Stable isotope Neptunium (Np)

Isotope Atomic Mass Half-life Mode of Decay Nuclear Spin Nuclear Magnetic Moment
Np-234 234.04289 4.40 days EC to U-234 0 No data available
Np-235 235.04406 1.058 years EC to U-235; α to Pa-231 5/2 No data available
Np-236 236.04657 155,000 years EC to U-236; α to Pa-232; β- to Pu-236 6 No data available
Np-237 237.0481678 2.14 x 106 years α to Pa-233; SF 5/2 3.14
Np-238 238.05094 2.117 days β- to Pu-238 2 No data available
Np-239 239.05293 2.355 days β- to Pu-239 5/2 No data available

Properties of Neptunium

Name Neptunium
Symbol Np
Atomic number 93
Atomic weight [237]
Standard state Solid at 298 ºK
CAS Registry ID 7439-99-8
Group in periodic table N/A
Group name Actinoid
Period in periodic table 7 (Actinoid)
Block in periodic table f-block
Color Silvery metallic
Classification Metallic
Melting point 910 °K [or 637 °C or 1179 °F]
Boiling point 4300 °K [or ca. 4000 °C or 7232 °F]
Density of solid 20.45 g/cm3
Electron configuration [Rn]5f46d17s2