Cerium-158

Properties and data of the isotope ¹⁵⁸Ce.

Contents

Cerium-158 is a radioisotope of the chemical element cerium, which has 100 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 158. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ¹⁵⁸Ce is exclusively for academic purposes.

The neutron-rich isotope cerium-158 was produced by fragmenting a 345 MeV/N uranium-238 beam on a beryllium target foil. The resulting reaction products were subsequently separated, analyzed, and unambiguously identified using the BigRIPS separator at the RIKEN Institute in Japan [1].

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

General data

Name of the isotope:Cerium-158; Ce-158Symbol:¹⁵⁸Ce or 15858CeMass number A:158 (= number of nucleons)Atomic number Z:58 (= number of protons)Neutrons N:100Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.7241379310345 (= neutron-proton ratio)Neutron excess (N-Z):42Isotopic mass:157.960770(430) u (atomic weight of Cerium-158)Nuclide mass:157.9289546 u (calculated nuclear mass without electrons)Mass excess:-36.54251 MeVMass defect:1.359573456 u (per nucleus)Nuclear binding energy:1266.43451682 MeV (per nucleus)
8.01540833 MeV (average binding energy per nucleon)Separation energy:S_N = 4.681(565) MeV (first neutron)
S_P = 14.759(500) MeV (first proton)Half-life:99(93) msDecay constant λ:7.0014866723227 s^-1Specific activity α:2.68560120826 × 10⁺²² Bq g^-1
725838164394.86 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Year of discovery:2016

Radioactive Decay

Half-life T_½ = 99(93) ms respectively 9.9 × 10^-2 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	¹⁵⁸Pr	100 %	7.610(500) MeV
β^-, n	¹⁵⁷Pr	?

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 100) and isobaric (same nucleon number A = 158) with Cerium-158. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 100	Isobar A = 158
58	¹⁵⁸Ce	¹⁵⁸Ce
59	¹⁵⁹Pr	¹⁵⁸Pr
60	¹⁶⁰Nd	¹⁵⁸Nd
61	¹⁶¹Pm	¹⁵⁸Pm
62	¹⁶²Sm	¹⁵⁸Sm
63	¹⁶³Eu	¹⁵⁸Eu
64	¹⁶⁴Gd	¹⁵⁸Gd
65	¹⁶⁵Tb	¹⁵⁸Tb
66	¹⁶⁶Dy	¹⁵⁸Dy
67	¹⁶⁷Ho	¹⁵⁸Ho
68	¹⁶⁸Er	¹⁵⁸Er
69	¹⁶⁹Tm	¹⁵⁸Tm
70	¹⁷⁰Yb	¹⁵⁸Yb
71	¹⁷¹Lu	¹⁵⁸Lu
72	¹⁷²Hf	¹⁵⁸Hf
73	¹⁷³Ta	¹⁵⁸Ta
74	¹⁷⁴W	¹⁵⁸W
75	¹⁷⁵Re
76	¹⁷⁶Os
77	¹⁷⁷Ir
78	¹⁷⁸Pt
79	¹⁷⁹Au
80	¹⁸⁰Hg
81	¹⁸¹Tl
82	¹⁸²Pb