Samarium(III) bromide is a crystalline compound of one samarium and three bromine atoms with the chemical formula of SmBr<sub>3</sub>. The compound has a crystal structure isotypic to that of plutonium(III) bromide.
SmBr<sub>3</sub>÷6H<sub>2</sub>O can be crystallized by dissolving samarium oxide in 40% hydrobromic acid. The hydrate and ammonium bromide are heated in a vacuum to obtain the anhydrous form of samarium(III) bromide.
Samarium(III) bromide forms some compounds with hydrazine, such as SmBr<sub>3</sub>÷3N<sub>2</sub>H<sub>4</sub>÷H<sub>2</sub>O which is a pale yellow needle-shaped crystal that is soluble in water and ethanol but insoluble in benzene, with d<sub>20 ðC</sub> = 3.147 g/cm<sup>3</sup>.