412 COMPOUNDS OF HYDROGEN. 



form two combinations, only one of which, however, the neutral 

 sulphate of ammonia, has been obtained in a definite state. 

 This salt appears to dissolve in water without decomposition, 

 and neither of its constituents is immediately affected or fully 

 precipitated by the reagents which usually have that effect. 

 Thus chloride of strontium and chloride of calcium do not dis- 

 turb its solution for several hours ; chloride of platinum preci- 

 pitates, at first, only a small portion of the ammonia, and chloride 

 of barium, a small portion of the sulphuric acid of the salt. By 

 boiling, its solution is gradually, but never completely converted 

 into the ordinary sulphate of the oxide of ammonium, and this 

 conversion seems always to precede the action of the reagents 

 mentioned upon it. But, as Dr. Kane remarks, this sulphate 

 of ammonia contains, on the binary theory of salts, a peculiar 

 salt-radical, S O 3 , N H 2 , and not S O 4 united with H ; so that its 

 salt-radical is not necessarily precipitated in the same circum- 

 stances as the salt-radical of a sulphate. 



Ammonia with anhydrous salts. Ammoniacal gas is absorbed 

 by many anhydrous salts, and easily expelled from several of 

 them again by heat. These combinations have also been most 

 fully examined by Rose.* In many of them, the ammonia ap- 

 pears to discharge a function analogous to that of water of 

 crystallization in salts, a function which is in accordance with 

 its constitution as an amide of hydrogen. The salt generally 

 rises in temperature during the absorption of the gas, and forms 

 a bulky light powder. Sulphate of manganese absorbs 2 equi- 

 valents of ammonia, sulphate of zinc 2^, sulphate of copper 2|, 

 sulphate of nickel 3 equivalents, sulphate of cobalt and sulphate 

 of cadmium also 3, sulphate of silver 1 equivalent, nitrate of 

 silver absorbs 3 equivalents, chloride of calcium and chloride of 

 strontium absorb 4 equivalents, chloride of copper 3, chloride of 

 cobalt 2, chloride of lead f ths of an equivalent, chloride of sil- 

 ver l, subchloride of mercury and chloride of mercury J eq., 

 iodide of mercury 1 eq. In some of these salts, the ammonia is 

 more intimately combined than in others ; the compound of 

 chloride of mercury with ammonia, for instance, may be sub- 

 limed without decomposition, while the compound with iodide 

 of mercury loses all its ammonia by exposure to the air ; and in 

 some salts, one poition of ammonia is retained more strongly 

 than the rest ; this I found to be the case with half an equiva- 



An. de Ch. et dePh. t. 62, p. 308. 



