Highly Condensed and Super-Incompressible Be₂PN₃

Although beryllium and its compounds show outstanding properties, owing to its toxic potential and extreme reaction conditions the chemistry of Be under high-pressure conditions has only been investigated sparsely. Herein, we report on the highly condensed wurtzite-type Be₂PN₃, which was synthesized from Be₃N₂ and P₃N₅ in a high-pressure high-temperature approach at 9 GPa and 1500 °C. It is the missing member in the row of formula type M₂PN₃ (M = Mg, Zn). The structure was elucidated by powder X-ray diffraction (PXRD), revealing that Be₂PN₃ is a double nitride, rather than a nitridophosphate. The structural model was further corroborated by ⁹Be and ³¹P solid-state nuclear magnetic resonance (NMR) spectroscopy. We present ⁹Be NMR data for tetrahedral nitride coordination for the first time. Infrared and energy-dispersive X-ray spectroscopy (FTIR and EDX), as well as temperature dependent PXRD complement the analytical characterization. Density functional theory (DFT) calculations reveal super-incompressible behavior and the remarkable hardness of this low-density material. The formation of Be₂PN₃ through a high-pressure high-temperature approach expands the synthetic access to Be-containing compounds and may open access to various multinary beryllium nitrides.