Arsenic trisulfide
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.
| 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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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 | Arsenic trioxide Arsenic triselenide | |
| Other cations | Phosphorus trisulfide Antimony trisulfide Bismuth sulfide | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | ||
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| Infobox references | ||
Properties change
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
Preparation change
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
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
- ↑ 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.