Lithium nitride

Lithium nitride is an inorganic compound with the chemical formula Li3N. It is the only stable alkali metal nitride. It is a reddish-pink solid with a high melting point. Lithium nitride is prepared by direct reaction of elemental lithium with nitrogen gas: Instead of burning lithium metal in an atmosphere of nitrogen, a solution of lithium in liquid sodium metal can be treated with N2. Lithium nitride is an extremely strong base, so it must be protected from moisture as it reacts violently with water to produce ammonia: Two other forms are known: Lithium nitride shows ionic conductivity for Li, with a value of c. 2×10 Ωcm, and an (intracrystal) activation energy of c. 0.26 eV (c. 24 kJ/mol). Hydrogen doping increases conductivity and doping with metal ions (Al, Cu, Mg) reduces it. The activation energy for lithium transfer across lithium nitride crystals (intercrystalline) has been determined to be higher, at c. 68.5 kJ/mol. The alpha form is a semiconductor with band gap of c. 2.1 eV. Reacting lithium nitride with carbon dioxide results in amorphous carbon nitride (C3N4), a semiconductor, and lithium cyanamide (Li2CN2), a precursor to fertilizers, in an exothermic reaction. Under hydrogen at around 200°C, Li3N will react to form lithium amide.