Polyhedral symbols and configuration indices

Although structural descriptors such as we’ve seen in the names of boron hydrides, for example catena or closo, provide information on atomic connectivity, they tell us little or nothing about the geometry of the molecule.

Have a look at the structures (a) and (b):

(a)	(b)

(SPY-5)-pentaoxidotungstate(4−) (additive) (TBPY-5)-pentaoxidotungstate(4−) (additive)

Both of them can be named additively pentaoxidotungstate(4−). Yet, as you can see, they have very different shapes.