Lanthanum phosphide is an inorganic compound of lanthanum and phosphorus with the chemical formula LaP. It belongs to the category of binary compounds, where lanthanum is a rare earth metal and phosphorus is a non-metal. It can be used in semiconductor applications, similar to other rare earth phosphides, due to its semiconducting properties.
Lanthanum phosphide typically crystallizes in a cubic structure. The exact arrangement of atoms within the crystal lattice affects its physical properties.
Synthesis
Lanthanum phosphide can be made by heating lanthanum metal with excess phosphorus in a vacuum:
4 La + P4 → 4 LaP
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. The crystals are very unstable and decompose in the open air.
Lanthanum phosphide is generally grayish-black in color. It has a high melting point, as is characteristic of many phosphide compounds. The density of lanthanum phosphide varies depending on the specific crystalline form, but it tends to be dense due to the lanthanum atoms.
- Chemical formula: LaP
- Molar mass: 169.88
- Appearance: Black crystals
- Density: 5.2 g/cm3
- Solubility in water: Reacts with water
- Crystal structure: Rock salt structure
Electronic properties
Lanthanum phosphide is an example of a strongly correlated material, 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. 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. Using EVGGA, the compound is predicted to have a band gap of 0.56 eV along the Γ-X direction. FP-LAPW has predicted an indirect gap of 0.33 eV along the Γ-X direction.
Chemical properties
Lanthanum phosphide reacts with water, releasing highly toxic phosphine gas:
LaP + 3H2O → La(OH)3 + PH3
Lanthanum phosphide is considered a semiconductor material. Its electronic properties make it potentially useful in various electronic applications. It reacts with acids to produce phosphine gas (PH3), a common reaction for phosphides.
Uses
Lanthanum phosphide compound is a semiconductor used in high power, high frequency applications, and in laser diodes. In semiconductor technology, it is used in combination with other materials to create specific electronic properties required for devices such as transistors and diodes. Its properties make it valuable in the development of advanced electronic components.
Lanthanum phosphide is of interest in semiconductor research and technology. It can be used in optoelectronic devices such as LEDs (light-emitting diodes) and in the production of photodetectors. It can also be alloyed with other materials to modify their properties, although its use in this regard is less common compared to other lanthanum compounds.
