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According to a question in my book (1​R,3​R)-1,3-dichloro-2,2-bis[(S)-chloro(2H1)methyl](1,3-2H2)propane has an S4 alternative axis symmetry. I tried trial-and-error method using an axis that passes through only the top group straight down, one that is a horizontal line across the screen and some others but couldn't find it. How exactly do I do this?And also this is a JEE practice question and I need to do it in at the most a minute or two.

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    $\begingroup$ The only way to get good at 3D visualization is to practice. Various books on group symmetry will have a flow chart, but I could never remember the thing. Typically we could use the "unmarked" character tables for the test in class. $\endgroup$
    – MaxW
    Commented Aug 11, 2018 at 7:34
  • $\begingroup$ @MaxW what is an unmarked character table? In my book actually just the definitions of plane of symmetry,centre, axis and alternating axis of symmetry is covered $\endgroup$
    – Hema
    Commented Aug 11, 2018 at 7:39
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    $\begingroup$ "unmarked" means that you didn't write cheat notes all over it. $\endgroup$
    – MaxW
    Commented Aug 11, 2018 at 7:40
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    $\begingroup$ The S4c operation is a rotation by 90 degrees and reflection in the perpendicular plane. Have a look at the answer chemistry.stackexchange.com/questions/58609/… and also you can practice adding symmetry elements if you search for www.molecule-viewer.com and look at molecules under the S4 point group for examples of the S4 operation. $\endgroup$
    – porphyrin
    Commented Aug 11, 2018 at 8:15
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    $\begingroup$ Spatial perception is not an easy thing to teach you because there are some many cases. Building a model will likely start helping you to visualize the symmetry elements. $\endgroup$
    – Zhe
    Commented Aug 11, 2018 at 13:19

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