Isotopes of niobium

Isotopes of niobium (₄₁Nb)
β+	91Zr
Standard atomic weight Ar°(Nb)
	92.90637±0.00001; 92.906±0.001 (abridged);
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Last updated September 06, 2025

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, followed by are ⁹⁴Nb at a half-life of 20,400 years and ⁹¹Nb at 680 years. Other radioisotopes that have been synthesized range from ⁸²Nb to ¹¹⁰Nb; these have half-lives that are less than two hours, except ⁹⁵Nb (34.991 days), ⁹⁶Nb (23.35 hours) and ⁹⁰Nb (14.60 hours).

The most stable of the meta states is ^93mNb with excitation energy 31 keV and a 16.1 year half-life; this is produced in the decay of ⁹³Zr. The primary decay mode before stable ⁹³Nb is electron capture to zirconium isotopes and the primary mode after is beta emission, with delayed neutron emission starting at ¹⁰⁴Nb, leading to molybdenum isotopes.

Only ⁹⁵Nb, along with ⁹⁷Nb (72 minutes) and heavier isotopes (seconds) are fission products in significant quantity, as the other isotopes are shadowed by stable or very long-lived (93) isotopes of the preceding element zirconium from the usual mode of production through 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.

List of isotopes

Nuclide ^{[n 1]}	Z	N	Isotopic mass (Da)^[4] ^{[n 2]}^{[n 3]}	Half-life ^[1] ^{[n 4]}	Decay mode ^[1] ^{[n 5]}	Daughter isotope ^{[n 6]}^{[n 7]}	Spin and parity ^[1] ^{[n 8]}^{[n 4]}	Isotopic abundance
Nuclide ^{[n 1]}	Excitation energy^{[n 4]}			Half-life ^[1] ^{[n 4]}	Decay mode ^[1] ^{[n 5]}	Daughter isotope ^{[n 6]}^{[n 7]}	Spin and parity ^[1] ^{[n 8]}^{[n 4]}	Isotopic abundance
⁸¹Nb	41	40
⁸²Nb	41	41	81.94438(32)	51(5) ms	β⁺	⁸²Zr	(0+)
^82mNb	1180(1) keV			93(20) ns	IT	⁸²Nb	(5+)
⁸³Nb	41	42	82.93815(17)	3.9(2) s	β⁺	⁸³Zr	9/2+#
⁸⁴Nb	41	43	83.93430571(43)	9.8(9) s	β⁺	⁸⁴Zr	(1+)
^84m1Nb	48(1) keV			176(46) ns	IT	⁸⁴Nb	(3+)
^84m2Nb	337.7(4) keV			92(5) ns	IT	⁸⁴Nb	(5−)
⁸⁵Nb	41	44	84.9288458(44)	20.5(7) s	β⁺	⁸⁵Zr	9/2+#
^85mNb	150(80)# keV			3.3(9) s	IT (?%)	⁸⁵Nb	(1/2−)
^85mNb	150(80)# keV			3.3(9) s	β⁺ (?%)	⁸⁵Zr	(1/2−)
⁸⁶Nb	41	45	85.9257815(59)	88(1) s	β⁺	⁸⁶Zr	(6+)
^86mNb^{[n 9]}	150(100)# keV			20# s	β⁺	⁸⁶Zr	(0−,1−,2−)
⁸⁷Nb	41	46	86.9206925(73)	3.7(1) min	β⁺	⁸⁷Zr	(1/2)−
^87mNb	3.9(1) keV			2.6(1) min	β⁺	⁸⁷Zr	(9/2)+
⁸⁸Nb	41	47	87.918226(62)	14.50(11) min	β⁺	⁸⁸Zr	(8+)
^88mNb^{[n 9]}	130(120) keV			7.7(1) min	β⁺	⁸⁸Zr	(4−)
⁸⁹Nb	41	48	88.913445(25)	2.03(7) h	β⁺	⁸⁹Zr	(9/2+)
^89mNb^{[n 9]}	0(30)# keV			1.10(3) h	β⁺	⁸⁹Zr	(1/2)−
⁹⁰Nb	41	49	89.9112592(36)	14.60(5) h	β⁺	⁹⁰Zr	8+
^90m1Nb	122.370(22) keV			63(2) μs	IT	⁹⁰Nb	6+
^90m2Nb	124.67(25) keV			18.81(6) s	IT	⁹⁰Nb	4-
^90m3Nb	171.10(10) keV			<1 μs	IT	⁹⁰Nb	7+
^90m4Nb	382.01(25) keV			6.19(8) ms	IT	^90m1Nb	1+
^90m5Nb	1880.21(20) keV			471(6) ns	IT	⁹⁰Nb	(11−)
⁹¹Nb	41	50	90.9069903(31)	680(130) y	EC (99.99%)	⁹¹Zr	9/2+
⁹¹Nb	41	50	90.9069903(31)	680(130) y	β⁺ (0.0138%)	⁹¹Zr	9/2+
^91m1Nb	104.60(5) keV			60.86(22) d	IT (96.6%)	⁹¹Nb	1/2−
					EC (3.4%)	⁹¹Zr
					β⁺ (0.0028%)	⁹¹Zr
^91m2Nb	2034.42(20) keV			3.76(12) μs	IT	⁹¹Nb	(17/2−)
⁹²Nb	41	51	91.9071886(19)	3.47(24)×10⁷ y	β⁺	⁹²Zr	7+	Trace
^92m1Nb	135.5(4) keV			10.116(13) d	β⁺	⁹²Zr	(2)+
^92m2Nb	225.8(4) keV			5.9(2) μs	IT	⁹²Nb	(2)−
^92m3Nb	2203.3(4) keV			167(4) ns	IT	⁹²Nb	(11−)
⁹³Nb	41	52	92.9063732(16)	Stable			9/2+	1.0000
^93m1Nb	30.760(5) keV			16.12(12) y	IT	⁹³Nb	1/2−
^93m2Nb	7460(17) keV			1.5(5) μs	IT	⁹³Nb	33/2−#
⁹⁴Nb	41	53	93.9072790(16)	2.04(4)×10⁴ y	β⁻	⁹⁴Mo	6+	Trace
^94mNb	40.892(12) keV			6.263(4) min	IT (99.50%)	⁹⁴Nb	3+
^94mNb	40.892(12) keV			6.263(4) min	β⁻ (0.50%)	⁹⁴Mo	3+
⁹⁵Nb^{[n 10]}	41	54	94.90683111(55)	34.991(6) d	β⁻	⁹⁵Mo	9/2+
^95mNb^{[n 10]}	235.69(2) keV			3.61(3) d	IT (94.4%)	⁹⁵Nb	1/2−
^95mNb^{[n 10]}	235.69(2) keV			3.61(3) d	β⁻ (5.6%)	⁹⁵Mo	1/2−
⁹⁶Nb	41	55	95.90810159(16)	23.35(5) h	β⁻	⁹⁶Mo	6+
⁹⁷Nb	41	56	96.9081016(46)	72.1(7) min	β⁻	⁹⁷Mo	9/2+
^97mNb	743.35(3) keV			58.7(18) s	IT	⁹⁷Nb	1/2−
⁹⁸Nb	41	57	97.9103326(54)	2.86(6) s	β⁻	⁹⁸Mo	1+
^98mNb	84(4) keV			51.1(4) min	β⁻	⁹⁸Mo	(5)+
⁹⁹Nb	41	58	98.911609(13)	15.0(2) s	β⁻	⁹⁹Mo	9/2+
^99mNb	365.27(8) keV			2.5(2) min	β⁻ (?%)	⁹⁹Mo	1/2−
^99mNb	365.27(8) keV			2.5(2) min	IT (?%)	⁹⁹Nb	1/2−
¹⁰⁰Nb	41	59	99.9143406(86)	1.5(2) s	β⁻	¹⁰⁰Mo	1+
^100m1Nb	313(8) keV			2.99(11) s	β⁻	¹⁰⁰Mo	(5+)
^100m2Nb	347(8) keV			460(60) ns	IT	¹⁰⁰Nb	(4−,5−)
^100m3Nb	734(8) keV			12.43(26) μs	IT	¹⁰⁰Nb	(8−)
¹⁰¹Nb	41	60	100.9153065(40)	7.1(3) s	β⁻	¹⁰¹Mo	5/2+
¹⁰²Nb	41	61	101.9180904(27)	4.3(4) s	β⁻	¹⁰²Mo	(4+)
^102mNb	94(7) keV			1.31(16) s	β⁻	¹⁰²Mo	(1+)
¹⁰³Nb	41	62	102.9194534(42)	1.34(7) s	β⁻	¹⁰³Mo	5/2+
¹⁰⁴Nb	41	63	103.9229077(19)	0.98(5) s	β⁻ (99.95%)	¹⁰⁴Mo	(1+)
¹⁰⁴Nb	41	63	103.9229077(19)	0.98(5) s	β⁻, n (0.05%)	¹⁰³Mo	(1+)
^104mNb^{[n 9]}	9.8(26) keV			4.9(3) s	β⁻ (99.94%)	¹⁰⁴Mo	(0−,1−)
^104mNb^{[n 9]}	9.8(26) keV			4.9(3) s	β⁻, n (0.06%)	¹⁰³Mo	(0−,1−)
¹⁰⁵Nb	41	64	104.9249426(43)	2.91(5) s	β⁻ (98.3%)	¹⁰⁵Mo	(5/2+)
¹⁰⁵Nb	41	64	104.9249426(43)	2.91(5) s	β⁻, n (1.7%)	¹⁰⁴Mo	(5/2+)
¹⁰⁶Nb	41	65	105.9289285(15)	900(20) ms	β⁻ (95.5%)	¹⁰⁶Mo	1−#
¹⁰⁶Nb	41	65	105.9289285(15)	900(20) ms	β⁻, n (4.5%)	¹⁰⁵Mo	1−#
^106m1Nb	100(50)# keV			1.20(6) s	β⁻	¹⁰⁶Mo	(4−)
^106m2Nb	204.8(5) keV			820(38) ns	IT	¹⁰⁶Nb	(3+)
¹⁰⁷Nb	41	66	106.9315897(86)	286(8) ms	β⁻ (92.6%)	¹⁰⁷Mo	(5/2+)
¹⁰⁷Nb	41	66	106.9315897(86)	286(8) ms	β⁻, n (7.4%)	¹⁰⁶Mo	(5/2+)
¹⁰⁸Nb	41	67	107.9360756(88)	201(4) ms	β⁻ (93.7%)	¹⁰⁸Mo	(2+)
¹⁰⁸Nb	41	67	107.9360756(88)	201(4) ms	β⁻, n (6.3%)	¹⁰⁷Mo	(2+)
^108mNb	166.6(5) keV			109(2) ns	IT	¹⁰⁸Nb	6−#
¹⁰⁹Nb	41	68	108.93914(46)	106.9(49) ms	β⁻ (69%)	¹⁰⁹Mo	3/2−#
¹⁰⁹Nb	41	68	108.93914(46)	106.9(49) ms	β⁻, n (31%)	¹⁰⁸Mo	3/2−#
^109mNb	312.5(4) keV			115(8) ns	IT	¹⁰⁹Nb	7/2+#
¹¹⁰Nb	41	69	109.94384(90)	75(1) ms	β⁻ (60%)	¹¹⁰Mo	5+#
¹¹⁰Nb	41	69	109.94384(90)	75(1) ms	β⁻, n (40%)	¹⁰⁹Mo	5+#
^110mNb^{[n 9]}	100(50)# keV			94(9) ms	β⁻ (60%)	¹¹⁰Mo	2+#
^110mNb^{[n 9]}	100(50)# keV			94(9) ms	β⁻, n (40%)	¹⁰⁹Mo	2+#
¹¹¹Nb	41	70	110.94744(32)#	54(2) ms	β⁻	¹¹¹Mo	3/2−#
¹¹²Nb	41	71	111.95269(32)#	38(2) ms	β⁻	¹¹²Mo	1+#
¹¹³Nb	41	72	112.95683(43)#	32(4) ms	β⁻	¹¹³Mo	3/2−#
¹¹⁴Nb	41	73	113.96247(54)#	17(5) ms	β⁻	¹¹⁴Mo	2−#
¹¹⁵Nb	41	74	114.96685(54)#	23(8) ms	β⁻	¹¹⁵Mo	3/2−#
¹¹⁶Nb	41	75	115.97291(32)#	12# ms [>550 ns]			1−#
¹¹⁷Nb^[5]	41	76
This table header & footer: view

↑ ^mNb – 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.
1 2 Fission product

Niobium-92

Niobium-92 is an extinct radionuclide ^[6] 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.^[6]^[7] A higher initial abundance of ⁹²Nb 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.^[8]

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.^[9]

References

1 2 3 4 Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3) 030001. doi:10.1088/1674-1137/abddae.
↑ "Standard Atomic Weights: Niobium". CIAAW. 2017.
↑ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
↑ Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3) 030003. doi:10.1088/1674-1137/abddaf.
↑ Sumikama, T.; et al. (2021). "Observation of new neutron-rich isotopes in the vicinity of Zr110". Physical Review C. 103 (1): 014614. Bibcode:2021PhRvC.103a4614S. doi:10.1103/PhysRevC.103.014614. hdl: 10261/260248 . S2CID 234019083.{{cite journal}}: CS1 maint: article number as page number (link)
1 2 Iizuka, Tsuyoshi; Lai, Yi-Jen; Akram, Waheed; Amelin, Yuri; Schönbächler, Maria (2016). "The initial abundance and distribution of ⁹²Nb in the Solar System". Earth and Planetary Science Letters. 439: 172–181. arXiv: 1602.00966 . Bibcode:2016E&PSL.439..172I. doi:10.1016/j.epsl.2016.02.005. S2CID 119299654.
↑ Hibiya, Y; Iizuka, T; Enomoto, H (2019). THE INITIAL ABUNDANCE OF NIOBIUM-92 IN THE OUTER SOLAR SYSTEM (PDF). Lunar and Planetary Science Conference (50th ed.). Retrieved 7 September 2019.
↑ Hibiya, Y.; Iizuka, T.; Enomoto, H.; Hayakawa, T. (2023). "Evidence for enrichment of niobium-92 in the outer protosolar disk". Astrophysical Journal Letters. 942 (L15): L15. Bibcode:2023ApJ...942L..15H. doi: 10.3847/2041-8213/acab5d . S2CID 255414098.
↑ Clayton, Donald D.; Morgan, John A. (1977). "Muon production of ^92,94Nb in the Earth's crust". Nature. 266 (5604): 712–713. doi:10.1038/266712a0. S2CID 4292459.

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[4] Nb – Excited nuclear isomer.

[6] ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.

[TMS-7] # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).

[TNN-8] 1 2 3 # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).

[9] Modes of decay:
EC: Electron capture
IT: Isomeric transition
n: Neutron emission
p: Proton emission

[10] Bold italics symbol as daughter – Daughter product is nearly stable.

[11] Bold symbol as daughter – Daughter product is stable.

[12] ( ) spin value – Indicates spin with weak assignment arguments.

[order-13] 1 2 3 4 5 Order of ground state and isomer is uncertain.

[FP-14] 1 2 Fission product

[NUBASE2020-1] 1 2 3 4 Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3) 030001. doi:10.1088/1674-1137/abddae.

[CIAAWniobium-2] "Standard Atomic Weights: Niobium". CIAAW. 2017.

[CIAAW2021-3] Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.

[AME2020_II-5] Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3) 030003. doi:10.1088/1674-1137/abddaf.

[15] Sumikama, T.; et al. (2021). "Observation of new neutron-rich isotopes in the vicinity of Zr110". Physical Review C. 103 (1): 014614. Bibcode:2021PhRvC.103a4614S. doi:10.1103/PhysRevC.103.014614. hdl: 10261/260248 . S2CID 234019083.{{cite journal}}: CS1 maint: article number as page number (link)

[iizuka-16] 1 2 Iizuka, Tsuyoshi; Lai, Yi-Jen; Akram, Waheed; Amelin, Yuri; Schönbächler, Maria (2016). "The initial abundance and distribution of ⁹²Nb in the Solar System". Earth and Planetary Science Letters. 439: 172–181. arXiv: 1602.00966 . Bibcode:2016E&PSL.439..172I. doi:10.1016/j.epsl.2016.02.005. S2CID 119299654.

[17] Hibiya, Y; Iizuka, T; Enomoto, H (2019). THE INITIAL ABUNDANCE OF NIOBIUM-92 IN THE OUTER SOLAR SYSTEM (PDF). Lunar and Planetary Science Conference (50th ed.). Retrieved 7 September 2019.

[92NbOuter-18] Hibiya, Y.; Iizuka, T.; Enomoto, H.; Hayakawa, T. (2023). "Evidence for enrichment of niobium-92 in the outer protosolar disk". Astrophysical Journal Letters. 942 (L15): L15. Bibcode:2023ApJ...942L..15H. doi: 10.3847/2041-8213/acab5d . S2CID 255414098.

[19] Clayton, Donald D.; Morgan, John A. (1977). "Muon production of ^92,94Nb in the Earth's crust". Nature. 266 (5604): 712–713. doi:10.1038/266712a0. S2CID 4292459.

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Isotopes of niobium

Contents

List of isotopes

Niobium-92

See also

References

EC:	Electron capture
IT:	Isomeric transition
n:	Neutron emission
p:	Proton emission