See also: List of individual Rhenium isotopes (and general data sources).
General data
Name of the isotope:Rhenium-187; Re-187Symbol:187Re or 18775ReMass number A:187 (= number of nucleons)Atomic number Z:75 (= number of protons)Neutrons N:112Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.4933333333333 (= neutron-proton ratio)Neutron excess (N-Z):37Isotopic mass:186.95575(1) u (atomic weight of Rhenium-187)Nuclide mass:186.9146107 u (calculated nuclear mass without electrons)Mass excess:-41.21861 MeVMass defect:1.601597992 u (per nucleus)Nuclear binding energy:1491.87891996 MeV (per nucleus) 7.97796214 MeV (average binding energy per nucleon)Separation energy:SN = 7.3605(9) MeV (first neutron) SP = 5.9969(11) MeV (first proton)Half-life:4.33(7) × 1010 yearsDecay constant λ:5.076109217018 × 10-19 s-1Specific activity α:1635.0951611821 Bq g-1 4.41917611130 × 10-8 Ci g-1Spin and parity: (nuclear angular momentum)5/2+Magnetic dipole moment:μ(μN) = + 3.2197(3)Charge radius:5.3698(173) femtometer fmYear of discovery:1931
Radioactive Decay
Half-life T½ = 4.33(7) × 1010 years respectively 1.3655088 × 1018 seconds s.
Comparison of the natural Rhenium isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):
Atomic Mass ma
Quantity
Half-life
Spin
Rhenium Isotopic mixture
186.207 u
100 %
Isotope 185Re
184.952955(8) u
37.40(5) %
stable
5/2+
Isotope 187Re
186.95575(1) u
62.60(5) %
4.33(7) × 1010 years
5/2+
NMR data
Nuclear magnetic properties and parameters of the NMR active Nuclide187Re
Isotope:187Re-NMRQuantity:62.60(5) %Spin:5/2+Nuclearmagnetic moment μ/μN:+ 3.2197(3)Gyromagnetic ratio γ:6.1682 · 107 rad T-1 s-1 9.81700 MHz T-1Nuclear g-factor:gl = 1.28788Quadrupole moment Q:+2.07(2) barn (100 fm2)Line width parameter (factor):l = 13711.68 fm4Resonance frequency:v0 = 9.8170 MHz at 1 TRelative Sensitivity:[related to 1H = 1.000]: 0.14300 (H0 = const.) 2.6900 (v0 = const.)
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 112) and isobaric (same nucleon number A = 187) with Rhenium-187. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
