The Osmotic Pressure of Concentrated Solutions, and the Laws of the Perfect Solution,

In a similar manner the non-existence of the compound LiNH, is established. In this case independent evidence is given which shows conclusively that in a system containing lithium and a small molecular per cent. of ammonia a saturated solution of the metal in ammonia is formed. This result is in agreement with the phase relationships existing in the system and demonstrates the inapplicability of the method employed b? Moissan in obtaining and identifying the supposcd compound of lithium and ammonia. It is shown that calcium forms a solid compound with ammonia w h o ~ c composition is represented by the formula Ca(NH,J,. The optical properties of this compound are apparently identical with those of its saturated solution in ammonia, and like its solution, the compound exhibits nietallic conduction. The vapor pressures of saturated solutions of lithium and of Ca(NH,\, in ammonia have been determined, as well as the dissociation pressures of the conipound itself. The heats of formation of the corresponding solutions and of the conipound froin metal and gaseous ammonia arc calculated to be 8700, 10230, and j460 calories per gram-molecule of aim monia, respectively. 'l'he constitution of the compound Ca(NH,), is discussed. I t appears that this compound is of the iiature of a solvate, corresponding, perhaps, to an ammoniated calciitm ion. It is suggested that the c o n pound be called calcium hexanimoiiiate in order to take account of these relations in the nomenclature. BOSTON, February bth, 1908