Promethium-142m

Properties and data of the isotope ^142mPm.

Contents

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

General data

Name of the isotope:Promethium-142m; Pm-142mSymbol:^142mPm or 142m61PmMass number A:142 (= number of nucleons)Atomic number Z:61 (= number of protons)Neutrons N:81Nucleon pairing (Z - N):odd - oddNuclear ratio (N/Z ratio):1.327868852459 (= neutron-proton ratio)Neutron excess (N-Z):20Excitation energy:883.17 (16) keVIsotopic mass:141.912890(25) u (atomic weight of Promethium-142m)Nuclide mass:141.8794292 u (calculated nuclear mass without electrons)Mass excess:-81.14244 MeVMass defect:1.266295148 u (per nucleus)Nuclear binding energy:1179.54633259 MeV (per nucleus)
8.30666431 MeV (average binding energy per nucleon)Half-life:2.0(2) msDecay constant λ:346.57359027997 s^-1Specific activity α:1.480223389361 × 10⁺²⁴ Bq g^-1
40006037550316 Ci g^-1Spin and parity:
(nuclear angular momentum)(8)-

Radioactive Decay

Half-life T_½ = 2.0(2) ms respectively 2.0 × 10^-3 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
Iso	¹⁴²Pm	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
¹⁴²Pm		40.5(5) s	1+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 81) and isobaric (same nucleon number A = 142) with Promethium-142m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 81	Isobar A = 142
45	¹²⁶Rh
46	¹²⁷Pd
47	¹²⁸Ag
48	¹²⁹Cd
49	¹³⁰In
50	¹³¹Sn
51	¹³²Sb
52	¹³³Te	¹⁴²Te
53	¹³⁴I	¹⁴²I
54	¹³⁵Xe	¹⁴²Xe
55	¹³⁶Cs	¹⁴²Cs
56	¹³⁷Ba	¹⁴²Ba
57	¹³⁸La	¹⁴²La
58	¹³⁹Ce	¹⁴²Ce
59	¹⁴⁰Pr	¹⁴²Pr
60	¹⁴¹Nd	¹⁴²Nd
61	¹⁴²Pm	¹⁴²Pm
62	¹⁴³Sm	¹⁴²Sm
63	¹⁴⁴Eu	¹⁴²Eu
64	¹⁴⁵Gd	¹⁴²Gd
65	¹⁴⁶Tb	¹⁴²Tb
66	¹⁴⁷Dy	¹⁴²Dy
67	¹⁴⁸Ho	¹⁴²Ho
68	¹⁴⁹Er
69	¹⁵⁰Tm
70	¹⁵¹Yb
71	¹⁵²Lu
72	¹⁵³Hf