Cerium-156

Properties and data of the isotope ¹⁵⁶Ce.

Contents

Cerium-156 is a radioisotope of the chemical element cerium, which has 98 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 156. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ¹⁵⁶Ce is exclusively for academic purposes.

According to a 2018 report, the neutron-rich isotope cerium-156 was produced by bombarding a Be template with uranium-238 ions at an energy of 345 MeV per nucleon and analyzed and 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-156; Ce-156Symbol:¹⁵⁶Ce or 15658CeMass number A:156 (= number of nucleons)Atomic number Z:58 (= number of protons)Neutrons N:98Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.6896551724138 (= neutron-proton ratio)Neutron excess (N-Z):40Isotopic mass:155.95188(32) u (atomic weight of Cerium-156)Nuclide mass:155.9200646 u (calculated nuclear mass without electrons)Mass excess:-44.82349 MeVMass defect:1.351133624 u (per nucleus)Nuclear binding energy:1258.57286395 MeV (per nucleus)
8.06777477 MeV (average binding energy per nucleon)Separation energy:S_N = 5.111(424) MeV (first neutron)
S_P = 14.178(500) MeV (first proton)Half-life:233(9) msDecay constant λ:2.9748806032616 s^-1Specific activity α:1.155816131247 × 10⁺²² Bq g^-1
312382738174.97 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Year of discovery:2016

Radioactive Decay

Half-life T_½ = 233(9) ms respectively 2.33 × 10^-1 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	¹⁵⁶Pr	100 %	6.62(30) MeV
β^-, n	¹⁵⁵Pr	?	2.52(30) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 98) and isobaric (same nucleon number A = 156) with Cerium-156. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 98	Isobar A = 156
57	¹⁵⁵La	¹⁵⁶La
58	¹⁵⁶Ce	¹⁵⁶Ce
59	¹⁵⁷Pr	¹⁵⁶Pr
60	¹⁵⁸Nd	¹⁵⁶Nd
61	¹⁵⁹Pm	¹⁵⁶Pm
62	¹⁶⁰Sm	¹⁵⁶Sm
63	¹⁶¹Eu	¹⁵⁶Eu
64	¹⁶²Gd	¹⁵⁶Gd
65	¹⁶³Tb	¹⁵⁶Tb
66	¹⁶⁴Dy	¹⁵⁶Dy
67	¹⁶⁵Ho	¹⁵⁶Ho
68	¹⁶⁶Er	¹⁵⁶Er
69	¹⁶⁷Tm	¹⁵⁶Tm
70	¹⁶⁸Yb	¹⁵⁶Yb
71	¹⁶⁹Lu	¹⁵⁶Lu
72	¹⁷⁰Hf	¹⁵⁶Hf
73	¹⁷¹Ta	¹⁵⁶Ta
74	¹⁷²W	¹⁵⁶W
75	¹⁷³Re
76	¹⁷⁴Os
77	¹⁷⁵Ir
78	¹⁷⁶Pt
79	¹⁷⁷Au
80	¹⁷⁸Hg
81	¹⁷⁹Tl
82	¹⁸⁰Pb