Element 5 — Boron (Z = 5) Isotopes

Format: Isotope shown with mass number as a left superscript (e.g., ¹⁰B). Columns: Isotope | Z | A | Stable? | Half‑life | Decay mode(s) | Daughter | Radiation | Origin | Uses | Notes

IsotopeZAStable?Half‑lifeDecay mode(s)DaughterRadiationOriginUsesNotes
⁷B57Unstable (unbound)≈ 5.7×10⁻²² sp emission (sequential multi‑p)⁶Be (+p) → ⁴He + 2p (+p net)protonsSyntheticResearch (proton‑rich dripline)Net reaction often written ⁷B → ⁴He + 3¹H. (Wikipedia)
⁸B58Unstable772 msβ⁺ / EC → ⁸Be → 2×⁴He⁸Be (unbound) → 2αβ⁺, νₑ; α (from ⁸Be breakup)Synthetic; stellar intermediateSolar‑neutrino spectrum studies; β‑decay standardsHigh‑precision t½ ≈ 772.1±1.7 ms. (TUNL Nuclear Data Project, CERN Document Server, Physical Review Links)
⁹B59Unstable (unbound)≈ 8×10⁻¹⁹ sp emission⁸Be → 2×⁴Heproton; α (via ⁸Be)SyntheticResearch (resonance + breakup)Unbound to p + ⁸Be; prompt 2α from ⁸Be. (Wikipedia)
¹⁰B510StablestableNaturalBNCT (neutron capture); control/shim (boric acid), neutron detectors (¹⁰B coatings)High thermal‑n capture (¹⁰B(n,α)⁷Li)). (WebElements)
¹¹B511StablestableNatural¹¹B NMR; p–¹¹B fusion research; neutron shieldingOne of few stable odd–odd nuclides. (WebElements)
¹²B512Unstable20.20 msβ⁻ (dominant); minor β⁻α → ⁸Be¹²C (dominant)β⁻; α (delayed, via ⁸Be)Synthetic; cosmogenicResearch (β‑decay tests; activation)Precise branches compiled in evaluations. (Wikipedia)
¹³B513Unstable17.16 msβ⁻ (dominant); β⁻n (minor)¹³C; ¹²C + nβ⁻; delayed nSyntheticResearch (structure near dripline)— (Wikipedia)
¹⁴B514Unstable12.36 msβ⁻ (≈94%); β⁻n (≈6%)¹⁴C; ¹³C + nβ⁻; delayed nSyntheticResearch (β‑delayed neutron emission)— (Wikipedia)
¹⁵B515Unstable10.18 msβ⁻n (≈99%); minor β⁻, β⁻2n¹⁴C; ¹⁵C; ¹³Cβ⁻; delayed nSyntheticResearch (multi‑n emission)— (Wikipedia)
¹⁶B516Unstable (unbound)> 4.6×10⁻²¹ sn emission¹⁵B + nneutronSyntheticResearch (near‑threshold n emission)Width‑/limit‑derived lifetime. (Wikipedia)
¹⁷B517Unstable5.08 msβ⁻n (≈63%); β⁻ (≈21%); β⁻2n (≈12%); rare β⁻3–4n¹⁶C; ¹⁷C; ¹⁵C…β⁻; delayed n (1–4n)SyntheticResearch (β‑delayed multi‑neutron)— (Wikipedia)
¹⁸B518Unstable (unbound)< 26 nsn emission¹⁷B + nneutronSyntheticResearch (continuum structure)— (Wikipedia)
¹⁹B519Unstable2.92 msβ⁻n (≈71%); β⁻2n (≈17%); β⁻ (≥≈3%); β⁻3n (<≈9%)¹⁸C; ¹⁷C; ¹⁹C…β⁻; delayed nSyntheticResearch (heavy B dripline)— (Wikipedia)
²⁰B520Unstable (unbound)> 9.1×10⁻²² sn emission¹⁹B + nneutronSyntheticResearchFirst observed 2018 (PRL). (Wikipedia)
²¹B521Unstable (unbound)> 7.6×10⁻²² s2n emission¹⁹B + 2nneutrons (2n)SyntheticResearchFirst observed 2018 (PRL). (Wikipedia)

Totals — Boron

  • Stable: 2 (¹⁰B, ¹¹B)
  • Unstable: 13 (⁷B, ⁸B, ⁹B, ¹²–²¹B)
  • Total isotopes: 15

Running cumulative totals (up to Z = 5)

  • Cumulative total isotopes: 51 (H: 7 • He: 8 • Li: 10 • Be: 11 • B: 15)
  • Cumulative stable: 9 (H: 2 • He: 2 • Li: 2 • Be: 1 • B: 2)
  • Cumulative unstable: 42

Notes & primary references

  • Master data backbone (half‑lives/decays, definitions): IAEA LiveChart (ENSDF) and documentation; NuDat 3 for cross‑checks. (IAEA Nuclear Data Services)
  • ⁸B recommended half‑life 772.1±1.7 ms; β⁺/EC to ⁸Be → 2α; solar‑neutrino relevance. (TUNL Nuclear Data Project, EPJ Conferences, Physical Review Links)
  • Isotope list with specific half‑lives/branches across ⁷–²¹B (including unbound lifetimes/limits): compiled table. (Wikipedia)
  • Applications of ¹⁰B/¹¹B (BNCT; neutron control/shim; detectors; NMR): element application pages. (WebElements)

Next: Carbon (Z = 6)


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