Xenon-136m

Properties and data of the isotope ^136mXe.

Contents

See also: List of individual Xenon isotopes (and general data sources).

General data

Name of the isotope:Xenon-136m; Xe-136mSymbol:^136mXe or 136m54XeMass number A:136 (= number of nucleons)Atomic number Z:54 (= number of protons)Neutrons N:82Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.5185185185185 (= neutron-proton ratio)Neutron excess (N-Z):28Excitation energy:1891.74(7) keVIsotopic mass:135.90721448(7) u (atomic weight of Xenon-136m)Nuclide mass:135.8775931 u (calculated nuclear mass without electrons)Mass excess:-86.42916 MeVMass defect:1.22586036 u (per nucleus)Nuclear binding energy:1141.88157018 MeV (per nucleus)
8.39618802 MeV (average binding energy per nucleon)Half-life:2.95(17) μsDecay constant λ:234965.14595252 s^-1Specific activity α:1.048143115630 × 10⁺²⁷ Bq g^-1
2.832819231434 × 10⁺¹⁶ Ci g^-1Spin and parity:
(nuclear angular momentum)6+

Radioactive Decay

Half-life T_½ = 2.95(17) μs respectively 2.95 × 10^-6 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
Iso	¹³⁶Xe	100 %

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
¹³⁶Xe		2.165(61) × 10²¹ a	0+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 82) and isobaric (same nucleon number A = 136) with Xenon-136m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 82	Isobar A = 136
45	¹²⁷Rh
46	¹²⁸Pd
47	¹²⁹Ag
48	¹³⁰Cd
49	¹³¹In	¹³⁶In
50	¹³²Sn	¹³⁶Sn
51	¹³³Sb	¹³⁶Sb
52	¹³⁴Te	¹³⁶Te
53	¹³⁵I	¹³⁶I
54	¹³⁶Xe	¹³⁶Xe
55	¹³⁷Cs	¹³⁶Cs
56	¹³⁸Ba	¹³⁶Ba
57	¹³⁹La	¹³⁶La
58	¹⁴⁰Ce	¹³⁶Ce
59	¹⁴¹Pr	¹³⁶Pr
60	¹⁴²Nd	¹³⁶Nd
61	¹⁴³Pm	¹³⁶Pm
62	¹⁴⁴Sm	¹³⁶Sm
63	¹⁴⁵Eu	¹³⁶Eu
64	¹⁴⁶Gd	¹³⁶Gd
65	¹⁴⁷Tb	¹³⁶Tb
66	¹⁴⁸Dy
67	¹⁴⁹Ho
68	¹⁵⁰Er
69	¹⁵¹Tm
70	¹⁵²Yb
71	¹⁵³Lu
72	¹⁵⁴Hf
73	¹⁵⁵Ta
74	¹⁵⁶W