Element Neptunium

Neptunium ElementA radioactive actinide metal, neptunium is the first transuranic element. Its position in the periodic table just after uranium, named after the planet Uranus, led to it being named after Neptune, the next planet beyond Uranus.
Neptunium is a chemical element with the symbol Np and atomic number 93.
Neptunium is a hard, silvery, ductile, radioactive actinide metal. In the periodic table, it is located to the right of the actinide uranium, to the left of the actinide plutonium and below the lanthanide promethium

Names and Identifiers

Chemical Formula:Np
CAS:7439-99-8
Molecular Weight:123.10900  g/mol
EC Number :n/a
MDL Number:n/a
Color:silvery metallic
Other Names:Nettunio
PubChem CID:23933
IUPAC Name:Neptunium
Inchl:InChI=1S/Np
InChI Key:LFNLGNPSGWYGGD-UHFFFAOYSA-N
Canonical SMILES:[Np]
ICSC Number:n/a

Physical & Chemical Properties

Phase:Solid
Density:19.38 g/cm³
Boiling Point:4447 K ​(4174 °C, ​7545 °F)
Melting Point:912±3 K ​(639±3 °C, ​1182±5 °F)
Molecular Formula:Np
Flash Point:n/a
Exact Mass:123.03200

24 neptunium radioisotopes have been characterized with the most stable being 237Np with a half-life of 2.14 million years, 236Np with a half-life of 154,000 years, and 235Np with a half-life of 396.1 days

Radiosotope data

IsotopeMass/DaHalf-lifeMode of decayNuclear spinNuclear magnetic moment
234Np234.042894.4 dEC to 234U0
235Np235.044061.058 yEC to 235U; α to 231Pa5/2
236Np236.04657155000 yEC to 236U; α to 232Pa; β to 236Pu6
237Np237.0481678 (23)2.14 x 106 yα to 233Pa; SF5/23.14
238Np238.050942.117 dβ to 238Pu2
239Np239.052932.355 dβ to 239Pu5/2

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