¹⁴⁵Tm — Unstable · t½ ≈ 400 ms · Decay: β⁺ → ¹⁴⁵Er · Type: synthetic · Uses: research.
¹⁴⁶Tm — Unstable · t½ ≈ 2.0 s · Decay: β⁺ → ¹⁴⁶Er · Type: synthetic · Uses: research.
¹⁴⁷Tm — Unstable · t½ ≈ 3.0 s · Decay: β⁺ → ¹⁴⁷Er · Type: synthetic · Uses: research.
¹⁴⁸Tm — Unstable · t½ ≈ 2.7 s · Decay: β⁺ → ¹⁴⁸Er · Type: synthetic · Uses: research.
¹⁴⁹Tm — Unstable · t½ ≈ 5.0 s · Decay: β⁺ → ¹⁴⁹Er · Type: synthetic · Uses: research.
¹⁵⁰Tm — Unstable · t½ ≈ 9.0 s · Decay: β⁺ → ¹⁵⁰Er · Type: synthetic · Uses: research.
¹⁵¹Tm — Unstable · t½ ≈ 20.0 s · Decay: β⁺ → ¹⁵¹Er · Type: synthetic · Uses: research.
¹⁵²Tm — Unstable · t½ ≈ 8.0 s · Decay: β⁺ → ¹⁵²Er · Type: synthetic · Uses: research.
¹⁵³Tm — Unstable · t½ ≈ 23.0 s · Decay: β⁺ → ¹⁵³Er · Type: synthetic · Uses: research.
¹⁵⁴Tm — Unstable · t½ ≈ 3.0 min · Decay: β⁺ → ¹⁵⁴Er · Type: synthetic · Uses: research.
¹⁵⁵Tm — Unstable · t½ ≈ 1.7 min · Decay: β⁺ → ¹⁵⁵Er · Type: synthetic · Uses: research.
¹⁵⁶Tm — Unstable · t½ ≈ 1.0 min · Decay: β⁺ → ¹⁵⁶Er · Type: synthetic · Uses: research.
¹⁵⁷Tm — Unstable · t½ ≈ 3.6 min · Decay: β⁺ → ¹⁵⁷Er · Type: synthetic · Uses: research.
¹⁵⁸Tm — Unstable · t½ ≈ 3.0 min · Decay: β⁺ → ¹⁵⁸Er · Type: synthetic · Uses: research.
¹⁵⁹Tm — Unstable · t½ ≈ 9.1 min · Decay: β⁺ → ¹⁵⁹Er · Type: synthetic · Uses: research.
¹⁶⁰Tm — Unstable · t½ ≈ 9.4 min · Decay: β⁺ → ¹⁶⁰Er · Type: synthetic · Uses: research.
¹⁶¹Tm — Unstable · t½ ≈ 30.2 min · Decay: β⁻ → ¹⁶¹Yb · Type: synthetic · Uses: research.
¹⁶²Tm — Unstable · t½ ≈ 8.2 min · Decay: β⁻ → ¹⁶²Yb · Type: synthetic · Uses: research.
¹⁶³Tm — Unstable · t½ ≈ 1.8 h · Decay: β⁻ → ¹⁶³Yb · Type: synthetic · Uses: research.
¹⁶⁴Tm — Unstable · t½ ≈ 2.0 min · Decay: β⁻ → ¹⁶⁴Yb · Type: synthetic · Uses: research.
¹⁶⁵Tm — Unstable · t½ ≈ 30.1 h · Decay: β⁻ → ¹⁶⁵Yb · Type: tracer · Uses: nuclear physics.
¹⁶⁶Tm — Unstable · t½ ≈ 7.7 h · Decay: β⁻ → ¹⁶⁶Yb · Type: tracer · Uses: nuclear physics.
¹⁶⁷Tm — Unstable · t½ ≈ 9.3 d · Decay: β⁻ → ¹⁶⁷Yb · Type: tracer · Uses: nuclear physics.
¹⁶⁸Tm — Unstable · t½ ≈ 93.1 d · Decay: β⁻ → ¹⁶⁸Yb · Type: tracer · Uses: nuclear physics.
¹⁶⁹Tm — Stable · — · Type: stable (primordial, only stable isotope) · Uses: isotope tracer, nuclear physics, lasers.
¹⁷⁰Tm — Unstable · t½ ≈ 128.6 d · Decay: β⁻ → ¹⁷⁰Yb · Type: tracer · Uses: research.
¹⁷¹Tm — Unstable · t½ ≈ 1.9 y · Decay: β⁻ → ¹⁷¹Yb · Type: tracer · Uses: research.
¹⁷²Tm — Unstable · t½ ≈ 63.6 h · Decay: β⁻ → ¹⁷²Yb · Type: tracer · Uses: nuclear physics.
¹⁷³Tm — Unstable · t½ ≈ 8.2 h · Decay: β⁻ → ¹⁷³Yb · Type: synthetic · Uses: research.
¹⁷⁴Tm — Unstable · t½ ≈ 5.8 h · Decay: β⁻ → ¹⁷⁴Yb · Type: synthetic · Uses: research.
¹⁷⁵Tm — Unstable · t½ ≈ 15.2 h · Decay: β⁻ → ¹⁷⁵Yb · Type: synthetic · Uses: research.
¹⁷⁶Tm — Unstable · t½ ≈ 5.2 h · Decay: β⁻ → ¹⁷⁶Yb · Type: synthetic · Uses: research.
¹⁷⁷Tm — Unstable · t½ ≈ 9.3 h · Decay: β⁻ → ¹⁷⁷Yb · Type: synthetic · Uses: research.
¹⁷⁸Tm — Unstable · t½ ≈ 2.2 h · Decay: β⁻ → ¹⁷⁸Yb · Type: synthetic · Uses: research.
¹⁷⁹Tm — Unstable · t½ ≈ 1.6 h · Decay: β⁻ → ¹⁷⁹Yb · Type: synthetic · Uses: research.
Thulium — isotope count: 35 total · Stable: 1 (¹⁶⁹Tm) · Unstable: 34.
(Data: IAEA LiveChart, NUBASE2020, ENSDF; notable applications: ¹⁶⁹Tm in lasers and isotope tracers, ¹⁶⁵–¹⁶⁸Tm in nuclear physics, long-lived Tm isotopes for tracer studies.)