Lanthanide tribromides are a family of inorganic compounds with the formula LnBr3, where Ln stands for a lanthanide metal. The tribromides are similar to the more widely used lanthanide trichlorides. They exist as anhydrous solids and as hydrates. For the hydrates, three structural motifs are recognized: [Ln2(μ-Br)2(H2O)14]Br4, [LnBr2(H2O)6]Br, and [Ln(H2O)8]Br3. The former two are also observed for the lanthanum trichlorides, but the last motif is unique to the bromides.
They can be prepared by heating the hydrated lanthanide bromides with excess ammonium bromide under an atmosphere of hydrogen bromide.
Inventory + Lanthanide bromides Ln formula for hydrate relationship to hydrated trichloride LaBr3 [La2(μ-Br)2(H2O)14]Br4 Like the corresponding chloride CeBr3 [Ce2(μ-Br)2(H2O)14]Br4 Like the corresponding chloride PrBr3 [PrBr2(H2O)6]Br Like the corresponding chloride NdBr3 [NdBr2(H2O)6]Br Like the corresponding chloride PmBr3 [PmBr2(H2O)6]Br Like the corresponding chloride SmBr3 [SmBr2(H2O)6]Br Like the corresponding chloride EuBr3 [EuBr2(H2O)6]Br Like the corresponding chloride GdBr3 [GdBr2(H2O)6]Br Like the corresponding chloride TbBr3 [TbBr2(H2O)6]Br Like the corresponding chloride DyBr3 [DyBr2(H2O)6]Br Like the corresponding chloride HoBr3 [Ho(H2O)8]Br3 chloride adopts [LnCl2(H2O)6]Cl motif ErBr3 [Er(H2O)8]Br3 chloride adopts [LnCl2(H2O)6]Cl motif TmBr3 [Tm(H2O)8]Br3 chloride adopts [LnCl2(H2O)6]Cl motif YbBr3 [Yb(H2O)8]Br3 chloride adopts [LnCl2(H2O)6]Cl motif LuBr3 [Lu(H2O)8]Br3 chloride adopts [LnCl2(H2O)6]Cl motif
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