franklin: the ammonia system 217 



The products of the action of acetamide on metallic magnesium 

 are magnesium acetamide, an ammono salt, and hydrogen. (5) 

 As potassium hydroxide in aqueous solution dissolves metallic zinc 

 to form potassium zincate, so a liquid ammonia solution of potas- 

 sium amide attacks the same metal with the evolution of hydrogen 

 and the formation of a beautifully crystalline potassium ammono- 

 zincate. The action is represented by the equation 



Zn + 2KNH 2 = Zn(NHK) 2 + H 2 

 (6) Just as the soluble alkali hydroxides when added to aqueous 

 solutions of the salts of the heavy metals brings about the pre- 

 cipitation of the hydroxides or oxides of the latter, so the anal- 

 ogous metallic amides, imides and nitrides are formed when 

 potassium amide is added to solutions of the salts of the heavy 

 metals in liquid ammonia. Silver iodide is readily soluble in 

 liquid ammonia. When potassium amide is added to such a 

 solution a precipitate of silver amide is formed in accordance with 

 the equation 



Agl + KNH 2 = AgNH 2 + KI 

 In a similar manner a soluble lead salt when treated with a solu- 

 tion of potassium amide gives a precipitate of lead imide, PbNH, 

 and a soluble mercuric salt a precipitate of mercuric nitride, 

 Hg 3 N 2 . (7) A considerable number of ammonia analogs of the 

 compound formed by the solution of the hydroxides of certain 

 heavy metals in aqueous solutions of alkali hydroxides have been 

 prepared by the action of liquid ammonia solutions of potassium 

 amide on the amides and nitrides of a number of heavy metals. 

 For example a beautifully crystalline ammonoplumbite has been 

 prepared in accordance with the reaction represented by the 

 equation 



PbNH + KNH 2 = PbNK + NH 3 

 The analogous reaction in the water system taking place in aque- 

 ous solution may be represented by the equation 



Pb(OH) 2 + 2KOH = Pb(OK) 2 + 2H 2 

 The preparation of potassium ammonoplumbite and of other 

 ammono salts of this class is especially interesting in view of the 

 fact that the analogous aquo salts have never been satisfactorily 

 isolated. (8) The analogies between the water system and the 



