نظائر النيوبيوم

نظائر niobium (41Nb)
النظائر الرئيسية[1] اضمحلال
توا­فر عمر النصف (t1/2) النمط نا­تج
91Nb synth 680 y ε 91Zr
92Nb trace 3.47×107 y β+ 92Zr
93Nb 100% stable
93mNb synth 16.12 y IT 93Nb
94Nb trace 20.4×103 y β− 94Mo
95Nb synth 34.991 d β− 95Mo

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 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 (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.

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قائمة النظائر

Nuclide
[n 1] 		Z N Isotopic mass (Da)
[n 2][n 3] 		Half-life
[n 4] 		Decay
mode
[n 5] 		Daughter
isotope
[n 6][n 7] 		Spin and
parity
[n 8][n 4] 		التوافر الطبيعي (mole fraction)
طاقة الإثارة[n 4] Normal proportion Range of variation
81Nb 41 40 80.94903(161)# <44 ns β+, p 80Y 3/2−#
p 80Zr
β+ 81Zr
82Nb 41 41 81.94313(32)# 51(5) ms β+ 82Zr 0+
83Nb 41 42 82.93671(34) 4.1(3) s β+ 83Zr (5/2+)
84Nb 41 43 83.93357(32)# 9.8(9) s β+ (>99.9%) 84Zr 3+
β+, p (<.1%) 83Y
84mNb 338(10) keV 103(19) ns (5−)
85Nb 41 44 84.92791(24) 20.9(7) s β+ 85Zr (9/2+)
85mNb 759.0(10) keV 12(5) s (1/2−)
86Nb 41 45 85.92504(9) 88(1) s β+ 86Zr (6+)
86mNb 250(160)# keV 56(8) s β+ 86Zr high
87Nb 41 46 86.92036(7) 3.75(9) min β+ 87Zr (1/2−)
87mNb 3.84(14) keV 2.6(1) min β+ 87Zr (9/2+)#
88Nb 41 47 87.91833(11) 14.55(6) min β+ 88Zr (8+)
88mNb 40(140) keV 7.8(1) min β+ 88Zr (4−)
89Nb 41 48 88.913418(29) 2.03(7) h β+ 89Zr (9/2+)
89mNb 0(30)# keV 1.10(3) h β+ 89Zr (1/2)−
90Nb 41 49 89.911265(5) 14.60(5) h β+ 90Zr 8+
90m1Nb 122.370(22) keV 63(2) μs 6+
90m2Nb 124.67(25) keV 18.81(6) s IT 90Nb 4-
90m3Nb 171.10(10) keV <1 μs 7+
90m4Nb 382.01(25) keV 6.19(8) ms 1+
90m5Nb 1880.21(20) keV 472(13) ns (11−)
91Nb 41 50 90.906996(4) 680(130) a EC (99.98%) 91Zr 9/2+
β+ (.013%)
91m1Nb 104.60(5) keV 60.86(22) d IT (93%) 91Nb 1/2−
EC (7%) 91Zr
β+ (.0028%)
91m2Nb 2034.35(19) keV 3.76(12) μs (17/2−)
92Nb 41 51 91.907194(3) 3.47(24)×107 a β+ (99.95%) 92Zr (7)+ Trace
β− (.05%) 92Mo
92m1Nb 135.5(4) keV 10.15(2) d β+ 92Zr (2)+
92m2Nb 225.7(4) keV 5.9(2) μs (2)−
92m3Nb 2203.3(4) keV 167(4) ns (11−)
93Nb 41 52 92.9063781(26) Stable 9/2+ 1.0000
93mNb 30.77(2) keV 16.13(14) a IT 93Nb 1/2−
94Nb 41 53 93.9072839(26) 2.03(16)×104 a β− 94Mo (6)+ Trace
94mNb 40.902(12) keV 6.263(4) min IT (99.5%) 94Nb 3+
β− (.5%) 94Mo
95Nb 41 54 94.9068358(21) 34.991(6) d β− 95Mo 9/2+
95mNb 235.690(20) keV 3.61(3) d IT (94.4%) 95Nb 1/2−
β− (5.6%) 95Mo
96Nb 41 55 95.908101(4) 23.35(5) h β− 96Mo 6+
97Nb 41 56 96.9080986(27) 72.1(7) min β− 97Mo 9/2+
97mNb 743.35(3) keV 52.7(18) s IT 97Nb 1/2−
98Nb 41 57 97.910328(6) 2.86(6) s β− 98Mo 1+
98mNb 84(4) keV 51.3(4) min β− (99.9%) 98Mo (5+)
IT (.1%) 98Nb
99Nb 41 58 98.911618(14) 15.0(2) s β− 99Mo 9/2+
99mNb 365.29(14) keV 2.6(2) min β− (96.2%) 99Mo 1/2−
IT (3.8%) 99Nb
100Nb 41 59 99.914182(28) 1.5(2) s β− 100Mo 1+
100mNb 470(40) keV 2.99(11) s β− 100Mo (4+, 5+)
101Nb 41 60 100.915252(20) 7.1(3) s β− 101Mo (5/2#)+
102Nb 41 61 101.91804(4) 1.3(2) s β− 102Mo 1+
102mNb 130(50) keV 4.3(4) s β− 102Mo high
103Nb 41 62 102.91914(7) 1.5(2) s β− 103Mo (5/2+)
104Nb 41 63 103.92246(11) 4.9(3) s β− (99.94%) 104Mo (1+)
β−, n (.06%) 103Mo
104mNb 220(120) keV 940(40) ms β− (99.95%) 104Mo high
β−, n (.05%) 103Mo
105Nb 41 64 104.92394(11) 2.95(6) s β− (98.3%) 105Mo (5/2+)#
β−, n (1.7%) 104Mo
106Nb 41 65 105.92797(21)# 920(40) ms β− (95.5%) 106Mo 2+#
β−, n (4.5%) 105Mo
107Nb 41 66 106.93031(43)# 300(9) ms β− (94%) 107Mo 5/2+#
β−, n (6%) 106Mo
108Nb 41 67 107.93484(32)# 0.193(17) s β− (93.8%) 108Mo (2+)
β−, n (6.2%) 107Mo
109Nb 41 68 108.93763(54)# 190(30) ms β− (69%) 109Mo 5/2+#
β−, n (31%) 108Mo
110Nb 41 69 109.94244(54)# 170(20) ms β− (60%) 110Mo 2+#
β−, n (40%) 109Mo
111Nb 41 70 110.94565(54)# 80# ms [>300 ns] 5/2+#
112Nb 41 71 111.95083(75)# 60# ms [>300 ns] 2+#
113Nb 41 72 112.95470(86)# 30# ms [>300 ns] 5/2+#
114Nb[2] 41 73
115Nb[2] 41 74
116Nb[3] 41 75
117Nb[4] 41 76
This table header & footer:  view 
  1. ^ mNb – Excited nuclear isomer.
  2. ^ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
  3. ^ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
  4. ^ أ ب ت # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  5. ^ أنماط الاضمحلال:
    EC: Electron capture
    IT: Isomeric transition
    n: Neutron emission
    p: Proton emission
  6. ^ Bold italics symbol as daughter – Daughter product is nearly stable.
  7. ^ Bold symbol as daughter – Daughter product is stable.
  8. ^ ( ) spin value – Indicates spin with weak assignment arguments.


Niobium-92

Niobium-92 is an extinct radionuclide[5] 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.[5][6] 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.[7]

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.[8]

References

  1. ^ 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.
  2. ^ أ ب Ohnishi, Tetsuya; Kubo, Toshiyuki; Kusaka, Kensuke; et al. (2010). "Identification of 45 New Neutron-Rich Isotopes Produced by In-Flight Fission of a 238U Beam at 345 MeV/nucleon". J. Phys. Soc. Jpn. Physical Society of Japan. 79 (7): 073201. arXiv:1006.0305. Bibcode:2010JPSJ...79g3201T. doi:10.1143/JPSJ.79.073201.
  3. ^ Shimizu, Yohei; et al. (2018). "Observation of New Neutron-rich Isotopes among Fission Fragments from In-flight Fission of 345MeV=nucleon 238U: Search for New Isotopes Conducted Concurrently with Decay Measurement Campaigns". Journal of the Physical Society of Japan. 87 (1): 014203. Bibcode:2018JPSJ...87a4203S. doi:10.7566/JPSJ.87.014203.
  4. ^ 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.
  5. ^ أ ب 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.
  6. ^ (2019) "THE INITIAL ABUNDANCE OF NIOBIUM-92 IN THE OUTER SOLAR SYSTEM" in Lunar and Planetary Science Conference., 50th. 
  7. ^ 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.
  8. ^ 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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