Stibnite

Each of these elements occurs naturally as a sulphide ore arsenic as realgar As S,, orpiment As, Sg and arsenical pyrites with approximate formula FeAsS antimony as stibnite Sb2S3 and bismuth as B12S3. 

The gas is washed with water to remove any hydrogen chloride. Since iron(II) sulphide is a non-stoichiometric compound and always contains some free iron, the hydrogen sulphide always contains some hydrogen, liberated by the action of the iron on the acid. A sample of hydrogen sulphide of better purity can be obtained if antimony(III) sulphide, (stibnite) SbjSj, is warmed with concentrated hydrochloric acid ... 

Many of these sulphides occur naturally, for example iron(ll) sulphide, FeS (magnetic pyrites), and antimony(III) sulphide, Sb S, (stibnite). They can usually be prepared by the direct combination of the elements, effected by heating, but this rarely produces a pure stoichiometric compound and the product often contains a slight excess of the metal, or of sulphur. 

Sulfur occurs native in the vicinity of volcanos and hot springs. It is widely distributed in nature as iron pyrites, galena, sphalerite, cinnabar, stibnite, gypsum, epsom salts, celestite, barite, etc. 

It is not abundant, but is found in over 100 mineral species. It is sometimes found native, but more frequently as the sulfide stibnite. 

Stannic and stannous, see under Tin Stibine, see Antimony hydride Stibnite, see Antimony(III) sulflde Stolzite, see Lead tungstate(VI)(2—)... 

Montana. These deposits consist of stibnite and other sulfide minerals containing base metals and silver or gold. Ores of the complex deposits are mined primarily for lead, copper, 2inc, or precious metals antimony is a by-product of the treatment of these ores. 

The filtered sodium thioantimonate solution obtained from the leaching of stibnite with sodium sulfide may also be reduced directly to metal by elemental sodium (17). Yields ia excess of 95% of 99.5 pure antimony are claimed (18). 

Antimony Trisulfide. Antimony(III) sulfide (antimony sesquisulftde) [1345-04-6] SbS, exists as a black crystalline soHd, stibnite [1317-86-8] and as an amorphous red to yeUow-orange powder. Stibnite melts at 550°C and has Ai i° 298 175 kJ/mol (—41.8 kcal/mol)) A°29g, 182 J/(182 mol-K) [43.5 cal/(43.5 mol-K)] for the amorphous soHd AH° 298 1 147 kJ/mol (—35.1 kcal/mol) (38). The crystal stmcture of stibnite contains two distiucdy different antimony sites and consists of two parallel Sb S chains that are linked together to form cmmpled sheets (two per unit cell). 

Antimony trioxide (SbaOj). It is produced from stibnite (antimony sulphide). Some typical properties are density 5.2-5.67 g/cm- pH of water suspension 2-6.5 particle size 0.2-3 p,m specific surface area 2-13 m-/g. Antimony trioxide has been the oxide universally employed as flame retardant, but recently antimony pentoxide (SbaOs) has also been used. Antimony oxides require the presence of a halogen compound to exert their fire-retardant effect. The flame-retarding action is produced in the vapour phase above the burning surface. The halogen and the antimony oxide in a vapour phase (above 315 C) react to form halides and oxyhalides which act as extinguishing moieties. Combination with zinc borate, zinc stannate and ammonium octamolybdate enhances the flame-retarding properties of antimony trioxide. 

Cu the latter two ean be removed by stibnite treatment or heating with eharcoal/Na2S04 flux the As and S ean be removed by an oxidizing flux of NaNOa and NaOH (or Na2C03) Pb is hard to remove but this is unneeessary if the Sb is to be used in Pb alloys (see below). Eleetrolysis yields >99.9% purity and remaining impurities ean be redueed to the ppm level by zone refining. The seale of produetion and the various uses of Sb and its eompounds are summarized in the Panel. 

Spiessglanz-asche, /. antimony ash. -bleierz, n. bournonite. -blende, /, antimony blende, kermesite. -blumen, /.pi. flowers of antimony. -butter, /. butter of antimony (old name for antimony trichloride), -erz, n. antimony ore (graues, stibnite schwarzes, bournonite weisses, valentinite), - las, n. glass of antimony. 

Spiessglas, n. antimony. See also Spiessglanz-. -erz, n. stibnite. -weiss, n. antimony white (tri oxide). 

FIGURE 15.3 The minerals (from left to right) orpiment, As2S, stibnite, Sb,S, and realgar, As4S4 are all ores that have been used as sources of Group 15A elements. 

Stern-Gerlach experiment, 31 stibnite, 626 stiffness of bond, 92 STM, FI6, 189 Stock number, F30 stock solution, F58 stoichiometric coefficient,... 

Minerals can form colorful regular crystals. Shown here are vanadinite, Pbj (V04)3 Cl lefty, quartz, Si02 center)-, fluorapatite, Caj (P04)3 F top right)-, and stibnite,... 

Antimony(III) sulfide, Sb2S3 (stibnite) antimony(V) sulfide, Sb2S5 anti-mony(III) selenide, Sb2Se3 antimony(III) telluride, Sb2Te3 bismuth(III) selenide,... 

Sanru aguilarite, naumannite, polybasite, pyrargyrite, stephanite electrum, miargyrite, chalcopyrite, fahore, arsenopyrite, marcasite, pyrite, sphalerite, stibnite cinnabar quartz, adularia, kaolinite, sericite, calcite... 

Hishikari naumannite electrum, chalcopyrite, marcasite, pyrite, galena, sphalerite, stibnite quartz, adularia, montmorillonite... 

Kobetsuzawa altaite. frohbergite, hessite, native tellurium, rickardite, sylvanite. tellurantimony dyscrasite, chalcopyrite, hematite, marcasite, pyrite, pyrrhotite, galena, sphalerite, realgar, stibnite quartz, sericite, zeolite, anatase... 

Opaque minerals include stibnite, jamesonite, cinnabar, gold, pyrite, pyrrhotite, arsenopyrite, marcasite, sphalerite, galena and chalcopyrite. 

From the mode of occurrence of opaque minerals it is considered that pyrrhotite and sphalerite were precipitated at an early-stage, gold, pyrite, marcasite, stibnite and cinnabar were precipitated at a late-stage, and arsenopyrite was precipitated throughout the mineralization period. 

---