Talk:Diatomic molecule

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Molecular Geometry Section[edit]

This is crucial for completing the set on Molecular Geometry. Because several admins thought that it was not proper to have its own page, it was moved to here. Please do not delete. Jokermole (talk) 15:43, 21 January 2008 (UTC)

Completing a set about which there's no agreement that it should exist at all? Please discuss it at Wikipedia talk:WikiProject_Chemistry#Geometry_boxes_-_what_gives.3F to avoid duplicating the discussion. --Itub (talk) 15:46, 21 January 2008 (UTC)

The section now reads:-

"The Linear N/A molecular geometry in chemistry describes the stereochemistry (spatial arrangement of atoms) that is adopted by diatomic molecules [1]. This configuration is more commonly referred to in the VSEPR theory as the AX1E* [citation needed]. Due to the fact that 2 atoms are equally bonded to each other, there is no central atom[2][3]."

Perhaps it would be better if it read something like:-

"The diatomic molecule molecular geometry is the simplest spatial arrangement of atoms.[4]. This configuration is more commonly referred to in the VSEPR theory as the AX1E* [citation needed]. Unlike other systems in VSEPR, there is no central atom.[5][6]"

What do others think? I did not check the references so perhpas other chnages will be needed. --Bduke (talk) 23:00, 21 January 2008 (UTC)

I'm all for it. Whatever you suggest is fine. It just needs editing. Jokermole (talk) 00:44, 22 January 2008 (UTC)


is sulfur, selenium, or tellurium a diatomic molecule in the atmosphere

If atoms in a diatomic molecule are not chemically bonded, what is the link between them?

S, Se, & Te don't (at least normaly) form diatomic molecules. S in the atmosphere is as SO2, SO3, H2S, or sulfate aerosols. And diatomic molecules are held together with single, double or triple covalent bonds. -Vsmith 15:53, 20 Apr 2005 (UTC)

Mono, di, tri, tetra, penta, hexa, hepta and octatomic elements and molecules[edit]

I was wondering if we should combine these in some way, as some of the articles are probably going to be pretty short. Each of them has at least two meanings. For example, a "tetratomic molecule" is one with four atoms and a "tetratomic element" is an element that forms a molecule with four atoms of that element. If they are combined, what should the article be named? "Mono and polyatomic elements and molecules"? -- Kjkolb 11:21, 26 November 2005 (UTC)

Please could we have a derivation for the ratio of specific heats for a diatomic ideal gas?

We really need a table of heteronuclear diatomic molecules, but I wasn't able to find one. ([1]) — Enigma55 (talkemail) 05:20, 29 May 2007 (UTC)

Nonsense: Comparison between rotation and vibration[edit]

"The lowest rotational energy level is when l = 0."

Um, OK.

Erot,0 = l*(l+1)*hbar**2 / (2*I) = 0 * (0+1) hbar**2 / (2*I) = 0

Not sure how that one got screwed up.

DrF 23:11, 15 August 2006 (UTC)

Harmonic oscillator?[edit]


"exactly the same as a harmonic oscillator" - no, it isn't. The vibration of a diatomic molecule is anharmonic and more closely follows the Morse potential than the parabolic well. The article on the morse potential actually links to this one.

Natural occurrence[edit]

The latest addition to the article says that "only a few diatomics are found to be naturally-occurring on Earth. These are hydrogen (H2), nitrogen (N2), oxygen (O2), and the halogens: fluorine (F2), chlorine (Cl2), bromine (Br2), iodine (I2), and astatine (At2)". I'm not sure this list is correct. N2 and O2 are certainly correct, but the halogens (especially fluorine!) are so reactive that they are normally found only in compounds. The same might be the case for H2. On the other hand, it should be possible to find some heteronuclear diatomic molecules in nature: NO has a biological role, and can be formed directly in the atmosphere by lightning; CO is a product of incomplete combustion, which can also occur naturally. --Itub —The preceding signed but undated comment was added at 15:42, August 24, 2007 (UTC).

You're right, the phrase "naturally occurring" is wrong. Let's see if we can find a correct way to say it. What I intended was something along the lines of "reasonably stable near 298 K and 1 bar pressure", but that's a lot of words. Something is needed that covers CO, HX, where X = a halogen, and perhaps more. I'll try again if someone else doesn't get there first. Maybe just restrict the sentence(s) to elemental diatomics? - Astrochemist 20:25, 24 August 2007 (UTC)
I tried to correct my earlier edit, so please check it when you have time. By the way, is it worth mentioning that the translational energy of a molecule is also subject to quantum mechanics? - Astrochemist 01:05, 25 August 2007 (UTC)
It looks good now. I see no problem mentioning the quantum translational energy. By the way, thanks for creating the article about the Karlsruhe Congress! --Itub 05:35, 27 August 2007 (UTC)

The article says that "H2 is, in fact, the most abundant molecule seen in nature, dominating the composition of stars". I believe that molecular hydrogen is almost never found in stars, it's atomic or ionised hydrogen, i.e. plasma. I suggest the wording be altered to distinguihs between H and H2. Skaffman (talk) 17:40, 21 November 2008 (UTC)


I'm removing the comments anonymously added today about astatine since they are not in a wiki format. As to their content, Emsley's book has redox potentials involving diatomic astatine. Are they measured or calculated ones? There are web pages giving astatine compounds, but I don't know of unequivocal statements about At2. The web page here seems reliable and gives some indirect evidence for At2. Another question to ask concerns the evidence that astatine is not diatomic. Can anyone shed light on this one way or the other? - Astrochemist 00:09, 15 September 2007 (UTC)

See also this page from Handbook of Inorganic Chemicals (2003), Pradyot Patnaik, McGraw-Hill: London, p. 76. - Astrochemist 00:09, 15 September 2007 (UTC)
According to the CRC Handbook of Chemistry and Physics, it is not yet known whether astatine forms diatomic astatine molecules. Unless someone can find a journal article that presents experimental data for its existence, please don't add it back. InverseHypercube 09:50, 6 March 2012 (UTC)

Diatomic elements are a very specific subset of diatomic molecules[edit]

I think it is a major confusion to redirect the diatomic element page to this diatomic molecule page. The seven (perhaps 8 if At is indeed naturally diatomic) elements are unique among elements and therefor should not be lumped in with chemical compounds composed of two dissimilar atoms.

Tmkkeller (talk) 02:41, 5 December 2010 (UTC)

You have a good point. But you have to agree that an article on diatomic molecule has to discuss the entire scope of the topic, not the tidy categories that you or I are burdened with. As the article points out, almost all elements go diatomic in the gas phase. --Smokefoot (talk) 14:28, 5 December 2010 (UTC)


So under standard conditions, iodine is a solid. Is this still made of diatomic molecules ?

Yes. The halogens are diatomic as solids, although under pressure, I am unsure what they do. When the gases are heated - way up - they fracture to give atoms (like everything). Diatomic sulfur (disulfur) phosphorus (diphosphorus) are also stable as gases, but they do polymerize, essentialy irreversibly, upon condensation into solid form.--Smokefoot (talk) 13:34, 7 November 2012 (UTC)


Given that Na2 is known to exist in gas phase [2], is it worth adding here? Would one consider that a molecule per se? DS (talk) 02:47, 12 March 2014 (UTC)

Standard Temperature and Pressure (STP)[edit]

I saw STP mentioned in the article and 25° C in parentheses. This is inaccurate. STP is 1 atm or bar, but it is 273.15 K, 0° C, 32° F; not room temperature, 25° C. — Preceding unsigned comment added by (talk) 06:05, 2 November 2016 (UTC)

And what about the cause???[edit]

Very disappointing piece! Why isn't there any information about the cause of forming diatomic molecules??? — Preceding unsigned comment added by Koitus~nlwiki (talkcontribs) 16:23, 1 May 2017 (UTC)

  1. ^ "VSEPR - A Summary". University of Berkeley College of Chemistry. 20 Jan 2008.
  2. ^ "Shapes of Molecules". 20 Jan 2008.
  3. ^ "VSEPR - A Summary". University of Berkeley College of Chemistry. 20 Jan 2008.
  4. ^ "VSEPR - A Summary". University of Berkeley College of Chemistry. 20 Jan 2008.
  5. ^ "Shapes of Molecules". 20 Jan 2008.
  6. ^ "VSEPR - A Summary". University of Berkeley College of Chemistry. 20 Jan 2008.