A Temperature‐dependent Structural Study of anti‐ReO3‐type Na3N: to Distort or not to Distort?

Abstract The rather open anti ‐ReO 3 ‐type crystal structure for sodium nitride is completely preserved in the temperature range between 20 K and its decomposition temperature at around 393 K according to temperature‐dependent X‐ray and neutron diffraction data collected on single crystals and microcrystalline powder of Na 3 N. Strong anisotropy of thermal displacement parameters even at low temperatures is attributed to purely dynamic effects. The tendency of ReO 3 ‐type and anti ‐ReO 3 ‐type compounds towards an octahedron‐tilting distortion is compared theoretically by using cubic AlF 3 and Li 3 N model compounds.