Erbium-156
Properties and data of the isotope 156Er.
See also: List of individual Erbium isotopes (and general data sources).
General data
Name of the isotope:Erbium-156; Er-156Symbol:156Er or 15668ErMass number A:156 (= number of nucleons)Atomic number Z:68 (= number of protons)Neutrons N:88Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.2941176470588 (= neutron-proton ratio)Neutron excess (N-Z):20Isotopic mass:155.931066(26) u (atomic weight of Erbium-156)Nuclide mass:155.8937659 u (calculated nuclear mass without electrons)Mass excess:-64.21161 MeVMass defect:1.363548784 u (per nucleus)Nuclear binding energy:1270.137511 MeV (per nucleus)
8.14190712 MeV (average binding energy per nucleon)Separation energy:SN = 10.074(25) MeV (first neutron)
SP = 5.46(3) MeV (first proton)Half-life:19.5(10) minDecay constant λ:0.00059243348765807 s-1Specific activity α:2.301753492142 × 10+18 Bq g-1
62209553.841684 Ci g-1Spin and parity:
(nuclear angular momentum)0+Charge radius:5.1429(285) femtometer fmYear of discovery:1967
Radioactive Decay
Half-life T½ = 19.5(10) min (minutes) respectively 1.170 × 103 seconds s.
Decay
mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| EC/β+ | 156Ho | ca. 100 % | 1.27(6) MeV | |
| α | 152Dy | trace | 3.481(25) MeV | |
Parent Nuclides
Direct parent isotope is: 156Tm.
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 88) and isobaric (same nucleon number A = 156) with Erbium-156. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 88 | Isobar A = 156 |
|---|
| 49 | 137In | |
| 50 | 138Sn | |
| 51 | 139Sb | |
| 52 | 140Te | |
| 53 | 141I | |
| 54 | 142Xe | |
| 55 | 143Cs | |
| 56 | 144Ba | |
| 57 | 145La | 156La |
| 58 | 146Ce | 156Ce |
| 59 | 147Pr | 156Pr |
| 60 | 148Nd | 156Nd |
| 61 | 149Pm | 156Pm |
| 62 | 150Sm | 156Sm |
| 63 | 151Eu | 156Eu |
| 64 | 152Gd | 156Gd |
| 65 | 153Tb | 156Tb |
| 66 | 154Dy | 156Dy |
| 67 | 155Ho | 156Ho |
| 68 | 156Er | 156Er |
| 69 | 157Tm | 156Tm |
| 70 | 158Yb | 156Yb |
| 71 | 159Lu | 156Lu |
| 72 | 160Hf | 156Hf |
| 73 | 161Ta | 156Ta |
| 74 | 162W | 156W |
| 75 | 163Re | |
| 76 | 164Os | |
| 77 | 165Ir | |
| 78 | 166Pt | |
External data and identifiers
Last update: 2020-10-09
Perma link: https://www.chemlin.org/isotope/erbium-156
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