CHEMICAL AND PHYSICAL PAPERS. 77 



For example, mercuric choride gives a small amount of mercury 

 chlor-amide, and mercuric iodide gives Hg = N — Hg — I, both of 

 which dissolve in excess of ammonium salts. Bismuth nitrate^ and 

 aluminum iodide give white precipitates of their respective basic 

 salts, both of which are soluble in ammonium salts. The reversible 

 equation representing the action of ammonia on mercury iodide is 

 given. 



2Hgl2 + 4NH3 ^^ Hg = N — Hg — I + 3NH3.HI. 



TheMercury Ammonium Bases. In the light of the above outlined 

 relations, it would seem that certain of the so-called mercury am- 

 monium bases are to be looked upon as mixed compounds containing 

 residues basic to both ammonia andj water, while others are simply 

 mercury salts with ammonia of crystallization. For example, the fu- 

 sible white precipitate is to be formulated HgCl2.2NH3, and not as a 

 double salt of mercury ammonium iodide and ammonium iodide, 

 Hg = NH2I.NH4I, nor as the double salt of dimercurammonium- 

 iodide and ammonium iodide, Hg.>NI.3NH4l, nor yet as mercury diam- 

 monium diodide, Hg(NH3)>I-2, although it may be that the latter 

 formula represents the manner in which ammonia of crystallization 

 associates itself with the salt. 



The chloride of Millon's base, instead of being oxydimercuram- 



monium chloride, O^ „ ^NH2.C1, or dimercurammonium chloride 



with water of crystallization, N( Hg2)Cl.H20, is better formulated as 

 a compound or mixture of salts basic to ammonia with salts basic to 

 water. Of the half-dozen or more possible formulas, the following 

 are given: HgO.HgClNHi; NH2 — Hg — O — Hg — CI ; 2HgO.Hg 



{NH2)2.HgCl2 



Compounds Related to Ammonia, as the Plumhates, Aluminates, 

 etc , are to Water. Certain metallic amides, the lead and aluminum 

 derivatives, for example, dissolve in excess of potassium amide, just as 

 metallic hydroxides and oxides dissolve in potassium hydroxide, form- 

 ing compounds presumably of the type PbNK or Pb(NHK)2. Sev- 

 eral amides have been found to dissolve in this way, but so far only in 

 the case of the lead compound has the attempt been made to isolate 

 and analyze the salt formed. The analysis indicates the compound 

 PbNK, but the difficulty of separating the pure substance from the 

 other products of the reaction has thus far rendered attempts to ob- 

 tain concordant analyses futile. 



1. Not the ordinary salt with water of crystallization, but the. salt formed electrolytically 

 at a bismuth electrode in ammonia solution. 



Note.— One further matter deserves mention, namely, a new instance of the catalytic action 

 of platinum and certain metallic oxides. The potassium amide used in the above-described ex- 

 periments is made by the action of liquid ammonia on metallic potassium. The action is a slow 

 one, a fraction of a gram of metallic potassium, with large excess of ammonia, being completely 

 converted into potassium amide only after the lapse of days. The writer finds that the pres- 

 ence of spongy platinum or of the oxide of iron greatly accelerates the reaction. The addition 

 of a very small quantity of spongy platinum brings the action to completion in the course of 

 about fifteen minutes. 



