Talk:Singlet oxygen

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Comment to Mathchem271828: In the first paragraph, I think it be more appropriate to use S.I. energy units for a energy difference between the two states instead of giving it as a temperature.

  • A the moment, it reads "The energy difference...is about 11,400 Kelvins... = 7918.1 cm-1" In dimensional terms, of course, neither K nor cm-1 is an energy. Joules everywhere, please -- no Hartrees, kcal, kcal/mole, kJ/mole, BTU, quads, foot-pounds, etc., etc., unless SI is there first.
Wavenumbers is the basic currency that chemists of all types, organic, physical, inorganic.. have an intuitive feel for because we are all familiar with IR spectroscopy. They are a fully accepted currency of energy as are kelvins for questions of thermodynamics. SI units are fine for other areas but not for chemistry, in general. Mathchem271828 00:21, 6 February 2007 (UTC)

lapo_dk

lapo_dk; I'll just throw this out there that the temperature is good for people to put the data into a thermodynamics perspective. The temperature might give you an idea of relative populations of the species. Mathchem271828 19:29, 15 December 2006 (UTC)

That temperature was totally wrong. It didn't take into account the O2's degrees of freedom and lookd like it took two atoms as one free atom. -lysdexia 11:01, 24 March 2007 (UTC)

"72 minutes" is a half-life, right? — Omegatron 00:16, 5 April 2007 (UTC)

I had that question, too, 4 years later. Given the sorry state of this article, it might be some sort of average! The best I could find on the Web was "lifetime", which is ambiguous. I don't think it can be half-life, because the decay is probably not exponential. Someone who knows should correct this poor information. David Spector (talk) 17:42, 30 December 2011 (UTC)

Lots of useful information, but the article is barely readable to someone outside the field (a link to nomenclature is not sufficient). 198.202.66.219 23:54, 3 May 2007 (UTC)


Energy difference[edit]

The article is self-contradictory: In the introductory paragraph the difference to the ground state is given as 7918.1 cm-1, corresponding to an energy of 94.7 kJ/mol or a wavelength of 1263 nm, while later the energy is given as 94.2 kJ/mol. And what does the "3625 kelvin" in the introductory paragraph refer to? It's not E/kB and not the temperature for maximum radiation in Wien's law, neither in the wavelength nor in the frequency view ... and even if it were, we should use a more common notation here. Icek 12:48, 27 August 2007 (UTC)

cf. Talk:Singlet oxygen#Singlet-triplet energy gap. (Sorry for splitting this discussion up...I didn't notice this thread until after I posted.)--GregRM (talk) 03:16, 1 February 2009 (UTC)

Orbital occupancy of the singlet state[edit]

Cotton and Wilkinson 6th edition shows 2 singlet states, the 1Δg where both electrons occupy the same orbital and the 1Σg+ where the electrons are of opposite spin but in different orbitals. The latter is higher energy. Axiosaurus 11:50, 9 November 2007 (UTC)

what image to use[edit]

Lets hold on to the original image in the lead. The replacement image is in German! so why not have both images V8rik (talk) 21:15, 11 March 2008 (UTC)

Image text[edit]

The text in the diagram currently in the article is not in English. -- Beland (talk) 19:09, 2 June 2008 (UTC)

Singlet-triplet energy gap[edit]

I have made the energy gap in the article consistent using the value from the "ChemRev" reference of 7882cm^(-1). The value previously in the article (7918.1 cm^-1) appears in the Webbook link in External links, but Webbook doesn't seem to provide a reference for the singlet state energy. The value from the ChemRev reference appears to agree better with the wavelength used elsewhere in the article of ~1270 nm. (Perhaps the discrepancy between the two references can be explained by the difference between the speed of light in air vs. vacuum?; I have used speed of light in vacuum in my conversions). Thus, I have limited justification for choosing the 7882 value over the 7918.1 value so if someone is familiar with this, feel free to change it to a more accurate value.

Also, I should note that I fixed the temperature. It looks like the correct temperature was originally in the article but was changed to 3625 K(cf. discussion at the top of this page). I believe the correct value is around 11340 K (rather than 3625 K) based on E/k or E/R. (Maybe 3625 K was meant to correspond to something else, like the vibrational temperature?)--GregRM (talk) 03:09, 1 February 2009 (UTC)

Singlet oxygen contains oxygen-oxygen double bond? --83.100.0.5 (talk) 17:23, 13 July 2009 (UTC)


Reactivty[edit]

The below was in the article on Triple Oxygen, shouldn't the same statement be made in this article.

Singlet oxygen, .. is many times more reactive than triplet oxygen,...

Dave 2346 (talk) 22:10, 19 July 2009 (UTC)

The essence is that triplet and singlet oxygen participate in different reactions, so whether or not singlet oxygen is "more reactive" than triplet oxygen depends on the kind on reaction we are talking about.

It can be confusing because singlet oxygen is often called a "reactive oxygen species" together with a bunch of highly reactive oxygen radical species. I would suggest that we stick with

The chemistry of singlet oxygen is different from that of ground state oxygen.

Lapo dk (talk) 09:31, 28 July 2009 (UTC)

"Ene" Reaction[edit]

You might want to note that the apparent ene reaction for singlet oxygen is actually only a net ene reaction. It actually is a non-concerted but non-radical process involving a zwitterionic intermediate. For more info, or possibly a good sitation for this page see:

"Mechanism of the ene reaction between singlet oxygen and olefins"

L. M. Stephenson, Mary Jo Grdina, Michael Orfanopoulos

Acc. Chem. Res., 1980, 13 (11), pp 419–425

DOI: 10.1021/ar50155a006

Publication Date: November 1980

Here is the link to the article serving page on the ACS website: http://pubs.acs.org/doi/abs/10.1021/ar50155a006

I only bring this up because I have been seeing a number of young people incorrectly declare this to be a true ene reaction (even in presentations) and many of them seem to be getting their info from here.149.155.3.152 (talk) 18:13, 24 January 2012 (UTC)

Yeah, this is a previously known fact, but full treatment of this would require some more work on this, this is why it was weaselled as "ene reaction-like". --vuo (talk) 00:15, 25 January 2012 (UTC)

Delta Singlet oxygen is not diamagnetic but paramagnetic[edit]

The first sentence "Singlet oxygen (or 1O2) is the common name used for the diamagnetic form of molecular oxygen (O2)" is wrong. While spins are paired, there is still a considerable magnetic moment due to the non-vanishing orbital angular momentum which makes at least the more stable Delta singlet oxygen nearly as paramagnetic as triplett oxygen. See e.g. references 20 and 21 from the German page on oxygen. http://de.wikipedia.org/wiki/Sauerstoff 195.126.85.201 (talk) 08:33, 12 April 2012 (UTC)