All ground‑state isotopes from A = 184…224 (no isomers in the main table; notable isomers are mentioned in notes). Primary data spine: NUBASE‑2020/Wikipedia “Isotopes of bismuth,” with point checks from LNHB/IAEA/KAERI where cited. (Wikipedia)
Abbreviations: t½ = half‑life; α = alpha; β⁻/β⁺ = beta minus/plus; EC = electron capture; IT = isomeric transition; p = proton emission.
Origins: Natural = present in decay series (radiogenic) or primordial; Synthetic = accelerator/spallation products.
| Isotope | Z | A | Stability | t½ | Main decay(s) → daughter | Origin | Notes & uses |
|---|---|---|---|---|---|---|---|
| ¹⁸⁴Bi | 83 | 184 | Unstable | 6.6 ms | α → ¹⁸⁰Tl | Synthetic | Nuclear‑structure R. (Wikipedia) |
| ¹⁸⁵Bi | 83 | 185 | Unstable | ~2.8 μs | p (≈92%) → ¹⁸⁴Pb; α (≈8%) → ¹⁸¹Tl | Synthetic | Notable proton emitter (odd‑odd); modern PRL study on ¹⁸⁵Bi proton radioactivity. (Wikipedia) |
| ¹⁸⁶Bi | 83 | 186 | Unstable | 14.8 ms | α (≈99.99%) → ¹⁸²Tl; tiny β⁺, SF | Synthetic | R. (Wikipedia) |
| ¹⁸⁷Bi | 83 | 187 | Unstable | 37 ms | α → ¹⁸³Tl | Synthetic | R. (Wikipedia) |
| ¹⁸⁸Bi | 83 | 188 | Unstable | 60 ms | α → ¹⁸⁴Tl | Synthetic | R. (Wikipedia) |
| ¹⁸⁹Bi | 83 | 189 | Unstable | 688 ms | α → ¹⁸⁵Tl | Synthetic | R. (Wikipedia) |
| ¹⁹⁰Bi | 83 | 190 | Unstable | 6.3 s | α (77%) → ¹⁸⁶Tl; β⁺ (23%) → ¹⁹⁰Pb | Synthetic | R. (Wikipedia) |
| ¹⁹¹Bi | 83 | 191 | Unstable | 12.4 s | α (51%) → ¹⁸⁷Tl; β⁺ (49%) → ¹⁹¹Pb | Synthetic | R. (Wikipedia) |
| ¹⁹²Bi | 83 | 192 | Unstable | 34.6 s | β⁺ (88%) → ¹⁹²Pb; α (12%) → ¹⁸⁸Tl | Synthetic | R. (Wikipedia) |
| ¹⁹³Bi | 83 | 193 | Unstable | 63.6 s | β⁺ (96.5%) → ¹⁹³Pb; α (3.5%) → ¹⁸⁹Tl | Synthetic | R. (Wikipedia) |
| ¹⁹⁴Bi | 83 | 194 | Unstable | 95 s | β⁺ (99.54%) → ¹⁹⁴Pb; α (0.46%) → ¹⁹⁰Tl | Synthetic | R. (Wikipedia) |
| ¹⁹⁵Bi | 83 | 195 | Unstable | 183 s | β⁺ (99.97%) → ¹⁹⁵Pb; α (0.03%) → ¹⁹¹Tl | Synthetic | R. (Wikipedia) |
| ¹⁹⁶Bi | 83 | 196 | Unstable | 5.13 min | β⁺ → ¹⁹⁶Pb; α (~1.15×10⁻³%) → ¹⁹²Tl | Synthetic | R. (Wikipedia) |
| ¹⁹⁷Bi | 83 | 197 | Unstable | 9.33 min | β⁺ → ¹⁹⁷Pb | Synthetic | R. (Wikipedia) |
| ¹⁹⁸Bi | 83 | 198 | Unstable | 10.3 min | β⁺ → ¹⁹⁸Pb | Synthetic | R. (Wikipedia) |
| ¹⁹⁹Bi | 83 | 199 | Unstable | 27 min | β⁺ → ¹⁹⁹Pb | Synthetic | R. (Wikipedia) |
| ²⁰⁰Bi | 83 | 200 | Unstable | 36.4 min | β⁺ → ²⁰⁰Pb | Synthetic | R. (Wikipedia) |
| ²⁰¹Bi | 83 | 201 | Unstable | 103 min | β⁺ → ²⁰¹Pb | Synthetic | R. (Wikipedia) |
| ²⁰²Bi | 83 | 202 | Unstable | 1.72 h | β⁺ → ²⁰²Pb (α <10⁻⁵) | Synthetic | R. (Wikipedia) |
| ²⁰³Bi | 83 | 203 | Unstable | 11.76 h | β⁺ → ²⁰³Pb | Synthetic | R. (Wikipedia) |
| ²⁰⁴Bi | 83 | 204 | Unstable | 11.22 h | β⁺ → ²⁰⁴Pb | Synthetic | Radiotracer in some Pb/Bi chemistry studies (R). (Wikipedia) |
| ²⁰⁵Bi | 83 | 205 | Unstable | 14.91 d | β⁺ → ²⁰⁵Pb | Synthetic | R. (Wikipedia) |
| ²⁰⁶Bi | 83 | 206 | Unstable | 6.243 d | β⁺ → ²⁰⁶Pb | Synthetic | R. (Wikipedia) |
| ²⁰⁷Bi | 83 | 207 | Unstable (long‑lived) | 31.22 y | EC (±β⁺) → ²⁰⁷Pb | Synthetic | Widely used γ/X‑ray calibration source (prominent 570, 1064, 1770 keV lines); NIST SRM and LNHB sheets. (NIST, gammaray.inl.gov, Lnhb) |
| ²⁰⁸Bi | 83 | 208 | Unstable (very long‑lived) | 3.68×10⁵ y | EC/β⁺ → ²⁰⁸Pb | Synthetic | Long‑lived EC nuclide; nuclear‑structure/background studies (R). (Wikipedia) |
| ²⁰⁹Bi | 83 | 209 | Very long‑lived | 2.01×10¹⁹ y | α → ²⁰⁵Tl | Natural (mononuclidic Bi in nature) | Formerly “stable”; α decay established with ~2×10¹⁹ y t½. Used chemically (e.g., Pb–Bi eutectic coolants); physics background studies. (Wikipedia) |
| ²¹⁰Bi | 83 | 210 | Unstable | 5.012 d | β⁻ → ²¹⁰Po (dominant); tiny α (≈1.3×10⁻⁴%) → ²⁰⁶Tl | Natural (U‑238 series) | Part of the ²¹⁰Pb→²¹⁰Bi→²¹⁰Po chain; environmental/radon progeny studies; dating via ²¹⁰Pb. (Wikipedia, periodictable.com) |
| ²¹¹Bi | 83 | 211 | Unstable | 2.14 min | α (99.72%) → ²⁰⁷Tl; β⁻ (0.276%) → ²¹¹Po | Natural (U‑235 series) | Short‑lived α source in actinium chain; precise decay data tabulated by LNHB. (Wikipedia, Lnhb) |
| ²¹²Bi | 83 | 212 | Unstable | 60.55 min | β⁻ (64.05%) → ²¹²Po; α (35.94%) → ²⁰⁸Tl; β⁻α (~0.014%) → ²⁰⁸Pb | Natural (Th‑232 series) | Important branch point in thorium series; high‑quality evaluations exist. (Wikipedia, Lnhb) |
| ²¹³Bi | 83 | 213 | Unstable | 45.60 min | β⁻ (97.91%) → ²¹³Po; α (2.09%) → ²⁰⁹Tl | Trace in Np‑237 series; produced from ²²⁵Ac | Targeted α‑therapy nuclide (e.g., ²¹³Bi‑PSMA, antibody conjugates). (Wikipedia, PMC) |
| ²¹⁴Bi | 83 | 214 | Unstable | 19.9 min | β⁻ (≈99.98%) → ²¹⁴Po; α (~0.021%) → ²¹⁰Tl; β⁻α (~0.003%) → ²¹⁰Pb | Natural (U‑238/radon series) | Environmental γ background lines at 609, 1120, 1764 keV; ubiquitous in radon studies & γ‑spectrometer calibration. (Wikipedia, www-nds.iaea.org, Lnhb, periodictable.com) |
| ²¹⁵Bi | 83 | 215 | Unstable | 7.62 min | β⁻ → ²¹⁵Po | Natural (U‑235 series) | R. (Wikipedia) |
| ²¹⁶Bi | 83 | 216 | Unstable | 2.21 min | β⁻ → ²¹⁶Po | Synthetic / trace | R. (Wikipedia) |
| ²¹⁷Bi | 83 | 217 | Unstable | 98.5 s | β⁻ → ²¹⁷Po | Synthetic / trace | R. (Wikipedia) |
| ²¹⁸Bi | 83 | 218 | Unstable | 33 s | β⁻ → ²¹⁸Po | Synthetic / trace | R. (Wikipedia) |
| ²¹⁹Bi | 83 | 219 | Unstable | 8.7 s | β⁻ → ²¹⁹Po | Synthetic / trace | R. (Wikipedia) |
| ²²⁰Bi | 83 | 220 | Unstable | 9.5 s | β⁻ → ²²⁰Po | Synthetic / trace | R. (Wikipedia) |
| ²²¹Bi | 83 | 221 | Unstable | ≳2 s | β⁻ → ²²¹Po (β⁻, n possible) | Synthetic | Very neutron‑rich; evaluated as β⁻ to Po. (Wikipedia, chemlin.org) |
| ²²²Bi | 83 | 222 | Unstable | ≳3 s | β⁻ → ²²²Po (expected) | Synthetic | Very limited data (near drip‑line); evaluated as β⁻ to Po. (Wikipedia) |
| ²²³Bi | 83 | 223 | Unstable | ≳1 s | β⁻ → ²²³Po (β⁻, n possible) | Synthetic | Very neutron‑rich; evaluated as β⁻ to Po. (Wikipedia, chemlin.org) |
| ²²⁴Bi | 83 | 224 | Unstable | ≳1 s | β⁻ → ²²⁴Po (β⁻, n possible) | Synthetic | Very neutron‑rich; evaluated as β⁻ to Po. (Wikipedia, chemlin.org) |
Notable isomers (context only, not counted above). ²¹⁰ᵐBi has t½ ≈ 3.04×10⁶ y (extraordinarily long for an isomer); it primarily undergoes α → ²⁰⁶Tl or very slow IT/β⁻ paths. This does not change the ground‑state counting. (Wikipedia)
Element totals — Bismuth (Bi)
- Ground‑state isotopes: 41 (A = 184–224). Stable: 0. Unstable: 41. (Wikipedia)
- Natural members of decay chains: ²¹⁰Bi & ²¹⁴Bi (U‑238/radon series), ²¹¹Bi & ²¹⁵Bi (U‑235/actinium series), ²¹²Bi (Th‑232 series), ²¹³Bi (Np‑237 series, mostly accessed via ²²⁵Ac generators). (Wikipedia, NIST, isotopes.gov)
Running total across elements so far (H → Bi)
- ≥2,691 ground‑state isotopes tabulated | Stable: 251 | Unstable: ≥2,439.
(Increment here: +41 total, +0 stable, +41 unstable vs. the Pb line.)
Sources (key citations for this Bi table)
- Master table & half‑lives/decay modes: “Isotopes of bismuth” (updated; includes NUBASE‑2020 references). (Wikipedia)
- Bi‑209 α‑decay (2.01×10¹⁹ y): Wikipedia summary page; discovery reports and reviews. (Wikipedia)
- Bi‑210 (chain membership & t½): NIST/U.S. radon series diagram; Wikipedia table. (periodictable.com, Wikipedia)
- Bi‑211 precision decay data: LNHB (LNE–CEA) nuclide tables. (Lnhb)
- Bi‑212 branching & t½: LNHB evaluation notes/tables. (Lnhb)
- Bi‑213 in medicine (TAT): Reviews and clinical reports. (PMC)
- Bi‑214 γ‑lines & t½: IAEA/LNHB sheets and spectrometry references. (www-nds.iaea.org, Lnhb, periodictable.com)
- Neutron‑rich tails (²²¹–²²⁴Bi): Evaluated summaries (ChemLin) used for mode confirmation where Wikipedia’s table omits explicit mode text. (chemlin.org)
- Bi‑207 calibration usage: NIST SRM sheet; detector calibration literature; LNHB comments. (NIST, gammaray.inl.gov, Lnhb)
Next element: Polonium (Po, Z = 84).