Metallic antimony is not poisonous unless partially oxidized. Commercial samples usually contain a little arsenic, which enters into the salts.
Antimonious chloride, Sb Cl3, when pure, forms colourless glistening deliquescent crystals. A solution in hydrochloric acid constitutes the commercial “butter of antimony” used for giving a dark bronzing to brass. It is a thick, powerfully acid liquid, coloured brown by the presence of iron, fuming in air, very corrosive, and of an irritating odour, distilling over at about 200° C. (pure Sb Cl3 boils at 223° C.), decomposed by water into a white magma of oxychloride, Sb O Cl, “powder of Algaroth” (tartar emetic is not decomposed by water). It is a violent corrosive poison, blackening and destroying the surfaces like oil of vitriol. For cases, see Woodman and Tidy, p. 130.
Antimonic chloride, Sb Cl5, is rarely met with. It resembles Sb Cl3, but is liquid.
Antimonious sulphide, Sb2 S3, is found native as “stibnite,” “speiss-glas,” “grey antimony,” or “antimony glance,” sp. gr. 4·63, in lead-grey striated prisms, fibrous or massive, of a strong metallic lustre, fusing readily to a dark-brown glass —“vitrum antimonii”), giving before the blowpipe white fumes, and an odour of sulphur dioxide —“brimstone”). It is the principal ore, the source of all the preparations, and is itself used in fireworks. When powdered it is black, and in this state was used by the Roman ladies under the name of “stibium,” by the Orientals as “Kohl,” for darkening the eyelids. It is soluble in hot hydrochloric acid to form SbCl3. The precipitated sulphide is orange, and will be noticed under the tests. Sb2 S3 would not be poisonous until oxidized.
Antimonious oxide, Sb2 O3, obtained by burning Sb in air, is a white powder, turned yellow on heating, soluble in hydrochloric acid to form Sb Cl3, and in cream of tartar (acid potass. tartrate) to form tartar emetic. Unlike As2 O3, it does not easily volatilize in crystals. It is occasionally found native.
Antimonic oxide, Sb2 O5, is a pale yellow powder. There is also an intermediate oxide, Sb2 O4.
Antimonious and antimonic acids are hydrates of the above oxides. They exist in several modifications, and form metallic salts, one of which, sodium pyrantimonate, Na2 H2 Sb2 O7, 6 H2 O, is the only known insoluble salt of sodium, and hence available as a test.
Antimonious hydride, Stibine, or “antimoniuretted hydrogen,” Sb H3, has never been obtained pure. In admixture with hydrogen, as given by Marsh’s test, it is a colourless gas, almost or quite inodorous (distinction from As H3 which smells like garlic), decomposed by heat into hydrogen and a “mirror” of Sb. Its poisonous properties have been doubted, but it is probably more dangerous than As H3, on account of the absence of the warning odour. It burns with a bluish-green flame, giving white clouds of Sb2 O3, and a spot of Sb, duller and greyer than As, when a cold porcelain surface is depressed into the flame. Passed into silver nitrate solution, the Sb is precipitated along with metallic silver as silver antimonide, Ag3 Sb, whereas arsenic under the same circumstances would remain in solution as As2 O3.
TARTAR EMETIC.
Potassio-antimonyl tartrate, tartrate of antimony and potash, “antimonium tartarizatum,” “tartarized antimony,” “stibiated tartar,” symbol K (Sb O) C4 H4 O6, ½ H2 O, occurs in colourless rhombic octahedral crystals, transparent at first, but becoming opaque by efflorescence, or as a white powder, inodorous, and with a strong metallic taste. The aqueous solution is faintly acid to test-paper, and becomes mouldy on keeping. When evaporated on a glass slide, it leaves a crystalline residue of tetrahedra, cubes and branching forms. (See figure in Guy and Ferrier’s For. Med., p. 469.) Heated on platinum, tartar emetic blackens and swells up with an odour of burnt sugar (due to the tartaric acid), gives a bluish-green tint to the flame, and quickly fuses and makes a hole in the platinum, from the formation of a fusible alloy. Heated in a closed tube, it gives charcoal, potass. carbonate, and metallic antimony, which does not sublime at a moderate temperature, is inodorous, and may be separated in metallic globules by washing (differences from arsenic; see p. 389). Sulph. hydrogen of course gives the orange-red sulphide.