110 On the Union of Ammonia Nitrate with Ammonia. [Jan. 9^ 



absorption of heat occurs during the admixture. The same thing happens 

 when a concentrated aqueous solution of the nitrate is poured into water, 

 as was first pointed out by Gay-Lussac. Other examples of this 

 remarkable phenomenon have been observed by different chemists, and 

 have received various explanations. P. Mohr considers that heat is used 

 up in the depression of the freezing-point of the water which the salt 

 produces. As this depression of the freezing-point is probably attended 

 by an increase in the latent heat of the water, his explanation appears to 

 be the correct one. Thomsen finds the specific heat of the mixture to 

 be less than the mean of the specific heats of its components. 



Its action upon a great number of substances, principally in- 

 organic, has been tried, and found to be for the most part like the 

 actions of dry ammonia and ammonia nitrate conjoined. The nitrate 

 appears to undergo double decomposition with most salts, and the 

 ammonia to unite with nearly all, including the salt of magnesium, 

 aluminium, iron, and manganese. The ammoniated chromium salts 

 possess considerable stability. The ammoniated mercuric iodide is re- 

 solved by washing into ammonia and mercuric iodide again. The am- 

 moniated compounds which do not dissolve in the liquid are very bulky, 

 as observed by Gore in his experiments upon ammonia liquefied by 

 pressure. Nitrates, chlorides, iodides, and bromides are either soluble, as 

 Gore has found them to be, in ammonia alone, or else are decomposed 

 into soluble chlorides &c. of ammonium, and insoluble ammoniated 

 compounds of the metals. Sulphates, oxalates, chromates, and arsenites 

 are insoluble, and phosphates are nearly so. Phosphoric and chromic 

 anhydrides do not act upon the liquid with the energy that might be 

 expected, but combine with the ammonia. Iodine dissolves freely, as it 

 ^es in ammonia alone (Gore). Bromine generates nitrogen. Lead 

 ^alts, including sulphate, chloride, iodide, and oxide, are freely soluble as 

 ammoniated compounds. Platinous chloride dissolves freely as tetra- 

 ammonio-platinous chloride. Potassium salts are very sparingly soluble. 

 Alkalis and their carbonates decompose the nitrate ; so do litharge, lime, 

 and baryta. Calomel is converted into metallic mercury and a soluble 

 ammoniated mercuric compound. Potassium, sodium, zinc, and cadmium 

 dissolve without liberating gas, by reducing the nitrate to nitrite, 

 potassium inflaming. Magnesium slowly dissolves, liberating a little hy- 

 drogen, reducing the nitrate, and becoming partly converted into Beetz's 

 black suboxide of magnesium. Methyl iodide is decomposed ; butyric 

 ether and chloroform are sparingly soluble without decomposition. Ether 

 is insoluble, but by its contact causes the liquid to break up into its two 

 constituents. 



It is a good electrolyte, ammonia and hydrogen appearing at the 

 negative electrode, and nitrogen and 'ammonia nitrate at the positive 

 electrode. Its decomposition may be thus represented 



