Cesium-149
Properties and data of the isotope 149Cs.
See also: List of individual Cesium isotopes (and general data sources).
General data
Name of the isotope:Cesium-149; Cs-149Symbol:149Cs or 14955CsMass number A:149 (= number of nucleons)Atomic number Z:55 (= number of protons)Neutrons N:94Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.7090909090909 (= neutron-proton ratio)Neutron excess (N-Z):39Isotopic mass:148.95357(43) u (atomic weight of Cesium-149)Nuclide mass:148.9234001 u (calculated nuclear mass without electrons)Mass excess:-43.24927 MeVMass defect:1.291308864 u (per nucleus)Nuclear binding energy:1202.84645896 MeV (per nucleus)
8.07279503 MeV (average binding energy per nucleon)Separation energy:SN = 4.41(40) MeV (first neutron)
SP = 11.94(50) MeV (first proton)Half-life:113(8) msDecay constant λ:6.1340458456632 s-1Specific activity α:2.495951900263 × 10+22 Bq g-1
674581594665.7 Ci g-1Spin and parity:
(nuclear angular momentum)Year of discovery:1979
Radioactive Decay
Half-life T½ = 113(8) ms respectively 1.13 × 10-1 seconds s.
Decay
mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| β- | 149Ba | 100 % | 9.87(59) MeV | |
| β-, n | 148Ba | ? | 6.27(40) MeV | |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 94) and isobaric (same nucleon number A = 149) with Cesium-149. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 94 | Isobar A = 149 |
|---|
| 54 | 148Xe | |
| 55 | 149Cs | 149Cs |
| 56 | 150Ba | 149Ba |
| 57 | 151La | 149La |
| 58 | 152Ce | 149Ce |
| 59 | 153Pr | 149Pr |
| 60 | 154Nd | 149Nd |
| 61 | 155Pm | 149Pm |
| 62 | 156Sm | 149Sm |
| 63 | 157Eu | 149Eu |
| 64 | 158Gd | 149Gd |
| 65 | 159Tb | 149Tb |
| 66 | 160Dy | 149Dy |
| 67 | 161Ho | 149Ho |
| 68 | 162Er | 149Er |
| 69 | 163Tm | 149Tm |
| 70 | 164Yb | 149Yb |
| 71 | 165Lu | 149Lu |
| 72 | 166Hf | |
| 73 | 167Ta | |
| 74 | 168W | |
| 75 | 169Re | |
| 76 | 170Os | |
| 77 | 171Ir | |
| 78 | 172Pt | |
| 79 | 173Au | |
| 80 | 174Hg | |
External data and identifiers
Last update: 2020-10-18
Perma link: https://www.chemlin.org/isotope/cesium-149
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