MancJiester Memoirs, Vol. liii. (1909), No. 11. 



XVII. The Action of Hydrogen on Sodium. 

 By Alfred Holt, Junr., M.A. 



Received and read Ma}-ch 2jrd, igog. 



Some time ago the author, while preparing some 

 specimens of sodium hydride according to the method 

 described by Moissan {Coviptes rendus, vol. 134, p. 71), 

 noticed certain features in the reaction of hydrogen with 

 molten sodium which seemed to throw light on the 

 relation of the hydride NaH with the compound Na„H 

 described by Troost and Hautefeuille {Comptes rejidus, 

 vol. 7^, p. 807). 



Many experiments were performed, of which the 

 following present points of interest : — 



1. A piece of pure, oil-free sodium was heated in a 

 glass tube filled with hydrogen and standing over mercury. 

 The metal was first heated for five days at 270° C. The 

 bright metallic surface was then found to be covered with 

 a white film of hydride, but none was sublimed on the 

 glass. The volume of hydrogen absorbed was extremely 

 small, not greater than that required to form the film of 

 hydride. More prolonged heating at the same tempera- 

 ture did not perceptibly increase the volume of hydrogen 

 absorbed by or combined with the metal. It is clear 

 from this that at 270° C. the absorption of gas is small 

 and is accounted for by the formation of the film of 

 hydride. 



2. Some sodium was heated in a current of hydrogen 

 to about 400" C, at which temperature the hydride was 

 subliming on the cooler portion of the tube. The sodium 



May nth, igog. 



