Cesium-116

Properties and data of the isotope ¹¹⁶Cs.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

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

General data

Name of the isotope:Cesium-116; Cs-116Symbol:¹¹⁶Cs or 11655CsMass number A:116 (= number of nucleons)Atomic number Z:55 (= number of protons)Neutrons N:61Nucleon pairing (Z - N):odd - oddNuclear ratio (N/Z ratio):1.1090909090909 (= neutron-proton ratio)Neutron excess (N-Z):6Isotopic mass:159.3339(11) u (atomic weight of Cesium-116)Nuclide mass:159.3037301 u (calculated nuclear mass without electrons)Mass excess:40365.26785 MeVMass defect:-42.374963364 u (per nucleus)Nuclear binding energy:-39472.02412379 MeV (per nucleus)
-340.27607003 MeV (average binding energy per nucleon)Separation energy:S_N = 10.41(14) MeV (first neutron)
S_P = 0.67(10) MeV (first proton)Half-life:0.70(4) sDecay constant λ:0.99021025794278 s^-1Specific activity α:3.750431229110 × 10⁺²¹ Bq g^-1
101363006192.18 Ci g^-1Spin and parity:
(nuclear angular momentum)(1+)Year of discovery:1975

Radioactive Decay

Half-life T_½ = 0.70(4) s respectively 7.0 × 10^-1 seconds s.

Decay mode	Daughter	Probability	Decay energy
EC/β⁺	¹¹⁶Xe	97.1 %	11.0(1) MeV
EC, p	¹¹⁵I	2.8(7) %
EC, α	¹¹²Te	0.049(25) %

Parent Nuclides

Direct parent isotope is: ¹¹⁶Ba.

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
^116mCs	100 keV	3.85(13) s	4+,5,6

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 61) and isobaric (same nucleon number A = 116) with Cesium-116. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 61	Isobar A = 116
34	⁹⁵Se
35	⁹⁶Br
36	⁹⁷Kr
37	⁹⁸Rb
38	⁹⁹Sr
39	¹⁰⁰Y
40	¹⁰¹Zr
41	¹⁰²Nb
42	¹⁰³Mo	¹¹⁶Mo
43	¹⁰⁴Tc	¹¹⁶Tc
44	¹⁰⁵Ru	¹¹⁶Ru
45	¹⁰⁶Rh	¹¹⁶Rh
46	¹⁰⁷Pd	¹¹⁶Pd
47	¹⁰⁸Ag	¹¹⁶Ag
48	¹⁰⁹Cd	¹¹⁶Cd
49	¹¹⁰In	¹¹⁶In
50	¹¹¹Sn	¹¹⁶Sn
51	¹¹²Sb	¹¹⁶Sb
52	¹¹³Te	¹¹⁶Te
53	¹¹⁴I	¹¹⁶I
54	¹¹⁵Xe	¹¹⁶Xe
55	¹¹⁶Cs	¹¹⁶Cs
56	¹¹⁷Ba	¹¹⁶Ba
57	¹¹⁸La	¹¹⁶La
58	¹¹⁹Ce