Np - Neptunium

There is no neptunium in our lab. Neptunium was produced by E. M. McMillan (who shared the 1951 Nobel Prize for Chemistry with Glenn Seaborg for the discovery of this and other transuranic elements) and P. Abelson in 1940 at Berkeley, and found naturally occuring in trace amounts in uranium minerals by Seaborg and Perlman in 1948.

Atomic number - 93 Density g/mL 20 .4
Atomic weight u 237 .0482 Melting point K 910
Bonding radius A - Boiling point K -
Atomic radius A - Heat of vaporization kJ/mol -
Ionization Potential V 6 .19 Heat of fusion kJ/mol 5 .19
Electronegativity - 1 .36 Specific heat J/gK 0 .12
The oxide is amphoteric.
Crystal are orthorhombic.

Electron config. : [Rn] 5f4 6d1 7s2

Isotopes of Np: Click mass number for decay process, product for element page.


226
35 msec
a,8.200 MeV
Pa-222
226.03512 		227
0.51 sec
a,7.816 MeV
Pa-223
227.03495 		228
1.07 min
EC/ECF,4.480
U-228/?
228.03617 		229
3.85 min
a/EC,7.010
Pa-225/U-229
229.03624 		230
4.6 min
a/EC,3.610
Pa-226/U-230
230.03779 		231
48.8 min
a/EC,1.840
Pa-227/U-231
231.03822 		232
14.7 min
EC,2.700 MeV
U-232
232.04004
233
36.2 min
a/EC,1.230
Pa-229/U-233
233.04095 		234
4.4 da
EC,1.810 MeV
U-234
234.04288 		235
396.1 da
a/EC,4.679
Pa-231/U-235
235.04405 		236
154E+3 yr
a/B-/EC,4.572
Pa-232/Pu-236/U-236
236.04657 		237
2.144E+6 yr
a/SF,4.959
Pa-233/?
237.04816 		238
2.117 da
B-,1.292 MeV
Pu-238
238.05093 		239
2.3565 da
B-,1.265 MeV
Pu-239
239.05293
240
61.9 min
B-,2.200 MeV
Pu-240
240.05616 		241
13.9 min
B-,1.310 MeV
Pu-241
241.05825 		242
2.2 min
B-,2.700 MeV
Pu-242
242.06163 		243
1.85 min
B-,2.170 MeV
Pu-243
243.06432 		MASS abund.
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass

e.