pees. 
Double Halogen Salts. 391 
obtained, and we are convinced that Deherain’s formula for it 
is wrong. ‘The second salt, 2NH,Cl.Cu,Cl,, has not been 
obtained by us, but since it corresponds in type to a bromide 
and an iodide which are easily prepared, its existence seems 
possible. The third salt of Deherain, NH,Cl.Cu,Cl,, probably 
does not exist, for we have failed to obtain it, as has Ritthausen 
also. Ritthausen,* while not being able to prepare NH,Ol. 
Cu,Cl,, obtained the compound 4NH,Cl. 3Cu,Cl,, and we have 
confirmed this result. The compositions required for the two 
formule do not differ widely, so that it is probable that 
Deherain analyzed the salt 4NH,Cl.3Cu,Cl, and gave it an 
incorrect formula. 
' As far as we know, no double bromides have been previously 
described. Sagliert has described an ammonium-cuprous 
iodide, to which the formula 2NH,I.Qu,I,.H,O is given. 
The single double iodide which we have obtained corresponds 
to Saglier’s description and to his formula, except that we have 
found it to be undoubtedly anhydrous. 
In the present investigation a great number of experiments 
have been made, with gradually varying proportions of the 
constituent salts in each case, in order to obtain as many com- 
pounds as possible. 
The Chlorides, 4NH,Cl. Cu,Cl, and 4NH,Cl.3Cu,Cl,.— 
These compounds were prepared by making hot hydrochloric 
acid solutions of mixtures of the simple salts, usually in the 
presence of copper wire, and cooling to crystallization. The 
first salt mentioned above is very readily oxidized by exposure 
to air, hence it has been found advisable in making it to use a 
flask and to protect the solution from air by means of a stream 
of carbonic acid. 
The compound 4NH,Cl.Cu,Cl, requires the presence of a 
comparatively large amount of ammonium chloride for its 
formation and crystallizes in colorless prisms which rapidly 
change in color through brown to green upon exposure to the 
air. Crystals 20™™ in length and 5™™ in thickness were 
observed. 3 
The following analyses of two separate crops were made: 
Caleulated for 
4NH,Cl 4 Cu.Cle. 
Ammonium....-.--.- 17°91 18°12 17°48 
Copper. .--- 2s... 29°69 29°28 30°79 
Whiorine ...2. 52. .. 50°66 50°37 51°73 
98°26 97°77 100°00 
Pid. r. On,, lix, 369; + Comptes Rendus, civ, 1440. 
