Cerium-122

Properties and data of the isotope ¹²²Ce.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

Literature

Cerium-122 is a radioisotope of the chemical element cerium, which has 64 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 122. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ¹²²Ce is exclusively for academic purposes [1].

Cerium-122 was first experimentally detected in 2005. The isotope was created in a fusion-evaporation reaction in which a zinc-64 beam with an energy of 260 MeV was fired at a ⁶⁴Zn target: ⁶⁴Zn(⁶⁴Zn,α2n)¹²²Ce [1].

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

General data

Name of the isotope:Cerium-122; Ce-122Symbol:¹²²Ce or 12258CeMass number A:122 (= number of nucleons)Atomic number Z:58 (= number of protons)Neutrons N:64Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.1034482758621 (= neutron-proton ratio)Neutron excess (N-Z):6Isotopic mass:121.93787(43) u (atomic weight of Cerium-122)Nuclide mass:121.9060546 u (calculated nuclear mass without electrons)Mass excess:-57.87372 MeVMass defect:1.07053648 u (per nucleus)Nuclear binding energy:997.1983079 MeV (per nucleus)
8.17375662 MeV (average binding energy per nucleon)Separation energy:S_N = 13.255(566) MeV (first neutron)
S_P = 2.972(500) MeV (first proton)Half-life:2 sDecay constant λ:0.34657359027997 s^-1Specific activity α:1.724888412396 × 10⁺²¹ Bq g^-1
46618605740.451 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Year of discovery:2005

Radioactive Decay

Half-life T_½ = 2 s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β⁺	¹²¹Ba	?	6.669(500) MeV
EC, β⁺	¹²²La	?

Parent Nuclides

Direct parent isotope is: ¹²²Pr.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 64) and isobaric (same nucleon number A = 122) with Cerium-122. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 64	Isobar A = 122
36	¹⁰⁰Kr
37	¹⁰¹Rb
38	¹⁰²Sr
39	¹⁰³Y
40	¹⁰⁴Zr
41	¹⁰⁵Nb
42	¹⁰⁶Mo
43	¹⁰⁷Tc
44	¹⁰⁸Ru	¹²²Ru
45	¹⁰⁹Rh	¹²²Rh
46	¹¹⁰Pd	¹²²Pd
47	¹¹¹Ag	¹²²Ag
48	¹¹²Cd	¹²²Cd
49	¹¹³In	¹²²In
50	¹¹⁴Sn	¹²²Sn
51	¹¹⁵Sb	¹²²Sb
52	¹¹⁶Te	¹²²Te
53	¹¹⁷I	¹²²I
54	¹¹⁸Xe	¹²²Xe
55	¹¹⁹Cs	¹²²Cs
56	¹²⁰Ba	¹²²Ba
57	¹²¹La	¹²²La
58	¹²²Ce	¹²²Ce
59	¹²³Pr	¹²²Pr
60	¹²⁴Nd

External data and identifiers

Adopted Levels, Gammas:NuDat 122Ce

Literature and References

[1] - J. F. Smith, C.J. Chiara, M.P. Carpenter et al.:
First observation of very neutron-deficient ¹²²Ce.
In: Physics Letters B, 625, 3-4, (2005), DOI 10.1016/j.physletb.2005.08.035.