Cerium(III) bromide is an inorganic compound with the formula CeBr<sub>3</sub>. This white hygroscopic solid is of interest as a component of scintillation counters.
The compound has been known since at least 1899, when Muthman and Stützel reported its preparation from cerium sulfide and gaseous HBr. Aqueous solutions of CeBr<sub>3</sub> can be prepared from the reaction of Ce<sub>2</sub>(CO<sub>3</sub>)<sub>3</sub>÷H<sub>2</sub>O with HBr. The product, CeBr<sub>3</sub>÷H<sub>2</sub>O can be dehydrated by heating with NH<sub>4</sub>Br followed by sublimation of residual NH<sub>4</sub>Br. CeBr<sub>3</sub> can be distilled at reduced pressure (~ 0.1 Pa) in a quartz ampoule at 875-880 ðC. Like the related salt CeCl<sub>3</sub>, the bromide absorbs water on exposure to moist air. The compound melts congruently at 722 ðC, and well ordered single crystals may be produced using standard crystal growth methods like Bridgman or Czochralski.
CeBr<sub>3</sub> adopts the hexagonal, UCl<sub>3</sub>-type crystal structure with the P6<sub>3</sub>/m space group. The cerium ions are 9-coordinate and adopt a tricapped trigonal prismatic geometry. The ceriumâÂÂbromine bond lengths are 3.11 àand 3.16 à.
CeBr<sub>3</sub>-doped lanthanum bromide single crystals are known to exhibit superior scintillation properties for applications in the security, medical imaging, and geophysics detectors.
Undoped single crystals of CeBr<sub>3</sub> have shown promise as a ó-ray scintillation detector in nuclear non-proliferation testing, medical imaging, environmental remediation, and oil exploration.