Lithium metal which is an alkali metal belongs to the Group I of the periodic table reacts spontaneously with nitrogen, (which remains in gaseous form at room temperature) to form solid lithium nitride ([tex]Li_{3}N[/tex]). The reaction can be shown as- 6Li (s) + [tex]N_{2}[/tex](g) = [tex]2Li_{3}N[/tex](s). This is the only example of alkali nitride in chemistry. The other alkali nitrides are either not stable or does not exist in solid form at room temperature.