Periodic table of the elements
UraniumNeptuniumPlutonium
93
Np
Neptunium
(237)
2
8
18
32
22
9
2
93
Np
Neptunium
(237)
2
8
18
32
22
9
2
General
NameNeptunium
SymbolNp
Number93
Chemical seriesActinides
Group / Period0 / 7
Blockf-block
CAS registry number7439-99-8

Neptunium is a radioactive element

Physical properties
Statesolid
Density20.45 g/cm3
Melting point910 K (637 °C, 1179 °F)
Boiling point4273 K (4000 °C, 7232 °F)
Critical point

Atomic properties
Atomic Weight(237) g/mol
Crystal structureorthorhombic, tetragonal and cubic
Electronegativity1.36
Atomic radius175 pm
Atomic radius (calculated)
Electron configuration[Rn] 5f4 6d1 7s2
Electrons per shell2, 8, 18, 32, 22, 9, 2
Number of protons93
Number of neutrons144

Other languages
SpanishNeptunio
PortugueseNeptúnio
FrenchNeptunium
GermanNeptunium
ItalianNettunio
RussianНептуний
PolishNeptun
Chinese
Arabicنبتونيوم
TurkishNeptünyum
DutchNeptunium


Periodic table of the elements
UraniumNeptuniumPlutonium