32 Wells and Johnston — Ammonium-Lead Halides. 



constituent of the substance, and that the substance is am- 

 monium chloride crystallized in an unusual form. Analysis 

 No. 1, corresponds to PbCl 2 .24E"H 4 Cl. This is not far from 

 Andre's formula and it shows what he probably analyzed. It 

 is to be noticed that, while our impure ammonium chloride 

 was practically anhydrous, Andre gives a considerable amount 

 of water in his formula. It seems probable that he did not 

 properly dry his products before analyzing them, and, more- 

 over, he evidently determined water from the deficiencies in 

 his analyses. There is more or less water in every one of his 

 formulae. 



Since it was evident that Andre's operation of boiling am- 

 monium chloride solutions with lead oxide could be imitated, 

 with possibilities for greater variations, by adding ammonia to 

 solutions of lead chloride in ammonium chloride, we have car- 

 ried out a series of experiments on that plan. No indications 

 of the existence of any of Andre's complicated compounds 

 were obtained in this way, but, besides the form of ammonium 

 chloride that adheres to the glass, a peculiar modification of it 

 in the form of large, transparent pointed crystals with no dis- 

 tinct faces was observed. A sample of these contained 3 "23 

 per cent of lead. When much ammonia was used in these 

 experiments, an oxychloride of lead was obtained. A pure 

 product of this was prepared by saturating a cold-saturated solu- 

 tion of ammonium chloride with lead chloride while boiling, 

 then adding an equal volume of the cold-saturated ammonium 

 chloride solution and finally adding a large excess of ammonia. 

 A precipitate was formed and re dissolved by the ammonia. 

 The oxychloride was deposited on cooling, in the form of small, 

 blade-like, transparent crystals. Analysis showed that it was 

 the compound PbClOH. 



Calculated for 

 Found. PbClOH. 



Lead 79-17 79*77 



Chlorine __ 14-06 13*68 



Oxygen [2-72] 3*08 



Water 4-05 3-47 



This compound has long been well known, having been used 

 as a white pigment. It is worthy of remark that Andre re- 

 described this body correctly in one of his papers that has 

 already been referred to.* He made it by heating a small 

 quantity of " PbCl 2 .6]S T H 4 CLII 2 " with water in a sealed tube. 

 It is evident that such a product could not have been produced 

 if the chlorides had not contained some basic substance. 



*Bull. Soc. Chim., II, xl, 15, (1883). 



