Cerium-131

Properties and data of the isotope ¹³¹Ce.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

Literature

Cerium-131 is a radioisotope of the chemical element cerium, which has 73 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 131. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ¹³¹Ce is exclusively for academic purposes.

Cerium-131 was first clearly identified in 1966. The isotope was created by bombarding barium-130 with 40 MeV helium-4 and 20 MeV helium-3 beams: ¹³⁰Ba(⁴He,3n)¹³¹Ce and ¹³⁰Ba(³He,2n)¹³¹Ce, respectively. Identification was achieved by γ-spectroscopy of chemically separated samples and by detecting the daughter nuclide lanthanum-131 [1].

General data

Name of the isotope:Cerium-131; Ce-131Symbol:¹³¹Ce or 13158CeMass number A:131 (= number of nucleons)Atomic number Z:58 (= number of protons)Neutrons N:73Isotopic mass:130.914430(40) u (atomic weight of Cerium-131)Nuclide mass:130.8826146 u (calculated nuclear mass without electrons)Mass excess:-79.70794 MeVMass defect:1.171960724 u (per nucleus)Nuclear binding energy:1091.67438264 MeV (per nucleus)
8.33339223 MeV (average binding energy per nucleon)Separation energy:S_N = 8.357(43) MeV (first neutron)
S_P = 5.370(42) MeV (first proton)Half-life:10.3(3) minDecay constant λ:0.0011215973795468 s^-1Specific activity α:5.195705698282 × 10⁺¹⁸ Bq g^-1
140424478.33195 Ci g^-1Spin and parity:
(nuclear angular momentum)7/2+Year of discovery:1966

Radioactive Decay

Half-life T_½ = 10.3(3) min (minutes) respectively 6.18 × 10² seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC/β⁺	¹³¹La	100 %	4.061(43)

Parent Nuclides

Direct parent isotope is: ¹³¹Pr.

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
^131mCe	63.09(9) keV	5.4(4) min	(1/2+)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 73) and isobaric (same nucleon number A = 131) with Cerium-131. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 73	Isobar A = 131
41	¹¹⁴Nb
42	¹¹⁵Mo
43	¹¹⁶Tc
44	¹¹⁷Ru
45	¹¹⁸Rh
46	¹¹⁹Pd
47	¹²⁰Ag	¹³¹Ag
48	¹²¹Cd	¹³¹Cd
49	¹²²In	¹³¹In
50	¹²³Sn	¹³¹Sn
51	¹²⁴Sb	¹³¹Sb
52	¹²⁵Te	¹³¹Te
53	¹²⁶I	¹³¹I
54	¹²⁷Xe	¹³¹Xe
55	¹²⁸Cs	¹³¹Cs
56	¹²⁹Ba	¹³¹Ba
57	¹³⁰La	¹³¹La
58	¹³¹Ce	¹³¹Ce
59	¹³²Pr	¹³¹Pr
60	¹³³Nd	¹³¹Nd
61	¹³⁴Pm	¹³¹Pm
62	¹³⁵Sm	¹³¹Sm
63	¹³⁶Eu	¹³¹Eu
64	¹³⁷Gd
65	¹³⁸Tb
66	¹³⁹Dy
67	¹⁴⁰Ho

External data and identifiers

Adopted Levels, Gammas:NuDat 131Ce

Literature and References

[1] - A. E. Norris, G. Friedlander, E. M. Franz:
On the decay of ¹³¹Ce.
In: Nuclear Physics, 86, 1, 102-112, (1966), DOI 10.1016/0029-5582(66)90293-8.