Group Theory Solutions: #4

4.* (1996 1 2) List all the symmetry elements of Ru(bipy)32+ (shown below). What is its point group? Does it have a dipole moment? Is it chiral?

Symmetry elements:

  • E (all molecules have the identity element.)
  • 3 C2 axes (bisecting each of the bonds connecting the pyridine rings)

  • C3 (straight through the middle, because the molecule is shaped like a 3-pronged propellor)


Ru(bipy)32+ belongs to the D3 point group, making it a chiral molecule. As a double check, we can see that Ru(bipy)32+ does not have, symmetry planes an inversion center, or improper rotation axes whatsoever. Ru(bipy)32+ is not polar because all of its dipole moment vectors cancel out. Look at any individual vector to see this. The one going from Ru up to the top N is cancelled by the one going from Ru down to the bottom N, etc.