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As the title suggests, I have been wondering why some chair conformations utilize wedged lines for some of the bonds while others have regular thin lines for all bonds, you can take cyclohexane as an example.

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  • $\begingroup$ That's not really an example... I still have no idea what you mean. Can you draw a diagram? $\endgroup$ Jan 7, 2016 at 4:22
  • $\begingroup$ google.it/… (wedged lines) and google.it/… (no wedged lines) $\endgroup$
    – Asker M
    Jan 7, 2016 at 8:59
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    $\begingroup$ Oh, it's really just the same, there's nothing special about them. $\endgroup$ Jan 7, 2016 at 9:15
  • $\begingroup$ Mant thanks orthocresol! I was kind of going crazy haha. $\endgroup$
    – Asker M
    Jan 7, 2016 at 9:46

1 Answer 1

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Cyclohexane is often drawn as a regular hexagon even though its prevailing chair conformation is not planar.

cyclohexane

Perspective diagrams are preferred when discussing conformation (since there is no other reasonable way to depict boat and chair forms) and acceptable when it is just desired to emphasize configuration. (For the depiction of carbohydrates and structurally related molecules, Haworth projections can be also preferred.)

perspective diagram

The use of wedged and bold bonds in such perspective diagrams is discussed in Graphical Representation of Stereochemical Configuration (IUPAC Recommendations 2006):

ST-3.3 Use of bold bonds to emphasize perspective

Since perspective diagrams imply a single absolute configuration, it is not necessary to use solid wedged or bold bonds to emphasize that configuration further. In some cases, such bonds may help an inexperienced viewer to understand the perspective used. (…)

perspective diagram

However, note that

Only solid wedged and bold bonds should be used for the purpose of emphasizing perspective. Hashed wedged bonds and hashed unwedged bonds should not be used, either in isolation or in combination with bold bonds.

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