Double Halogen Salts. 393 
long and 9™" wide, and it is more stable in the air than the 
first bromide. Analyses of two separate crops gave: 
Calculated for 
il II. 2NH,Br.Cu.Br,. H.0. 
Ammonium _._-_.-_-- 6°88 6°90 7°19 
Mopper 222.1222. 25°61 25°20 25°32 
Iprombme § 2 8 63°76 64°08 63°90 
Water (difference)... 3°75 3°82 3°59 
The lodide, 2N HI . Cu,I,— Only one double iodide could 
be obtained by the use of ammonium iodide and cuprous iodide in 
widely varying proportions in hydroiodie acid solutions. This 
circumstance agrees with the observation made upon several other 
series of double salts studied in this laboratory, that the number 
of double salts possible decreases from the chlorides to the 
iodides. Two separate crops gave the following results upon 
analysis : 
Calculated for 
I. INE 2N Hl 5 Cugla.. 
Ammonium .._._.. 5°84 5°95 5°36 
Papper ee 2... 18°75 Rat 18:90 
acimey ss: 3202... 75°07 75°55 (omy 
99°66 100°00 
Summary.—The double salts obtained in the present inves- 
tigation are as follows: 
231 Type. 1:1 Type. 2:3 Type. 
ecw el =~ - 4NH,Cl.3Cu,Cl, 
4NH,Br.Cu,Br, Abie Ou br. eno’ \ Weis wl. 
2 
Reo. | 2NHI.Cu,I, Sara a Ne 
The two bromides are apparently new compounds, while a 
formula without water has been given to Saglier’siodide. The 
compound, NH,Cl.Cu,Cl, of Deherain probably does not 
exist. 
It was hoped that ammonium-cuprous salts of other types, 
corresponding to the ceesium-cuprous salts described by one of 
us* would be found, but such has not been the case, and there 
is no correspondence between the two series. The view 
advanced in the article just mentioned, that the formula 
4NH,Cl.3Cu,C!, might be considered somewhat doubtful on 
account of its complexity and because its variation from the 
1:2 type is slight, seems to have been unfounded. 
Sheffield Scientific School, New Haven, Conn., June, 1895. 
*This Journal, xlvii, 96. 
