Terbium phosphide
Terbium phosphide is an inorganic compound of terbium and phosphorus with the chemical formula TbP. Synthesis
TbP can be obtained by the reaction of terbium and red phosphorus at 800–1000 °C:
4 Tb + P4 → 4 TbP

The compound can also be obtained by the reaction of sodium phosphide and anhydrous terbium chloride at 700~800 °C. Physical properties
TbP undergoes a phase transition at 40 GPa from a NaCl-structure to a CsCl-structure. The compound can be sintered with zinc sulfide to make a green phosphor layer. TbP forms crystals of a cubic system, space group Fm3m. Uses
The compound is a semiconductor used in high power, high frequency applications and in laser diodes and other photo diodes. References

Phosphides
Terbium compounds
Semiconductors
Rock salt crystal structure