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