Neptunium(IV) fluoride

Neptunium(IV) fluoride or neptunium tetrafluoride is a chemical compound of neptunium and fluorine with the formula NpF₄.

Neptunium(IV) fluoride

Names
IUPAC name Neptunium(IV) fluoride
Other names Neptunium tetrafluoride
Identifiers
CAS Number	14529-88-5
3D model (JSmol)	Interactive image
PubChem CID	101946363 wrong charge
InChI InChI=1S/4FH.Np/h4*1H;/q;;;;+4/p-4 Key: SOLQLNAXKAQIPH-UHFFFAOYSA-J
SMILES F[Np](F)(F)F
Properties
Chemical formula	NpF4
Molar mass	313 g/mol
Appearance	Green solid[1]
Structure
Crystal structure	Monoclinic, mS60[1]
Space group	C2/c, No. 15[2]
Lattice constant	a = 1.27 nm, b = 1.0082 nm, c = 0.833 nm α = 90°, β = 126.03°, γ = 90°
Lattice volume (V)	0.86256 nm^3
Formula units (Z)	12
Thermochemistry
Heat capacity (C)	116 ± 4 J/mol·K[1]
Std molar entropy (S^o298)	148 ± 3 J/mol·K[1]
Std enthalpy of formation (ΔfH^⦵298)	−1874 ± 16 kJ/mol[1]
Gibbs free energy (ΔfG˚)	-1783 ± 16 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

Synthesis

Neptunium(IV) fluoride can be prepared by reacting neptunium(III) fluoride or neptunium dioxide with a gas mixture of oxygen and hydrogen fluoride at 500 °C:[1]

${\displaystyle \mathrm {4\ NpF_{3}\ +\ O_{2}\ +\ 4\ HF\ \longrightarrow \ 4\ NpF_{4}\ +\ 2\ H_{2}O} }$

It can also be prepared by treating neptunium dioxide with HF gas:[1]

${\displaystyle \mathrm {NpO_{2}\ +\ 4\ HF\ \longrightarrow \ NpF_{4}\ +\ 2\ H_{2}O} }$

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. doi:10.1107/S0365110X49001016.