Boron-7 is a radioisotope of the chemical element boron, which, in addition to the element-specific 5 protons, has 2 neutrons in the atomic nucleus, resulting in the mass number 7. The very short-lived, unstable and therefore radioactive nuclide, which can only be produced artificially, has no practical significance; The study of 7B serves exclusively academic purposes.
See also: List of individual Boron isotopes (and general data sources).
General data
Name of the isotope:Boron-7; B-7Symbol:7B or 75BMass number A:7 (= number of nucleons)Atomic number Z:5 (= number of protons)Neutrons N:2Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):0.4 (= neutron-proton ratio)Neutron excess (N-Z):-3Isotopic mass:7.029712(27) u (atomic weight of Boron-7)Nuclide mass:7.0269691 u (calculated nuclear mass without electrons)Mass excess:27.67655 MeVMass defect:0.026742991999999 u (per nucleus)Nuclear binding energy:24.91093659 MeV (per nucleus) 3.55870523 MeV (average binding energy per nucleon)Separation energy:SN = 27.21(200) MeV (first neutron)Half-life:570(14) × 10-24 sDecay constant λ:1.216047685192 × 10+21 s-1Specific activity α:1.041751117414 × 10+44 Bq g-1 2.815543560580 × 10+33 Ci g-1Spin and parity: (nuclear angular momentum)(3/2-)Isobaric spin: 3/2Mirror nucleus:Helium-7Year of discovery:1967
Radioactive Decay
Half-life T½ = 570(14) × 10-24 s respectively 5.70 × 10-22 seconds s.
Decay mode
Daughter
Probability
Decay energy
γ energy (intensity)
p
6Be
11.9 MeV
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 2) and isobaric (same nucleon number A = 7) with Boron-7. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
