Which of the following compounds have a nonzero dipole moment?

Question

a) Cl2 b) GaBrH2 c) SiCl4 d) NO3-

I know (a) isn't right for sure. I don't think (d) is right either since is symmetrical. I drew out (b) and (c), but I'm doing something wrong if I'm not getting it right...Any help would be appreciated. Thanks.

Answer 1

a) Cl2 - zero dipole, linear geometry
b) GaBrH2 - nonzero, net dipole points towards Br
c) SiCl4 - zero dipole, symmetrical, tetrahedral geometry
d) NO3- - zero dipole, trigonal planar geometry