<unk>  is a compound of<unk>  and nitrogen with the formula Li3N. It is the only stable alkali metal<unk> . The solid is a red or purple color, has a high melting point and is ionic. It has an unusual crystal structure which consists of two different types of layer, one sheet, composition Li2N, containing 6 coordinate<unk>  ions and the other consisting only of<unk>  ions. Solid<unk>  is a  fast ion conductor and has the highest conductivity of any inorganic<unk>  salt. It has been studied extensively as a solid electrolyte and an anode material for use in batteries.. It can be formed by direct reaction of the elements, either by burning<unk>  metal in pure nitrogen gas or by reacting nitrogen gas with<unk>  dissolved in liquid sodium metal. The second method gives a purer product.<unk>  reacts violently with water to produce ammonia:
Li3N (s) + 3 H2O (l) → 3 LiOH (aq) + NH3 (g)
All ionic<unk> s display this pattern, due to the N3− ion being an extremely strong Bronsted base. It easily qualifies as a superbase. It is, in fact, a stronger base than the hydride ion, so deprotonates hydrogen itself:
Li3N (s) + 2 H2 (g) → LiNH2 (s) + 2 LiH (s).<unk>  is being investigated as a potential storage medium for hydrogen gas, as the reaction is reversible at 270oC. Up to 11.5% by weight absorption of hydrogen has been achieved.
Lithium nitride
Tantalum carbide
Psyllium
Chromium carbide
Calcium silicate
Hexavalent chromium
Manganese dioxide
Cadmium oxide