ANTIMONY. 
§ 794 -] 
in the proportion of three times the bulk of the sodium peroxide, and 
boiling ; the tin separates as a white, gelatinous precipitate. 
The filtrate is now first acidified with hydrochloric acid and warmed 
until oxygen ceases to be evolved. It is then cooled and treated with 
a rapid current of SH 2 . Antimony, if present, is at once precipitated 
as an orange or golden-yellow sulphide ; this is filtered off and confirmed. 
To the filtrate, which ought to smell feebly of SH 2 , a few drops of 
sodium thiosulphate are added and the solution warmed until a pre¬ 
cipitate begins to separate. The solution is then treated with SH 2 . If 
the precipitate is white, it consists merely of sulphur ; if bright yellow, 
it contains arsenious sulphide, which must be confirmed in the usual 
manner. 1 
Friedrich L. Hain ( Zeit . /. anorg. Chem., 1915) separates a mixture 
of the three sulphides, arsenic, antimony, tin, as follows :—t 
The sulphides are dissolved in ammonium sulphide, and precipitated 
therefrom by acid. The sulphide precipitate is collected on a filter, 
and dissolved out by a cold 5 per cent, solution of sodium sulphide, which 
does not dissolve sulphur. To the filtrate is added twice as much of a 
10 per cent, solution of sodium hydrate as was used of sodium sulphide. 
To this mixture hydrogen peroxide is added, and the solution heated to 
boiling. Antimony separates in crystals of Na 2 H 2 Sb 2 0 7 , which cling 
to the glass when rubbed. On adding one-fourth of the volume of 
alcohol the precipitation is complete. After filtering off the crystalline 
precipitate, the alcohol is expelled by boiling and solid ammonium nitrate 
added, and the liquid boiled until the ammonia is expelled. This pro¬ 
cedure precipitates the tin as stannic acid. After filtering off the stannic 
acid, the arsenic is precipitated by ammonium magnesia mixture as 
ammonium magnesium arsenate. 
Separation of Antimony and Tin by Distillation. — A dis¬ 
tillation process has been devised by Wilhelm Plato (Zeit. /. anorg. Chem., 
1910). If the tin is fixed by phosphoric acid, and the antimony con¬ 
verted into chloride, the latter can be distilled in a vacuum. The 
apparatus required is a Jena Kjeldahl flask. This is provided with a side 
tube, an india-rubber stopper carrying thermometer, and a tap funnel; 
the latter reaches to the bottom of the flask, and the side tube is cooled by 
a condenser. The delivery tube is fitted into a small receiver by means 
of a rubber stopper, into which also is fitted a second condenser (reflex), 
which last is connected with a water pump. The substance, e.g. mixed 
sulphides, is dissolved in 6 c.c. of concentrated sulphuric acid, 7 c.c. of 
syrupy phosphoric acid added, and, after cooling, 10 c.c. of HC1. 50 c.c. 
of HC1 are placed in the receiver, then the reflex condenser is connected 
with a water pump and carbon dioxide drawn through for a little time. 
This operation finished, the flask and its contents are heated from 155°- 
1 James Walker, Journ. Chem. Soc., T., 1903. 
