Naturally occurring niobium (₄₁Nb) is composed of one stable isotope (⁹³Nb). The most stable radioisotope is ⁹²Nb with a half-life of 34.7 million years. The next longest-lived niobium isotopes are ⁹⁴Nb (half-life: 20,300 years) and ⁹¹Nb with a half-life of 680 years. There is also a meta state of ⁹³Nb at 31 electronvolt, 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 ⁹⁵Nb (35 days), ⁹⁶Nb (23.4 hours) and ⁹⁰Nb (14.6 hours). The primary decay mode before stable ⁹³Nb is electron capture and the primary mode after is beta emission with some neutron emission occurring in ^104–110Nb. Only ⁹⁵Nb (35 days) and ⁹⁷Nb (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 (Zirconium-93, ⁹³Zr) isotopes of the preceding element zirconium from production via beta decay of neutron-rich fission fragments. ⁹⁵Nb is the decay product of ⁹⁵Zr (64 days), so disappearance of ⁹⁵Nb 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

, - , rowspan=3, ⁸¹Nb , rowspan=3 style="text-align:right" , 41 , rowspan=3 style="text-align:right" , 40 , rowspan=3, 80.94903(161)# , rowspan=3, <44 ns , beta decay, β⁺, proton emission, p , ⁸⁰Y , rowspan=3, 3/2−# , rowspan=3, , rowspan=3, , - , p , ⁸⁰Zr , - , β⁺ , ⁸¹Zr , - , ⁸²Nb , style="text-align:right" , 41 , style="text-align:right" , 41 , 81.94313(32)# , 51(5) ms , β⁺ , ⁸²Zr , 0+ , , , - , ⁸³Nb , style="text-align:right" , 41 , style="text-align:right" , 42 , 82.93671(34) , 4.1(3) s , β⁺ , ⁸³Zr , (5/2+) , , , - , rowspan=2, ⁸⁴Nb , rowspan=2 style="text-align:right" , 41 , rowspan=2 style="text-align:right" , 43 , rowspan=2, 83.93357(32)# , rowspan=2, 9.8(9) s , β⁺ (>99.9%) , ⁸⁴Zr , rowspan=2, 3+ , rowspan=2, , rowspan=2, , - , β⁺, p (<.1%) , ⁸³Y , - , style="text-indent:1em" , ^84mNb , colspan="3" style="text-indent:2em" , 338(10) keV , 103(19) ns , , , (5−) , , , - , ⁸⁵Nb , style="text-align:right" , 41 , style="text-align:right" , 44 , 84.92791(24) , 20.9(7) s , β⁺ , ⁸⁵Zr , (9/2+) , , , - , style="text-indent:1em" , ^85mNb , colspan="3" style="text-indent:2em" , 759.0(10) keV , 12(5) s , , , (1/2−) , , , - , ⁸⁶Nb , style="text-align:right" , 41 , style="text-align:right" , 45 , 85.92504(9) , 88(1) s , β⁺ , ⁸⁶Zr , (6+) , , , - , style="text-indent:1em" , ^86mNb , colspan="3" style="text-indent:2em" , 250(160)# keV , 56(8) s , β⁺ , ⁸⁶Zr , high , , , - , ⁸⁷Nb , style="text-align:right" , 41 , style="text-align:right" , 46 , 86.92036(7) , 3.75(9) min , β⁺ , ⁸⁷Zr , (1/2−) , , , - , style="text-indent:1em" , ^87mNb , colspan="3" style="text-indent:2em" , 3.84(14) keV , 2.6(1) min , β⁺ , ⁸⁷Zr , (9/2+)# , , , - , ⁸⁸Nb , style="text-align:right" , 41 , style="text-align:right" , 47 , 87.91833(11) , 14.55(6) min , β⁺ , ⁸⁸Zr , (8+) , , , - , style="text-indent:1em" , ^88mNb , colspan="3" style="text-indent:2em" , 40(140) keV , 7.8(1) min , β⁺ , ⁸⁸Zr , (4−) , , , - , ⁸⁹Nb , style="text-align:right" , 41 , style="text-align:right" , 48 , 88.913418(29) , 2.03(7) h , β⁺ , ⁸⁹Zr , (9/2+) , , , - , style="text-indent:1em" , ^89mNb , colspan="3" style="text-indent:2em" , 0(30)# keV , 1.10(3) h , β⁺ , ⁸⁹Zr , (1/2)− , , , - , ⁹⁰Nb , style="text-align:right" , 41 , style="text-align:right" , 49 , 89.911265(5) , 14.60(5) h , β⁺ , ⁹⁰Zr , 8+ , , , - , style="text-indent:1em" , ^90m1Nb , colspan="3" style="text-indent:2em" , 122.370(22) keV , 63(2) μs , , , 6+ , , , - , style="text-indent:1em" , ^90m2Nb , colspan="3" style="text-indent:2em" , 124.67(25) keV , 18.81(6) s , Isomeric transition, IT , ⁹⁰Nb , 4- , , , - , style="text-indent:1em" , ^90m3Nb , colspan="3" style="text-indent:2em" , 171.10(10) keV , <1 μs , , , 7+ , , , - , style="text-indent:1em" , ^90m4Nb , colspan="3" style="text-indent:2em" , 382.01(25) keV , 6.19(8) ms , , , 1+ , , , - , style="text-indent:1em" , ^90m5Nb , colspan="3" style="text-indent:2em" , 1880.21(20) keV , 472(13) ns , , , (11−) , , , - , rowspan=2, ⁹¹Nb , rowspan=2 style="text-align:right" , 41 , rowspan=2 style="text-align:right" , 50 , rowspan=2, 90.906996(4) , rowspan=2, 680(130) a , Electron capture, EC (99.98%) , ⁹¹Zr , rowspan=2, 9/2+ , rowspan=2, , rowspan=2, , - , β⁺ (.013%) , ⁹¹Zr , - , rowspan=3 style="text-indent:1em" , ^91m1Nb , rowspan=3 colspan="3" style="text-indent:2em" , 104.60(5) keV , rowspan=3, 60.86(22) d , IT (93%) , ⁹¹Nb , rowspan=3, 1/2− , rowspan=3, , rowspan=3, , - , EC (7%) , ⁹¹Zr , - , β⁺ (.0028%) , ⁹¹Zr , - , style="text-indent:1em" , ^91m2Nb , colspan="3" style="text-indent:2em" , 2034.35(19) keV , 3.76(12) μs , , , (17/2−) , , , - , rowspan=2, ⁹²Nb , rowspan=2 style="text-align:right" , 41 , rowspan=2 style="text-align:right" , 51 , rowspan=2, 91.907194(3) , rowspan=2, 3.47(24)×10⁷ a , β⁺ (99.95%) , ⁹²Zr , rowspan=2, (7)+ , rowspan=2, , rowspan=2, , - , β⁻ (.05%) , ⁹²Mo , - , style="text-indent:1em" , ^92m1Nb , colspan="3" style="text-indent:2em" , 135.5(4) keV , 10.15(2) d , β⁺ , ⁹²Zr , (2)+ , , , - , style="text-indent:1em" , ^92m2Nb , colspan="3" style="text-indent:2em" , 225.7(4) keV , 5.9(2) μs , , , (2)− , , , - , style="text-indent:1em" , ^92m3Nb , colspan="3" style="text-indent:2em" , 2203.3(4) keV , 167(4) ns , , , (11−) , , , - , ⁹³Nb , style="text-align:right" , 41 , style="text-align:right" , 52 , 92.9063781(26) , colspan=3 align=center, StableTheoretically capable of spontaneous fission, lightest nuclide so capable , 9/2+ , 1.0000 , , - , style="text-indent:1em" , ^93mNb , colspan="3" style="text-indent:2em" , 30.77(2) keV , 16.13(14) a , IT , ⁹³Nb , 1/2− , , , - , ⁹⁴Nb , style="text-align:right" , 41 , style="text-align:right" , 53 , 93.9072839(26) , 2.03(16)×10⁴ a , β⁻ , ⁹⁴Mo , (6)+ , , , - , rowspan=2 style="text-indent:1em" , ^94mNb , rowspan=2 colspan="3" style="text-indent:2em" , 40.902(12) keV , rowspan=2, 6.263(4) min , IT (99.5%) , ⁹⁴Nb , rowspan=2, 3+ , rowspan=2, , rowspan=2, , - , β⁻ (.5%) , ⁹⁴Mo , - , ⁹⁵Nb , style="text-align:right" , 41 , style="text-align:right" , 54 , 94.9068358(21) , 34.991(6) d , β⁻ , ⁹⁵Mo , 9/2+ , , , - , rowspan=2 style="text-indent:1em" , ^95mNb , rowspan=2 colspan="3" style="text-indent:2em" , 235.690(20) keV , rowspan=2, 3.61(3) d , IT (94.4%) , ⁹⁵Nb , rowspan=2, 1/2− , rowspan=2, , rowspan=2, , - , β⁻ (5.6%) , ⁹⁵Mo , - , ⁹⁶Nb , style="text-align:right" , 41 , style="text-align:right" , 55 , 95.908101(4) , 23.35(5) h , β⁻ , ⁹⁶Mo , 6+ , , , - , ⁹⁷Nb , style="text-align:right" , 41 , style="text-align:right" , 56 , 96.9080986(27) , 72.1(7) min , β⁻ , ⁹⁷Mo , 9/2+ , , , - , style="text-indent:1em" , ^97mNb , colspan="3" style="text-indent:2em" , 743.35(3) keV , 52.7(18) s , IT , ⁹⁷Nb , 1/2− , , , - , ⁹⁸Nb , style="text-align:right" , 41 , style="text-align:right" , 57 , 97.910328(6) , 2.86(6) s , β⁻ , ⁹⁸Mo , 1+ , , , - , rowspan=2 style="text-indent:1em" , ^98mNb , rowspan=2 colspan="3" style="text-indent:2em" , 84(4) keV , rowspan=2, 51.3(4) min , β⁻ (99.9%) , ⁹⁸Mo , rowspan=2, (5+) , rowspan=2, , rowspan=2, , - , IT (.1%) , ⁹⁸Nb , - , ⁹⁹Nb , style="text-align:right" , 41 , style="text-align:right" , 58 , 98.911618(14) , 15.0(2) s , β⁻ , ⁹⁹Mo , 9/2+ , , , - , rowspan=2 style="text-indent:1em" , ^99mNb , rowspan=2 colspan="3" style="text-indent:2em" , 365.29(14) keV , rowspan=2, 2.6(2) min , β⁻ (96.2%) , ⁹⁹Mo , rowspan=2, 1/2− , rowspan=2, , rowspan=2, , - , IT (3.8%) , ⁹⁹Nb , - , ¹⁰⁰Nb , style="text-align:right" , 41 , style="text-align:right" , 59 , 99.914182(28) , 1.5(2) s , β⁻ , ''¹⁰⁰Mo'' , 1+ , , , - , style="text-indent:1em" , ^100mNb , colspan="3" style="text-indent:2em" , 470(40) keV , 2.99(11) s , β⁻ , ''¹⁰⁰Mo'' , (4+, 5+) , , , - , ¹⁰¹Nb , style="text-align:right" , 41 , style="text-align:right" , 60 , 100.915252(20) , 7.1(3) s , β⁻ , ¹⁰¹Mo , (5/2#)+ , , , - , ¹⁰²Nb , style="text-align:right" , 41 , style="text-align:right" , 61 , 101.91804(4) , 1.3(2) s , β⁻ , ¹⁰²Mo , 1+ , , , - , style="text-indent:1em" , ^102mNb , colspan="3" style="text-indent:2em" , 130(50) keV , 4.3(4) s , β⁻ , ¹⁰²Mo , high , , , - , ¹⁰³Nb , style="text-align:right" , 41 , style="text-align:right" , 62 , 102.91914(7) , 1.5(2) s , β⁻ , ¹⁰³Mo , (5/2+) , , , - , rowspan=2, ¹⁰⁴Nb , rowspan=2 style="text-align:right" , 41 , rowspan=2 style="text-align:right" , 63 , rowspan=2, 103.92246(11) , rowspan=2, 4.9(3) s , β⁻ (99.94%) , ¹⁰⁴Mo , rowspan=2, (1+) , rowspan=2, , rowspan=2, , - , β⁻, neutron emission, n (.06%) , ¹⁰³Mo , - , rowspan=2 style="text-indent:1em" , ^104mNb , rowspan=2 colspan="3" style="text-indent:2em" , 220(120) keV , rowspan=2, 940(40) ms , β⁻ (99.95%) , ¹⁰⁴Mo , rowspan=2, high , rowspan=2, , rowspan=2, , - , β⁻, n (.05%) , ¹⁰³Mo , - , rowspan=2, ¹⁰⁵Nb , rowspan=2 style="text-align:right" , 41 , rowspan=2 style="text-align:right" , 64 , rowspan=2, 104.92394(11) , rowspan=2, 2.95(6) s , β⁻ (98.3%) , ¹⁰⁵Mo , rowspan=2, (5/2+)# , rowspan=2, , rowspan=2, , - , β⁻, n (1.7%) , ¹⁰⁴Mo , - , rowspan=2, ¹⁰⁶Nb , rowspan=2 style="text-align:right" , 41 , rowspan=2 style="text-align:right" , 65 , rowspan=2, 105.92797(21)# , rowspan=2, 920(40) ms , β⁻ (95.5%) , ¹⁰⁶Mo , rowspan=2, 2+# , rowspan=2, , rowspan=2, , - , β⁻, n (4.5%) , ¹⁰⁵Mo , - , rowspan=2, ¹⁰⁷Nb , rowspan=2 style="text-align:right" , 41 , rowspan=2 style="text-align:right" , 66 , rowspan=2, 106.93031(43)# , rowspan=2, 300(9) ms , β⁻ (94%) , ¹⁰⁷Mo , rowspan=2, 5/2+# , rowspan=2, , rowspan=2, , - , β⁻, n (6%) , ¹⁰⁶Mo , - , rowspan=2, ¹⁰⁸Nb , rowspan=2 style="text-align:right" , 41 , rowspan=2 style="text-align:right" , 67 , rowspan=2, 107.93484(32)# , rowspan=2, 0.193(17) s , β⁻ (93.8%) , ¹⁰⁸Mo , rowspan=2, (2+) , rowspan=2, , rowspan=2, , - , β⁻, n (6.2%) , ¹⁰⁷Mo , - , rowspan=2, ¹⁰⁹Nb , rowspan=2 style="text-align:right" , 41 , rowspan=2 style="text-align:right" , 68 , rowspan=2, 108.93763(54)# , rowspan=2, 190(30) ms , β⁻ (69%) , ¹⁰⁹Mo , rowspan=2, 5/2+# , rowspan=2, , rowspan=2, , - , β⁻, n (69%) , ¹⁰⁸Mo , - , rowspan=2, ¹¹⁰Nb , rowspan=2 style="text-align:right" , 41 , rowspan=2 style="text-align:right" , 69 , rowspan=2, 109.94244(54)# , rowspan=2, 170(20) ms , β⁻ (60%) , ¹¹⁰Mo , rowspan=2, 2+# , rowspan=2, , rowspan=2, , - , β⁻, n (40%) , ¹⁰⁹Mo , - , ¹¹¹Nb , style="text-align:right" , 41 , style="text-align:right" , 70 , 110.94565(54)# , 80# ms [>300 ns] , , , 5/2+# , , , - , ¹¹²Nb , style="text-align:right" , 41 , style="text-align:right" , 71 , 111.95083(75)# , 60# ms [>300 ns] , , , 2+# , , , - , ¹¹³Nb , style="text-align:right" , 41 , style="text-align:right" , 72 , 112.95470(86)# , 30# ms [>300 ns] , , , 5/2+# , , , - , ¹¹⁴Nb , style="text-align:right" , 41 , style="text-align:right" , 73 , , , , , , , , - , ¹¹⁵Nb , style="text-align:right" , 41 , style="text-align:right" , 74 , , , , , , , , - , ¹¹⁶Nb , style="text-align:right" , 41 , style="text-align:right" , 75 , , , , , , , , - , ¹¹⁷Nb , style="text-align:right" , 41 , style="text-align:right" , 76 , , , , , , ,

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 ⁹³Nb in the early Solar System, estimated at 1.7×10⁻⁵, has been measured to investigate the origin of p-nuclei. This isotope, along with ⁹⁴Nb, has been detected in refined samples of terrestrial niobium and may originate from bombardment by cosmic ray muons in Earth's crust.

References

* Isotope masses from: ** * Isotopic compositions and standard atomic masses from: ** ** * Half-life, spin, and isomer data selected from the following sources. ** ** ** {{Authority control Isotopes of niobium, Niobium Lists of isotopes by element, Niobium