Cerium(III) bromide
# Cerium(III) bromide

Cerium(III) bromide is an inorganic compound with the formula $CeBr_3.$ This white hygroscopic solid is of interest as a component of scintillation counters.

## Preparation and basic properties

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 $CeBr_3$ can be prepared from the reaction of $Ce_2(CO_3)_3·H_2O$ with HBr. The product, $CeBr_3·H_2O$ can be dehydrated by heating with $NH_4Br$ followed by sublimation of residual $NH_4Br.$ $CeBr_3$ can be distilled at reduced pressure (~ 0.1 Pa) in a quartz ampoule at 875-880 °C. Like the related salt $CeCl_3,$ the bromide absorbs water on exposure to moist air. The compound melts congruently at 722 °C, and well ordered single crystals may be produced using standard crystal growth methods like Bridgman or Czochralski.

$CeBr_3$ adopts the hexagonal, $UCl_3-type$ crystal structure with the $P6_3/m$ space group. The cerium ions are 9-coordinate and adopt a tricapped trigonal prismatic geometry. The cerium–bromine bond lengths are 3.11 Å and 3.16 Å.

## Applications

$CeBr_3-doped$ 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 $CeBr_3$ have shown promise as a γ-ray scintillation detector in nuclear non-proliferation testing, medical imaging, environmental remediation, and oil exploration.

## Suppliers

* Sigma-Aldrich
