Terbium-149m

Properties and data of the isotope ^149mTb.

Contents

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

General data

Name of the isotope:Terbium-149m; Tb-149mSymbol:^149mTb or 149m65TbMass number A:149 (= number of nucleons)Atomic number Z:65 (= number of protons)Neutrons N:84Excitation energy:35.78(13) keVIsotopic mass:148.923254(4) u (atomic weight of Terbium-149m)Nuclide mass:148.8875993 u (calculated nuclear mass without electrons)Mass excess:-71.48844 MeVMass defect:1.313226024 u (per nucleus)Nuclear binding energy:1223.262162 MeV (per nucleus)
8.20981317 MeV (average binding energy per nucleon)Half-life:4.16(4) minDecay constant λ:0.0027770319733972 s^-1Specific activity α:1.129978224077 × 10⁺¹⁹ Bq g^-1
305399520.02092 Ci g^-1Spin and parity:
(nuclear angular momentum)11/2-

Radioactive Decay

Half-life T_½ = 4.16(4) min (minutes) respectively 2.496 × 10² seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC/β⁺	¹⁴⁹Gd	99.978(3) %
α	¹⁴⁵Eu	0.022(3) %

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
¹⁴⁹Tb		4.118(25) h	1/2+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 84) and isobaric (same nucleon number A = 149) with Terbium-149m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 84	Isobar A = 149
47	¹³¹Ag
48	¹³²Cd
49	¹³³In
50	¹³⁴Sn
51	¹³⁵Sb
52	¹³⁶Te
53	¹³⁷I
54	¹³⁸Xe
55	¹³⁹Cs	¹⁴⁹Cs
56	¹⁴⁰Ba	¹⁴⁹Ba
57	¹⁴¹La	¹⁴⁹La
58	¹⁴²Ce	¹⁴⁹Ce
59	¹⁴³Pr	¹⁴⁹Pr
60	¹⁴⁴Nd	¹⁴⁹Nd
61	¹⁴⁵Pm	¹⁴⁹Pm
62	¹⁴⁶Sm	¹⁴⁹Sm
63	¹⁴⁷Eu	¹⁴⁹Eu
64	¹⁴⁸Gd	¹⁴⁹Gd
65	¹⁴⁹Tb	¹⁴⁹Tb
66	¹⁵⁰Dy	¹⁴⁹Dy
67	¹⁵¹Ho	¹⁴⁹Ho
68	¹⁵²Er	¹⁴⁹Er
69	¹⁵³Tm	¹⁴⁹Tm
70	¹⁵⁴Yb	¹⁴⁹Yb
71	¹⁵⁵Lu	¹⁴⁹Lu
72	¹⁵⁶Hf
73	¹⁵⁷Ta
74	¹⁵⁸W
75	¹⁵⁹Re
76	¹⁶⁰Os