Give the ideal bond angle for BrO3- ion?

Question

I know this has trigonal bipyramidal geometry and therefore the bond angle is < 109.5. Is there a way to determine a more specific bond angle?

Answer 1

If I tell you it is 107.4 degrees, you will ask me why, so I wont tell you.

Answer 2

Hmmm. The "ideal" bond angle is 109.5 The "real" bond angle is what I gave you.

Answer 3

I believe the electronic geometry is tetrahedral and the molecular geometry is trigonal pyramidal and not trigonal bipyramidal. I don't know of any way to predict the exact bond angles; usually it's the other way around. That is usually we know the angle from measurements and we look for reasons to support that measurement.