Lanthanum(III) sulfide
Chemical compound
From Wikipedia, the free encyclopedia
Lanthanum(III) sulfide is a binary inorganic chemical compound of lanthanum metal and sulfur with the chemical formula La2S3. At least three polymorphs are known, referred to as α, β, and γ.[2][3]
| Names | |
|---|---|
| IUPAC name
lanthanum(3+);trisulfide | |
| Other names
Dilanthanum trisulfide, lanthanum sesquisulfide | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.031.580 |
| EC Number |
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PubChem CID |
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CompTox Dashboard (EPA) |
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| Properties | |
| La2S3 | |
| Molar mass | 373.99 g·mol−1 |
| Appearance | reddish-yellow crystals |
| Density | 4.9 g/cm3[1] |
| Melting point | 2,100 °C (3,810 °F; 2,370 K) |
| reacts with hot water | |
| Hazards | |
| GHS labelling: | |
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| Structure | |
| cubic | |
| Related compounds | |
Other cations |
Cerium(III) sulfide, Promethium(III) 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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Synthesis
Lanthanum(III) sulfide can directly be produced by treating metallic lanthanum with sulfur:
- 2La + 3S → La2S3
Once prepared, lanthanum(III) sulfide can be purified by chemical vapor transport using iodine.[4]
Lanthanum(III) sulfide can also be prepared by treating the sulfate with hydrogen sulfide at elevated temperatures:[5]
- La2(SO4)3 + 12 H2S → La2S3 + 12 H2O + 12 S
Physical properties
Dilanthanum trisulfide forms reddish-yellow crystals of the cubic system, with space group I43d, and unit cell parameters a = 0.8706 nm.[6] The α polymorph features two types of La3+ centers, one with Capped trigonal prismatic molecular geometry and one is bicapped trigonal prismatic molecular geometry.[2]
It does not dissolve in cold water.
Chemical properties
- Reacts with hot water:
- La2S3 + 6 H2O → 2 La(OH)3 + 3 HS
- Reacts with acids:
- La2S3 + 3 HCl → 2 LaCl3 + 3 H2S
- Oxidized by oxygen in atmosphere:
- 2 La2S3 + 9 O2 → 2 La2O3 + 6 SO2
Uses
La2S3 is used as a precursor to prepare complex compounds. It is also used in glass manufacturing and in optical fibers.[7]