Bonding, bending and the ground state of CrCl2

Local density-functional calculations within the linear combination of Gaussian-type orbitals framework on the CrCl2 molecule predict a linear 5Πg ground state. This ground state is unusual in having larger π than σ-bonding and differs from that predicted by earlier work. The linear geometry is consistent with spectroscopic studies of this molecule but is at variance with a recent calculation of the third law entropy. A reanalysis of the experimental entropy, allowing for the likelihood of impurities, appears to be consistent with the theoretical prediction of a linear molecule.