# Isotopes of niobium

Naturally occurring niobium ($_{41}$Nb) is composed of one stable isotope ($^{93}$Nb). The most stable radioisotope is $^{92}$Nb with a half-life of 34.7 million years. The next longest-lived niobium isotopes are $^{94}$Nb (half-life: 20,300 years) and $^{91}$Nb with a half-life of 680 years. There is also a meta state of $^{93}$Nb at 31 keV whose half-life is 16.13 years. Twenty-seven other radioisotopes have been characterized. Most of these have half-lives that are less than two hours, except $^{95}$Nb (35 days), $^{96}$Nb (23.4 hours) and $^{90}$Nb (14.6 hours). The primary decay mode before stable $^{93}$Nb is electron capture and the primary mode after is beta emission with some neutron emission occurring in $^{104–110}$Nb.
Only $^{95}$Nb (35 days) and $^{97}$Nb (72 minutes) and heavier isotopes (half-lives in seconds) are fission products in significant quantity, as the other isotopes are shadowed by stable or very long-lived ($^{93}$Zr) isotopes of the preceding element zirconium from production via beta decay of neutron-rich fission fragments. $^{95}$Nb is the decay product of $^{95}$Zr (64 days), so disappearance of $^{95}$Nb in used nuclear fuel is slower than would be expected from its own 35-day half-life alone. Small amounts of other isotopes may be produced as direct fission products.

## List of isotopes

| Nuclide | Z | N | Isotopic mass (Da) | Half-life | Decay mode | Daughter isotope | Spin and parity | Isotopic abundance |
| Isotopic abundance |||
| $^{82}$Nb | 41 | 41 | 81.94438(32) | 51(5) ms | β$^+$ | $^{82}$Zr | (0+) | |
| $^{82m}$Nb | 1180(1) keV | 1180(1) keV | 1180(1) keV | 93(20) ns | IT | $^{82}$Nb | (5+) | |
| $^{83}$Nb | 41 | 42 | 82.93815(17) | 3.9(2) s | β$^+$ | $^{83}$Zr | 9/2+# | |
| $^{84}$Nb | 41 | 43 | 83.93430571(43) | 9.8(9) s | β$^+$ | $^{84}$Zr | (1+) | |
| $^{84m1}$Nb | 48(1) keV | 48(1) keV | 48(1) keV | 176(46) ns | IT | $^{84}$Nb | (3+) | |
| $^{84m2}$Nb | 337.7(4) keV | 337.7(4) keV | 337.7(4) keV | 92(5) ns | IT | $^{84}$Nb | (5−) | |
| $^{85}$Nb | 41 | 44 | 84.9288458(44) | 20.5(7) s | β$^+$ | $^{85}$Zr | 9/2+# | |
| $^{85m}$Nb | 150(80)# keV | 150(80)# keV | 150(80)# keV | 3.3(9) s | IT (?%) | $^{85}$Nb | (1/2−) | |
| $^{85m}$Nb | 150(80)# keV | 150(80)# keV | 150(80)# keV | 3.3(9) s | β$^+$ (?%) | $^{85}$Zr | (1/2−) | |
| $^{86}$Nb | 41 | 45 | 85.9257815(59) | 88(1) s | β$^+$ | $^{86}$Zr | (6+) | |
| $^{86m}$Nb | 150(100)# keV | 150(100)# keV | 150(100)# keV | 20# s | β$^+$ | $^{86}$Zr | (0−,1−,2−) | |
| $^{87}$Nb | 41 | 46 | 86.9206925(73) | 3.7(1) min | β$^+$ | $^{87}$Zr | (1/2)− | |
| $^{87m}$Nb | 3.9(1) keV | 3.9(1) keV | 3.9(1) keV | 2.6(1) min | β$^+$ | $^{87}$Zr | (9/2)+ | |
| $^{88}$Nb | 41 | 47 | 87.918226(62) | 14.50(11) min | β$^+$ | $^{88}$Zr | (8+) | |
| $^{88m}$Nb | 130(120) keV | 130(120) keV | 130(120) keV | 7.7(1) min | β$^+$ | $^{88}$Zr | (4−) | |
| $^{89}$Nb | 41 | 48 | 88.913445(25) | 2.03(7) h | β$^+$ | $^{89}$Zr | (9/2+) | |
| $^{89m}$Nb | 0(30)# keV | 0(30)# keV | 0(30)# keV | 1.10(3) h | β$^+$ | $^{89}$Zr | (1/2)− | |
| $^{90}$Nb | 41 | 49 | 89.9112592(36) | 14.60(5) h | β$^+$ | $^{90}$Zr | 8+ | |
| $^{90m1}$Nb | 122.370(22) keV | 122.370(22) keV | 122.370(22) keV | 63(2) μs | IT | $^{90}$Nb | 6+ | |
| $^{90m2}$Nb | 124.67(25) keV | 124.67(25) keV | 124.67(25) keV | 18.81(6) s | IT | $^{90}$Nb | 4- | |
| $^{90m3}$Nb | 171.10(10) keV | 171.10(10) keV | 171.10(10) keV | <1 μs | IT | $^{90}$Nb | 7+ | |
| $^{90m4}$Nb | 382.01(25) keV | 382.01(25) keV | 382.01(25) keV | 6.19(8) ms | IT | $^{90m1}$Nb | 1+ | |
| $^{90m5}$Nb | 1880.21(20) keV | 1880.21(20) keV | 1880.21(20) keV | 471(6) ns | IT | $^{90}$Nb | (11−) | |
| $^{91}$Nb | 41 | 50 | 90.9069903(31) | 680(130) y | EC (99.99%) | $^{91}$Zr | 9/2+ | |
| $^{91}$Nb | 41 | 50 | 90.9069903(31) | 680(130) y | β$^+$ (0.0138%) | $^{91}$Zr | 9/2+ | |
| $^{91m1}$Nb | 104.60(5) keV | 104.60(5) keV | 104.60(5) keV | 60.86(22) d | IT (96.6%) | $^{91}$Nb | 1/2− | |
| $^{91m1}$Nb | 104.60(5) keV | 104.60(5) keV | 104.60(5) keV | 60.86(22) d | EC (3.4%) | $^{91}$Zr | 1/2− | |
| $^{91m1}$Nb | 104.60(5) keV | 104.60(5) keV | 104.60(5) keV | 60.86(22) d | β$^+$ (.0028%) | $^{91}$Zr | 1/2− | |
| $^{91m2}$Nb | 2034.42(20) keV | 2034.42(20) keV | 2034.42(20) keV | 3.76(12) μs | IT | $^{91}$Nb | (17/2−) | |
| $^{92}$Nb | 41 | 51 | 91.9071886(19) | 3.47(24)×10$^7$ y | β$^+$ | $^{92}$Zr | 7+ | Trace |
| $^{92m1}$Nb | 135.5(4) keV | 135.5(4) keV | 135.5(4) keV | 10.116(13) d | β$^+$ | $^{92}$Zr | (2)+ | |
| $^{92m2}$Nb | 225.8(4) keV | 225.8(4) keV | 225.8(4) keV | 5.9(2) μs | IT | $^{92}$Nb | (2)− | |
| $^{92m3}$Nb | 2203.3(4) keV | 2203.3(4) keV | 2203.3(4) keV | 167(4) ns | IT | $^{92}$Nb | (11−) | |
| $^{93}$Nb | 41 | 52 | 92.9063732(16) | Stable | Stable | Stable | 9/2+ | 1.0000 |
| $^{93m1}$Nb | 30.760(5) keV | 30.760(5) keV | 30.760(5) keV | 16.12(12) y | IT | $^{93}$Nb | 1/2− | |
| $^{93m2}$Nb | 7460(17) keV | 7460(17) keV | 7460(17) keV | 1.5(5) μs | IT | $^{93}$Nb | 33/2−# | |
| $^{94}$Nb | 41 | 53 | 93.9072790(16) | 2.04(4)×10$^4$ y | β$^−$ | $^{94}$Mo | 6+ | Trace |
| $^{94m}$Nb | 40.892(12) keV | 40.892(12) keV | 40.892(12) keV | 6.263(4) min | IT (99.50%) | $^{94}$Nb | 3+ | |
| $^{94m}$Nb | 40.892(12) keV | 40.892(12) keV | 40.892(12) keV | 6.263(4) min | β$^−$ (0.50%) | $^{94}$Mo | 3+ | |
| $^{95}$Nb | 41 | 54 | 94.90683111(55) | 34.991(6) d | β$^−$ | $^{95}$Mo | 9/2+ | |
| $^{95m}$Nb | 235.69(2) keV | 235.69(2) keV | 235.69(2) keV | 3.61(3) d | IT (94.4%) | $^{95}$Nb | 1/2− | |
| $^{95m}$Nb | 235.69(2) keV | 235.69(2) keV | 235.69(2) keV | 3.61(3) d | β$^−$ (5.6%) | $^{95}$Mo | 1/2− | |
| $^{96}$Nb | 41 | 55 | 95.90810159(16) | 23.35(5) h | β$^−$ | $^{96}$Mo | 6+ | |
| $^{97}$Nb | 41 | 56 | 96.9081016(46) | 72.1(7) min | β$^−$ | $^{97}$Mo | 9/2+ | |
| $^{97m}$Nb | 743.35(3) keV | 743.35(3) keV | 743.35(3) keV | 58.7(18) s | IT | $^{97}$Nb | 1/2− | |
| $^{98}$Nb | 41 | 57 | 97.9103326(54) | 2.86(6) s | β$^−$ | $^{98}$Mo | 1+ | |
| $^{98m}$Nb | 84(4) keV | 84(4) keV | 84(4) keV | 51.1(4) min | β$^−$ | $^{98}$Mo | (5)+ | |
| $^{99}$Nb | 41 | 58 | 98.911609(13) | 15.0(2) s | β$^−$ | $^{99}$Mo | 9/2+ | |
| $^{99m}$Nb | 365.27(8) keV | 365.27(8) keV | 365.27(8) keV | 2.5(2) min | β$^−$ (?%) | $^{99}$Mo | 1/2− | |
| $^{99m}$Nb | 365.27(8) keV | 365.27(8) keV | 365.27(8) keV | 2.5(2) min | IT (?%) | $^{99}$Nb | 1/2− | |
| $^{100}$Nb | 41 | 59 | 99.9143406(86) | 1.5(2) s | β$^−$ | $^{100}$Mo | 1+ | |
| $^{100m1}$Nb | 313(8) keV | 313(8) keV | 313(8) keV | 2.99(11) s | β$^−$ | $^{100}$Mo | (5+) | |
| $^{100m2}$Nb | 347(8) keV | 347(8) keV | 347(8) keV | 460(60) ns | IT | $^{100}$Nb | (4−,5−) | |
| $^{100m3}$Nb | 734(8) keV | 734(8) keV | 734(8) keV | 12.43(26) μs | IT | $^{100}$Nb | (8−) | |
| $^{101}$Nb | 41 | 60 | 100.9153065(40) | 7.1(3) s | β$^−$ | $^{101}$Mo | 5/2+ | |
| $^{102}$Nb | 41 | 61 | 101.9180904(27) | 4.3(4) s | β$^−$ | $^{102}$Mo | (4+) | |
| $^{102m}$Nb | 94(7) keV | 94(7) keV | 94(7) keV | 1.31(16) s | β$^−$ | $^{102}$Mo | (1+) | |
| $^{103}$Nb | 41 | 62 | 102.9194534(42) | 1.34(7) s | β$^−$ | $^{103}$Mo | 5/2+ | |
| $^{104}$Nb | 41 | 63 | 103.9229077(19) | 0.98(5) s | β$^−$ (99.95%) | $^{104}$Mo | (1+) | |
| $^{104}$Nb | 41 | 63 | 103.9229077(19) | 0.98(5) s | β$^−$, n (0.05%) | $^{103}$Mo | (1+) | |
| $^{104m}$Nb | 9.8(26) keV | 9.8(26) keV | 9.8(26) keV | 4.9(3) s | β$^−$ (99.94%) | $^{104}$Mo | (0−,1−) | |
| $^{104m}$Nb | 9.8(26) keV | 9.8(26) keV | 9.8(26) keV | 4.9(3) s | β$^−$, n (0.06%) | $^{103}$Mo | (0−,1−) | |
| $^{105}$Nb | 41 | 64 | 104.9249426(43) | 2.91(5) s | β$^−$ (98.3%) | $^{105}$Mo | (5/2+) | |
| $^{105}$Nb | 41 | 64 | 104.9249426(43) | 2.91(5) s | β$^−$, n (1.7%) | $^{104}$Mo | (5/2+) | |
| $^{106}$Nb | 41 | 65 | 105.9289285(15) | 900(20) ms | β$^−$ (95.5%) | $^{106}$Mo | 1−# | |
| $^{106}$Nb | 41 | 65 | 105.9289285(15) | 900(20) ms | β$^−$, n (4.5%) | $^{105}$Mo | 1−# | |
| $^{106m1}$Nb | 100(50)# keV | 100(50)# keV | 100(50)# keV | 1.20(6) s | β$^−$ | $^{106}$Mo | (4−) | |
| $^{106m2}$Nb | 204.8(5) keV | 204.8(5) keV | 204.8(5) keV | 820(38) ns | IT | $^{106}$Nb | (3+) | |
| $^{107}$Nb | 41 | 66 | 106.9315897(86) | 286(8) ms | β$^−$ (92.6%) | $^{107}$Mo | (5/2+) | |
| $^{107}$Nb | 41 | 66 | 106.9315897(86) | 286(8) ms | β$^−$, n (7.4%) | $^{106}$Mo | (5/2+) | |
| $^{108}$Nb | 41 | 67 | 107.9360756(88) | 201(4) ms | β$^−$ (93.7%) | $^{108}$Mo | (2+) | |
| $^{108}$Nb | 41 | 67 | 107.9360756(88) | 201(4) ms | β$^−$, n (6.3%) | $^{107}$Mo | (2+) | |
| $^{108m}$Nb | 166.6(5) keV | 166.6(5) keV | 166.6(5) keV | 109(2) ns | IT | $^{109}$Nb | 6−# | |
| $^{109}$Nb | 41 | 68 | 108.93914(46) | 106.9(49) ms | β$^−$ (69%) | $^{109}$Mo | 3/2−# | |
| $^{109}$Nb | 41 | 68 | 108.93914(46) | 106.9(49) ms | β$^−$, n (31%) | $^{108}$Mo | 3/2−# | |
| $^{109m}$Nb | 312.5(4) keV | 312.5(4) keV | 312.5(4) keV | 115(8) ns | IT | $^{109}$Nb | 7/2+# | |
| $^{110}$Nb | 41 | 69 | 109.94384(90) | 75(1) ms | β$^−$ (60%) | $^{110}$Mo | 5+# | |
| $^{110}$Nb | 41 | 69 | 109.94384(90) | 75(1) ms | β$^−$, n (40%) | $^{109}$Mo | 5+# | |
| $^{110m}$Nb | 100(50)# keV | 100(50)# keV | 100(50)# keV | 94(9) ms | β$^−$ (60%) | $^{104}$Mo | 2+# | |
| $^{110m}$Nb | 100(50)# keV | 100(50)# keV | 100(50)# keV | 94(9) ms | β$^−$, n (40%) | $^{103}$Mo | 2+# | |
| $^{111}$Nb | 41 | 70 | 110.94744(32)# | 54(2) ms | β$^−$ | $^{111}$Mo | 3/2−# | |
| $^{112}$Nb | 41 | 71 | 111.95269(32)# | 38(2) ms | β$^−$ | $^{112}$Mo | 1+# | |
| $^{113}$Nb | 41 | 72 | 112.95683(43)# | 32(4) ms | β$^−$ | $^{113}$Mo | 3/2−# | |
| $^{114}$Nb | 41 | 73 | 113.96247(54)# | 17(5) ms | β$^−$ | $^{114}$Mo | 2−# | |
| $^{115}$Nb | 41 | 74 | 114.96685(54)# | 23(8) ms | β$^−$ | $^{115}$Mo | 3/2−# | |
| $^{116}$Nb | 41 | 75 | 115.97291(32)# | 12# ms [>550 ns] | | | 1−# | |
| $^{117}$Nb | 41 | 76 | | | | | | |
| This table header & footer: view |||||||||
* ↑ $^m$Nb – Excited nuclear isomer.
* ↑ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
* ↑ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
* 1 2 3 # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
* ↑ Modes of decay: EC:Electron capture IT:Isomeric transition n:Neutron emission p:Proton emission
* ↑ Bold italics symbol as daughter – Daughter product is nearly stable.
* ↑ Bold symbol as daughter – Daughter product is stable.
* ↑ ( ) spin value – Indicates spin with weak assignment arguments.
* 1 2 3 4 5 Order of ground state and isomer is uncertain.

## Niobium-92

Niobium-92 is an extinct radionuclide with a half-life of 34.7 million years, decaying predominantly via β$^+$ decay. Its abundance relative to the stable $^{93}$Nb in the early Solar System, estimated at 1.7×10$^{−5}$, has been measured to investigate the origin of p-nuclei. A higher initial abundance of $^{92}$Nb has been estimated for material in the outer protosolar disk (sampled from the meteorite NWA 6704), suggesting that this nuclide was predominantly formed via the gamma process (photodisintegration) in a nearby core-collapse supernova.
Niobium-92, along with niobium-94, has been detected in refined samples of terrestrial niobium and may originate from bombardment by cosmic ray muons in Earth's crust.