Antimony trisulfide is found in nature as the crystalline mineral stibnite and the amorphous red mineral (actually a mineraloid)[1] metastibnite.[2] It is manufactured for use in safety matches, military ammunition, explosives and fireworks. It also is used in the production of ruby-colored glass and in plastics as a flame retardant. Historically the stibnite form was used as a grey pigment in paintings produced in the 16th century.[3] In 1817, the dye and fabric chemist, John Mercer discovered the non-stoichiometric compound Antimony Orange (approximate formula), the first good orange pigment available for cotton fabric printing.[4]
Antimony trisulfide was also used as the image sensitive photoconductor in vidicon camera tubes. It is a semiconductor with a direct band gap of 1.8–2.5 eV. With suitable doping, p and n type materials can be produced.[5]
can be prepared from the elements at temperature 500–900 °C:
is precipitated when is passed through an acidified solution of Sb(III). This reaction has been used as a gravimetric method for determining antimony, bubbling through a solution of Sb(III) compound in hot HCl deposits an orange form of which turns black under the reaction conditions.[6]
is readily oxidised, reacting vigorously with oxidising agents. It burns in air with a blue flame. It reacts with incandescence with cadmium, magnesium and zinc chlorates. Mixtures of and chlorates may explode.[7]
In the extraction of antimony from antimony ores the alkaline sulfide process is employed where reacts to form thioantimonate(III) salts (also called thioantimonite):[8]
A number of salts containing different thioantimonate(III) ions can be prepared from . These include:[9]
Schlippe's salt,, a thioantimonate(V) salt is formed when is boiled with sulfur and sodium hydroxide. The reaction can be represented as:
The structure of the black needle-like form of, stibnite, consists of linked ribbons in which antimony atoms are in two different coordination environments, trigonal pyramidal and square pyramidal. Similar ribbons occur in and .[10] The red form, metastibnite, is amorphous. Recent work suggests that there are a number of closely related temperature dependent structures of stibnite which have been termed stibnite (I) the high temperature form, identified previously, stibnite (II) and stibnite (III).[11] Other paper shows that the actual coordination polyhedra of antimony are in fact, with (3+4) coordination at the M1 site and (5+2) at the M2 site. These coordinations consider the presence of secondary bonds. Some of the secondary bonds impart cohesion and are connected with packing.[12]