Reaction between barium and nitrogen in liquid sodium

Nitrogen in increasing amounts has been added to separate solutions of barium in sodium of constant composition (ca.4.40 mol % Ba) at 3000C. After rendering each mixture homogenous using an electromagnetic pump, filtration, and nitrogen analysis, all the N2 added has been found in solution up to a solution composition approximating to Ba4N (i.e. 1.1 mol % N) beyond which the quantity of dissolved N2 decreases progressively due to precipitation of the nitride Ba2N. The solubilization is interpreted in terms of strong preferential solvation of the nitride ion by barium cations. (author)