Notation. Nuclides are written with the mass number as a left superscript (e.g., ²¹¹At).
Columns. Stable? refers to the ground state (At has no stable isotopes). Half‑lives are evaluated values; # marks values partly inferred from trends near the drip lines. Decay → daughter(s) lists dominant branch(es). Radiation uses α, β⁺, β⁻, EC (electron capture), p (proton). Origin is typical production path; Uses flags M (medical), I (industrial), R (research).
Primary data spine: evaluated Isotopes of astatine table (NUBASE 2020/ENSDF lineage; updated Aug 2025). (Wikipedia)
Table — ground states
| Nuclide | Z | A | Stable? | Half‑life | Decay → daughter(s) | Radiation | Origin (typical) | Uses / notes |
|---|---|---|---|---|---|---|---|---|
| ¹⁸⁸At | 85 | 188 | No | 190⁺³⁵⁰₋₈₀ µs | α (~50%) → ¹⁸⁴Bi; p (~50%) → ¹⁸⁷Po | α; p | Fusion‑evaporation | New proton‑emitter (2025); discovery paper reports mixed α/p decay. R. (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) |
(The above row’s citation glitch repeats unintentionally due to formatting; see corrected, clean table below.)
| Nuclide | Z | A | Stable? | Half‑life | Decay → daughter(s) | Radiation | Origin (typical) | Uses / notes |
|---|---|---|---|---|---|---|---|---|
| ¹⁸⁸At | 85 | 188 | No | 190⁺³⁵⁰₋₈₀ µs | α (~50%) → ¹⁸⁴Bi; p (~50%) → ¹⁸⁷Po | α; p | Fusion‑evaporation | New proton‑emitter (2025). (Wikipedia) (Wikipedia) (Wikipedia) (Wikipedia) |
| ¹⁹⁰At | 85 | 190 | No | 1.0⁺¹·⁴₋₀·₄ ms | α → ¹⁸⁶Bi | α | Fusion‑evaporation | New α‑decayer (2023). R. (Wikipedia) (Wikipedia) |
| ¹⁹¹At | 85 | 191 | No | 2.1(8) ms | α → ¹⁸⁷Bi | α | Fusion‑evaporation | R. (Wikipedia) |
| ¹⁹²At | 85 | 192 | No | 11.5(6) ms | α → ¹⁸⁸Bi | α | Fusion‑evaporation | R. (Wikipedia) |
| ¹⁹³At | 85 | 193 | No | 29(5) ms | α → ¹⁸⁹Bi | α | Fusion‑evaporation | R. (Wikipedia) |
| ¹⁹⁴At | 85 | 194 | No | 286(7) ms | α (≈91.7%#) → ¹⁹⁰Bi; β⁺ (≈8.3%#) → ¹⁹⁴Po | α; β⁺ | Fusion‑evaporation | R. (Wikipedia) |
| ¹⁹⁵At | 85 | 195 | No | 290(20) ms | α → ¹⁹¹Bi (β⁺?) | α; β⁺? | Fusion‑evaporation | R. (Wikipedia) |
| ¹⁹⁶At | 85 | 196 | No | 377(4) ms | α (≈97.5%) → ¹⁹²Bi; β⁺ (≈2.5%) → ¹⁹⁶Po | α; β⁺ | Fusion‑evaporation | R. (Wikipedia) |
| ¹⁹⁷At | 85 | 197 | No | 388.2(56) ms | α (≈96.1%) → ¹⁹³Bi; β⁺ (≈3.9%) → ¹⁹⁷Po | α; β⁺ | Activation/FE | R. (Wikipedia) |
| ¹⁹⁸At | 85 | 198 | No | 4.47(5) s | α (≈97%) → ¹⁹⁴Bi; β⁺ (≈3%) → ¹⁹⁸Po | α; β⁺ | Activation | R. (Wikipedia) |
| ¹⁹⁹At | 85 | 199 | No | 7.02(12) s | α (≈89%) → ¹⁹⁵Bi; β⁺ (≈11%) → ¹⁹⁹Po | α; β⁺ | Activation | R. (Wikipedia) |
| ²⁰⁰At | 85 | 200 | No | 43.2(9) s | α (≈52%) → ¹⁹⁶Bi; β⁺ (≈48%) → ²⁰⁰Po | α; β⁺ | Activation | R. (Wikipedia) |
| ²⁰¹At | 85 | 201 | No | 85.2(16) s | α (≈71%) → ¹⁹⁷Bi; β⁺ (≈29%) → ²⁰¹Po | α; β⁺ | Activation | R. (Wikipedia) |
| ²⁰²At | 85 | 202 | No | 184(1) s | β⁺ (≈88%) → ²⁰²Po; α (≈12%) → ¹⁹⁸Bi | β⁺; α | Activation | R. (Wikipedia) |
| ²⁰³At | 85 | 203 | No | 7.4(2) min | β⁺ (≈69%) → ²⁰³Po; α (≈31%) → ¹⁹⁹Bi | β⁺; α | Activation | R. (Wikipedia) |
| ²⁰⁴At | 85 | 204 | No | 9.12(11) min | β⁺ (≈96.2%) → ²⁰⁴Po; α (≈3.8%) → ²⁰⁰Bi | β⁺; α | Activation | R. (Wikipedia) |
| ²⁰⁵At | 85 | 205 | No | 26.9(8) min | β⁺ (≈90%) → ²⁰⁵Po; α (≈10%) → ²⁰¹Bi | β⁺; α | Activation | R. (Wikipedia) |
| ²⁰⁶At | 85 | 206 | No | 30.6(8) min | β⁺ (≈99.1%) → ²⁰⁶Po; α (≈0.9%) → ²⁰²Bi | β⁺; α | Activation | R. (Wikipedia) |
| ²⁰⁷At | 85 | 207 | No | 1.81(3) h | β⁺ (~90%) → ²⁰⁷Po; α (~10%) → ²⁰³Bi | β⁺; α | Activation | R. (Wikipedia) |
| ²⁰⁸At | 85 | 208 | No | 1.63 h | β⁺ (99.5%) → ²⁰⁸Po; α (0.55%) → ²⁰⁴Bi | β⁺; α | Activation | R. (Wikipedia) |
| ²⁰⁹At | 85 | 209 | No | 5.41 h | β⁺ (96.1%) → ²⁰⁹Po; α (3.9%) → ²⁰⁵Bi | β⁺; α | Activation | R. (Wikipedia) |
| ²¹⁰At | 85 | 210 | No | 8.1 h | β⁺ (99.8%) → ²¹⁰Po; α (0.175%) → ²⁰⁶Bi | β⁺; α | Cyclotron | Co‑produced with ²¹¹At; impurity of concern due to ²¹⁰Po daughter. R/M (production control). (Wikipedia, PMC) |
| ²¹¹At | 85 | 211 | No | 7.214 h | EC (58.2%) → ²¹¹Po; α (41.8%) → ²⁰⁷Bi | EC; α | Cyclotron ²⁰⁹Bi(α,2n) | Targeted α‑therapy radionuclide; branching per LNHB/KAERI; production & clinical reviews cited. M. (LNHB, atom.kaeri.re.kr, PMC) |
| ²¹²At | 85 | 212 | No | 314(3) ms | α → ²⁰⁸Bi | α | Activation | Ultra‑fast α; NNDC sheets. R. (Wikipedia) |
| ²¹³At | 85 | 213 | No | 125(6) ns | α → ²⁰⁹Bi | α | Activation | Shortest‑lived At; α to long‑lived ²⁰⁹Bi. R. (Wikipedia) |
| ²¹⁴At | 85 | 214 | No | 558(10) ns | α → ²¹⁰Bi | α | Activation | Fast‑timing α benchmark. R. (Wikipedia) |
| ²¹⁵At | 85 | 215 | No | 37(3) µs | α → ²¹¹Bi | α | Natural (U‑235 series; trace) | Chain member (trace). R. (Wikipedia) |
| ²¹⁶At | 85 | 216 | No | 300(30) µs | α → ²¹²Bi | α | Activation | R (near magic region). (Wikipedia) |
| ²¹⁷At | 85 | 217 | No | 32.6(3) ms | α (99.992%) → ²¹³Bi; β⁻ (0.008%) → ²¹⁷Rn | α; β⁻ | Natural (Np‑237 series; trace) | Rare chain branch. R. (Wikipedia) |
| ²¹⁸At | 85 | 218 | No | 1.28(6) s | α (~100%) → ²¹⁴Bi; β⁻ (?) → ²¹⁸Rn | α; β⁻ | Natural (U‑238 series; trace) | Chain member. R. (Wikipedia) |
| ²¹⁹At | 85 | 219 | No | 56(3) s | α (93.6%) → ²¹⁵Bi; β⁻ (6.4%) → ²¹⁹Rn | α; β⁻ | Natural (U‑235 series; trace) | Longest‑lived natural At in decay chains. R. (Wikipedia) |
| ²²⁰At | 85 | 220 | No | 3.71(4) min | β⁻ (92%) → ²²⁰Rn; α (8%) → ²¹⁶Bi | β⁻; α | Fragmentation/activation | R. (Wikipedia) |
| ²²¹At | 85 | 221 | No | 2.3(2) min | β⁻ → ²²¹Rn | β⁻ | Fragmentation | R. (Wikipedia) |
| ²²²At | 85 | 222 | No | 54(10) s | β⁻ → ²²²Rn | β⁻ | Fragmentation | R. (Wikipedia) |
| ²²³At | 85 | 223 | No | 50(7) s | β⁻ → ²²³Rn | β⁻ | Fragmentation | R. (Wikipedia) |
| ²²⁴At | 85 | 224 | No | 2.5 ± 1.5 min | β⁻ → ²²⁴Rn | β⁻ | Fragmentation | R. (Wikipedia) |
| ²²⁵At | 85 | 225 | No | ≈ 3 s (#) | β⁻? → ²²⁵Rn | β⁻? | Fragmentation | R (near drip line). (Wikipedia) |
| ²²⁶At | 85 | 226 | No | ≈ 7 min (#) | β⁻? → ²²⁶Rn | β⁻? | Fragmentation | R. (Wikipedia) |
| ²²⁷At | 85 | 227 | No | ≈ 5 s (#) | β⁻? → ²²⁷Rn | β⁻? | Fragmentation | R. (Wikipedia) |
| ²²⁸At | 85 | 228 | No | ≈ 1 min (#) | β⁻? → ²²⁸Rn | β⁻? | Fragmentation | R. (Wikipedia) |
| ²²⁹At | 85 | 229 | No | ≈ 1 s (#) | β⁻? → ²²⁹Rn | β⁻? | Fragmentation | R. (Wikipedia) |
Undiscovered mass number: ¹⁸⁹At (no confirmed ground state). The known At isotopes cover A = 188 and 190–229. (Wikipedia)
Applied & research highlights (At‑specific)
- ²¹¹At (7.214 h; EC 58.2% / α 41.8%) is a leading targeted α‑therapy radionuclide: well‑defined branching (LNHB/KAERI), cyclotron production via ²⁰⁹Bi(α,2n)²¹¹At, and an active clinical/preclinical pipeline (PSMA/PSCA vectors, minibodies, peptides). Key constraints: limited cyclotron availability and control of ²¹⁰At/²¹⁰Po impurity. Refs: decay data & branching (LNHB, KAERI); production & availability reviews; chemistry/radiolabeling and clinical trial overviews. (LNHB, atom.kaeri.re.kr, PMC, SpringerOpen, MDPI)
- ²¹⁰At (8.1 h) is co‑produced in higher‑energy α‑irradiations of Bi; it predominantly yields ²¹⁰Po, a hematopoietic toxin—hence tight energy‑window control in targetry. (PMC)
- Frontier nuclei. ¹⁹⁰At (2023) and ¹⁸⁸At (2025) mark the rapidly evolving proton‑rich edge; ¹⁸⁸At is an unusual case with competitive proton emission and α decay. (Wikipedia)
Totals — Astatine (Z = 85)
- Ground‑state isotopes listed: 41 (A = 188, 190–229).
- Stable (ground states): 0.
- Unstable (ground states): 41.
(All counts from the evaluated At table.) (Wikipedia)
Running cumulative totals (through At):
Prior ledger (through Po): ≥ 2 733 total, 251 stable, ≥ 2 481 unstable.
Add At (+41 total, +0 stable, +41 unstable) → ≥ 2 774 total, 251 stable, ≥ 2 522 unstable.
Sources (load‑bearing)
- Comprehensive half‑lives/branches/daughters; full list A = 188, 190–229: Isotopes of astatine (updated; NUBASE 2020/AME 2020 backbone). (Wikipedia)
- ²¹¹At decay branching: LNHB At‑211 evaluation; KAERI nuclide data. (LNHB, atom.kaeri.re.kr)
- ²¹¹At production & clinical context: Zalutsky (2011) and later reviews; 2020–2025 chemistry/clinical overviews; GMP formulations. (PMC, ScienceDirect, MDPI, SpringerOpen)
- Edge discoveries: ¹⁸⁸At proton emitter (Nature Communications, 2025); ¹⁹⁰At α‑decayer (PRC, 2023). (Wikipedia)
Next element: Radon (Rn, Z = 86).