Two phases of bis­(tetraethyl­ammonium) di‐μ‐chloro‐bis­[di­chloro­palladium(II)]

A phase transition was found to occur at ～153 K in the title compound, (C₈H₂₀N)₂PdCl₆]. The structures of the two phases are reported at 292 and 130 K. The low‐temperature phase is twinned. The phase transition is accompanied by a minor displacement of the ions. There are C—H?Cl interactions as short as ～2.80 Å, indicating the existence of hydrogen bonds, and this was confirmed by vibrational spectroscopy. The Pd₂Cl₆]^2? anion occupies sites of mmm and 2/m symmetry in the room‐temperature and low‐temperature phases, respectively.