High‐Pressure Synthesis of Ultra‐Incompressible Beryllium Tungsten Nitride Pernitride BeW$_{10}$N$ _{14}$(N$_2$)

For the activation of nitrogen and its reduction to ammonia, transition metals are crucial in biological as wellas industrial processes. So far, only a few binary transition metal compounds with nitrogen dimer anions are known,whereas a ternary compound has remained undiscovered as yet. Here, we report on the synthesis and properties of thefirst ternary transition metal compound, namely, BeW$_{10}$N$_{14}$(N$_2$ ), which exhibits dinitrogen anions. It was synthesized ina high-temperature high-pressure approach from W$_2$Be$_4$N$_5$ . The crystal structure, elucidated with synchrotron radiation,unites WN7 capped trigonal prisms with intriguing BeN$_6$ octahedra and (N$_2$ )-anions. Elastic and electronic properties of thetitle compound were corroborated by DFT calculations, revealing simultaneous ultra-incompressible and metallic behavior.The synthesis and investigation of the first ternary transition metal nitride with dinitrogen units opens the door to a newfield of research on nitride and pernitride chemistry.