The vibrational spectrum of K2PdCl4: first detection of the silent mode ν5 Original Research Article

The use of inelastic neutron scattering (INS) spectroscopy has allowed the determination of the infrared and Raman inactive out-of-plane bending mode ν5 in the [PdCl4]2− ion at 136 cm−1. To our knowledge, this is the first time this mode has been observed in any homoleptic square planar complex. An initial highly anomalous INS spectrum was shown by the use of Raman microscopy to be due to an impurity phase that is most probably a hydrate.