Strontium-85
Properties and data of the isotope 85Sr.
See also: List of individual Strontium isotopes (and general data sources).
General data
Name of the isotope:Strontium-85; Sr-85Symbol:85Sr or 8538SrMass number A:85 (= number of nucleons)Atomic number Z:38 (= number of protons)Neutrons N:47Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.2368421052632 (= neutron-proton ratio)Neutron excess (N-Z):9Isotopic mass:84.912932(3) u (atomic weight of Strontium-85)Nuclide mass:84.8920868 u (calculated nuclear mass without electrons)Mass excess:-81.10332 MeVMass defect:0.791670268 u (per nucleus)Nuclear binding energy:737.43610462 MeV (per nucleus)
8.67571888 MeV (average binding energy per nucleon)Separation energy:SN = 8.525(3) MeV (first neutron)
SP = 8.633(4) MeV (first proton)Half-life:64.849(7) dDecay constant λ:1.237110335091 × 10-7 s-1Specific activity α:8.869110353816 × 10+14 Bq g-1
23970.568523829 Ci g-1Spin and parity:
(nuclear angular momentum)9/2+Magnetic dipole moment:μ(μN) = -1.0001(7)Quadrupole moment Q:+0.282(15) barn (100 fm2)Nuclear g-factor:gl = -0.22224444444444Charge radius:4.2304(21) femtometer fmYear of discovery:1940
Radioactive Decay
Half-life T½ = 64.849(7) d respectively 5.6029536 × 106 seconds s.
Decay
mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| EC | 85Rb | 100% | 1.0640(28) MeV | |
Parent Nuclides
Direct parent isotope is: 85Y.
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 |
|---|
| 85mSr | 238.79(5) keV | 67.63(4) min | 1/2- |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 47) and isobaric (same nucleon number A = 85) with Strontium-85. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 47 | Isobar A = 85 |
|---|
| 26 | 73Fe | |
| 27 | 74Co | |
| 28 | 75Ni | |
| 29 | 76Cu | |
| 30 | 77Zn | 85Zn |
| 31 | 78Ga | 85Ga |
| 32 | 79Ge | 85Ge |
| 33 | 80As | 85As |
| 34 | 81Se | 85Se |
| 35 | 82Br | 85Br |
| 36 | 83Kr | 85Kr |
| 37 | 84Rb | 85Rb |
| 38 | 85Sr | 85Sr |
| 39 | 86Y | 85Y |
| 40 | 87Zr | 85Zr |
| 41 | 88Nb | 85Nb |
| 42 | 89Mo | 85Mo |
| 43 | 90Tc | 85Tc |
| 44 | 91Ru | 85Ru |
| 45 | 92Rh | |
| 46 | 93Pd | |
| 47 | 94Ag | |
| 48 | 95Cd | |
| 49 | 96In | |
External data and identifiers
Last update: 2020-10-14
Perma link: https://www.chemlin.org/isotope/strontium-85
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