Group Theory Solutions: #6
6.* (1994 F 1A)
What is the point group of each of the following disubstituted cyclobutanes? Assume that cyclobutane itself has D4h symmetry and that substituting H by X changes no other structure parameters. Which structures are polar and which chiral?
A has a mirror plane in the plane of the molecule, rendering it achiral. B has a mirror plane perpendicular to the plane of the molecule; it is achiral also. C does not posses a rotation axis and ao is chiral. D has an inversion center and so is achiral. E has a mirror plane through the X-containing carbons, which renders it achiral also. The dipole moments, where they exist, are shown below.