Structural Influence of Lone Pairs in GeP₂ N₄ , a Germanium(II) Nitridophosphate

Owing to their widespread properties, nitridophosphates are of high interest in current research. Explorative high-pressure high-temperature investigations yielded various compounds with stoichiometry MP₂ N₄ (M=Be, Ca, Sr, Ba, Mn, Cd), which are discussed as ultra-hard or luminescent materials, when doped with Eu²⁺ . Herein, we report the first germanium nitridophosphate, GeP₂ N₄ , synthesized from Ge₃ N₄ and P₃ N₅ at 6 GPa and 800 °C. The structure was determined by single-crystal X-ray diffraction and further characterized by energy-dispersive X-ray spectroscopy, density functional theory calculations, IR and NMR spectroscopy. The highly condensed network of PN₄ -tetrahedra shows a strong structural divergence to other MP₂ N₄ compounds, which is attributed to the stereochemical influence of the lone pair of Ge²⁺ . Thus, the formal exchange of alkaline earth cations with Ge²⁺ may open access to various compounds with literature-known stoichiometry, however, new structures and properties.