Europium-136

Properties and data of the isotope ¹³⁶Eu.

Content

General data

Name of the isotope:Europium-136; Eu-136Symbol:¹³⁶Eu or 13663EuMass number A:136 (= number of nucleons)Atomic number Z:63 (= number of protons)Neutrons N:73Isotopic mass:135.93962(21) u (atomic weight of Europium-136)Nuclide mass:135.9050622 u (calculated nuclear mass without electrons)Mass excess:-56.24361 MeVMass defect:1.185895884 u (per nucleus)Nuclear binding energy:1104.65490057 MeV (per nucleus)
8.1224625 MeV (average binding energy per nucleon)Separation energy:S_N = 10.17(28) MeV (first neutron)
S_P = 0.67(25) MeV (first proton)Half-life:3.3(3) sDecay constant λ:0.21004460016968 s^-1Specific activity α:9.369764215488 × 10⁺²⁰ Bq g^-1
25323687068.887 Ci g^-1Spin and parity:
(nuclear angular momentum)(7+)Year of discovery:1987

Radioactive Decay

Half-life T_½ = 3.3(3) s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EE/β⁺	¹³⁶Sm	99.91 %	10.57(20) MeV
β⁺, p	¹³⁵Pm	0.09 %

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
^136mEu	Y	3.8(3) s	(3+)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 73) and isobaric (same nucleon number A = 136) with Europium-136. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 73	Isobar A = 136
41	¹¹⁴Nb
42	¹¹⁵Mo
43	¹¹⁶Tc
44	¹¹⁷Ru
45	¹¹⁸Rh
46	¹¹⁹Pd
47	¹²⁰Ag
48	¹²¹Cd
49	¹²²In	¹³⁶In
50	¹²³Sn	¹³⁶Sn
51	¹²⁴Sb	¹³⁶Sb
52	¹²⁵Te	¹³⁶Te
53	¹²⁶I	¹³⁶I
54	¹²⁷Xe	¹³⁶Xe
55	¹²⁸Cs	¹³⁶Cs
56	¹²⁹Ba	¹³⁶Ba
57	¹³⁰La	¹³⁶La
58	¹³¹Ce	¹³⁶Ce
59	¹³²Pr	¹³⁶Pr
60	¹³³Nd	¹³⁶Nd
61	¹³⁴Pm	¹³⁶Pm
62	¹³⁵Sm	¹³⁶Sm
63	¹³⁶Eu	¹³⁶Eu
64	¹³⁷Gd	¹³⁶Gd
65	¹³⁸Tb	¹³⁶Tb
66	¹³⁹Dy
67	¹⁴⁰Ho