= Solution
\b[<Antimony> is the brittle, silvery crystalline element $\mathrm{Sb}$, encountered especially in sulfide ores and in compounds of oxidation states $+3$ and $+5$.] Its historical treatment as a metal is understandable from appearance and alloying behaviour; modern classifications commonly call it a <metalloid>. It is too brittle to behave like a readily drawn, ductile metal and is used in suitable alloys to alter properties such as hardness.
The important ore is <stibnite>, $\mathrm{Sb}_2\mathrm S_3$. A historical reduction can use <iron> to bind the <sulfur>:
$$
\boxed{\mathrm{Sb}_2\mathrm S_3+3\mathrm{Fe}\longrightarrow2\mathrm{Sb}+3\mathrm{FeS}.}
$$
Another route roasts suitable sulfide material to an oxide and then reduces that oxide with <carbon>. For an ideal trioxide product,
$$
2\mathrm{Sb}_2\mathrm S_3+9\mathrm O_2\longrightarrow2\mathrm{Sb}_2\mathrm O_3+6\mathrm{SO}_2,
$$
$$
\mathrm{Sb}_2\mathrm O_3+3\mathrm C\longrightarrow2\mathrm{Sb}+3\mathrm{CO}.
$$
Real ore processing requires control of impurities and volatile losses, so these balances do not alone constitute a complete extraction flowsheet.<Periodic Table by Royal Society of Chemistry/Antimony — Element information, properties and uses>[Appearance, Uses and Natural abundance]{ref}
Among its principal combinations, <antimony(III) oxide> is an amphoteric oxide. It dissolves under suitable acidic or alkaline conditions rather than fitting a universal rule that a metal oxide must be solely basic. <Antimony(III) chloride>, historically “butter of antimony”, hydrolyses on dilution and can deposit a white oxychloride-containing material. A useful simplified balance is
$$
\mathrm{SbCl}_3+\mathrm H_2\mathrm O\rightleftharpoons\mathrm{SbOCl}\downarrow+2\mathrm{HCl}.
$$
Added acid favours dissolution; a more extensively hydrolysed precipitate need not be pure $\mathrm{SbOCl}$. Pentavalent compounds include <antimony(V) chloride> and antimonate species; chloride-rich solutions and their hydrolysis require attention to the medium.
<Antimony(III) sulfide> can occur as the dark crystalline ore and as an orange precipitate obtained from a suitable solution with <hydrogen sulfide>:
$$
2\mathrm{Sb}^{3+}+3\mathrm H_2\mathrm S\longrightarrow\mathrm{Sb}_2\mathrm S_3\downarrow+6\mathrm H^+.
$$
Its dissolution in suitable alkaline sulfide solutions forms thioantimony species, providing an analytical separation from some other sulfides. Acidification can reverse that operational separation. A volatile hydride, <stibine>, $\mathrm{SbH}_3$, can decompose to a dark antimony deposit and thus interfere with the <Marsh test> for <arsenic>.
<Antimony potassium tartrate>, “tartar emetic”, is a historically important complex salt, not merely an arbitrary mixture of an antimony salt and a potassium salt. It was used medicinally, but historical use is not proof of safety or a present indication; antimony-containing substances can cause serious poisoning. No dosage or treatment recommendation follows from describing them.<Antimony potassium tartrate by the National Poisons Information Service>[Identity and toxicity]{ref}
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