Cerium(III) bromide

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 CeBr3 can be prepared from the reaction of Ce2(CO3)3·H2O with HBr. The product, CeBr3·H2O can be dehydrated by heating with NH4Br followed by sublimation of residual NH4Br. CeBr3 can be distilled at reduced pressure (~ 0.1 Pa) in a quartz ampoule at 875-880 °C. Like the related salt CeCl3, 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.

CeBr3 adopts the hexagonal, UCl3-type crystal structure with the P63/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

CeBr3-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 CeBr3 have shown promise as a γ-ray [[Scintillator| scintillation detector]] in nuclear non-proliferation testing, medical imaging, environmental remediation, and oil exploration.

Suppliers

• Sigma-Aldrich

References

References

1. (2013). "IUPAC-NIST Solubility Data Series. 94. Rare Earth Metal Iodides and Bromides in Water and Aqueous Systems. Part 2. Bromides". AIP Publishing.
2. (1899). "Eine einfache Methode zur Darstellung der Schwefel-, Chlor- und Brom-Verbindungen der Ceritmetalle". Wiley.
3. (2007). "Thermodynamic Functions of Congruently Melting Compounds Formed in the CeBr₃−KBr Binary System". American Chemical Society (ACS).
4. Morosin, B.. (1968). "Crystal Structures of Anhydrous Rare-Earth Chlorides". AIP Publishing.
5. (1984). "Structural Inorganic Chemistry". Oxford University Press.
6. {{Greenwood&Earnshaw2nd
7. (1948). "Crystal chemical studies of the 5f-series of elements. I. New structure types". [[Acta Crystallographica.
8. (2001-09-03). "High-energy-resolution scintillator: Ce³⁺ activated LaBr₃". AIP Publishing.
9. (2007). "Performance of large lanthanum bromide scintillators". Elsevier BV.
10. (2008). "Crystal growth of large diameter LaBr₃:Ce and CeBr₃". Elsevier BV.