Xenon-125m1

Properties and data of the isotope ¹²⁵Xe.

Content

General data

Name of the isotope:Xenon-125m1; Xe-125m1Symbol:¹²⁵Xe or 12554XeMass number A:125 (= number of nucleons)Atomic number Z:54 (= number of protons)Neutrons N:71Isotopic mass:124.906394(2) u (atomic weight of Xenon-125m1)
Excitation energy: 252.61(14) keVNuclide mass:124.8767726 u (calculated nuclear mass without electrons)Mass excess:-87.19343 MeVMass defect:1.131366764 u (per nucleus)Nuclear binding energy:1053.86135247 MeV (per nucleus)
8.43089082 MeV (average binding energy per nucleon)Half-life:57(1) sDecay constant λ:0.012160476851929 s^-1Specific activity α:5.905814881154 × 10⁺¹⁹ Bq g^-1
1596166184.0958 Ci g^-1Spin and parity:
(nuclear angular momentum)9/2(-)Magnetic dipole moment:μ(μ_N) = -0.7453(8)Quadrupole moment Q:+0.424(15) barn (100 fm²)Nuclear g-factor:g_l = -0.16562222222222

Radioactive Decay

Half-life T_½ = 57(1) s respectively 5.7 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
Iso	¹²⁵Xe	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
¹²⁵Xe		16.9(2) h	1/2(+)
^125m2Xe	295.89(15) keV	0.14(3) μs	7/2(+)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 71) and isobaric (same nucleon number A = 125) with Xenon-125m1. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 71	Isobar A = 125
40	¹¹¹Zr
41	¹¹²Nb
42	¹¹³Mo
43	¹¹⁴Tc
44	¹¹⁵Ru
45	¹¹⁶Rh	¹²⁵Rh
46	¹¹⁷Pd	¹²⁵Pd
47	¹¹⁸Ag	¹²⁵Ag
48	¹¹⁹Cd	¹²⁵Cd
49	¹²⁰In	¹²⁵In
50	¹²¹Sn	¹²⁵Sn
51	¹²²Sb	¹²⁵Sb
52	¹²³Te	¹²⁵Te
53	¹²⁴I	¹²⁵I
54	¹²⁵Xe	¹²⁵Xe
55	¹²⁶Cs	¹²⁵Cs
56	¹²⁷Ba	¹²⁵Ba
57	¹²⁸La	¹²⁵La
58	¹²⁹Ce	¹²⁵Ce
59	¹³⁰Pr	¹²⁵Pr
60	¹³¹Nd	¹²⁵Nd
61	¹³²Pm
62	¹³³Sm
63	¹³⁴Eu
64	¹³⁵Gd
65	¹³⁶Tb