[mir]

I have a descriptor called YZ-shadow, which is defines as the shadow projected from the YZ-plane in a molecule. YZ-plane is defined as the plane between the second most important and third most important principal axis for moment of inertia. For the molecule 1,3,5-trimetoksybenzene I can easily spot the first two important axis (the X-axis is coming out of the ring-plane, the Y axis is along one of the metoksygroups, as illustrated). But not the third one. Where is it? Any suggestions?

Btw - After some playing with a moleculeset I have found it harder to rotate the "Y-axis" as defined in the drawing. So the X-axis is probably the "Y-axis" and vice versa...

[enahs]

You have a cyclohexane ring, it is not flat. Are you making a molecule and looking at it as a flat molecule, or are you using a conformation? If the question did not give you a conformation, tell your professor it was a poor question, or just assume it is chair.

[mir]

Its a benzene-ring :-)
And the conformation is correct. All of the metoxy-groups are in plane with the ring.

Its not my professor. Im doing a research into metoxy-methyl benzenes as a part of my thesis. And this molecule is very unique.

[enahs]

I am a tard and blind, what can I say.

Thinking of the right molecule, there is on obvious rotation-reflection primary axis, which would also have certain spectroscopic mojo, if that is what you are trying to account for?

[mir]

No-no, not spectroscopy. Its a descriptor from DFT-calculations and using the Codessa software. I am looking into some similarities between the HOMO-LUMO gap and the YZ-shadow indexes for this molecule. But the Codessa software doesn't tell me where the plane is going through. So I have to use logic. Which I am not very good in, because, I have only my molecule set.

If you are very interested I can send you the references to our publication when it is approved.