Talk:Diradical

Thanks for getting involved with diradicals but your internal contradiction tag lacks motivation. Please motivate your edit on this page V8rik 19:19, 8 April 2007 (UTC)
 * contradiction resolved V8rik 21:36, 12 April 2007 (UTC)

Eh?
[Ar][↑ ][↑ ][↑ ] is a triplet state? Where 3 electrons have the same spin and are unpaired?Wolfmankurd 22:51, 7 May 2007 (UTC)

No Sir, Seems to be quadruple state with S = 4  the states are: 3down 2down1up 1down2up 3up

Also another error to be corrected: "a singlet diradical displays a single peak" should be: "a singlet diradical displays no signal at EPR" b.c only 1 state possible S=2*0+1=1   : 1up/1down

Move to Physics Article "Singlet"?
At the moment, these two and rather closely interrelated topics are unnecessarily separated from each other. Perhaps, we might think about moving this over there? Jwuthe2 08:19, 23 May 2007 (UTC)


 * Bad idea, the current singlet article is incomprehensible for the non-initiated and lacks key concepts, references and a single example how a singlet occurs in atom physics. There is not even a matching triplet article. The diradical article captures singlet, doublet and triplet in one go. I suggest merging singlet into diradical. If this is not feasible I will redirect all the chemistry related topics from singlet state to diradical that should also solve the problem  V8rik 19:44, 23 May 2007 (UTC)

Image
The image of orbitals on the external link is very helpful. Are there any similar images that can be posted here? Tospik 23:24, 24 July 2007 (UTC)

Definition
The article starts off with "In organic chemistry" - diradicals occur in inorganic e.g. singlet and triplet dioxygen are mentioned later. I am reluctant to change the article as the organic stuff is not my area.Axiosaurus 11:42, 9 November 2007 (UTC)

Singlet diradical -chemogenesis article reference
IMHO the chemogenesis article link pictures of singlet orbital occupancy are incorrect. A singlet state also occurs when the electrons remain in different orbitals but they have opposite spin.The molecule remains a diradical as both electrons are unpaired. This description of the singlet state is also a problem with the singlet oxygen article and I shall post my concerns there. Axiosaurus 11:42, 9 November 2007 (UTC)

Perhaps incorrect is too strong. Incomplete is better. When the ground state is a triplet as in O2 there are 2 singlet excited states corresponding to (a) both electrons paired in one orbital and (b)the electrons in different orbitals but with opposite spin. It may also be worth pointing out that diradicals need not necessarily have a triplet ground state. This is common and certainly true for O2 and e.g S2 but is not the case for S2N2 which is a singlet diradical, where the electrons in different orbitals are coupled (it is a moot point which ring atoms they reside on) Axiosaurus 12:16, 9 November 2007 (UTC)

biradicals and diradicals
Please note that biradicals and diradicals are not the same. V8rik (talk) 16:55, 14 February 2008 (UTC)

Degeneracy and pairing
"degenerate molecular orbitals (MO) of the same energy "

"Degeneracy" infers orbitals of the same energy, hence "of the same energy" is technically redundant. However, that's not really common knowledge, and there is no Wiki definition of degeneracy that suits chemistry. I propose: "degenerate molecular orbitals (MO), or orbitals of the same energy"

"The electrons can pair up with opposite spin in one MO leaving the other empty. This is called a singlet state."

AFAIK if the two orbitals are near or equal in energy, one electron will reside in each. Due to the spin-pairing energy, there needs to be a certain energy difference for the electrons to reside together in the lower energy of the two orbitals. This will have implications on the first para too.

I'm happy to re-word this but just thought I'd throw it out there as I'm pretty new. Freestyle-69 (talk) 02:43, 18 March 2008 (UTC)


 * Aha, just found Degenerate energy level. Freestyle-69 (talk) 05:23, 18 March 2008 (UTC)


 * Interested in updating the examples section to better reflect diradicals in main group chemistry, namely for carbene/nitrene and their analogues and cyclic compounds (Ex. S2N2 and P2B2) Ngin227 (talk) 00:29, 21 November 2022 (UTC)
 * Also note that diradicaloid (partial diradical character) is a term that is often thrown around with diradicals. Both diradicaloid and diradical also behave differently than monoradicals and closed-shell compounds, which has not been mentioned yet. Ngin227 (talk) 22:03, 22 November 2022 (UTC)