Neptunium element properties

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Name: Neptunium Symbol: Np
Group: Rare Earth, Actinides Atomic weight: 237.0482
Density @ 293 K: 20.45 g/cm3 Atomic volume: 11.62 cm3/mol
Group: Rare Earth, Actinides discovered: 1940


state (s, l, g): s
melting point: 913.2 K boiling point: 4175 K
Heat of fusion: 5.190 kJ/mol Heat of vaporization: ?


1st ionization energy: 597 kJ/mole
electronegativity: 1.3 2nd ionization energy: kJ/mole
electron affinity: kJ/mole 3rd ionization energy: kJ/mole
Specific heat: 0.12 J/gK heat atomization: kJ/mole atoms

Oxidation & Electrons:

Shells: 2,8,18,32,23,8,2 electron configuration: [Rn] 5f4 6d1 7s2
minimum oxidation number: 0 maximum oxidation number: 7
min. common oxidation no.: 0 max. common oxidation no.: 5

Appearance & Characteristics:

structure: special:complex color: silvery
uses: toxicity:
hardness: mohs characteristics: Radioactive


reaction with air:
reaction with 6M HCl: reaction with 6M HCl:
reaction with 15M HNO3: reaction with 6M NaOH:

Other Forms:

number of isotopes: 0 hydride(s): NpH2 NpH3
oxide(s): NpO NpO2 Np2O5 chloride(s): NpCl3 NpCl4


ionic radius (2- ion): pm ionic radius (1- ion): pm
atomic radius: 155 pm ionic radius (1+ ion): pm
ionic radius (2+ ion): 124 pm ionic radius (3+ ion): 115 pm


thermal conductivity: 6.3 J/m-sec-deg
electrical conductivity: 1/mohm-cm polarizability: 24.8 A^3


source: Synthetic
rel. abund. solar system: log abundance earth's crust: log
cost, pure: $/100g cost, bulk: $/100g

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