28 Wells and Johnston — Ammonium- Lead Halides. 



ing 5 g of PbO in 200 cc of a boiling solution of NH.Cl which 

 was nearly cold-saturated. The last method was suggested by 

 Andre's experiments. 



Calculated for 

 A B 3NH 4 PbCl 3 .H 2 



Ammonium 5*22- 5-45 5*33 



Lead...._ 61-12-60-60 61-84-61-88 61*31 



Chlorine.., 31-78-31-79 31*64 31-56 



Water. -.. 1-78 1-78 



The water in A was determined by heating at about 120° for 

 one hour. The limits of the conditions under which this salt 

 is formed are narrow, for, on slightly diluting the solutions 

 which have given it, the following compound is produced. 



1:2 Ammonium- Lead Chloride, NHJPo^Cl^: — This salt 

 is produced under wide limits of conditions. It forms color- 

 less, short, transparent prisms which are usually doubly ter- 

 minated and are apparently orthorhombic in form. The crys- 

 tals retain their luster on drying and are anhydrous. 



Four crops were made under the following conditions: 



NH 4 C1 PbCl a Volume. 



A 100 g. 30 g. 1000 cc 



B 100 20 1000 



C 200 15 550 



D 200 60 700 



These crops gave the following analyses : 



Ammonium. Lead. Chlorine. 



A 2-36-2-67 67-38-67-36 29*08-29-14 



B 66-26-67-56 



C 66-94-66-76 29-16-29'24 



I) 68-00-67-28 



€ NHPboI 0r ( 2 ' 95 67 ' 93 29 ' 12 



Another double chloride was observed, the composition of 

 which was not determined. It will be referred to beyond, 

 under the discussion of Andrews products. 



2:1 Ammonium- Lead Bromide, {NLL^PoBr^Hft : — 

 This salt is easily prepared by dissolving lead bromide in con- 

 centrated solutions of ammonium bromide. Its formation was 

 also observed when lead oxide was dissolved in ammonium 

 bromide by boiling. It forms beautiful radiating groups of 

 highly refracting, slender prisms. Three crops were made as 

 follows : 



NH 4 Br PbBr a Volume. 



A 200 g. 50 g. 380 cc 



B ? 25 ^ 260 



C 200 50 380 



