We recently reported the hexagonal planar palladium complex 1. Addition of 1 bar of H2 to a C6H6 solution of 1 at 25 °C resulted in clean formation of Pd-Mg and 0.5 equiv. of the molecular magnesium hydride In C6H6 solution, Pd-Mg demonstrated a characteristic hydride resonance at  = -6.64 ppm integrating to four protons. The simplicity of the 1 H-NMR spectrum was suggestive of a highly symmetric structure. H2 activation to 1 was found to be reversible. Removal of H2 from mixtures of Pd-Mg + [2]2 by freeze-pump-thaw cycles results in the regeneration of 1. Due to its reversible formation, attempts to isolate Pd-Mg were unsuccessful; 1 crystallises preferentially from solution. As such, we undertook alternative synthetic approaches to verify the structure of Pd-Mg.