REACTION OF URANIUM WITH AMMONIA

NH3 can remain without being decomposed over a long period of time at temperatures of 300-degrees-C or less. In this case NH3 must be considered to be in a thermodynamically unstable state with respect to the dissociation equilibrium NH3 = 1/2N2 + 3/2H-2 and high nitrogen and hydrogen activities may be brought about by its instability. To gain some insight to the role of unstable NH3 in chemical reactions with metals, reactions of U with static NH3 were performed at 250 and 300-degrees-C. The experimental results are discussed in terms of the nitrogen activity a(N) and hydrogen activity a(H) of unstable gaseous mixtures consisting of NH3, H-2 and N2.