[citation needed] The hydride ion H− is stabilised by being surrounded by electropositive elements such as alkalis or alkaline earths.
[1] Quaternary compounds exist where nitrogen forms a complex with bonds to a transition or main group element.
[1] Hydridonitrides may be produced by a process called self-propagating high-temperature synthesis (SHS) where a metal nitride is ignited in a hydrogen atmosphere.
[2] A metal (Ti, Zr, Hf, Y) can also be ignited in an atmosphere mixing hydrogen and nitrogen, and a hydridonitride is formed exothermically.
One lutetium hydride doped with nitrogen is claimed to be a room-temperature superconductor at up to 21°C at a pressure of 1 GPa, which is considerably lower than for other polyhydrides.