A N T I M O N Y : ITS HISTORY, CHEMISTRY, MINERALOGY ...

30 THE METALLURGY OF ANTIMONY.
ochre, cervantite, and stiblith. It is obtained by heating the metal or
the trioxide or the trisulphide for a long time in air. The same
result is obtained when nitrate of antimony is heated to red heat.
Pure antimony tetroxide is a white powder, which changes to
yellow on being heated, and changes back to the original colour when
it becomes cold again. Its specific density = 6'69 at moderate temperatures.
It cannot be melted and is not volatile. It is not soluble
in acids, with the exception of concentrated hydrochloric acid. It can
be reduced by carbon, potassium cyanide, potassium, and sodium.
At the temperature of the melting of silver, the dissociation pressure
of the oxygen is so great that the trioxide is formed.
When the tetroxide is heated with antimony the trioxide is
formed. The tetroxide is reduced by sulphur, with the formation
of SO2.
Under certain circumstances the tetroxide behaves as if it were a
mixture of the trioxide and the pentoxide.
Some of the important chemical reactions are :—
Sb2O4 + 5S = Sb2S3 + 2SO2.
Sb2O4 + 2Sb = 4Sb2O3 (fusion).
9Sb.2O4 + Sb2Ss=10Sb2O3 + 3SO2.
Sb2O4.H2O, the hydrate, was first prepared by Berzelius.
Antimony Tetrasulphide, Sb2S4.—This was obtained by Berzelius
by passing hydrogen sulphide gas into a solution of the tetroxide.
Rose was able to obtain it from the decomposition of an aqueous
solution of the fusion-product of the trisulphide and bisulphato of
potassium by tartaric acid. It is a reddish-yellow powder.
Antimony Tetrahaloids.—The tetrachloride and the tetrabromide
are not known in the free state, but only in solution.
C The Compounds of Antimony of 5 Valences.
Antimony Pentafluoride, SbF5.—Berzelius first indicated its existence
in the action between hydrofluoric acid and antimonic acid.
It was obtained by Marignac, Moissan, 0. Ruff, and W. Plats. According
to Ruff and Plats, the pure pentafluoride can be obtained by
allowing the pentachloride to be acted upon by hydrofluoric acid for
three days at 25°-30\
It is a heavy liquid, having a consistency like that of oil, and
solidifying into a substance resembling paraffin. Specific density at