Bond Angles for Expanded Octet

[C_Montemayor_3J]

How do you determine bond angles using VSEPR for atoms with expanded octets in a molecule? Are there specific calculations for dividing traditionally expected bond angles to estimate?

[jasonrorr 2J]

For atoms with expanded octets, there are specific shapes that they take such as the trigonal bipyramidal molecule we saw in the homework with 5 atoms bonded to a central molecule. In cases like this you can intuitively see the bond angles, in the previous example, realizing that the shape is a trigonal planar with poles, meaning the bond lengths between the trigonal planar atoms would remain the same, and the angle between the poles would be 90 deg. In more complex cases I would assume memorization of the shape is required. Hope this helps!