View source for Neptunium arsenide

{{Chembox
|OtherNames = Neptunium monoarsenide 
|Section1={{Chembox Identifiers
|CASNo = 39350-08-8
|CASNo_Ref = {{cascite|correct|CAS}}
|UNII_Ref = {{fdacite|changed|FDA}}
|StdInChI= 1S/As.Np
|StdInChIKey = AUGTYUNFKAYNPM-UHFFFAOYSA-N
|SMILES = [Np].[As]
}}
|Section2={{Chembox Properties
|Formula =  {{chem|Np|As}}
|MolarMass = 311.92
|Appearance = Crystals
}}
|Section3={{Chembox Related
|OtherCompounds = [[Neptunium diarsenide]]
}}
}}

'''Neptunium arsenide''' is a binary [[inorganic compound]] of [[neptunium]] and [[arsenic]] with the chemical formula {{chem|Np|As}}.<ref>{{cite book |title=Los Alamos Science |date=2000 |publisher=[[Los Alamos National Laboratory]] |page=172 |url=https://books.google.com/books?id=_CdVAAAAMAAJ&dq=Neptunium+arsenide+NpAs&pg=PA172 |access-date=8 August 2021 |language=en}}</ref> The compound forms crystals.

==Synthesis==
Heating stoichiometric amounts of pure substances:
::<math>\mathsf{ Np + As \ \xrightarrow{T, I_2}\ NpAs }</math>

==Physical properties==
Neptunium arsenide forms crystals of several modifications:<ref>{{cite web |title=mp-2186: NpAs (cubic, Fm-3m, 225) |url=https://materialsproject.org/materials/mp-2186/ |publisher=[[Materials Project]] |access-date=8 August 2021}}</ref><ref>{{cite journal |last1=Arya |first1=Balwant Singh |last2=Patle |first2=U. S. |last3=Aynyas |first3=Mahendra |title=High pressure structural and elastic properties of neptunium arsenide |journal=AIP Conference Proceedings |date=24 April 2019 |volume=2100 |issue=1 |pages=020148 |doi=10.1063/1.5098702 |bibcode=2019AIPC.2100b0148A |s2cid=149517034 |url=https://aip.scitation.org/doi/abs/10.1063/1.5098702?journalCode=apc |access-date=8 August 2021 |issn=0094-243X}}</ref>

*[[Cubic crystal system|Cubic system]], [[space group]] ''Fm''3''m'', cell parameters a = 0.5835 nm, exists at temperatures below –131 °С.
*[[Tetragonal crystal system|Tetragonal system]], cell parameters a = 0.58312 nm, c = 0.58281 nm, exists in the temperature range –131 to –98 °С.
*Cubic system, space group ''Fm''3''m'', cell parameters a = 0.58318 nm, exists at temperatures above –98 °C.

Neptunium arsenide becomes [[antiferromagnetic]] at 175 K.<ref>{{cite book |last1=Erdos |first1=Paul |title=The Physics of Actinide Compounds |date=6 December 2012 |publisher=[[Springer Science & Business Media]] |isbn=978-1-4613-3581-8 |page=40 |url=https://books.google.com/books?id=wZjfBwAAQBAJ&dq=Neptunium+arsenide+NpAs&pg=PA40 |access-date=8 August 2021 |language=en}}</ref><ref>{{cite journal |last1=Aldred |first1=A. T. |last2=Dunlap |first2=B. D. |last3=Harvey |first3=A. R. |last4=Lam |first4=D. J. |last5=Lander |first5=G. H. |last6=Mueller |first6=M. H. |title=Magnetic properties of the neptunium monopnictides |journal=[[Physical Review B]] |date=1 May 1974 |volume=9 |issue=9 |pages=3766–3779 |doi=10.1103/PhysRevB.9.3766 |bibcode=1974PhRvB...9.3766A |url=https://journals.aps.org/prb/abstract/10.1103/PhysRevB.9.3766 |access-date=8 August 2021}}</ref><ref>{{cite journal |title=Magnetization of neptunium monoarsenide |journal=[[Journal of Magnetism and Magnetic Materials]] |date=1 February 1983 |volume=31-34 |pages=233–234 |doi=10.1016/0304-8853(83)90229-9 |url=https://www.sciencedirect.com/science/article/abs/pii/0304885383902299 |access-date=8 August 2021 |language=en |issn=0304-8853|last1=Blaise |first1=A. |last2=Fournier |first2=J.M. |last3=Damien |first3=D. |last4=Wojakowski |first4=A. |bibcode=1983JMMM...31..233B}}</ref>

==References==
{{Reflist}}

{{Neptunium compounds}}
{{Arsenic compounds}}
{{Arsenides}}

[[Category:Neptunium(III) compounds]]
[[Category:Arsenides]]
[[Category:Rock salt crystal structure]]