[brun2008]

Hey guys, I'm currently studying fo my Inorganic and Stuctural exam and have ran into a bit of a problem, I have a bit of confusion when it comes to determining Axial and Equitorial ligands, my textbook so far hasn't been much help.

When it comes to something like a Trigonal Bipyrmaid how can I tell whether a ligand is axial or equatorial? And is there a rule of thumb for working this out? Any help would be greatly appreciated!

[discodermolide]

Axial means above or below the plane, equatorial means in the plane.
So in the trigonal bipyramid what is above and below the plane?

[brun2008]

http://www.uwplatt.edu/~sundin/images/vspr5.gif
If I used this diagram as an example would it be the two B ligands to the right which have the dashed and bold lines which are axial? My thinking here is that the other 3 B ligands are in the plane of the paper and therefore must be equatorial, is my reasoning correct?

Thank you for responding!

[discodermolide]

The two "Bs" at 180° to each other are axial, the rest are equatorial.
That is the B at the very top and the B at the bottom.
It may actually be better for you to build a model.

[brun2008]

I have taken your advice and made some models, thank you it really helped! Visualising shapes and geometries has always been a bit tricky for me, something I'm gonna have to work on.
Thanks for your help and time.