Neptunium

Metal

Symbol: Np
Atomic number: 93
Atomic mass: (237.0482)
Group: Actinide
CAS-number: 7439-99-8

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Pm

U				Pu

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Electronic data

Shells: 2, 8, 18, 32, 22, 9, 2
Orbitals: [Rn] 5f⁴ 6d¹ 7s²
Electronegativity: --, 1.2
1. Ionization potential: 6.2657 eV
2. Ionization potential: -- eV
3. Ionization potential: -- eV
Oxidation states: 6, 5, 4, 3
Electrical conductivity: 0.00822 10^6

Thermal data

Melting point: 640 °C
Boiling point: 3902 °C
Specific heat: 0.12 J/gK
Heat of fusion: 5.190 kJ/mol
Heat of vaporization: -- kJ/mol
Thermal conductivity: 0.063 W/cmK

Steric data

Atomic radius: -- Å
Ionic radius: -- Å
Covalent radius: -- Å
Atomic volume: 11.62 cm³/mol
Density (293 K): 20.45 g/cm³
Crystal structure: orthorhombic

Nuclide	Mass	Spin	Halflife	Decay mode	Decay tree
²³⁵Np	235	5/2	1.085y	EC, α	View
²³⁶Np	236	6	1.55E05y	EC, β-	View
²³⁶Npm	236.047	1	22.5h	EC, β-	View
²³⁷Np	237.048	5/2	2.14E06y	α	View
²³⁸Np	238	2	2.117d	β-	View
²³⁹Np	239	5/2	2.355d	β-	View
²⁴⁰Np	240	5	1.032h	β-	View
²⁴⁰Npm	240	1	7.22m	β-, IT	View

Name origin:	Named for the planet Neptune.
Description:	Rare, silvery radioactive metal.
Discovered by:	E.M. McMillan, P.H. Abelson
Year:	1940
Place:	United States
Sources:	Produced by bombarding uranium with slow neutrons.
Use(s):	It has no significant commercial applications.

Neptunium

Physical data

Electronic data

Thermal data

Steric data

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