Americium-237

Properties and data of the isotope ²³⁷Am.

Content

General data

Name of the isotope:Americium-237; Am-237Symbol:²³⁷Am or 23795AmMass number A:237 (= number of nucleons)Atomic number Z:95 (= number of protons)Neutrons N:142Isotopic mass:237.050000(60) u (atomic weight of Americium-237)Nuclide mass:236.9978921 u (calculated nuclear mass without electrons)Mass excess:46.5747 MeVMass defect:1.923796112 u (per nucleus)Nuclear binding energy:1792.00453555 MeV (per nucleus)
7.56120057 MeV (average binding energy per nucleon)Separation energy:S_N = 7.542(133) MeV (first neutron)
S_P = 3.621(59) MeV (first proton)Half-life:73.6(8) minDecay constant λ:0.00015696267675723 s^-1Specific activity α:3.988402317235 × 10⁺¹⁷ Bq g^-1
10779465.722258 Ci g^-1Spin and parity:
(nuclear angular momentum)5/2(-)Year of discovery:1970

Radioactive Decay

Half-life T_½ = 73.6(8) min (minutes) respectively 4.416 × 10³ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²³³Np	0.025(3) %	6.196(30) MeV
EE/β⁺	²³⁷Pu	99.975(3) %	1.478(59) MeV

Parent Nuclides

Direct parent isotope is: ²⁴¹Bk.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 142) and isobaric (same nucleon number A = 237) with Americium-237. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 142	Isobar A = 237
84	²²⁶Po
85	²²⁷At
86	²²⁸Rn
87	²²⁹Fr
88	²³⁰Ra
89	²³¹Ac
90	²³²Th	²³⁷Th
91	²³³Pa	²³⁷Pa
92	²³⁴U	²³⁷U
93	²³⁵Np	²³⁷Np
94	²³⁶Pu	²³⁷Pu
95	²³⁷Am	²³⁷Am
96	²³⁸Cm	²³⁷Cm
97	²³⁹Bk	²³⁷Bk
98	²⁴⁰Cf	²³⁷Cf
99	²⁴¹Es
100	²⁴²Fm