Pressure-induced internal redox reaction of Cs2[PdI4] • I2, Cs2[PdBr4] • I2, and Cs2[PdCl4] • I2

The pressure-induced redox reaction within the system Cs-2[Pd-2 + I-4], I-2/Cs-2[Pd4+ I-6] was investigated by means of powder X-ray diffraction. Analogous high-pressure X-ray diffraction experiments were performed on the isostructural compounds Cs-2[PdX4]center dot I-2 (X = Cl, Br). Additionally, the phase transition of Cs-2[PdBr4]center dot I-2 to Cs-2[PdBr4I2] was characterized by means of Raman scattering experiments as well as theoretical calculations based on density functional theory. On the basis of experimentally determined crystal structure data, a pathway for the topology of the redox reactions was developed and outlined.