Combination of Ambient and High-Temperature Beryllium Nitride Motifs in W2Be4N5 and W4Be8N9

Compounds of transition metals and beryllium have a wide range of applications, from everyday tools to high tech applications. Remarkably, no single ternary beryllium nitride with a transition metal is known. Here, we report on the synthesis and properties of the first transition metal nitridoberyllates, namely W₂Be₄N₅ and W₄Be₈N₉. Both compounds were synthesized in a high-temperature high-pressure approach from Be₃N₂ and W, using azide generated N₂ as an oxidizing agent. The crystal structures, consisting of alternating layers of WN₆ trigonal prisms and BeN₄ tetrahedra, were elucidated by single-crystal X-ray diffraction (sc-XRD). The separating nitridoberyllate layers show either ambient temperature (α-Be₃N₂ type) or high temperature (β-Be₃N₂ type) motifs. W₂Be₄N₅ was further corroborated by infrared (IR), nuclear magnetic resonance (NMR) and UV/Vis spectroscopy and vibrating sample magnetometry (VSM) measurements. The latter revealed a mixed valence with an intermediate oxidation state of 3.5 for the W atoms. Both, the synthesis of the first transition metal nitridoberyllates and the synthesis approach using elemental W pave the way to a new field of nitride chemistry.