Neptunium

ElementNeptuniumSymbolNp
Atomic Number93Molar Mass237.05 g mol-1
Electron Configuration[Rn]5f46d17s2Normal Statesolid metal
Density @STP20.45 g cm-3Melting Point644oC
Boiling Point3902oCStable Isotopesnone
Atomic Radius131 pmIonic Radius88 (5+) pm
Electronegativity (Pauling)1.3Ionization Energy (1st)604.5 kJ mol-1
Ionization Energy (2nd) kJ mol-1Ionization Energy (3rd) kJ mol-1
Molar Heat Capacity J K-1mol-1Standard Molar Entropy J K-1mol-1
Enthalpy of Fusion kJ mol-1Enthalpy of Vapourization kJ mol-1
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