392 Wells and Hurlburt—On the Ammonium Cuprous 
It was necessary to dry the samples for analysis very rapidly 
on account of their instability, and some water was unavoidably 
left in them, causing the low summations. The amount of 
water corresponding to one molecule (Deherain’s formula) is 
4-19 per cent. 
The other chloride, 4NH,Cl.38Cu,Cl,, is produced when the 
simple salts are mixed in the required proportion in hydro- 
ehloric acid solution, and also under considerable variations from 
these proportions. It forms brilliant, colorless dodecahedrons 
which are moderately stable in the air at ordinary temperatures, 
but gradually turn green on exposure. 
The following analyses of three separate crops were made: 
Calculated for 
ig 10h JO0b 4NH,Cl. 3CueCle. 
Ammonium - 9°39 9°73 9°73 8°92 
Copper #22 22 47°19 46°73 46°79 47°15 
Chlorine..-. 42°81 43°11 ee ls ' 4AS-93 
99°39 99°57 99°65 100°00 
The calculated amounts of ammonium, copper and chlorine 
for Deherain’s formula, NH,Cl.Cu,Cl,, are 7:15, 50°50 and 
49°35 respectively, and it does not seem possible that this for- 
mula represents the true composition of the salt, because the 
samples analyzed were well crystallized and evidently very 
ure. 
. The Bromides, 4NH,Br. Cu,Br, and 2NH,Br . Qu,Br, . 
H,O.—By the use of ammonium bromide, cuprous bromide, 
hydrobromic acid and copper wire, these compounds were 
produced similarly to the chlorides, but since these salts oxidize 
much less readily than the chlorides, no protection by means 
of carbon dioxide was necessary in any case. 
The first salt, 4NH,Br.Cu,Br,, is formed in the presence of 
an excess of ammonium bromide and resembles the correspond- 
ing chloride in form, occurring in long, colorless prisms which 
turn green after long exposure to the air. Analyses of two 
separate crops gave: 
Calculated for 
i fp 10E 4NH,Br ¢ CueBre. 
Ammonium .-..----- 10°24 10:24 10°61 . 
Copperereice. . -<s 18°81 18°47 18°68 
Bromine 22.5). .-.- > 705938 70°60 70°71 
99°98 99°31 100:00 
The other bromide, 2NH,Br.Cu,bBr,.H,O, is formed in 
the presence of a relatively greater amount of cuprous bromide. 
It forms brilliant, colorless rhombohedrons, sometimes 15™™ 
