Promethium-126

Properties and data of the isotope ¹²⁶Pm.

Contents

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

General data

Name of the isotope:Promethium-126; Pm-126Symbol:¹²⁶Pm or 12661PmMass number A:126 (= number of nucleons)Atomic number Z:61 (= number of protons)Neutrons N:65Nucleon pairing (Z - N):odd - oddNuclear ratio (N/Z ratio):1.0655737704918 (= neutron-proton ratio)Neutron excess (N-Z):4Isotopic mass:125.95752(54) u (atomic weight of Promethium-126)Nuclide mass:125.9240592 u (calculated nuclear mass without electrons)Mass excess:-39.56987 MeVMass defect:1.083026492 u (per nucleus)Nuclear binding energy:1008.83267914 MeV (per nucleus)
8.00660856 MeV (average binding energy per nucleon)Half-life:~ 0.5 sDecay constant λ:1.3862943611199 s^-1Specific activity α:6.678767932 × 10⁺²¹ Bq g^-1
180507241427.03 Ci g^-1Spin and parity:
(nuclear angular momentum)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 65) and isobaric (same nucleon number A = 126) with Promethium-126. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 65	Isobar A = 126
36	¹⁰¹Kr
37	¹⁰²Rb
38	¹⁰³Sr
39	¹⁰⁴Y
40	¹⁰⁵Zr
41	¹⁰⁶Nb
42	¹⁰⁷Mo
43	¹⁰⁸Tc
44	¹⁰⁹Ru
45	¹¹⁰Rh	¹²⁶Rh
46	¹¹¹Pd	¹²⁶Pd
47	¹¹²Ag	¹²⁶Ag
48	¹¹³Cd	¹²⁶Cd
49	¹¹⁴In	¹²⁶In
50	¹¹⁵Sn	¹²⁶Sn
51	¹¹⁶Sb	¹²⁶Sb
52	¹¹⁷Te	¹²⁶Te
53	¹¹⁸I	¹²⁶I
54	¹¹⁹Xe	¹²⁶Xe
55	¹²⁰Cs	¹²⁶Cs
56	¹²¹Ba	¹²⁶Ba
57	¹²²La	¹²⁶La
58	¹²³Ce	¹²⁶Ce
59	¹²⁴Pr	¹²⁶Pr
60	¹²⁵Nd	¹²⁶Nd
61	¹²⁶Pm	¹²⁶Pm