Neptunium tetrachloride

Neptunium tetrachloride

Identifiers
CAS Number	15597-84-9^Y
3D model (JSmol)	Interactive image
InChI InChI=1S/4ClH.Np/h4*1H;/q;;;;+4/p-4 Key: XFAAJSLPXNXKKA-UHFFFAOYSA-J
SMILES [Np+4].[Cl-].[Cl-].[Cl-].[Cl-]
Properties
Chemical formula	Cl4Np
Molar mass	379 g·mol^−1
Appearance	orange-brown crystals
Density	4.95 g/cm^3
Melting point	538 °C (1,000 °F; 811 K)
Related compounds
Related compounds	Uranium tetrachloride, Thorium tetrachloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Neptunium tetrachloride is a binary inorganic compound of neptunium metal and chlorine with the chemical formula NpCl₄.^[1][2]

Synthesis

The compound can be prepared by:

• the reaction of neptunium nitride with HCl:^[3]

2 NpN + 8 HCl → N₂ + 4 H₂ + 2 NpCl₄

• the reaction of neptunium sulfide with HCl:

Np₂S₃ + 8 HCl → 2 NpCl₄ + 3 H₂S + H₂

• the reaction of carbon tetrachloride with neptunium(IV) oxide or NpO₂. Neptunium tetrachloride is formed as a yellow sublimate.^[4]

NpO₂ + CCl₄ → NpCl₄ + CO₂

Other reactions are also used.^[5]

Physical properties

NpCl₄ crystallizes in tetragonal crystal system of space group I4/amd.^[6]

Chemical properties

The compound reacts with ammonia to produce neptunium trichloride:^[3]

6 NpCl₄ + 2 NH₃ → 6 NpCl₃ + 6 HCl + N₂

Neptunium tetrachloride can be reduced to neptunium trichloride by hydrogen at 450 °C.

2 NpCl₄ + H₂ → 2 NpCl₃ + 2HCl

NpCl₄ can form Lewis base adducts with non-protic solvents such as 1,2-dimethoxyethane (DME), pyridine and acetonitrile. These compounds are more accessible in practice than the binary NpCl₄ salt. Solvates of the general formula NpCl₄L_x may thus be isolated.^[7] The most commonly used starting material for metal-organic neptunium chemistry is NpCl₄(DME)₂, which can be isolated as a pink powder.^[8]

NpCl₄(DME)₂ in 1,2-dimethoxyethane.

References

1. "WebElements Periodic Table » Neptunium » neptunium tetrachloride". webelements.com. Retrieved 1 April 2024.
2. Stone, J. A.; Jones, E. R. (15 February 1971). "Mössbauer Spectra and Magnetic Susceptibility of Neptunium Tetrachloride below 85°K". The Journal of Chemical Physics. 54 (4): 1713–1718. Bibcode:1971JChPh..54.1713S. doi:10.1063/1.1675076. Retrieved 1 April 2024.
3. Sheft, Irving; Fried, Sherman (1950). New Neptunium Compounds. U.S. Atomic Energy Commission, Technical Information Division. p. 5. Retrieved 1 April 2024.
4. Fried, S. (1947). The Basic Dry Chemistry of Neptunium. Atomic Energy Commission. p. 1. Retrieved 1 April 2024.
5. Ahrland, S.; Bagnall, K. W.; Brown, D. (7 June 2016). The Chemistry of the Actinides: Comprehensive Inorganic Chemistry. Elsevier. p. 181. ISBN 978-1-4831-5934-8. Retrieved 1 April 2024.
6. Spirlet, Marie-Rose; Jemine, Xavier; Goffart, Jean (1 January 1995). "A single-crystal X-ray structure determination of neptunium tetrachloride". Journal of Alloys and Compounds. 216 (2): 269–271. doi:10.1016/0925-8388(94)01264-I. ISSN 0925-8388. Retrieved 1 April 2024.
7. Lopez, Lauren M.; Uible, Madeleine C.; Zeller, Matthias; Bart, Suzanne C. (2024-06-04). "Lewis base adducts of NpCl4". Chemical Communications. 60 (46): 5956–5959. doi:10.1039/D4CC01560F. ISSN 1364-548X. PMID 38766982.
8. Reilly, Sean D.; Brown, Jessie L.; Scott, Brian L.; Gaunt, Andrew J. (2013-12-18). "Synthesis and characterization of NpCl4(DME)2 and PuCl4(DME)2 neutral transuranic An(IV) starting materials". Dalton Transactions. 43 (4): 1498–1501. doi:10.1039/C3DT53058B. ISSN 1477-9234. PMID 24285347.