Rubidium-85
Properties and data of the isotope 85Rb.
See also: list of Rubidium isotopes.
General data
Name of the isotope:Rubidium-85; Rb-85Symbol:85Rb or 8537RbMass number A:85 (= number of nucleons)Atomic number Z:37 (= number of protons)Neutrons N:48Isotopic mass:84.91178974(3) u (atomic weight of Rubidium-85)Nuclide mass:84.8914931 u (calculated nuclear mass without electrons)Mass excess:-82.16733 MeVMass defect:0.793652412 u (per nucleus)Nuclear binding energy:739.28245986 MeV (per nucleus)
8.6974407 MeV (average binding energy per nucleon)Separation energy:SN = 10.4797(22) MeV (first neutron)
SP = 7.01697 MeV (first proton)Half-life:stableSpin and parity:
(nuclear angular momentum)5/2-Magnetic dipole moment:μ(μN) = +1.35306(4)Charge radius:4.2036(23) femtometer fmYear of discovery:1921
Parent Nuclides
Direct parent isotopes are: 85Kr, 85Sr.
Occurrence
Comparison of the natural Rubidium isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):
| | Atomic Mass ma | Quantity | Half-life | Spin |
|---|
Rubidium
Isotopic mixture | 85.4678 u | 100 % | | |
| Isotope 85Rb | 84.91178974(3) u | 72.17(2) % | stable | 5/2- |
| Isotope 87Rb | 86.909180529(6) u | 27.83(2) % | 4.97(3) × 1010 a | 3/2- |
NMR data
Nuclear magnetic properties of the NMR active Nuclide 85Rb
Isotope:85Rb-NMRQuantity:72.17(2) %Spin:5/2-Nuclearmagnetic moment
μ/μN:+1.35306(4)Gyromagnetic ratio γ:2.5923 · 107 rad T-1 s-1Nuclear g-factor:gl = 0.541224Quadrupole moment Q:+ 0.276(1) barn (100 fm2)Resonance frequency:v0 = 4.1253 at 1 TRelative Sensitivity:0.01061 (H0 = const.)
1.1304 (v0 = const.)
[related to 1H = 1.000]
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 |
|---|
| 85mRb | 514.0065(22) keV | 1.015 μs | 9/2+ |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 48) and isobaric (same nucleon number A = 85) with Rubidium-85. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 48 | Isobar A = 85 |
|---|
| 26 | 74Fe | |
| 27 | 75Co | |
| 28 | 76Ni | |
| 29 | 77Cu | |
| 30 | 78Zn | 85Zn |
| 31 | 79Ga | 85Ga |
| 32 | 80Ge | 85Ge |
| 33 | 81As | 85As |
| 34 | 82Se | 85Se |
| 35 | 83Br | 85Br |
| 36 | 84Kr | 85Kr |
| 37 | 85Rb | 85Rb |
| 38 | 86Sr | 85Sr |
| 39 | 87Y | 85Y |
| 40 | 88Zr | 85Zr |
| 41 | 89Nb | 85Nb |
| 42 | 90Mo | 85Mo |
| 43 | 91Tc | 85Tc |
| 44 | 92Ru | 85Ru |
| 45 | 93Rh | |
| 46 | 94Pd | |
| 47 | 95Ag | |
| 48 | 96Cd | |
| 49 | 97In | |
External data and identifiers
Last update: 2020-10-14
Perma link: https://www.chemlin.org/isotope/rubidium-85
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