Talk:Molecular symmetry

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Some work[edit]

I have been making some stylistic rewrites of this article for readability/tone and consistency, and will probably continue to do so. Leave a note if something I do looks or reads silly. Baccyak4H (Yak!) 16:09, 18 October 2007 (UTC)

Overall the article is much improved after your edits. I have made a few (4) more revisions. Dirac66 01:55, 19 October 2007 (UTC)
Thanks for the feedback and the continued improvement. "Matrixes"...  :-) Baccyak4H (Yak!) 02:19, 19 October 2007 (UTC)
  • mmmm matrices... even in my native language it is matrices that way so no excuses there. V8rik 21:17, 19 October 2007 (UTC)

Thionyl chloride[edit]

In the symmetry groups section I think Thionyl chloride is not planar, please edit — Preceding unsigned comment added by (talk) 12:15, 29 September 2011 (UTC)

Thank you for pointing this out. The word "planar" in the description is misleading as it incorrectly suggests that the molecule is planar. The correct geometry is shown at the article Thionyl chloride. The symmetry group is in fact Cs as the article says, but the mirror plane is the plane which bisects the Cl-S-Cl angle, with one Cl on each side of the plane. I will change the verbal description to read "Mirror plane, no other symmetry". Dirac66 (talk) 12:55, 29 September 2011 (UTC)

Diagrams - further explanation needed[edit]

@Project Osprey: The diagrams you have added are well drawn and seem helpful. I expanded the description of the first diagram, and added a link to chirality for the second. What I think is also needed on the second diagram is an explanation of the subscripts R and S on the X and Y groups, please. Are they somehow related to R- and S- enantiomers?? Dirac66 (talk) 03:45, 10 February 2016 (UTC)
I'll be honest and say that I adapted the second diagram from one on the Japanese Wikipedia. My interpretation was that the R- and S- tags do refer to the chirality of those X and Y groups; so that the top middle and right compounds are meso compounds. Would you agree with that? --Project Osprey (talk) 09:31, 10 February 2016 (UTC)
The top middle molecule is meso, but I am not certain about the top right since it has no mirror plane. However in this article, the Symmetry elements section deals with much simpler molecules – the examples given are H2O, NH3, XeF4, SiF4 and C2H6. So I think that examples with chiral substituents may be mystifying to many readers who can follow the discussion on the simpler molecules.
Instead I suggest that we move this diagram down to a new section near the end of the article, perhaps entitled Symmetry and chirality or Symmetry with chiral substituents. This section could include brief definitions and links for terms such as chiral(ity), enantiomer and meso.
I also glanced at the Japanese article with these diagrams which you mention. Although I can read no Japanese, the figures in that article suggest it is about stereochemistry of organic molecules, and not about molecular symmetry as such. Dirac66 (talk) 16:54, 10 February 2016 (UTC)
That seems reasonable, advanced definitions of chirality are based around molecular symmetry, so it could probably do with its own section. I'm pretty sure that inversion centers count, surely mesotartaric acid can have either a mirror plane or an inversion center depending on its conformation. --Project Osprey (talk) 21:44, 10 February 2016 (UTC)