The δ-NbN structure was resolved by X-ray diffraction by Aschermann et al. in 1941, and at its discovery NbN held the record high superconducting transition temperature.
The cubic rocksalt (Fm3m) nitride, density 8.470 g/cm³, becomes superconducting at about 16 K.
Since the early 2000s NbN has been the foundational material of superconducting nanowire single-photon detectors, sensing single photons across the 1–10 μm infrared range at count rates up to 25 GHz.