Cerium-133

Properties and data of the isotope ¹³³Ce.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

Literature

Cerium-133 is a radioisotope of the chemical element cerium, which has 75 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 133. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ¹³³Ce is exclusively for academic purposes.

Cerium-133 was first identified in 1951. The isotope was formed by proton bombardment of lanthanum oxide with proton energies between 60 and 80 MeV in the reaction ¹³⁹La(p,7n)¹³³Ce. Identification was based on absorption curves and measurements with magnetic counters. The assignment was based on the growth of the characteristic activity of the daughter nuclide lanthanum-133 during the decay of cerium activity, which clearly demonstrated the existence of the isotope [1].

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

General data

Name of the isotope:Cerium-133; Ce-133Symbol:¹³³Ce or 13358CeMass number A:133 (= number of nucleons)Atomic number Z:58 (= number of protons)Neutrons N:75Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.2931034482759 (= neutron-proton ratio)Neutron excess (N-Z):17Isotopic mass:132.911520(18) u (atomic weight of Cerium-133)Nuclide mass:132.8797046 u (calculated nuclear mass without electrons)Mass excess:-82.41859 MeVMass defect:1.192200556 u (per nucleus)Nuclear binding energy:1110.52766471 MeV (per nucleus)
8.34983207 MeV (average binding energy per nucleon)Separation energy:S_N = 8.021(26) MeV (first neutron)
S_P = 5.984(40) MeV (first proton)Half-life:97(4) minDecay constant λ:0.00011909745370446 s^-1Specific activity α:5.433497289909 × 10⁺¹⁷ Bq g^-1
14685127.810566 Ci g^-1Spin and parity:
(nuclear angular momentum)1/2+Year of discovery:1951

Radioactive Decay

Half-life T_½ = 97(4) min (minutes) respectively 5.820 × 10³ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC/β⁺	¹³³La	100 %	3.076(32) MeV

Parent Nuclides

Direct parent isotope is: ¹³³Pr.

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
^133mCe	37.2(7) keV	5.1(3) h	9/2-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 75) and isobaric (same nucleon number A = 133) with Cerium-133. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 75	Isobar A = 133
42	¹¹⁷Mo
43	¹¹⁸Tc
44	¹¹⁹Ru
45	¹²⁰Rh
46	¹²¹Pd
47	¹²²Ag
48	¹²³Cd	¹³³Cd
49	¹²⁴In	¹³³In
50	¹²⁵Sn	¹³³Sn
51	¹²⁶Sb	¹³³Sb
52	¹²⁷Te	¹³³Te
53	¹²⁸I	¹³³I
54	¹²⁹Xe	¹³³Xe
55	¹³⁰Cs	¹³³Cs
56	¹³¹Ba	¹³³Ba
57	¹³²La	¹³³La
58	¹³³Ce	¹³³Ce
59	¹³⁴Pr	¹³³Pr
60	¹³⁵Nd	¹³³Nd
61	¹³⁶Pm	¹³³Pm
62	¹³⁷Sm	¹³³Sm
63	¹³⁸Eu	¹³³Eu
64	¹³⁹Gd
65	¹⁴⁰Tb
66	¹⁴¹Dy
67	¹⁴²Ho
68	¹⁴³Er
69	¹⁴⁴Tm