e smell. In its general
behaviour it resembles arsine, burning with a violet flame and being
decomposed by heat into its constituent elements. When passed into
silver nitrate solution it gives a black precipitate of silver
antimonide, SbAg3. It is decomposed by the halogen elements and also by
sulphuretted hydrogen. All three hydrogen atoms are replaceable by
organic radicals and the resulting compounds combine with compounds of
the type RCl, RBr and RI to form stibonium compounds.

There are three known oxides of antimony, the trioxide Sb4O6 which is
capable of combining with both acids and bases to form salts, the
tetroxide Sb2O4 and the pentoxide Sb2O5. Antimony trioxide occurs as
the minerals valentinite and senarmontite, and can be artificially
prepared by burning antimony in air; by heating the metal in steam to
a bright red heat; by oxidizing melted antimony with litharge; by
decomposing antimony trichloride with an aqueous solution of sodium
carbonate, or by the action of dilute nitric acid on the metal. It is
a white powder, almost insoluble in water, and when volatilized,
condenses in two crystalline forms, either octahedral or prismatic. It
is insoluble in sulphuric and nitric acids, but is readily soluble in
hydrochloric and tartaric acids and in solutions of the caustic
alkalies. On strongly heating in air it is converted into the
tetroxide. The corresponding hydroxide, orthoantimonious acid,
Sb(OH)3, can be obtained in a somewhat impure form by precipitating
tartar emetic with dilute sulphuric acid; or better by decomposing
antimonyl tartaric acid with sulphuric acid and drying the
precipitated white powder at 100 deg. C. Antimony tetroxide is formed
by strongly heating either the trioxide or pentoxide. It is a
nonvolatile white powder, and has a specific gravity of 6.6952; it is
insoluble in water and almost so in acids--concentrated hydrochloric
acid dissolving a small quantity. It is decomposed by a hot solution
of potassium bitartrate. Antimony pentoxide is obtained by repeatedly
evaporating antimony with nitric acid and heating the resulting
antimonic acid to a temperature not above 275 deg. C.; by heating
antimony with red mercuric oxide until the mass becomes yellow (J.
Berzelius); or by evaporating antimony trichloride to dryness with
nitric acid. It is a pale yellow powder (of specific gravity 6.5),
which on being heated strongly gives up o