 | |
| Names | |
|---|---|
| IUPAC name Arsenic pentasulfide | |
| Other names Arsenic(V) sulfide Diarsenic pentasulfide | |
| Identifiers | |
3D model (JSmol) | |
| ChemSpider |
|
| ECHA InfoCard | 100.154.195 |
| EC Number |
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| UNII | |
| UN number | 1557 |
| |
| |
| Properties | |
| As2S5 | |
| Molar mass | 310.14 g·mol−1 |
| Appearance | Vivid, dark orange, opaque crystals |
| Melting point | 300 °C (572 °F; 573 K)(minimum) |
| Boiling point | 500 °C (932 °F; 773 K)(decomposes) |
| 0.014 g dm−3 (at 0 °C) | |
| Hazards | |
| GHS labelling: | |
  | |
| Danger | |
| H301,H331,H410 | |
| P261,P264,P270,P271,P273,P301+P310,P304+P340,P311,P321,P330,P391,P403+P233,P405,P501 | |
| Related compounds | |
Related compounds | Arsenic pentoxide |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Arsenic pentasulfide is aninorganic compound containing arsenic and sulfur.[1]
Solids of the approximate formulaAs2S5 have been used aspigments and chemical intermediates but are generally only of interest in academic laboratories.[2]
Arsenic pentasulfide is prepared by precipitation from an acidic solution of soluble As(V) salts by treatment withhydrogen sulfide.[3] It may be also prepared by heating a mixture of arsenic and sulfur, extracting the fused mass with anammonia solution and reprecipitating arsenic pentasulfide at low temperature by addition ofhydrochloric acid.
Phosphorus pentasulfide with the formula P4S10, is a molecular compound featuring tetrahedral phosphorus(V) centres. Trends in arsenic redox potentials suggest that As2S5 adopts a similar structure, a plausible alternative being an arsenic polysulfide.
Arsenic pentasulfide hydrolyzes in boiling water, givingarsenous acid andsulfur:
It oxidizes in air at elevated temperatures producing arsenic oxides, the products and yields of which are variable. In alkali metal sulfide solutions arsenic pentasulfide forms athioarsenate anion, [AsS4]3−, which contain As(V) centres.
