Arsenic, Antimony, Bismuth

Antimony is the fourth member of the nitrogen family and has a valence shell configuration of 5 s 2 5 p 3 . The utilization of these orbitals and, in some cases, of one or two 5 d orbitals permits the existence of compounds in which the antimony atom forms three, four, five, or six covalent bonds. A recommended exposure limit for antimony compounds of 0.5 mg/m 3 (as Sb) has been given. Disposal may be effected by washing residues down the drain at very high dilution unless prohibited by local regulations. Stibine, SbH 3 , is a colorless, poisonous gas having a disagreeable odor. It is the only well‐characterized binary compound of antimony and hydrogen. Stibine is readily oxidized and may be ignited in the presence of air or oxygen to form water and antimony trioxide; at lower temperatures metallic antimony and water are slowly formed. High purity stibine is used as an n ‐type, gas‐phase dopant for Si in semiconductors. The most important binary compounds of antimony with metallic elements are indium antimonide, InSb, gallium antimonide, GaSb, and aluminum antimonide, AlSb, which find extensive use as semiconductors. Antimony trioxide is insoluble in organic solvents and only very slightly soluble in water. Antimony trioxide has numerous practical applications. Its principal use is as a flame retardant in textiles and plastics. Antimony tetroxide finds use as an oxidation catalyst, particularly for the dehydrogenation of olefins. Antimonic acid has been used as an ion‐exchange material for a number of cations in acidic solution. Antimony trifluoride is used as a fluorinating agent to replace nonmetal chloride with fluorine. Antimony trichloride is used as a catalyst or as a component of catalysts to effect polymerization of hydrocarbons and to chlorinate olefins. It is also used in hydrocracking of coal and heavy hydrocarbons. Both antimony tribromide and antimony triiodide readily hydrolyze, form complex halide ions, and form a wide variety of adducts with ethers, aldehydes, mercaptans, etc. Antimony pentafluoride is a strong Lewis acid and a good oxidizing and fluorinating agent. Antimony pentachloride is a strong Lewis acid and a useful chlorine carrier. Antimony trisulfide is used in fireworks, in certain types of matches, as a pigment, and in the manufacture of ruby glass. Antimony pentasulfide, Sb 2 S 5 , commercially known as golden sulfide of antimony, is used in vulcanization to produce a red variety of rubber. The material is also used as a pigment and in fireworks. A large number of compounds have been prepared in which the antimony atom is linked to carbon through an oxygen or sulfur atom. By far the largest group are those obtained by reaction of an antimony oxide with an α‐hydroxy acid, o ‐dihydric phenol, sugar alcohol, or some other polyhydroxy compound containing at least two adjacent hydroxyl groups. The best known compound of this type is antimony potassium tartrate (tartar emetic), used as an antiparasitic agent in medicine. A wide variety of compounds containing the Sb–C bond is known. Organoantimony compounds can be broadly divided in Sb(III) and Sb(V) compounds. A large number of trialkyl‐ and triarylstibines are known. Tertiary stibines have been widely employed as ligands in a variety of transition‐metal complexes, and they appear to have numerous uses in synthetic organic chemistry, eg, for the olefination of carbonyl compounds. They have also been used for the formation of semiconductors, as catalysts or cocatalysts for a number of polymerization reactions, as ingredients of light‐sensitive substances, and for many other industrial purposes. A considerable number of tetraalkyl‐ and tetraaryldistibines have been investigated. A number of organoantimony compounds containing rings of four, five, or six antimony atoms have been prepared. Antimonin(stibabenzene), C 5 H 5 Sb, the antimony analogue of pyridine, can be prepared by the dehydrohalogenation of a cyclic chlorostibine. The stibonic and stibinic acids are polymeric compounds of unknown structure. Dialkylstibinic acids can be readily prepared. Both aliphatic and 'aromatic stibine oxides, R 3 SbO, or their hydrates, R 3 Sb(OH) 2 , are known, as are both trialkyl‐ and triarylstibine sulfides and selenides. Both dialkyl‐ and diaryltrihaloantimony compounds are known. The best known of the halides are the trialkyldihalo‐ and triaryldihaloantimony compounds. Dichlorotriphenylantimony has been suggested as a flame retardant and as a catalyst for the polymerization of ethylene carbonate. Dibromotriphenylantimony has been used as a catalyst for the reaction between carbon dioxide and epoxides to form cyclic carbonates and for the oxidation of α‐keto alcohols to diketones. In addition to the trialkyldihalo‐ and triaryldihaloantimony compounds, mixed dihalo compounds such as chloroiodotriphenylantimony, (C 6 H 5 ) 3 SbClI, have been reported. Tetraalkyl and tetraaryl compounds, R 4 SbX, are well‐known and are often referred to as stibonium salts. There is evidence, however, that most of the tetraaryl compounds contain pentacovalent antimony. In contrast to phosphorus and arsenic, only a few antimony ylids have been prepared. A new method, utilizing an organic copper compound as a catalyst, has resulted in the synthesis of a number of new antimony ylids. A number of pentaalkyl‐ and pentaalkenylantimony compounds have been prepared from tetraalkyl‐ or tetraalkenylstibonium halides and alkyl or alkenyllithium or Grignard reagents. Compounds of antimony have been used as therapeutic agents for thousands of years. The toxicity of these substances was noted at an early date. The therapeutic use of antimonials reached a peak during the eighteenth or early nineteenth century. The introduction of antimony compounds for the treatment of parasitic diseases (eg, American mucocutaneous leishmaniasis, visceral leishmaniasis, and oriental sore) is undoubtedly one of the important milestones in the history of therapeutics. Therapeutic compounds include antimony potassium tartrate (tartar emetic), antimony(V) sodium gluconate, and meglumine antimonate.

Antimony Compounds

Freedman¹,

Doak²,

Long³

2000

Antimony Compounds

Freedman¹,

Doak²,

Long³

et al. 2003

Antimony is the fourth member of the nitrogen family and has a valence shell configuration of 5 s 2 5 p 3 . A recommended exposure limit for antimony compounds of 0.5 mg/m 3 (as Sb) has been given. Stibine, SbH 3 , is a colorless, poisonous gas having a disagreeable odor. It is the only well‐characterized binary compound of antimony and hydrogen. Stibine is readily oxidized and may be ignited in the presence of air or oxygen to form water and antimony trioxide; at lower temperatures metallic antimony and water are slowly formed. High purity stibine is used as an n ‐type, gas‐phase dopant for Si in semiconductors. The most important binary compounds of antimony with metallic elements are indium antimonide, InSb, gallium antimonide, GaSb, and aluminum antimonide, AlSb, which find extensive use as semiconductors. Antimony trioxide is insoluble in organic solvents and only very slightly soluble in water. Antimony trioxide has numerous practical applications. Its principal use is as a flame retardant in textiles and plastics. Antimony tetroxide finds use as an oxidation catalyst, particularly for the dehydrogenation of olefins. Antimonic acid has been used as an ion‐exchange material for a number of cations in acidic solution. Antimony trifluoride is used as a fluorinating agent to replace nonmetal chloride with fluorine. Antimony trichloride is used as a catalyst or as a component of catalysts to effect polymerization of hydrocarbons and to chlorinate olefins. It is also used in hydrocracking of coal and heavy hydrocarbons. Both antimony tribromide and antimony triiodide readily hydrolyze, form complex halide ions, and form a wide variety of adducts with ethers, aldehydes, mercaptans, etc. Antimony pentafluoride is a strong Lewis acid and a good oxidizing and fluorinating agent. Antimony pentachloride is a strong Lewis acid and a useful chlorine carrier. Antimony trisulfide is used in fireworks, in certain types of matches, as a pigment, and in the manufacture of ruby glass. Antimony pentasulfide, Sb 2 S 5 , commercially known as golden sulfide of antimony, is used in vulcanization to produce a red variety of rubber. The material is also used as a pigment and in fireworks. A large number of compounds have been prepared in which the antimony atom is linked to carbon through an oxygen or sulfur atom. The best known compound of this type is antimony potassium tartrate (tartar emetic), used as an antiparasitic agent in medicine. A wide variety of compounds containing the Sb–C bond is known. Organoantimony compounds can be broadly divided in Sb(III) and Sb(V) compounds. A large number of trialkyl‐ and triarylstibines are known. Tertiary stibines have been widely employed as ligands in a variety of transition‐metal complexes, and they appear to have numerous uses in synthetic organic chemistry, eg, for the olefination of carbonyl compounds. They have also been used for the formation of semiconductors, as catalysts or cocatalysts for a number of polymerization reactions, as ingredients of light‐sensitive substances, and for many other industrial purposes. A considerable number of tetraalkyl‐ and tetraaryldistibines have been investigated. A number of organoantimony compounds containing rings of four, five, or six antimony atoms have been prepared. Antimonin(stibabenzene), C 5 H 5 Sb, the antimony analogue of pyridine, can be prepared by the dehydrohalogenation of a cyclic chlorostibine. The stibonic and stibinic acids are polymeric compounds of unknown structure. Dialkylstibinic acids can be readily prepared. Dichlorotriphenylantimony has been suggested as a flame retardant and as a catalyst for the polymerization of ethylene carbonate. Dibromotriphenylantimony has been used as a catalyst for the reaction between carbon dioxide and epoxides to form cyclic carbonates and for the oxidation of α‐keto alcohols to diketones. In addition to the trialkyldihalo‐ and triaryldihaloantimony compounds, mixed dihalo compounds such as chloroiodotriphenylantimony, (C 6 H 5 ) 3 SbClI, have been reported. Tetraalkyl and tetraaryl compounds, R 4 SbX, are well‐known and are often referred to as stibonium salts. In contrast to phosphorus and arsenic, only a few antimony ylids have been prepared. A new method, utilizing an organic copper compound as a catalyst, has resulted in the synthesis of a number of new antimony ylids. A number of pentaalkyl‐ and pentaalkenylantimony compounds have been prepared from tetraalkyl‐ or tetraalkenylstibonium halides and alkyl or alkenyllithium or Grignard reagents.

Arsenic Compounds

Doak¹,

Long²,

Freedman³

2000

Arsenic is the third member of the nitrogen family of elements and hence possesses an outermost shell having the electron configuration of 4 s 2 4 p 3 . The most common oxidation states of arsenic are \documentclass{article}\pagestyle{empty}\begin{document}${-3}$\end{document} , \documentclass{article}\pagestyle{empty}\begin{document}${+3}$\end{document} , and \documentclass{article}\pagestyle{empty}\begin{document}${+5}$\end{document} , although compounds containing the simple \documentclass{article}\pagestyle{empty}\begin{document}${{\rm{As}}{^{3-}}}$\end{document} , \documentclass{article}\pagestyle{empty}\begin{document}${{\rm{As}}{^{3+}}}$\end{document} , and \documentclass{article}\pagestyle{empty}\begin{document}${{\rm{As}}{^{5+}}}$\end{document} ions are unknown. In the majority of arsenic compounds the arsenic atom is in the tetrahedral valence state. Arsenic compounds have numerous practical applications. Although a variety of inorganic and organic arsenicals are used in commerce, arsenic trioxide, As 2 O 3 , accounted for 98% of the arsenic consumed in 1988. The commercial uses of arsenic compounds in 1988 were wood preservatives, agricultural products (herbicides and desiccants), glass, nonferrous alloys and electronics, and animal feed additives and pharmaceuticals. Chromated copper arsenate (CCA) is the most widely used arsenic‐based wood preservative. Arsenic compounds must be considered extremely poisonous. Arsine, AsH 3 , is a colorless, exceedingly poisonous gas with an unpleasant garlic‐like odor, soluble to the extent of 2 mL at 101 kPa (1 atm) per 100 g of water at RT. Arsine is formed when any inorganic arsenic‐bearing material is brought in contact with zinc and sulfuric acid. Arsine is a good reducing agent, capable of reducing many substances. Arsine is used for the preparation of gallium arsenide, GaAs, and there are numerous patents covering this subject. Arsenic forms a complete series of trihalides, but arsenic pentafluoride is the only well‐known simple pentahalide. The trihalides may be prepared by direct combination of the elements. The only arsenic oxides of commercial importance are the trioxide and the pentoxide. Arsenic trioxide (arsenic(III) oxide, arsenic sesquioxide, arsenous oxide, white arsenic, arsenic), As 2 O 3 , is the most important arsenic compound of commerce. Arsenic trioxide may be made by burning arsenic in air or by the hydrolysis of an arsenic trihalide. Commercially, it is obtained by roasting arsenopyrite, FeAsS. Commercial arsenic acid corresponds to the composition, one mole of arsenic pentoxide to four moles of water. Arsenic combines readily with carbon to form a wide variety of compounds containing one or more As–C bonds. These may be broadly divided into As(III) and As(V) compounds. The As(III) compounds contain from one to four organic groups; the As(V) compounds from one to six organic groups. Primary arsines are commonly prepared by the zinc–hydrochloric acid reduction of substances containing one organic group attached to arsenic (such as arsonic acids, dihaloarsines, and compounds with arsenic–arsenic bonds). Secondary arsines are obtained in good yields by the reduction of arsinic acids or haloarsines with amalgamated zinc and hydrochloric acid. These compounds are extremely sensitive to oxygen, and in some cases are spontaneously inflammable in air. They readily undergo addition reactions with alkenes, alkynes, aldehydes, ketones, isocyanates, and azo compounds. An enormous number of trialkyl‐ and triarylarsines are known. They are usually prepared by the reaction of an organometallic compound with an arsenic trihalide, a haloarsine, or a dihaloarsine. Most trialkylarsines are volatile liquids with intensely disagreeable odors. They react readily with oxygen, and in some cases they ignite spontaneously when exposed to air. Triarylarsines are solids that can usually be handled in air without danger of oxidation. They are, however, easily converted to triarylarsine oxides with suitable oxidizing agents. Tertiary arsines have been widely employed as ligands in a variety of transition metal complexes. Haloarsines, dihaloarsines, and related compounds, and diarsines and diarsenes have been obtained. A number of organoarsenic compounds containing rings of four, five, or six arsenic atoms have been prepared (cyclic polyarsines). A large number of polymeric substances, (RAs) x or (ArAs) x , are also known. They are usually prepared by the reduction of arsonic acids with hypophosphorous acid or sodium dithionite. Arsenin (arsabenzene), C 5 H 5 As, the arsenic analogue of pyridine, can be prepared by the treatment of 1,4‐dihydro‐1,1‐dibutylstannabenzene with arsenic trichloride. A large number of arsenin derivatives have also been studied. The arsonic acids, compounds of the type RAsO (OH) 2 , are among the most important organic arsenicals. Both arsonic and arsinic acids give precipitates with many metal ions, a property which has found considerable use in analytical chemistry. Of particular importance are certain azo dyes containing both arsonic and sulfonic acid groups. Both aliphatic and aromatic arsine oxides, compounds of the type R 3 AsO, are well known. The products are extremely hygroscopic and can only be handled under dry box conditions. Halides of the types RAsX 4 , R 2 AsX 3 , R 3 AsX 2 , and R 4 AsX are known. The R 4 AsX compounds are ionic in nature and are discussed under arsonium salts. Arsonium salts are compounds of the type R 4 AsY, where R may be either an alkyl or aryl group and Y is a wide variety of negative groups, such as halogen, nitrate, sulfate, and perchlorate. Arsonium salts have found considerable use in analytical chemistry. Compounds of the type R 5 As, where R may be aliphatic or aromatic, have assumed considerable importance in arsenic chemistry. A large number of pentaarylarsoranes have been prepared, including a number of spirocyclic compounds. These compounds are of particular interest in studies on the stereochemistry of five‐covalent compounds. Since 1943, when penicillin was shown to be effective for the therapy of syphilis, there has been much less work on the use of organoarsenic compounds in medicine. No important new arsenical drug has been introduced. However, arsenicals are still important for the treatment of African trypanosomiasis; they are probably indispensable for the late neurological stage of the disease. Arsenamide (thiacetarsamide), C 11 H 12 AsNO 5 , is a thioarsenite that is employed in veterinary medicine. Although relatively toxic, it has proved useful for the treatment of Dirofilaria immitis (heartworm) infestation in dogs.