Nitrogen lithium nitride formation

Normally, lithium hydride ignites in air only at high temperatures. When heated it reacts vigorously with CO2 and nitrogen. With the former, lithium formate is obtained. Reaction at high temperature with nitrogen produces lithium nitride. Therefore, dry limestone or NaCl powders are used to extinguish LiH fires. Lithium hydride reacts exothermically with moist air and violently with water. 

Since finely divided lithium floats on the surface of the solvent and will be in contact with the atmosphere in the reaction vessel, an argon atmosphere, rather than a nitrogen atmosphere, should be used to avoid formation of the insoluble reddish-brown lithium nitride. 

H.3 Write balanced chemical equations for the following reactions (a) Sodium metal reacts with water to produce hydrogen gas and sodium hydroxide, (b) The reaction of sodium oxide, Na20, and water produces sodium hydroxide, (c) Hot lithium metal reacts in a nitrogen atmosphere to produce lithium nitride, Li3N. (d) The reaction of calcium metal with water leads to the evolution of hydrogen gas and the formation of calcium hydroxide, Ca(OH)2. 

The only reactions of molecular nitrogen at ambient temperature are the formation of lithium nitride Li3N, reactions with certain transition metal complexes, and nitrogen fixation with nitrogenase in the bacteria of the root nodules of legumes and in blue algae (Sections 14.1.1 and 14.1.2). Above 500 °C nitrogen reacts with some elements, especially with metals (nitride formation). 

Nitrides.— The solubility study of nitrogen in liquid lithium also yielded results on the thermal decomposition of solid lithium nitride. The problems encountered in the nitridation of Sr and Ca to the stoicheiometric M3N2 are explained by the presence of hydrogen in the starting metals, which leads to the formation of non-stoicheiometric nitride hydrides, until now assumed to be Ca2N and Sr2N. The so-called SrN, which is formed only in the presence of oxygen is, in fact, a NaCl-type cubic quaternary phase that is rich in N and of variable composition... 

Nitrogen contents in molten lithium give rise to enhanced corrosion of iron based alloys due to the formation of complex nitrides stabilized by high chemical activities of nitrogen. Such souble nitrides are more or less soluble in the alkali metal and do not form protecting layers. 

The nitrogen exchange between lithium and several transition metals gives rise to the formation of binary or ternary nitrides, which show analogies with the ternary oxides formed in Na—O—Me systems . In the lithium-nitrogen-stainless steel system, nitrogen is picked-up by the stainless steel due to the getter reaction of the... 

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