Cerium-146

Properties and data of the isotope ¹⁴⁶Ce.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

Literature

Cerium-146 is a radioisotope of the chemical element cerium, which has 88 neutrons in its atomic nucleus in addition to the element-specific 58 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 146. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ¹⁴⁶Ce is exclusively for academic purposes.

According to a 1953 report, cerium-146 was investigated as a short-lived fission product from the irradiation of uranyl nitrate with thermal neutrons [1]. The activity curves were recorded with an end-window Geiger counter; the decay signal yielded a half-life of 13.9(6) min, accompanied by β-radiation up to about 0.9 MeV and subsequent soft γ-quanta. This work was intended as a reinvestigation rather than a discovery report. A half-life of 14.6(8) min had previously been reported for the same nuclide (in an unpublished article); moreover, an earlier observation of approximately 11 minutes of activity in cerium existed without a mass assignment.

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

General data

Name of the isotope:Cerium-146; Ce-146Symbol:¹⁴⁶Ce or 14658CeMass number A:146 (= number of nucleons)Atomic number Z:58 (= number of protons)Neutrons N:88Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.5172413793103 (= neutron-proton ratio)Neutron excess (N-Z):30Isotopic mass:145.918812(16) u (atomic weight of Cerium-146)Nuclide mass:145.8869966 u (calculated nuclear mass without electrons)Mass excess:-75.62613 MeVMass defect:1.297552464 u (per nucleus)Nuclear binding energy:1208.6623349 MeV (per nucleus)
8.27850914 MeV (average binding energy per nucleon)Separation energy:S_N = 6.630(37) MeV (first neutron)
S_P = 10.080(19) MeV (first proton)Half-life:13.49(16) minDecay constant λ:0.00085637160929077 s^-1Specific activity α:3.55668307558 × 10⁺¹⁸ Bq g^-1
96126569.610432 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Charge radius:4.9590(28) femtometer fmYear of discovery:1953

Radioactive Decay

Half-life T_½ = 13.49(16) min (minutes) respectively 8.094 × 10² seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	¹⁴⁶Pr	100 %	1.05(3) MeV

Parent Nuclides

Direct parent isotope is: ¹⁴⁶La.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 88) and isobaric (same nucleon number A = 146) with Cerium-146. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 88	Isobar A = 146
49	¹³⁷In
50	¹³⁸Sn
51	¹³⁹Sb
52	¹⁴⁰Te
53	¹⁴¹I
54	¹⁴²Xe	¹⁴⁶Xe
55	¹⁴³Cs	¹⁴⁶Cs
56	¹⁴⁴Ba	¹⁴⁶Ba
57	¹⁴⁵La	¹⁴⁶La
58	¹⁴⁶Ce	¹⁴⁶Ce
59	¹⁴⁷Pr	¹⁴⁶Pr
60	¹⁴⁸Nd	¹⁴⁶Nd
61	¹⁴⁹Pm	¹⁴⁶Pm
62	¹⁵⁰Sm	¹⁴⁶Sm
63	¹⁵¹Eu	¹⁴⁶Eu
64	¹⁵²Gd	¹⁴⁶Gd
65	¹⁵³Tb	¹⁴⁶Tb
66	¹⁵⁴Dy	¹⁴⁶Dy
67	¹⁵⁵Ho	¹⁴⁶Ho
68	¹⁵⁶Er	¹⁴⁶Er
69	¹⁵⁷Tm	¹⁴⁶Tm
70	¹⁵⁸Yb
71	¹⁵⁹Lu
72	¹⁶⁰Hf
73	¹⁶¹Ta
74	¹⁶²W
75	¹⁶³Re
76	¹⁶⁴Os
77	¹⁶⁵Ir
78	¹⁶⁶Pt

External data and identifiers

Adopted Levels, Gammas:NuDat 146Ce

Literature and References

[1] - A. A. Caretto Jr., S. Katcoff:
Short-Lived Cerium Isotopes from Uranium Fission.
In: Physical Review, 89, 1267, (1953), DOI 10.1103/PhysRev.89.1267.