Cerium-118

Properties and data of the isotope ¹¹⁸Ce.

Contents

Cerium-118 is a radioisotope of the chemical element cerium, featuring 58 protons and 60 neutrons in its atomic nucleus, resulting in a mass number of 118. This very short-lived nuclide—which can only be produced artificially—is radioactive and has no practical application; its study serves exclusively the purposes of nuclear physics research.

The observation and identification of cerium-118 were first reported in 2026. The nuclide was produced by bombarding a beryllium target with lead-208 ions at an energy of 345 MeV per nucleon [1].

Experimental data for ¹¹⁸Ce are not yet available. The nuclear properties listed below are based on systematic extrapolations and theoretical estimates derived from the trends of neighboring nuclides and should therefore be considered preliminary.

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

General data

Name of the isotope:Cerium-118; Ce-118Symbol:¹¹⁸Ce or 11858CeMass number A:118 (= number of nucleons)Atomic number Z:58 (= number of protons)Neutrons N:60Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.0344827586207 (= neutron-proton ratio)Neutron excess (N-Z):2Isotopic mass:117.956(2)# u (atomic weight of Cerium-118)Nuclide mass:117.9241846 u (calculated nuclear mass without electrons)Mass excess:-40.98574 MeVMass defect:1.017746816 u (per nucleus)Nuclear binding energy:948.02505262 MeV (per nucleus)
8.03411062 MeV (average binding energy per nucleon)Half-life:Spin and parity:
(nuclear angular momentum)(0+)Year of discovery:2026

Radioactive Decay

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC, β⁺ ?	¹¹⁸La		9.05 MeV #

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 60) and isobaric (same nucleon number A = 118) with Cerium-118. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 60	Isobar A = 118
34	⁹⁴Se
35	⁹⁵Br
36	⁹⁶Kr
37	⁹⁷Rb
38	⁹⁸Sr
39	⁹⁹Y
40	¹⁰⁰Zr
41	¹⁰¹Nb
42	¹⁰²Mo	¹¹⁸Mo
43	¹⁰³Tc	¹¹⁸Tc
44	¹⁰⁴Ru	¹¹⁸Ru
45	¹⁰⁵Rh	¹¹⁸Rh
46	¹⁰⁶Pd	¹¹⁸Pd
47	¹⁰⁷Ag	¹¹⁸Ag
48	¹⁰⁸Cd	¹¹⁸Cd
49	¹⁰⁹In	¹¹⁸In
50	¹¹⁰Sn	¹¹⁸Sn
51	¹¹¹Sb	¹¹⁸Sb
52	¹¹²Te	¹¹⁸Te
53	¹¹³I	¹¹⁸I
54	¹¹⁴Xe	¹¹⁸Xe
55	¹¹⁵Cs	¹¹⁸Cs
56	¹¹⁶Ba	¹¹⁸Ba
57	¹¹⁷La	¹¹⁸La
58	¹¹⁸Ce	¹¹⁸Ce

Literature and References

[1] - N. Fukuda, S. Michimasa, H. Suzuki et al.:
First Observation of 22 Exotic Isotopes Using a ²⁰⁸Pb Primary Beam at the RI Beam Factory.
In: Progress of Theoretical and Experimental Physics, 6, 061D01, (2026), DOI 10.1093/ptep/ptag082.