ANTIMONY. 
§§ 778 , 779 -] 
613 
mixture is transferred to a suitable tube, sealed at one end. An 
arsenical mirror is readily obtained, and, if the heat is continued long 
enough, no arsenic remains behind—an excellent and easy method, in 
which the reducing gas is carbonic oxide, in an atmosphere of carbonic 
anhydride. (2) The sulphide is oxidised by aqua regia, and the solution 
evaporated to complete dryness. The residue is then dissolved in a few 
drops of water, with the addition of some largish grains of good wood 
charcoal (which absorb most of the solution), and the whole carefully 
dried. The mass is now transferred to a tube closed at one end, a little 
charcoal added in the form of an upper layer, and heat applied first to 
this upper layer, so as to replace the air with C0 2 , and then to bring 
the whole tube gradually to redness from above downwards. In this 
case also the whole of the arsenic sublimes as a metallic mirror. 
There are various other modifications, but the above are trustworthy, 
and quite sufficient. 
2. ANTIMONY. 
§ 778. Metallic Antimony. —Atomic weight, 120-3 (R. Schneider), 
120-14 (Cook) ; specific gravity, 6-715 ; fusing-point about 621° 
(1150° F.). In the course of analysis, metallic antimony may be seen 
as a black powder thrown down from solutions ; as a film deposited on 
copper or platinum ; and, lastly, as a ring on the inside of a tube from 
the decomposition of stibine. At a bright-red heat it is volatilised 
slowly, even when hydrogen is passed over it; chlorine, bromine, and 
iodine combine with it directly. It may be boiled in concentrated 
C1H without solution ; but aqua regia, sulphides of potassium and 
sodium, readily dissolve it. The distinction between thin films of this 
metal and arsenic on copper and glass is pointed out at pp. 593 and 
595. It is chiefly used in the arts for purposes of alloy, and enters to a 
small extent into the composition of fireworks [vide p. 564). 
§ 779. Antimonious Sulphide. —Sulphide of antimony=336 ; com¬ 
position in 100 parts, Sb 71-76, S 28-24. The commercial article, known 
under the name of black antimony, is the native sulphide, freed from 
siliceous matter by fusion, and afterwards pulverised. It is a crystalline, 
metallic-looking powder, of a steel-grey colour, and is often much con¬ 
taminated with iron, lead, copper, and arsenic. 
The amorphous sulphide (as obtained by saturating a solution of 
tartar emetic with SH 2 ) is an orange-red powder, soluble in potash and 
in ammonic, sodic, and potassic sulphides, and dissolving also in 
• hydrochloric acid with evolution of SH 2 . It is insoluble in water and 
very dilute acid, scarcely dissolves in carbonate of ammonia, and is 
quite insoluble in potassic bisulphite. If ignited gently in a stream of 
carbonic acid gas, the weight remains constant. To render it anhydrous, 
a heat of 200° is required. 
