Neptunium-236m

Properties and data of the isotope ²³⁶Np.

Content

General data

Name of the isotope:Neptunium-236m; Np-236mSymbol:²³⁶Np or 23693NpMass number A:236 (= number of nucleons)Atomic number Z:93 (= number of protons)Neutrons N:143Isotopic mass:236.04657(5) u (atomic weight of Neptunium-236m)
Excitation energy: +x keVNuclide mass:235.9955589 u (calculated nuclear mass without electrons)Mass excess:43.37968 MeVMass defect:1.920240964 u (per nucleus)Nuclear binding energy:1788.69293652 MeV (per nucleus)
7.57920736 MeV (average binding energy per nucleon)Half-life:22.5(4) hDecay constant λ:8.557372599505 × 10^-6 s^-1Specific activity α:2.183631490897 × 10⁺¹⁶ Bq g^-1
590170.67321559 Ci g^-1Spin and parity:
(nuclear angular momentum)1Isobaric spin: 1

Radioactive Decay

Half-life T_½ = 22.5(4) h (hours) respectively 8.1000 × 10⁴ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EE	²³⁶U	50(3) %
β^-	²³⁶Pu	50(3) %

Nuclear Isomers

Nuclear isomers or excited states with the activation energy in keV related to the ground state.

Nuclear Isomer	Excitation Energy	Half-life	Spin
²³⁶Np		153000 a	(6-)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 143) and isobaric (same nucleon number A = 236) with Neptunium-236m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 143	Isobar A = 236
84	²²⁷Po
85	²²⁸At
86	²²⁹Rn
87	²³⁰Fr
88	²³¹Ra
89	²³²Ac	²³⁶Ac
90	²³³Th	²³⁶Th
91	²³⁴Pa	²³⁶Pa
92	²³⁵U	²³⁶U
93	²³⁶Np	²³⁶Np
94	²³⁷Pu	²³⁶Pu
95	²³⁸Am	²³⁶Am
96	²³⁹Cm	²³⁶Cm
97	²⁴⁰Bk	²³⁶Bk
98	²⁴¹Cf
99	²⁴²Es
100	²⁴³Fm
101	²⁴⁴Md