Tantalum-159m

Properties and data of the isotope ¹⁵⁹Ta.

Content

General data

Name of the isotope:Tantalum-159m; Ta-159mSymbol:¹⁵⁹Ta or 15973TaMass number A:159 (= number of nucleons)Atomic number Z:73 (= number of protons)Neutrons N:86Isotopic mass:158.963028(21) u (atomic weight of Tantalum-159m)
Excitation energy: 64(5) keVNuclide mass:158.9229856 u (calculated nuclear mass without electrons)Mass excess:-34.4392 MeVMass defect:1.353382112 u (per nucleus)Nuclear binding energy:1260.66731704 MeV (per nucleus)
7.92872526 MeV (average binding energy per nucleon)Half-life:0.56(6) sDecay constant λ:1.2377628224285 s^-1Specific activity α:4.717710169529 × 10⁺²¹ Bq g^-1
127505680257.56 Ci g^-1Spin and parity:
(nuclear angular momentum)11/2-

Radioactive Decay

Half-life T_½ = 0.56(6) s respectively 5.6 × 10^-1 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	¹⁵⁵Lu	55(1) %
EE/β⁺	¹⁵⁹Hf	45(1) %

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
¹⁵⁹Ta		0.83(18) s	1/2+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 86) and isobaric (same nucleon number A = 159) with Tantalum-159m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 86	Isobar A = 159
48	¹³⁴Cd
49	¹³⁵In
50	¹³⁶Sn
51	¹³⁷Sb
52	¹³⁸Te
53	¹³⁹I
54	¹⁴⁰Xe
55	¹⁴¹Cs
56	¹⁴²Ba
57	¹⁴³La
58	¹⁴⁴Ce
59	¹⁴⁵Pr	¹⁵⁹Pr
60	¹⁴⁶Nd	¹⁵⁹Nd
61	¹⁴⁷Pm	¹⁵⁹Pm
62	¹⁴⁸Sm	¹⁵⁹Sm
63	¹⁴⁹Eu	¹⁵⁹Eu
64	¹⁵⁰Gd	¹⁵⁹Gd
65	¹⁵¹Tb	¹⁵⁹Tb
66	¹⁵²Dy	¹⁵⁹Dy
67	¹⁵³Ho	¹⁵⁹Ho
68	¹⁵⁴Er	¹⁵⁹Er
69	¹⁵⁵Tm	¹⁵⁹Tm
70	¹⁵⁶Yb	¹⁵⁹Yb
71	¹⁵⁷Lu	¹⁵⁹Lu
72	¹⁵⁸Hf	¹⁵⁹Hf
73	¹⁵⁹Ta	¹⁵⁹Ta
74	¹⁶⁰W	¹⁵⁹W
75	¹⁶¹Re	¹⁵⁹Re
76	¹⁶²Os