Question

Is a bent tetraheydral the only shape that doesn't have a precise angle (as in it's less than 109.5 degrees)?

Answer 1

I don't think so although I'm not exactly sure what you mean by a bent tetrahedral. Other shapes have different angles, of course; however, those are not exact either if there are unpaired electrons in some of the unfilled positions.

Answer 2

By the way, I think you meant
VSEPR, not VESPR

Answer 3

On one of my pages of notes, it lists all the different shapes and the bond angles that go along with them. Next to bent (2 lone pairs, 2 bonds), it says <109.5 degrees for bond angles. I don't understand why that one is less than 109.5, when a trigonal pyramidal isn't.

Answer 4

NH3 is less than 109.5.
NF3 is less than 109.5.
SO3^-2 is less than that.
H3O^+ is less than that.
SOCl2 is less than that.
In fact, as long as there is at least one lone pair, the angles will not be 109.5^o
If you remove the lone pair, by for example, making NH4^+, then you get the 109.5 back.

Answer 5

But is a molecule with an electronic geometry of tetraheydral and a molecular geometry of bent the only one like that? Why doesn't a square pyramidal have <120 degree angles when it has a lone pair? Or does it? I feel like more of the bond angles should be less than the listed angle for 0 lone pairs per electronic geometry type, but it only says for the bent shape that it's <109.5