a positive sign of the quadrupole splitting indicates an oblate charge distribution, while a negative sign corresponds to a prolate one. When |V zz | approaches |V yy |, the relationship between sign and shape becomes less clear. The sign keeps its dependence on the shape of the charge distribution, and thus the symmetry; however, this relation becomes increasingly subtle and difficult to quantify. Once |V zz | = |V yy |, the sign of the quadrupole splitting loses its physical meaning. Even from basic crystal field theory considerations it is clear that the EFG will be influenced by the ligand field splitting. Vibrational movements will influence the charge distribution as well as the ligand field splitting and consequently the magnitude and shape of the EFG. Since the macroscopic measurement probes the superposition of all vibrationally accessible structures, the observed quadrupole splitting is expected to be sensitive to the temperature.