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Mel Siegel

Point group of cis- and trans-decalin

Dominic Tramonte  Follow

cis-Decalin

Here is a view of cis-decalin with the bridging C-C bond in the plane of the paper:

enter image description here

(It was made using the Jmol software, e.g. at https://chemapps.stolaf.edu/jmol/jsmol/simple.htm using the "Load by name" button and entering "cis-decalin".) At https://www.chemtube3d.com/stdecalinflips/, you can see that this can flip into the mirror image (much like a cylcohexane chair flip).

What is the point group of of cis-decalin?

I see a two-fold axis (perpendicular to the paper). I don't see a center of inversion or any mirror planes; the molecule looks chiral (the flip mentioned above changes it to its mirror image). So maybe C2?

trans-Decalin

Here is a view of trans-decalin with 5 carbons closer to us and 5 further away from us:

enter image description here

I see a center of inversion, a mirror plane (left:right swap), and a two-fold horizontally in the plane of view. I guess that's C2h.

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Gene Ewald  Follow
-decalin, we do indeed find C2h as already stated. There are other (higher-energy) conformations with twist-boat rings in their conformations, which (mostly) would be of C1 symmetry.More
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Giancarlo Bellucci  Follow
I have run some conformational checks on the structures. The maximum point group for More
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Jay Beez  Follow
Trigger warning:More
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HoldingonLou  Follow
You might be watching the gif forever...More
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Edible History  Follow
Does trans-decalin really have a plane of symmetry?More
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