Question

How do you assign molecular geometry?

Answer 1

With difficulty...........

Explanation:

On the desks of distinguished professors of inorganic and organic chemistry, you will invariably find sets of molecular models that are representations of the molecules and complexes on which the prof (and his students) are working. Why? Because it is hard to think in 3 dimensions, and such models help you to vizualize molecular geometry plainly and straightforwardly.

So how do you assign `R` and `S` geometries? Use a model to inform your spatial reasoning. And thus you can twiddle and twirl the model in your hand, and give the appropriate view, with the appropriate substituent in the correct orientation. Of course you have to practise, and, as importantly, you have to practise representing that 3D geometry on the printed page - no mean task.

Molecular model sets are allowed examination materials in all exams. You would be a fool to yourself if you ignore their utility.