Cover Feature: PdCl(NO) – an iconic compound with corrugated Pd ₄ Cl ₄ octagons built up by Pd ₂ Cl ₂ (NO) ₂ moieties (Z. Anorg. Allg. Chem. 6‐7/2023)

The cover picture presents a structural motif of a distorted Pd2Cl2 square in solid PdCl(NO). This iconic compound was firstly synthesized during outstanding research in the late 1950s in Munich, which led to the development of the Wacker process for the conversion of ethene into acetaldehyde by catalysis with PdCl2. More than sixty years after its synthesis, crystals of PdCl(NO) were prepared for the first time and the structure determined by X-ray diffraction. In the monoclinic structure distorted Pd4Cl4 octagons in chair arrangement are interconnected to corrugated layers, forming a two-dimensional polymer insoluble in common solvents. In this compound each Pd atom is connected to a N-O group, bonded alternatively up and down with a Pd-N-O angle of 129°. The bonding situation in PdCl(NO) was investigated by vibrational, electronic and X-ray absorption (XAS) spectroscopies. The XAS measurement at the KIT synchrotron facility uncovers that the charge located at the Pd atom in PdCl(NO) is comparable to that in PdCl2 or PdO (DOI: 10.1002/zaac.202200337).