Names | |
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Preferred IUPAC name Arsenic trisulfide | |
Other names
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Identifiers | |
3D model (JSmol) | |
ChemSpider | |
ECHA InfoCard | 100.013.744 |
EC Number |
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PubChem CID | |
RTECS number |
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UNII | |
CompTox Dashboard (EPA) | |
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Properties | |
As2S3 | |
Molar mass | 246.02 g·mol−1 |
Appearance | yellow or orange crystals |
Density | 3.43 g/cm3 |
Melting point | 310 °C (590 °F; 583 K) |
Boiling point | 707 °C (1,305 °F; 980 K) |
insoluble | |
Solubility | soluble in ammonia |
−70.0·10−6 cm3/mol | |
Structure [1] | |
monoclinic | |
P21/n (No. 11) | |
a = 1147.5(5) pm, b = 957.7(4) pm, c = 425.6(2) pm α = 90°, β = 90.68(8)°, γ = 90° | |
pyramidal (As) | |
Hazards | |
GHS labelling: [2] [3] | |
Danger | |
H300, H331, H400, H411 | |
NFPA 704 (fire diamond) | |
NIOSH (US health exposure limits): | |
PEL (Permissible) | [1910.1018] TWA 0.010 mg/m3 [4] |
REL (Recommended) | Ca C 0.002 mg/m3 [15-minute] [4] |
IDLH (Immediate danger) | Ca [5 mg/m3 (as As)] [4] |
Related compounds | |
Related compounds | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Arsenic trisulfide is the inorganic compound with the formula As 2 S 3. It is a dark yellow solid that is insoluble in water. It also occurs as the mineral orpiment (Latin: auripigmentum), which has been used as a pigment called King's yellow. It is produced in the analysis of arsenic compounds. It is a group V/VI, intrinsic p-type semiconductor and exhibits photo-induced phase-change properties.[ clarification needed ]
As2S3 occurs both in crystalline and amorphous forms. Both forms feature polymeric structures consisting of trigonal pyramidal As(III) centres linked by sulfide centres. The sulfide centres are two-fold coordinated to two arsenic atoms. In the crystalline form, the compound adopts a ruffled sheet structure. [5] The bonding between the sheets consists of van der Waals forces. The crystalline form is usually found in geological samples. Amorphous As2S3 does not possess a layered structure but is more highly cross-linked. Like other glasses, there is no medium or long-range order, but the first co-ordination sphere is well defined. As2S3 is a good glass former and exhibits a wide glass-forming region in its phase diagram.
It is a semiconductor, with a direct band gap of 2.7 eV. [6] The wide band gap makes it transparent to infrared light between 620 nm and 11 µm.
Amorphous As2S3 is obtained via the fusion of the elements at 390 °C. Rapid cooling of the reaction melt gives a glass. The reaction can be represented with the chemical equation:
As2S3 forms when aqueous solutions containing As(III) are treated with H2S. Arsenic was in the past analyzed and assayed by this reaction, which results in the precipitation of As2S3, which is then weighed. As2S3 can even be precipitated in 6 M HCl. As2S3 is so insoluble that it is not toxic.
Upon heating in a vacuum, polymeric As2S3 "cracks" to give a mixture of molecular species, including molecular As4S6. [7] [8] As4S6 adopts the adamantane geometry, like that observed for P4O6 and As4O6. When a film of this material is exposed to an external energy source such as thermal energy (via thermal annealing [9] ), electromagnetic radiation (i.e. UV lamps, lasers, [10] electron beams) [11] ), As4S6 polymerizes:
As2S3 characteristically dissolves upon treatment with aqueous solutions containing sulfide ions.[ clarification needed ] The dissolved arsenic species is the pyramidal trithioarsenite anion AsS3−3:
As2S3 is the anhydride of the hypothetical trithioarsenous acid, As(SH)3. Upon treatment with polysulfide ions, As2S3 dissolves to give a variety of species containing both S–S and As–S bonds. One derivative is S7As−S−, an eight-membered ring that contains 7 S atoms and 1 As atom, and an exocyclic sulfido center attached to the As atom. As2S3 also dissolves in strongly alkaline solutions to give a mixture of AsS3−3 and AsO3−3. [12]
"Roasting" As2S3 in air gives volatile, toxic derivatives, this conversion being one of the hazards associated with the refining of heavy metal ores:
Due to its high refractive index of 2.45 and its large Knoop hardness compared to organic photoresists, As2S3 has been investigated for the fabrication of photonic crystals with a full-photonic band-gap. Advances in laser patterning techniques such as three-dimensional direct laser writing (3-D DLW) and chemical wet-etching chemistry, has allowed this material to be used as a photoresist to fabricate 3-D nanostructures. [13] [14]
As2S3 has been investigated for use as a high resolution photoresist material since the early 1970s, [15] [16] using aqueous etchants. Although these aqueous etchants allowed for low-aspect ratio 2-D structures to be fabricated, they do not allow for the etching of high aspect ratio structures with 3-D periodicity. Certain organic reagents, used in organic solvents, permit the high-etch selectivity required to produce high-aspect ratio structures with 3-D periodicity.
As2S3 and As4S4 have been investigated as treatments for acute promyelocytic leukemia (APL).
Arsenic trisulfide manufactured into amorphous form is used as a chalcogenide glass for infrared optics. It is transparent for light between wavelengths of 620 nm and 11 µm. The arsenic trisulfide glass is more resistant to oxidation than crystalline arsenic trisulfide, which minimizes toxicity concerns. [17] It can be also used as an acousto-optic material.
Arsenic trisulfide was used for the distinctive eight-sided conical nose over the infra-red seeker of the de Havilland Firestreak missile.
The ancient Egyptians reportedly used orpiment, natural or synthetic, as a pigment in artistry and cosmetics.
Arsenic trisulfide is also used as a tanning agent. It was formerly used with indigo dye for the production of pencil blue, which allowed dark blue hues to be added to fabric via pencil or brush.
Precipitation of arsenic trisulfide is used as an analytical test for presence of dissimilatory arsenic-reducing bacteria (DARB). [18]
As2S3 is so insoluble that its toxicity is low. Aged samples can contain substantial amounts of arsenic oxides, which are soluble and therefore highly toxic.
Orpiment is found in volcanic environments, often together with other arsenic sulfides, mainly realgar. It is sometimes found in low-temperature hydrothermal veins, together with some other sulfide and sulfosalt minerals.
Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, but only the gray form, which has a metallic appearance, is important to industry.
Realgar, also known as "ruby sulphur" or "ruby of arsenic", is an arsenic sulfide mineral with the chemical formula α-As4S4. It is a soft, sectile mineral occurring in monoclinic crystals, or in granular, compact, or powdery form, often in association with the related mineral, orpiment. It is orange-red in color, melts at 320 °C, and burns with a bluish flame releasing fumes of arsenic and sulfur. Realgar is soft with a Mohs hardness of 1.5 to 2 and has a specific gravity of 3.5. Its streak is orange colored. It is trimorphous with pararealgar and bonazziite. Its name comes from the Arabic rahj al-ġār, via Medieval Latin, and its earliest record in English is in the 1390s.
Orpiment is a deep-colored, orange-yellow arsenic sulfide mineral with formula As
2S
3. It is found in volcanic fumaroles, low-temperature hydrothermal veins, and hot springs and is formed both by sublimation and as a byproduct of the decay of another arsenic sulfide mineral, realgar.
Antimony trisulfide is found in nature as the crystalline mineral stibnite and the amorphous red mineral metastibnite. 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. In 1817, the dye and fabric chemist, John Mercer discovered the non-stoichiometric compound Antimony Orange, the first good orange pigment available for cotton fabric printing.
Chalcogenide glass is a glass containing one or more chalcogens. Such glasses are covalently bonded materials and may be classified as covalent network solids. Polonium is also a chalcogen but is not used because of its strong radioactivity. Chalcogenide materials behave rather differently from oxides, in particular their lower band gaps contribute to very dissimilar optical and electrical properties.
Arsenic trioxide, sold under the brand name Trisenox among others, is an inorganic compound with the formula As
2O
3. As an industrial chemical, its major uses include the manufacture of wood preservatives, pesticides, and glass. It is also used as a medication to treat a type of cancer known as acute promyelocytic leukemia. For this use it is given by injection into a vein.
Arsenous acid (or arsenious acid) is the inorganic compound with the formula H3AsO3. It is known to occur in aqueous solutions, but it has not been isolated as a pure material, although this fact does not detract from the significance of As(OH)3.
Sodium thioantimoniate or sodium tetrathioantimonate(V) is an inorganic compound with the formula Na3SbS4. The nonahydrate of this chemical, Na3SbS4·9H2O, is known as Schlippe's salt, named after Johann Karl Friedrich von Schlippe (1799–1867). These compounds are examples of sulfosalts. They were once of interest as species generated in qualitative inorganic analysis.
Copper monosulfide is a chemical compound of copper and sulfur. It was initially thought to occur in nature as the dark indigo blue mineral covellite. However, it was later shown to be rather a cuprous compound, formula Cu+3S(S2). CuS is a moderate conductor of electricity. A black colloidal precipitate of CuS is formed when hydrogen sulfide, H2S, is bubbled through solutions of Cu(II) salts. It is one of a number of binary compounds of copper and sulfur (see copper sulfide for an overview of this subject), and has attracted interest because of its potential uses in catalysis and photovoltaics.
Arsenic pentoxide is the inorganic compound with the formula As2O5. This glassy, white, deliquescent solid is relatively unstable, consistent with the rarity of the As(V) oxidation state. More common, and far more important commercially, is arsenic(III) oxide (As2O3). All inorganic arsenic compounds are highly toxic and thus find only limited commercial applications.
Arsenic triselenide is an inorganic chemical compound with the chemical formula As2Se3.
Arsenic trichloride is an inorganic compound with the formula AsCl3, also known as arsenous chloride or butter of arsenic. This poisonous oil is colourless, although impure samples may appear yellow. It is an intermediate in the manufacture of organoarsenic compounds.
Cadmium nitrate describes any of the related members of a family of inorganic compounds with the general formula , the most commonly encountered form being the tetrahydrate. The anhydrous form is volatile, but the others are colourless crystalline solids that are deliquescent, tending to absorb enough moisture from the air to form an aqueous solution. Like other cadmium compounds, cadmium nitrate is known to be carcinogenic.
Potassium arsenite (KAsO2) is an inorganic compound that exists in two forms, potassium meta-arsenite (KAsO2) and potassium ortho-arsenite (K3AsO3). It is composed of arsenite ions (AsO33− or AsO2−) with arsenic always existing in the +3 oxidation state, and potassium existing in the +1 oxidation state. Like many other arsenic containing compounds, potassium arsenite is highly toxic and carcinogenic to humans. Potassium arsenite forms the basis of Fowler’s solution, which was historically used as a medicinal tonic, but due to its toxic nature its use was discontinued. Potassium arsenite is still, however, used as a rodenticide.
Calcium chromate is an inorganic compound with the formula CaCrO4, i.e. the chromate salt of calcium. It is a bright yellow solid which is normally found in the dihydrate form CaCrO4·2H2O. A very rare anhydrous mineral form exists in nature, which is known as chromatite.
Gallium lanthanum sulfide glass is the name of a family of chalcogenide glasses, referred to as gallium lanthanum sulfide (Ga-La-S) glasses. They are mixtures of La2S3, La2O3, and Ga2S3, which form the basic glass with other glass modifiers added as needed. Gallium-lanthanum-sulfide glasses have a wide range of vitreous formation centered around a 70% Ga2S3 : 30% La2S3 mixture, and readily accept other modifier materials into their structure. This means that Ga-La-S composition can be adjusted to give a wide variety of optical and physical properties.
Gallium(III) sulfide, Ga2S3, is a compound of sulfur and gallium, that is a semiconductor that has applications in electronics and photonics.
Hydrogen chalcogenides are binary compounds of hydrogen with chalcogen atoms. Water, the first chemical compound in this series, contains one oxygen atom and two hydrogen atoms, and is the most common compound on the Earth's surface.
The arsenic (As) cycle is the biogeochemical cycle of natural and anthropogenic exchanges of arsenic terms through the atmosphere, lithosphere, pedosphere, hydrosphere, and biosphere. Although arsenic is naturally abundant in the Earth's crust, long-term exposure and high concentrations of arsenic can be detrimental to human health.
Arsenic(III) telluride is an inorganic compound with the chemical formula As2Te3. It exists in two forms, the monoclinic α phase which transforms under high pressure to a rhombohedral β phase. The compound is a semiconductor, with most current carried by holes. Arsenic telluride has been examined for its use in nonlinear optics.