Open‐Shell 3d Transition Metal Nitridophosphates M II P 8 N 14 ( M II =Fe, Co, Ni) by High‐Pressure Metathesis

3d transition metal nitridophosphates M II P 8 N 14 ( M II =Fe, Co, Ni) were prepared by high‐pressure metathesis indicating that this route might give a systematic access to a structurally rich family of M ‐P‐N compounds. Their structures, which are stable in air up to at least 1273 K, were determined through powder X‐ray diffraction and consist of highly condensed tetra‐layers of PN 4 tetrahedra and M N 6 octahedra. Magnetic measurements revealed paramagnetic behavior of CoP 8 N 14 and NiP 8 N 14 down to low temperatures while, FeP 8 N 14 exhibits an antiferromagnetic transition at T N =3.5(1) K. Curie–Weiss fits of the paramagnetic regime indicate that the transition metal cations are in a oxidation state +II, which was corroborated by Mössbauer spectroscopy for FeP 8 N 14 . The ligand field exerted by the nitride ions in CoP 8 N 14 and NiP 8 N 14 was determined from UV/Vis/NIR data and is comparable to that of aqua‐ligands and oxophosphates.