Boron-7

Properties and data of the isotope ⁷B.

Content

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.

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:2Isotopic 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:S_N = 27.21(200) MeV (first neutron)Half-life:570(14) × 10^-24 sDecay constant λ:1.216047685192 × 10⁺²¹ s^-1Specific activity α:1.046172921804 × 10⁺⁴⁴ Bq g^-1
2.827494383255 × 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 T_½ = 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.