Xenon-123

Properties and data of the isotope ¹²³Xe.

Content

General data

Name of the isotope:Xenon-123; Xe-123Symbol:¹²³Xe or 12354XeMass number A:123 (= number of nucleons)Atomic number Z:54 (= number of protons)Neutrons N:69Isotopic mass:122.908482(10) u (atomic weight of Xenon-123)Nuclide mass:122.8788606 u (calculated nuclear mass without electrons)Mass excess:-85.24847 MeVMass defect:1.111948932 u (per nucleus)Nuclear binding energy:1035.77375846 MeV (per nucleus)
8.42092487 MeV (average binding energy per nucleon)Separation energy:S_N = 7.965(15) MeV (first neutron)
S_P = 6.457(11) MeV (first proton)Half-life:2.08(2) hDecay constant λ:9.256773244657 × 10^-5 s^-1Specific activity α:4.569310851460 × 10⁺¹⁷ Bq g^-1
12349488.787732 Ci g^-1Spin and parity:
(nuclear angular momentum)(1/2)+Magnetic dipole moment:μ(μ_N) = - 0.150(3)Nuclear g-factor:g_l = -0.3Year of discovery:1952

Radioactive Decay

Half-life T_½ = 2.08(2) h (hours) respectively 7.488 × 10³ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EE/β⁺	¹²³I	100 %	2.695(10) MeV

Parent Nuclides

Direct parent isotope is: ¹²³Cs.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 69) and isobaric (same nucleon number A = 123) with Xenon-123. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 69	Isobar A = 123
38	¹⁰⁷Sr
39	¹⁰⁸Y
40	¹⁰⁹Zr
41	¹¹⁰Nb
42	¹¹¹Mo
43	¹¹²Tc
44	¹¹³Ru	¹²³Ru
45	¹¹⁴Rh	¹²³Rh
46	¹¹⁵Pd	¹²³Pd
47	¹¹⁶Ag	¹²³Ag
48	¹¹⁷Cd	¹²³Cd
49	¹¹⁸In	¹²³In
50	¹¹⁹Sn	¹²³Sn
51	¹²⁰Sb	¹²³Sb
52	¹²¹Te	¹²³Te
53	¹²²I	¹²³I
54	¹²³Xe	¹²³Xe
55	¹²⁴Cs	¹²³Cs
56	¹²⁵Ba	¹²³Ba
57	¹²⁶La	¹²³La
58	¹²⁷Ce	¹²³Ce
59	¹²⁸Pr	¹²³Pr
60	¹²⁹Nd
61	¹³⁰Pm
62	¹³¹Sm
63	¹³²Eu