Neptunium(V) fluoride

Neptunium(V) fluoride

Names
IUPAC name Neptunium(V) fluoride
Other names Neptunium pentafluoride
Identifiers
CAS Number	31479-18-2
3D model (JSmol)	Interactive image
CompTox Dashboard (EPA)	DTXSID701312633
InChI InChI=1S/5FH.Np/h5*1H;/q;;;;;+5/p-5 Key: QROYIGAVOZBRHJ-UHFFFAOYSA-I
SMILES F[Np](F)(F)(F)F
Properties
Chemical formula	NpF5
Molar mass	332 g/mol
Appearance	Bluish-white solid[1]
Melting point	318 °C[1] (dec.)
Structure
Crystal structure	Tetragonal, tI12[1]
Space group	I4/m, No. 87[2]
Lattice constant	a = 0.65358 nm, c = 0.44562 nm
Lattice volume (V)	0.1904 nm^3
Formula units (Z)	2
Thermochemistry
Heat capacity (C)	133 ± 8 J/mol·K[1]
Std molar entropy (S^⦵298)	200 ± 15 J/mol·K[1]
Std enthalpy of formation (ΔfH^⦵298)	−1941 ± 25 kJ/mol[1]
Gibbs free energy (ΔfG^⦵)	-1834 ± 25 kJ/mol[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Neptunium(V) fluoride or neptunium pentafluoride is a chemical compound of neptunium and fluorine with the formula NpF₅.

Synthesis

Neptunium(V) fluoride can be prepared by reacting neptunium(VI) fluoride with iodine:^[1]

${\displaystyle \mathrm {10\ NpF_{6}\ +\ I_{2}\ \longrightarrow \ 10\ NpF_{5}\ +\ 2\ IF_{5}} }$

From the equation above, iodine pentafluoride is a byproduct.

Properties

Neptunium(V) fluoride thermally decomposes at 318 °C to produce neptunium(IV) fluoride and neptunium(VI) fluoride. Contrary to uranium(V) fluoride, neptunium(V) fluoride does not react with boron trichloride, but it reacts with lithium fluoride in anhydrous HF to produce LiNpF₆.^[1]

References

1. Haire, Richard G. (2006). "Neptunium". In Morss; Edelstein, Norman M.; Fuger, Jean (eds.). The Chemistry of the Actinide and Transactinide Elements (3rd ed.). Dordrecht, The Netherlands: Springer Science+Business Media. pp. 730–736. doi:10.1007/1-4020-3598-5_9. ISBN 1-4020-3555-1.
2. Zachariasen, W. H. (1949). "Crystal chemical studies of the 5f-series of elements. XII. New compounds representing known structure types". Acta Crystallographica. 2 (6): 388–390. doi:10.1107/S0365110X49001016.