The anhydrous compound is an off-white to pale green solid at room temperature, with an orthorhombic PuBr3-type crystal structure.

[6][7] The material is hygroscopic[8][9] and forms a hexahydrate in water (NdBr3· 6H2O), similar to the related neodymium(III) chloride.

[10] The direct reaction of neodymium with bromine can create neodymium(III) bromide: In the presence of carbon, neodymium(III) oxide reacts with carbon tetrabromide to produce neodymium(III) bromide.

[12] The neodymium ions are 8-coordinate and adopt a bicapped trigonal prismatic geometry.

[14] Neodymium(III) bromide forms compounds with hydrazine, such as NdBr3·N2H4·2H2O, which is a pink crystal that is soluble in water but insoluble in benzene, with d20 °C = 3.2376 g/cm3.