Boron-9

Properties and data of the isotope ⁹B.

Content

General data

Name of the isotope:Boron-9; B-9Symbol:⁹B or 95BMass number A:9 (= number of nucleons)Atomic number Z:5 (= number of protons)Neutrons N:4Isotopic mass:9.0133296(10) u (atomic weight of Boron-9)Nuclide mass:9.0105867 u (calculated nuclear mass without electrons)Mass excess:12.41644 MeVMass defect:0.060455224 u (per nucleus)Nuclear binding energy:56.31367842 MeV (per nucleus)
6.25707538 MeV (average binding energy per nucleon)Separation energy:S_N = 18.5764(13) MeV (first neutron)Half-life:800(300) × 10^-21 sDecay constant λ:8.664339756999 × 10⁺¹⁷ s^-1Specific activity α:5.797541608333 × 10⁺⁴⁰ Bq g^-1
1.566903137387 × 10⁺³⁰ Ci g^-1Spin and parity:
(nuclear angular momentum)3/2-Isobaric spin: 1/2Mirror nucleus:Beryllium-9Year of discovery:1940

Radioactive Decay

Half-life T_½ = 800(300) × 10^-21 s respectively 8.0 × 10^-19 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
p	⁸Be	100 %

Parent Nuclides

Direct parent isotope is: ⁹C.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 4) and isobaric (same nucleon number A = 9) with Boron-9. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.