66 
CHEMISTRY: E. C FRANKLIN 
zincate, so potassium; amide in liquid ammonia reacts with zinc amide 
to -form .potassium ammonozincate.^ These analogous reactions are 
represented by the equations: 
• ' •• Zn(0H)2 + 2K0H = Zn(0K)2 + H2O, 
. • ^' • • Zn(NH2)2 + 2KNH2 = Zn(NHK)2 + 2NH3. 
In view of the many close analogies which have been shown to exist 
between the derivatives of water and the derivatives of ammonia the 
formation of this potass'um ammonozincate and of potassium ammono- 
stannate^ and potassium ammonoplumbite^ was not unexpected. Fur- 
ther work has, however, shown that elements which do not give rise to 
similar salts in water form these compounds in ammonia. Thus in pre- 
vious articles this was shown to be true of copper'* and thalKum;^ and 
researches have now been completed which show it to be true of silver, 
cadmium, ,and nickel. The work on silver will be here briefly described; 
that on cadmium and nickel, which was carried out by G. S. Bohart, 
will be later reported upon. 
Some, years ago while studying the action of potassium amide on 
liquid-ammonia solutions of silver salts^ it was observed that silver 
amide dissolves readily in an excess of potassium amide solution. This 
solubility recalled the amphoteric properties of the hydroxides of alumi- 
nium, zinc, arid lead, and suggested that in all probability the solution 
resulting from the action of a solution of potassium amide on silver 
amide would be found to contain an ammonoargentate of potassium. 
It was found in fact that a crop of beautiful crystals of the composition 
represented by the formula AgNHK.NHs or AgNH2.KNH2 is obtained 
when a liquid-ammonia solution prepared by dissolving silver amide in 
an excess of potassium amide is first adjusted to a proper concentration 
and then cooled in a bath of liquid ammonia. After two or three re- 
crystallizations the salt is pure. The equation expressing its formation 
is AgNHa -f KNH2 AgNHK + NH3. Because of the relationship 
of the compound to the familiar (aquo) zincates and aluminates it is 
appropriately called potassium ammonoargentate. 
More surprising was the result of a later investigation^ in which the 
amide of such a strongly electropositive element as magnesium was found 
to react with potassium amide to form potassium ammonomagnesate, 
a compound of the formula Mg(NHK)2- 2NH3. This made it seem prob- 
able that potassium amide possesses the property of forming similar 
compounds with the amides of all the metals. It was therefore deemed 
advisable to study the action of solut.ons of potassiimi amide on the 
