278 M. Ufer on Nitride of Chromium. 
creasing considerably in bulk. This mass is placed in water, 
wherein it separates as a brick-red powder, which is collected on 
a filter and dried over sulphuric acid. 
By a blow or by friction, or by being heated, this substance 
explodes with a loud report, formimg clouds of selenium vapour. 
It is not pure nitride of selenium, but contains an admixture of 
selenium. This latter can be dissolved out by digestion with 
solution of cyanide of potassium, which leaves the nitride of sele- 
nium unattacked. 
Pure nitride of selenium is an orange-yellow powder which 
undergoes no change at 150°, but explodes at 200°. It is ex- 
tremely explosive ; the smallest pressure causes a detonation. It 
also explodes when placed in chlorine, or in hydrochloric acid. 
It is dissolved by nitric acid with formation of ammonia and 
selenious acid. By treatment with potass, ammonia is liberated, 
and selenate and selenide of potassium formed. Hypochlorite of 
soda converts it into selenate of soda, with liberation of hydrogen. 
Heated with water in a sealed tube to 150°—160., it is completely 
changed into ammonia, selenious acid, and pure selenium. 
Espenschied’s analyses did not give very concordant results. 
The mean numbers obtained were, selenium 83°69, nitrogen 
16°33, which corresponds pretty closely to Se? N. The body, 
however, most likely contaims hydrogen, and the formula 
Se® N5 H= Se? NH + 2S8e?N, 
which Espenschied considers probable, requires selenium, 84°57 ; 
nitrogen, 15-07; hydrogen, 0°36. 
Experiments by Espenschied to obtain a corresponding tellu- 
rlum compound have not given the expected results. Chloride 
of tellurium, TeCl?, absorbs ammonia, forming a greenish-yellow 
mass which is not deliquescent. It consists of TeCl? + 2NH°*, 
Ufer has investigated nitride of chromium}. In preparing it 
he tried several methods, but found none superior to Schrotter’s, 
which consists in passing ammoniacal gas over sesquichloride of 
chromium heated to a high temperature. The violet chloride 
gradually changes, becomes first dark green, and ultimately 
black. Vapours of chloride of ammonium are given off, and 
when these cease to appear, the reaction is complete. At the 
close of the experiment, as high a heat is required as the tube 
will bear. The decomposition is thus expressed :— 
Cr? Cl?+ 4. NH8=Cr? N+3NH?*Cl. 
Sesquichloride Nitride 
of chromium, of chromium. 
* Which might be written NH* Cl, NH? TeCl. 
T Liebig’s Annalen, December 1859. 
