Tin-123m

Properties and data of the isotope ¹²³Sn.

Content

General data

Name of the isotope:Tin-123m; Sn-123mSymbol:¹²³Sn or 12350SnMass number A:123 (= number of nucleons)Atomic number Z:50 (= number of protons)Neutrons N:73Isotopic mass:122.9057254(26) u (atomic weight of Tin-123m)
Excitation energy: 24.6(4) keVNuclide mass:122.878298 u (calculated nuclear mass without electrons)Mass excess:-87.81622 MeVMass defect:1.118065068 u (per nucleus)Nuclear binding energy:1041.47090245 MeV (per nucleus)
8.46724311 MeV (average binding energy per nucleon)Half-life:40.06(1) minDecay constant λ:0.00028837875709766 s^-1Specific activity α:1.423489751029 × 10⁺¹⁸ Bq g^-1
38472695.973762 Ci g^-1Spin and parity:
(nuclear angular momentum)3/2+

Radioactive Decay

Half-life T_½ = 40.06(1) min (minutes) respectively 2.4036 × 10³ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	¹²⁴Sb	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
¹²³Sn		129.2(4) d	11/2-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 73) and isobaric (same nucleon number A = 123) with Tin-123m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

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