Indicate how many stereoisomers are possible for square planar [Pt(NH3)2BrCl]?

1 Answer
Nov 24, 2015

Two.

One might think that there are four because the ammonia can be cis/trans while the bromine and chlorine can switch places. However....

The bottom two are identical molecules with respect to the molecules above each of them due to the planarity of the molecule.

(i.e. the bottom left is the superimposable mirror image of the upper left and the bottom right is the superimposable mirror image of the upper right.)

As such, there are only two unique ones.