Lanthanum phosphide
Chemical compound
From Wikipedia, the free encyclopedia
Lanthanum phosphide is an inorganic compound of lanthanum and phosphorus with the chemical formula LaP.
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| Names | |
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| Other names
Phosphanylidynelanthanum | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.042.515 |
| EC Number |
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PubChem CID |
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CompTox Dashboard (EPA) |
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| Properties | |
| LaP | |
| Molar mass | 169.88 |
| Appearance | Black crystals |
| Density | 5.2 g/cm3 |
| Reacts with water | |
| Structure[1] | |
| Rock salt structure | |
| Fm3m | |
a = 0.6025 nm | |
Formula units (Z) |
4 |
| Octahedral at La3+, Octahedral at P3- | |
| Related compounds | |
Other anions |
Lanthanum nitride Lanthanum arsenide Lanthanum bismuthide |
Other cations |
Scandium phosphide Yttrium phosphide Cerium phosphide |
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 phosphide can be made by heating lanthanum metal with excess phosphorus in a vacuum:[2]
- 4 La + P4 → 4 LaP
Physical properties
Lanthanum phosphide forms black crystals of a cubic system, space group Fm3m, cell parameters a = 0.6025 nm, with number of formulas per unit cell Z = 4.[1]
The crystals are very unstable and decompose in the open air.
Electronic properties
Lanthanum phosphide is an example of a strongly correlated material,[3] complicating theoretical prediction of its properties.
According to HSE06 calculations, lanthanum phosphide has been theoretically predicted to have an indirect band gap of 0.25 eV along the Γ-X direction.[4] According to HSE06 calculations with spin-orbit coupling, the band gap is predicted to be a direct gap of 0.72 eV at the X point.[5] Using EVGGA, the compound is predicted to have a band gap of 0.56 eV along the Γ-X direction.[6] FP-LAPW has predicted an indirect gap of 0.33 eV along the Γ-X direction.[3]
Chemical properties
Lanthanum phosphide reacts with water, releasing highly toxic phosphine gas:
- LaP + 3H2O → La(OH)3 + PH3
Uses
Lanthanum phosphide is a semiconductor used in high power, high frequency applications, and in laser diodes.[7][8]