Contents

Neptunium(III) bromide

Neptunium(III) bromide

Identifiers
CAS Number	20730-39-6
3D model (JSmol)	Interactive image
InChI InChI=1S/3BrH.Np/h3*1H;/q;;;+3/p-3 Key: HVGILCLFCSGPEI-UHFFFAOYSA-K
SMILES [Np+3].[Br-].[Br-].[Br-]
Properties
Chemical formula	Br3Np
Molar mass	477 g·mol−1
Appearance	green solid[1]
Density	6.62 g·cm−3[2]
Structure
Crystal structure	α-NpBr3: hexagonal β-NpBr3: orthorhombic
Space group	α-NpBr3: P63/m (No. 176) β-NpBr3: Ccmm (No. 63)
Lattice constant	a = 791.7 pm (α), 411 pm (β), b = 791.7 pm (α), 1265 pm (β), c = 438.2 pm (α), 915 pm (β)
Related compounds
Other anions	neptunium(III) fluoride neptunium(III) chloride neptunium(III) iodide
Other cations	uranium(III) bromide plutonium(III) bromide
Related compounds	neptunium(IV) bromide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Chemical compound

Neptunium(III) bromide is a bromideofneptunium, with the chemical formula of NpBr₃.

Preparation[edit]

Neptunium(III) bromide can be prepared by reacting neptunium dioxide and aluminium bromide:^[3]

6 NpO₂ + 8 AlBr₃ → 6 NpBr₃ + 4 Al₂O₃ + 3 Br₂

Properties[edit]

Neptunium(III) bromide is a green solid. It can crystallize in two crystal systems:

• α-NpBr3 is hexagonal with lattice parameters a = 791.7 pm and c = 438.2 pm.^[2] It has the same structure as uranium trichloride.

• β-NpBr3 is orthorhombic with lattice parameters a = 411 pm, b = 1265 pm and c = 915 pm.^[2] It has the same structure as the bromides from plutonium to californium.

Neptunium(III) bromide also has a green hexahydrate, which is monoclinic.^[3]

Reactions[edit]

At 425 °C, neptunium(III) bromide bromide can be further brominated by bromine to form neptunium(IV) bromide.^[2]

2 NpBr₃ + Br₂ → 2 NpBr₄

References[edit]

External reading[edit]

• Yoshida, Zenko; Johnson, Stephen G.; Kimura, Takaumi; Krsul, John R. (2006), Morss, Lester R.; Edelstein, Norman M.; Fuger, Jean (eds.), "Neptunium", The Chemistry of the Actinide and Transactinide Elements, Dordrecht: Springer Netherlands, pp. 699–812, doi:10.1007/1-4020-3598-5_6, ISBN 978-1-4020-3555-5, retrieved 2023-12-23
• Keller, C. (1969), "Die Chemie des Neptuniums", Anorganische Chemie, Fortschritte der Chemischen Forschung (in German), vol. 13/1, Berlin/Heidelberg: Springer-Verlag, pp. 1–124, doi:10.1007/bfb0051170, ISBN 978-3-540-04488-8, retrieved 2023-12-23