow into a mass of content mostly independent of the core topic.

Using the gas colors in the intro is a separate issue because the intro image is generally cut a lot of slack. It has a different purpose. I agree with DMacks that other suitable images could be in that spot. Alternatively we could look for sources comparing colors of discharge across the noble gases and build a section around that. (Maybe Ray, Sidney F. (1999). Scientific photography and applied imaging. Focal Press. pp. 383–384. ISBN 0-240-51323-1. even?) The key issue is do we have reliable sources on "noble gases" for the content. Johnjbarton (talk) 00:46, 27 February 2026 (UTC)

I should add that I also agree that "Neon lighting is widely known", which is why I'm baffled by this proposal to delete the section. Off and running (talk) 18:03, 24 February 2026 (UTC)

The section is not about Neon lighting nor is its role in the article introductory. The section is off topic. Johnjbarton (talk) 04:12, 25 February 2026 (UTC)

I'm somewhat confused by your statement. The section is about light emmitted by noble gasses, Neon being one of them. Off and running (talk) 18:54, 26 February 2026 (UTC)

The content I deleted neverdid not mention noble gases. Johnjbarton (talk) 00:47, 27 February 2026 (UTC)

What does that mean? Off and running (talk) 22:35, 6 March 2026 (UTC) typo in above post corrected. Off and running (talk) 14:28, 7 March 2026 (UTC)

What do you mean "did not mention noble gases"? It was a table of noble gases and their characteristic discharge. Off and running (talk) 14:27, 7 March 2026 (UTC)

It was a table of He, Ne, Kr, Ar, and so on. The relationship between the table and the article topic is unstated and unsourced. It provided no encyclopedic information on characteristics of "noble gas". The line spectrum of Neon is not information about noble gases, it is advanced, unsourced, unexplained information about Neon.

Why do we have articles about Helium, Neon, Krypton, Argon and so on? Why not just have all that content here in Noble gas? Why stop there? Let's put all of the information about all of the elements in Element! Now we are getting somewhere, let's merge it all into Universe!

We need to draw a line. In my opinion that line is simple: the source must be specifically about "noble gas", not about any individual gas. Is this any clearer?

As I said earlier, I think one decorative table of the discharge colors at the beginning of the article illustrating the collection elements is great. Johnjbarton (talk) 15:59, 7 March 2026 (UTC)

What are you talking about "relationship between the table and the article topic is unstated and unsourced"? Those are the Noble gasses, and it's stated throughout the article.

"the source must be specifically about "noble gas", not about any individual gas. Is this any clearer?"

Not clear at all. A table comparing and contrasting the different noble gasses is within the scope of an article about noble gasses. Off and running (talk) 16:05, 7 March 2026 (UTC)

Well it is unsourced as such, so the claim is original research. I guess you would be able to find sources comparing the discharge colors and possibly the spectra. Such sources would be about the "noble gas" and thus on-topic. Johnjbarton (talk) 17:11, 7 March 2026 (UTC)

How about these papers:

1. Spectral line broadening of atoms by noble gases by A V Demura, S Ya Umanskii, A V Scherbinin and A V Zaitsevskii
2. Infrared Spectra of the Noble Gases by Craig J Sansonetti, Marion M Blackwell and E B Saloman
3. Optical spectra excited in high pressure noble gases by alpha impact by W.R Bennett Jr.

And if those three are not acceptable, there is a pool of 80,000 more papers to consider. Off and running (talk) 13:14, 8 March 2026 (UTC)

Those are sources for a section on optical spectra of noble gases. Sansonetti is basically a review and would be suitable for discussing infrared spectra. However section in question was on gas discharge tubes and visible spectra. The Bennett source might reference earlier work on visible spectra.

For the colors of gas discharge I would try plain web searches. Google Scholar sources are typically highly technical and don't often cover practical applications well. Look for articles on exotic neon lights. This source

• Waymouth, John (1971). Electric Discharge Lamps. Cambridge, MA: The M.I.T. Press. ISBN 978-0-262-23048-3.

has material on mercury vapor lamps including discussion of why argon is used rather than another "rare gas" around page 67.

Similarly, the visual spectra were probably analyzed 125 years ago so a textbook from mid-20th century would be a better bet. For example pg 301 of

• The Theory of Atomic Spectra By E. U. Condon, G. H. Shortley · 1935

briefly discusses characteristics of spectra. This source uses "rare gas" so also search using that form.

I'm skeptical of the line spectra images used in the table. They look too perfect to me. A user claims they are solely their own work. Johnjbarton (talk) 16:07, 8 March 2026 (UTC)

The existing section is problematic in several ways. This is how it looked prior to the recent major set of edits initiated by User:Off and running. Part of the non-table explanation doesn't even make sense now, as the unrationalized pivot of its table left content talking about a row that instead became a column. That explanation, which does have encyclopediac value, actually exactly explains why the former first row removed in this edit is worthwhile. I had later removed that other now-column because I did not see any visual or content-related value to it due to the now-incorrect description text. For the record, I prefer the columnar layout for the spectra so their relative X-axis values can be seen easily. But I think re-adding both of the removed portions (the capsules and the element-symbol tubes) would make the table too wide for narrow screens. — Preceding unsigned comment added by DMacks (talk • contribs) 19:20, 23 February 2026 (UTC)

I am taking this as a request for rationalization of my edits, which is definitely a legitimate ask:

• I pivoted the table from a format of the different gasses being displayed as columns to being displayed as rows becasue the former format was just too wide, even after the resolution of the images were limited. There are either 5 or 7 gasses to list (depending if we include the last two gasses for which there are no photos). The table initially had 5 rows, which after the pivoting I reduced to 3 columns (with the removal of one of the former rows discussed in the bullet below). The new format (of the different gasses presented as rows rather than columns) allows displaying of the spectral lines at a higher resolution, which in my opinion, is the most useful parameter displayed by the table.
• I removed the light emitted by some mixture of the gas (rather than the pure gas) because there was no information on the mixture. Hence, I didn't see any value of displaying such images. I think the bullet under the table stating that the color emitted is a function of the purity of the gas still has value even without the images of light emitted from a non-pure gas.

Let me know if there are any other questions. Off and running (talk) 20:07, 23 February 2026 (UTC)