Americium-246

Properties and data of the isotope ²⁴⁶Am.

Content

General data

Name of the isotope:Americium-246; Am-246Symbol:²⁴⁶Am or 24695AmMass number A:246 (= number of nucleons)Atomic number Z:95 (= number of protons)Neutrons N:151Isotopic mass:246.069774(19) u (atomic weight of Americium-246)Nuclide mass:246.0176661 u (calculated nuclear mass without electrons)Mass excess:64.99406 MeVMass defect:1.982006356 u (per nucleus)Nuclear binding energy:1846.22702858 MeV (per nucleus)
7.50498792 MeV (average binding energy per nucleon)Separation energy:S_N = 4.978(18) MeV (first neutron)
S_P = 5.473(22) MeV (first proton)Half-life:39(3) minDecay constant λ:0.00029621674382904 s^-1Specific activity α:7.251459172399 × 10⁺¹⁷ Bq g^-1
19598538.303782 Ci g^-1Spin and parity:
(nuclear angular momentum)(7-)Year of discovery:1955

Radioactive Decay

Half-life T_½ = 39(3) min (minutes) respectively 2.340 × 10³ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	²⁴⁶Cm	100 %	2.377(18) MeV

Parent Nuclides

Direct parent isotope is: ²⁴⁶Pu.

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
^246m1Am		25.0(2) min	2(-)
^246m2Am	2000 keV	73(10) µs

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 151) and isobaric (same nucleon number A = 246) with Americium-246. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 151	Isobar A = 246
92	²⁴²U
93	²⁴⁴Np
94	²⁴⁵Pu	²⁴⁶Pu
95	²⁴⁶Am	²⁴⁶Am
96	²⁴⁷Cm	²⁴⁶Cm
97	²⁴⁸Bk	²⁴⁶Bk
98	²⁴⁹Cf	²⁴⁶Cf
99	²⁵⁰Es	²⁴⁶Es
100	²⁵¹Fm	²⁴⁶Fm
101	²⁵²Md	²⁴⁶Md
102	²⁵³No
103	²⁵⁴Lr
104	²⁵⁵Rf
105	²⁵⁶Db