Neptunium tetrachloride
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| Name = Neptunium tetrachloride
| ImageFile1 = Kristallstruktur Uran(IV)-chlorid.png
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|Section1={{Chembox Identifiers
| CASNo = 15597-84-9
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| StdInChI=1S/4ClH.Np/h4*1H;/q;;;;+4/p-4
| StdInChIKey = XFAAJSLPXNXKKA-UHFFFAOYSA-J
| SMILES = [Np+4].[Cl-].[Cl-].[Cl-].[Cl-]
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|Section2={{Chembox Properties
| Np=1 | Cl=4
| Appearance = orange-brown crystals
| Density = 4.95 g/cm3
| MeltingPtC = 538
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|Section6={{Chembox Related
| OtherCompounds = Uranium tetrachloride, Thorium tetrachloride
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Neptunium tetrachloride is a binary inorganic compound of neptunium metal and chlorine with the chemical formula {{chem2|NpCl4}}.{{cite web |title=WebElements Periodic Table » Neptunium » neptunium tetrachloride |url=https://webelements.com/compounds/neptunium/neptunium_tetrachloride.html |publisher=webelements.com |access-date=1 April 2024}}{{cite journal |last1=Stone |first1=J. A. |last2=Jones |first2=E. R. |title=Mössbauer Spectra and Magnetic Susceptibility of Neptunium Tetrachloride below 85°K |journal=The Journal of Chemical Physics |date=15 February 1971 |volume=54 |issue=4 |pages=1713–1718 |doi=10.1063/1.1675076 |bibcode=1971JChPh..54.1713S |url=https://pubs.aip.org/aip/jcp/article-abstract/54/4/1713/445637/Mossbauer-Spectra-and-Magnetic-Susceptibility-of?redirectedFrom=fulltext |access-date=1 April 2024}}
Synthesis
The compound can be prepared by:
- the reaction of neptunium nitride with HCl:{{cite book |last1=Sheft |first1=Irving |last2=Fried |first2=Sherman |title=New Neptunium Compounds |date=1950 |publisher=U.S. Atomic Energy Commission, Technical Information Division |page=5 |url=https://books.google.com/books?id=c1bcqdRlz4IC&dq=Neptunium+tetrachloride&pg=PA5 |access-date=1 April 2024 |language=en}}
:{{chem2|2 NpN + 8 HCl -> N2 + 4 H2 + 2 NpCl4}}
- the reaction of neptunium sulfide with HCl:
:{{chem2|Np2S3 + 8 HCl -> 2 NpCl4 + 3 H2S + H2}}
- the reaction of carbon tetrachloride with neptunium(IV) oxide or {{chem2|NpO2}}. Neptunium tetrachloride is formed as a yellow sublimate.{{cite book |last1=Fried |first1=S. |title=The Basic Dry Chemistry of Neptunium |date=1947 |publisher=Atomic Energy Commission |page=1 |url=https://books.google.com/books?id=LLlctQDFobUC&dq=Neptunium+tetrachloride&pg=PA1 |access-date=1 April 2024 |language=en}}
:{{chem2|NpO2 + CCl4 -> NpCl4 + CO2}}
Other reactions are also used.{{cite book |last1=Ahrland |first1=S. |last2=Bagnall |first2=K. W. |last3=Brown |first3=D. |title=The Chemistry of the Actinides: Comprehensive Inorganic Chemistry |date=7 June 2016 |publisher=Elsevier |isbn=978-1-4831-5934-8 |page=181 |url=https://books.google.com/books?id=awRPDAAAQBAJ&dq=Neptunium+tetrachloride&pg=PA181 |access-date=1 April 2024 |language=en}}
Physical properties
{{chem2|NpCl4}} crystallizes in tetragonal crystal system of space group I4/amd.{{cite journal |last1=Spirlet |first1=Marie-Rose |last2=Jemine |first2=Xavier |last3=Goffart |first3=Jean |title=A single-crystal X-ray structure determination of neptunium tetrachloride |journal=Journal of Alloys and Compounds |date=1 January 1995 |volume=216 |issue=2 |pages=269–271 |doi=10.1016/0925-8388(94)01264-I |url=https://www.sciencedirect.com/science/article/abs/pii/092583889401264I |access-date=1 April 2024 |issn=0925-8388|url-access=subscription }}
Chemical properties
The compound reacts with ammonia to produce neptunium trichloride:
:{{chem2|6 NpCl4 + 2 NH3 -> 6 NpCl3 + 6 HCl + N2}}
Neptunium tetrachloride can be reduced to neptunium trichloride by hydrogen at 450 °C.
:{{chem2|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 NpCl4Lx may thus be isolated.{{Cite journal |last1=Lopez |first1=Lauren M. |last2=Uible |first2=Madeleine C. |last3=Zeller |first3=Matthias |last4=Bart |first4=Suzanne C. |date=2024-06-04 |title=Lewis base adducts of NpCl4 |journal=Chemical Communications |language=en |volume=60 |issue=46 |pages=5956–5959 |doi=10.1039/D4CC01560F |issn=1364-548X|doi-access=free |pmid=38766982 }} The most commonly used starting material for metal-organic neptunium chemistry is NpCl4(DME)2, which can be isolated as a pink powder.{{Cite journal |last1=Reilly |first1=Sean D. |last2=Brown |first2=Jessie L. |last3=Scott |first3=Brian L. |last4=Gaunt |first4=Andrew J. |date=2013-12-18 |title=Synthesis and characterization of NpCl4(DME)2 and PuCl4(DME)2 neutral transuranic An(IV) starting materials |url=https://pubs.rsc.org/en/content/articlelanding/2014/dt/c3dt53058b |journal=Dalton Transactions |language=en |volume=43 |issue=4 |pages=1498–1501 |doi=10.1039/C3DT53058B |pmid=24285347 |issn=1477-9234|url-access=subscription }}File:NpCl₄(DME)₂ in 1,2-dimethoxyethane..jpg
References
{{reflist}}
{{Neptunium compounds}}
{{Chlorides}}
{{Actinide halides}}