VOLATILE CHLORIDES WITH AMMONIA. 37 
they, on attempting to distil a mixture of arsenic acid and 
chloride of sodium, with sulphuric acid. Chlorine and proto- 
chloride of arsenic are obtained, with strong effervescence. 
Even when metallic arsenic is treated with great excess of chlo- 
rine gas, and the protochloride of arsenic obtained kept long in 
contact with chlorine, no per-chloride of arsenic can be obtained. 
I endeavoured to combine chloride of selenium (Se Cl?) with 
ammonia; but the chloride takes up none of it in the cold, 
and when warmed it is decomposed. In fact only the liquid 
chlorides appear to combine with ammonia with energy, and not 
the solid ones. 
From the few combinations with ammonia which the chlo- 
rides form corresponding to the more powerful acids, we, how- 
ever, distinctly see that they contain more ammonia than the 
combinations of ammonia with the chlorides forming such weak 
acids that they are not capable of forming salt-like compounds 
with ammonia. The latter take up at the utmost only so much, 
that on the solution of the compound in water its ammonia suf- 
fices to form with the hydrochloric acid produced the chlo- 
ride. of ammonium; frequently, however, they even take up 
much less ammonia. The other chlorides, on the contrary, 
take up more ammonia, and in part so much that they can form 
a neutral ammoniacal salt with the acid generated, besides chlo- 
ride of ammonium. 
Phosphorous acid is evidently a far more powerful acid than 
arsenious acid. On the solution of the protochloride of phos- 
phorus-ammonia in water, a neutral phosphite of the oxide of 
ammonium and chloride of ammonium are consequently formed ; 
while on treating the protochloride of arsenic-ammonia with 
water, besides chloride of ammonium, binarsenite of the oxide 
of ammonia only is produced. 
We may, therefore, in all probability conclude, that if the 
chlorides of sulphur, of selenium and of arsenic, which corre- 
spond to sulphuric selenic and arsenic acids, were known to us 
in their isolated state, their combinations with ammonia, if such 
could be produced, would, on being treated with water, give 
sulphate, seleniate, and arseniate of the oxide of ammonium, be- 
sides chloride of ammonium. 
Again, the compounds of the protochloride of phosphorus, and 
protochloride of arsenic with ammonia, must not be regarded 
after their treatment with water as mixtures of the chloride of 
