Neptunium(IV) oxide

Neptunium(IV) oxide
Names
	IUPAC name Neptunium(IV) oxide
	Other names Neptunium oxide, neptunium dioxide
Identifiers
CAS Number	12035-79-9 ;
3D model (JSmol)	Interactive image;
ChemSpider	34997056;
ECHA InfoCard	100.031.651
EC Number	234-830-1;
PubChem CID	44148103;
	InChI InChI=1S/Np.2O/q+4;2*-2 Key: QKUTVYUEUPNRBO-UHFFFAOYSA-N;
	SMILES [O-2].[O-2].[Np+4];
Properties
Chemical formula	NpO2
Molar mass	269 g/mol
Appearance	Green cubic crystals
Density	11.1 g/cm3
Melting point	2,800 °C; 5,070 °F; 3,070 K
Structure
Crystal structure	Flourite (cubic), cF12
Space group	Fm3m, #225
Lattice constant	a = 543.4 pm
Formula units (Z)	4
Thermochemistry
Std molar; entropy (S⦵298)	19.19 ± 0.1 cal·mol−1·K−1 ; (80.3 ± 0.4 J·mol−1·K−1)
Std enthalpy of; formation (ΔfH⦵298)	−256.7 ± 0.6 kcal·mol−1 ; (−1074 ± 3 kJ·mol−1)
Related compounds
Other anions	Neptunium(III) chloride; Neptunium(IV) chloride
Other cations	Protactinium(IV) oxide; Uranium(IV) oxide ; Plutonium(IV) oxide; Americium(IV) oxide
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Neptunium(IV) oxide, or neptunium dioxide, is a radioactive, olive green^[5] cubic^[6] crystalline solid with the formula NpO₂. It emits both α- and γ-particles.^[4]

^ Böhler, R.; M. J. Welland; F. De Bruycker; K. Boboridis; A. Janssen; R. Eloirdi; R. J. M. Konings; D. Manara (2012). "Revisiting the melting temperature of NpO2 and the challenges associated with high temperature actinide compound measurements". Journal of Applied Physics. 111 (11). American Institute of Physics: 113501–113501–8. Bibcode:2012JAP...111k3501B. doi:10.1063/1.4721655.
^ Christine Guéneau; Alain Chartier; Paul Fossati; Laurent Van Brutzel; Philippe Martin (2020). "Thermodynamic and Thermophysical Properties of the Actinide Oxides". Comprehensive Nuclear Materials 2nd Ed. 7: 111–154. doi:10.1016/B978-0-12-803581-8.11786-2. ISBN 9780081028667. S2CID 261051636.
^ Westrum, Jr., Edgar F.; J. B. Hatcher; Darrell W. Osborne (March 1953). "The Entropy and Low Temperature Heat Capacity of Neptunium Dioxide". Journal of Chemical Physics. 21 (3): 419. Bibcode:1953JChPh..21..419W. doi:10.1063/1.1698923.
^ ^a ^b Huber Jr, Elmer J.; Charles E. Holley Jr (October 1968). "Enthalpy of formation of neptunium dioxide". Journal of Chemical & Engineering Data. 13 (4): 545–546. doi:10.1021/je60039a029.
^ Patnaik, Pradyot (2003). Handbook of Inorganic Chemical Compounds. McGraw-Hill Professional. p. 271. ISBN 0-07-049439-8.
^ Lide, D. R. (1998). Handbook of Chemistry and Physics 87 ed. CRC Press. p. 471. ISBN 0-8493-0594-2.

[hand-1] Böhler, R.; M. J. Welland; F. De Bruycker; K. Boboridis; A. Janssen; R. Eloirdi; R. J. M. Konings; D. Manara (2012). "Revisiting the melting temperature of NpO2 and the challenges associated with high temperature actinide compound measurements". Journal of Applied Physics. 111 (11). American Institute of Physics: 113501–113501–8. Bibcode:2012JAP...111k3501B. doi:10.1063/1.4721655.

[cry-2] Christine Guéneau; Alain Chartier; Paul Fossati; Laurent Van Brutzel; Philippe Martin (2020). "Thermodynamic and Thermophysical Properties of the Actinide Oxides". Comprehensive Nuclear Materials 2nd Ed. 7: 111–154. doi:10.1016/B978-0-12-803581-8.11786-2. ISBN 9780081028667. S2CID 261051636.

[entr-3] Westrum, Jr., Edgar F.; J. B. Hatcher; Darrell W. Osborne (March 1953). "The Entropy and Low Temperature Heat Capacity of Neptunium Dioxide". Journal of Chemical Physics. 21 (3): 419. Bibcode:1953JChPh..21..419W. doi:10.1063/1.1698923.

[enth-4] Huber Jr, Elmer J.; Charles E. Holley Jr (October 1968). "Enthalpy of formation of neptunium dioxide". Journal of Chemical & Engineering Data. 13 (4): 545–546. doi:10.1021/je60039a029.

[5] Patnaik, Pradyot (2003). Handbook of Inorganic Chemical Compounds. McGraw-Hill Professional. p. 271. ISBN 0-07-049439-8.

[6] Lide, D. R. (1998). Handbook of Chemistry and Physics 87 ed. CRC Press. p. 471. ISBN 0-8493-0594-2.

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