⁸¹Nb — Unstable · t½ ≈ 420 ms · Decay: β⁺ → ⁸¹Zr · Type: synthetic · Uses: research.
⁸²Nb — Unstable · t½ ≈ 130 ms · Decay: β⁺ → ⁸²Zr · Type: synthetic · Uses: research.
⁸³Nb — Unstable · t½ ≈ 3.5 s · Decay: β⁺ → ⁸³Zr · Type: synthetic · Uses: research.
⁸⁴Nb — Unstable · t½ ≈ 10.3 s · Decay: β⁺ → ⁸⁴Zr · Type: synthetic · Uses: research.
⁸⁵Nb — Unstable · t½ ≈ 20.9 s · Decay: β⁺ → ⁸⁵Zr · Type: synthetic · Uses: research.
⁸⁶Nb — Unstable · t½ ≈ 103 s · Decay: β⁺ → ⁸⁶Zr · Type: synthetic · Uses: research.
⁸⁷Nb — Unstable · t½ ≈ 3.75 min · Decay: β⁺ → ⁸⁷Zr · Type: synthetic · Uses: research.
⁸⁸Nb — Unstable · t½ ≈ 14.5 min · Decay: β⁺ → ⁸⁸Zr · Type: activation product · Uses: tracer.
⁸⁹Nb — Unstable · t½ ≈ 2.03 h · Decay: β⁺ → ⁸⁹Zr · Type: activation · Uses: tracer.
⁹⁰Nb — Unstable · t½ ≈ 14.6 h · Decay: β⁻ → ⁹⁰Mo · Type: activation product · Uses: tracer.
⁹¹Nb — Unstable · t½ ≈ 680 y · Decay: β⁻ → ⁹¹Mo · Type: cosmogenic · Uses: long-term geophysical tracer.
⁹²Nb — Unstable · t½ ≈ 3.5×10⁷ y · Decay: β⁻ → ⁹²Mo · Type: extinct radionuclide · Uses: early solar system chronometer.
⁹³Nb — Stable · — · Type: stable (primordial, only stable isotope) · Uses: alloys, superconductors, nuclear reactors.
⁹⁴Nb — Unstable · t½ ≈ 20.3 kyr · Decay: β⁻ → ⁹⁴Mo · Type: cosmogenic · Uses: geochronology.
⁹⁵Nb — Unstable · t½ ≈ 35 d · Decay: β⁻ → ⁹⁵Mo · Type: fission product · Uses: reactor monitoring.
⁹⁶Nb — Unstable · t½ ≈ 23.4 h · Decay: β⁻ → ⁹⁶Mo · Type: activation product · Uses: tracer.
⁹⁷Nb — Unstable · t½ ≈ 72 min · Decay: β⁻ → ⁹⁷Mo · Type: activation · Uses: tracer.
⁹⁸Nb — Unstable · t½ ≈ 51 min · Decay: β⁻ → ⁹⁸Mo · Type: synthetic · Uses: research.
⁹⁹Nb — Unstable · t½ ≈ 15 s · Decay: β⁻ → ⁹⁹Mo · Type: synthetic · Uses: research.
¹⁰⁰Nb — Unstable · t½ ≈ 1.5 s · Decay: β⁻ → ¹⁰⁰Mo · Type: synthetic · Uses: research.
¹⁰¹Nb — Unstable · t½ ≈ 0.7 s · Decay: β⁻ → ¹⁰¹Mo · Type: synthetic · Uses: research.
¹⁰²Nb — Unstable · t½ ≈ 2.5 s · Decay: β⁻ → ¹⁰²Mo · Type: synthetic · Uses: research.
¹⁰³Nb — Unstable · t½ ≈ 1.5 s · Decay: β⁻ → ¹⁰³Mo · Type: synthetic · Uses: research.
¹⁰⁴Nb — Unstable · t½ ≈ 1.0 s · Decay: β⁻ → ¹⁰⁴Mo · Type: synthetic · Uses: research.
¹⁰⁵Nb — Unstable · t½ ≈ 620 ms · Decay: β⁻ → ¹⁰⁵Mo · Type: synthetic · Uses: research.
¹⁰⁶Nb — Unstable · t½ ≈ 460 ms · Decay: β⁻ → ¹⁰⁶Mo · Type: synthetic · Uses: research.
¹⁰⁷Nb — Unstable · t½ ≈ 340 ms · Decay: β⁻ → ¹⁰⁷Mo · Type: synthetic · Uses: research.
¹⁰⁸Nb — Unstable · t½ ≈ 250 ms · Decay: β⁻ → ¹⁰⁸Mo · Type: synthetic · Uses: research.
¹⁰⁹Nb — Unstable · t½ ≈ 200 ms · Decay: β⁻ → ¹⁰⁹Mo · Type: synthetic · Uses: research.
¹¹⁰Nb — Unstable · t½ ≈ 140 ms · Decay: β⁻ → ¹¹⁰Mo · Type: synthetic · Uses: research.
¹¹¹Nb — Unstable · t½ ≈ 110 ms · Decay: β⁻ → ¹¹¹Mo · Type: synthetic · Uses: research.
¹¹²Nb — Unstable · t½ ≈ 85 ms · Decay: β⁻ → ¹¹²Mo · Type: synthetic · Uses: research.
¹¹³Nb — Unstable · t½ ≈ 65 ms · Decay: β⁻ → ¹¹³Mo · Type: synthetic · Uses: research.
¹¹⁴Nb — Unstable · t½ ≈ 50 ms · Decay: β⁻ → ¹¹⁴Mo · Type: synthetic · Uses: research.
¹¹⁵Nb — Unstable · t½ ≈ 40 ms · Decay: β⁻ → ¹¹⁵Mo · Type: synthetic · Uses: research.

Niobium — isotope count: 35 total · Stable: 1 (⁹³Nb) · Unstable: 34.
(Data: IAEA LiveChart, NUBASE2020, ENSDF; notable applications: ⁸⁹Zr/⁹³Nb alloys, ⁸⁹Zr-PET, long-lived ⁹³Nb stable use in superconductors, extinct ⁹²Nb in cosmochemistry.)