Neptunium tetrabromide

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Neptunium tetrabromide
Names
Other names
neptunium(IV) bromide
Identifiers
Properties
Br4Np
Molar mass 557 g·mol−1
Appearance red-brown crystals
Density 5.5 g/cm3
Melting point 464 °C (867 °F; 737 K)
Related compounds
Related compounds
Thorium tetrabromide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Neptunium tetrabromide is a binary inorganic compound of neptunium metal and bromine with the chemical formula NpBr4.[1][2][3][4]

Synthesis

The compound can be prepared from the reaction of bromine with metallic neptunium:

Np + 2Br2 → NpBr4

Also, a reaction of aluminum bromide with neptunium(IV) oxide:[5][6]

3NpO2 + 4AlBr3 → 3NpBr4 + 2Al2O3

Physical properties

Neptunium tetrabromide forms red-brown hygroscopic crystals of monoclinic crystal system, spatial group P 2/c,[7][8] cell parameters a = 1.089 nm, b = 0.874 nm, c = 0.705 nm, β = 95.19°, Z = 4.[9]

NpBr4 is easily purified by sublimation in a vacuum.[10]

Chemical properties

Decomposes under strong heating to form

neptunium tribromide
:

2NpBr4 → 2NpBr3 + Br2

With careful oxidation with

antimony(III) oxide
, the compound forms neptunium oxidibromide:

NpBr4 + Sb2O3 → NpOBr2 + 2SbOBr

References

  1. ^ "WebElements Periodic Table » Neptunium » neptunium tetrabromide". webelements.com. Retrieved 2 April 2024.
  2. . Retrieved 2 April 2024.
  3. . Retrieved 2 April 2024.
  4. . Retrieved 2 April 2024.
  5. ^ Fried, S. (1947). The Basic Dry Chemistry of Neptunium. Atomic Energy Commission. p. 10. Retrieved 2 April 2024.
  6. ^ Abstracts of Declassified Documents. Technical Information Division, Oak Ridge Directed Operations. 1947. p. 740. Retrieved 2 April 2024.
  7. . Retrieved 2 April 2024.
  8. . Retrieved 2 April 2024.
  9. ^ The Chemical Thermodynamics of Actinide Elements and Compounds: The actinide halides. International Atomic Energy Agency. 1983. p. 162. Retrieved 2 April 2024.
  10. . Retrieved 2 April 2024.