Arsenic trisulfide
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| Names | ||
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| Preferred IUPAC name
Arsenic trisulfide | ||
| Other names
Arsenic(III) sulfide Orpiment | ||
| Identifiers | ||
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3D model (JSmol) |
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| ChemSpider | ||
| ECHA InfoCard | 100.013.744 | |
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PubChem CID |
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CompTox Dashboard (EPA) |
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| Properties | ||
| As2S3 | ||
| Molar mass | 246.02 g·mol−1 | |
| Appearance | Orange crystals | |
| Density | 3.43 g cm−3 | |
| Melting point | 310 °C (590 °F; 583 K) | |
| Boiling point | 707 °C (1,305 °F; 980 K) | |
| -70.0·10−6 cm3/mol | ||
| Structure[1] | ||
| P21/n (No. 11) | ||
a = 1147.5(5) pm
, b = 957.7(4) pm , c = 425.6(2) pmα = 90°, β = 90.68(8)°, γ = 90°
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| pyramidal (As) | ||
| Hazards | ||
| NFPA 704 |
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| U.S. Permissible exposure limit (PEL) |
[1910.1018] TWA 0.010 mg/m3 | |
| Related compounds | ||
| Other anions | {{{value}}} | |
| Other cations | {{{value}}} | |
| Related compounds | {{{value}}} | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | ||
 verify (what is  ?) | ||
| Infobox references | ||
Arsenic trisulfide, also known as orpiment or arsenic(III) sulfide, is a chemical compound. Its chemical formula is As2S3. It has arsenic and sulfide ions in it. The arsenic is in its +3 oxidation state.
Properties
[change | change source]Arsenic trisulfide is a yellow solid. It is a semiconductor. It has a glass (amorphous) form and a crystalline form. It burns in air to make sulfur dioxide and arsenic trioxide, which makes a highly toxic smoke. Arsenic trisulfide can oxidize on the surface to make a highly toxic layer of arsenic trioxide as well. Arsenic trisulfide is not toxic unless it oxidizes. It does not react with acids.
Occurrence
[change | change source]Preparation
[change | change source]Arsenic trisulfide is made when an arsenic compound like arsenic trichloride reacts with hydrogen sulfide. It is also made when arsenic and sulfur are heated together.
Uses
[change | change source]It was looked at for treating cancer. It was used by the Egyptians as a pigment and cosmetic. It is used in glass.
References
[change | change source]- ↑ Mullen, D. J. E.; Nowacki, W (1972), "Refinement of the crystal structures of realgar, AsS and orpiment, As2S3" (PDF), Z. Kristallogr., 136 (1–2): 48–65, doi:10.1524/zkri.1972.136.1-2.48.