Promethium-154

Properties and data of the isotope ¹⁵⁴Pm.

Content

General data

Name of the isotope:Promethium-154; Pm-154Symbol:¹⁵⁴Pm or 15461PmMass number A:154 (= number of nucleons)Atomic number Z:61 (= number of protons)Neutrons N:93Isotopic mass:153.92645(5) u (atomic weight of Promethium-154)Nuclide mass:153.8929892 u (calculated nuclear mass without electrons)Mass excess:-68.51138 MeVMass defect:1.35671414 u (per nucleus)Nuclear binding energy:1263.77108113 MeV (per nucleus)
8.20630572 MeV (average binding energy per nucleon)Separation energy:S_N = 5.4(5) MeV (first neutron)
S_P = 8.47(5) MeV (first proton)Half-life:2.68(7) minDecay constant λ:0.004310616794527 s^-1Specific activity α:1.696675916983 × 10⁺¹⁹ Bq g^-1
458561058.64424 Ci g^-1Spin and parity:
(nuclear angular momentum)(3.4)Year of discovery:1959

Radioactive Decay

Half-life T_½ = 2.68(7) min (minutes) respectively 1.608 × 10² seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	¹⁵⁴Sm	100 %	3.940(5) MeV

Parent Nuclides

Direct parent isotope is: ¹⁵⁴Nd.

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
^154mPm	+x keV	1.73(10) min	(0-,1-)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 93) and isobaric (same nucleon number A = 154) with Promethium-154. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 93	Isobar A = 154
54	¹⁴⁷Xe
55	¹⁴⁸Cs
56	¹⁴⁹Ba
57	¹⁵⁰La	¹⁵⁴La
58	¹⁵¹Ce	¹⁵⁴Ce
59	¹⁵²Pr	¹⁵⁴Pr
60	¹⁵³Nd	¹⁵⁴Nd
61	¹⁵⁴Pm	¹⁵⁴Pm
62	¹⁵⁵Sm	¹⁵⁴Sm
63	¹⁵⁶Eu	¹⁵⁴Eu
64	¹⁵⁷Gd	¹⁵⁴Gd
65	¹⁵⁸Tb	¹⁵⁴Tb
66	¹⁵⁹Dy	¹⁵⁴Dy
67	¹⁶⁰Ho	¹⁵⁴Ho
68	¹⁶¹Er	¹⁵⁴Er
69	¹⁶²Tm	¹⁵⁴Tm
70	¹⁶³Yb	¹⁵⁴Yb
71	¹⁶⁴Lu	¹⁵⁴Lu
72	¹⁶⁵Hf	¹⁵⁴Hf
73	¹⁶⁶Ta
74	¹⁶⁷W
75	¹⁶⁸Re
76	¹⁶⁹Os
77	¹⁷⁰Ir
78	¹⁷¹Pt
79	¹⁷²Au
80	¹⁷³Hg