Question

What is the VSEPR shape of `SO_2`?

Answer 1

The molecule is bent around the central sulfur, with an `/_O-S-O` `=` `<120""^@`.

Explanation:

There are 18 valence electrons to distribute around the molecule; and the least electronegative atom, sulfur, is ASSUMED to be central.

Resonance structures of `""^(-)O-S^(+)=O` and `""^(-)O-S^(2+)-O^-` are valid. In either case there are 3 regions of electron density around the central sulfur: a lone pair, and `2xxS-O` bonds, The electronic geometry should be based on a trigonal plane. But, because we describe molecular geometry on the basis of bonds not electron pairs, we describe the geometry of `SO_2` as bent. The actual molecule has `/_O-S-O` `=` `119""^@`.