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Naturally occurring zirconium (40Zr) is composed of four stable isotopes (of which one may in the future be found radioactive), and one very long-lived radioisotope (96Zr), a primordial nuclide that decays via double beta decay with an observed half-life of 2.0×1019 years;[3] it can also undergo single beta decay, which is not yet observed, but the theoretically predicted value of t1/2 is 2.4×1020 years.[4] The second most stable radioisotope is 93Zr, which has a half-life of 1.53 million years. Twenty-seven other radioisotopes have been observed. All have half-lives less than a day except for 95Zr (64.02 days), 88Zr (83.4 days), and 89Zr (78.41 hours). The primary decay mode is electron capture for isotopes lighter than 92Zr, and the primary mode for heavier isotopes is beta decay.

Main isotopes of zirconium (40Zr)
Iso­tope Decay
abun­dance half-life (t1/2) mode pro­duct
88Zr syn 83.4 d ε 88Y
γ
89Zr syn 78.4 h ε 89Y
β+ 89Y
γ
90Zr 51.45% stable
91Zr 11.22% stable
92Zr 17.15% stable
93Zr trace 1.53×106 y β 93Nb
94Zr 17.38% stable
96Zr 2.80% 2.0×1019 y[1] ββ 96Mo
Standard atomic weight Ar, standard(Zr)

Contents

List of isotopesEdit

Nuclide
[n 1]
Z N Isotopic mass (u)
[n 2][n 3]
Half-life
[n 4][n 5]
Decay
mode

Daughter
isotope

[n 6]
Spin and
parity
[n 7][n 5]
Natural abundance (mole fraction)
Excitation energy Normal proportion Range of variation
78Zr 40 38 77.95523(54)# 50# ms
[>170 ns]
0+
79Zr 40 39 78.94916(43)# 56(30) ms β+, p 78Sr 5/2+#
β+ 79Y
80Zr 40 40 79.9404(16) 4.6(6) s β+ 80Y 0+
81Zr 40 41 80.93721(18) 5.5(4) s β+ (>99.9%) 81Y (3/2−)#
β+, p (<.1%) 80Sr
82Zr 40 42 81.93109(24)# 32(5) s β+ 82Y 0+
83Zr 40 43 82.92865(10) 41.6(24) s β+ (>99.9%) 83Y (1/2−)#
β+, p (<.1%) 82Sr
84Zr 40 44 83.92325(21)# 25.9(7) min β+ 84Y 0+
85Zr 40 45 84.92147(11) 7.86(4) min β+ 85Y 7/2+
85mZr 292.2(3) keV 10.9(3) s IT (92%) 85Zr (1/2−)
β+ (8%) 85Y
86Zr 40 46 85.91647(3) 16.5(1) h β+ 86Y 0+
87Zr 40 47 86.914816(9) 1.68(1) h β+ 87Y (9/2)+
87mZr 335.84(19) keV 14.0(2) s IT 87Zr (1/2)−
88Zr[n 8] 40 48 87.910227(11) 83.4(3) d EC 88Y 0+
89Zr 40 49 88.908890(4) 78.41(12) h β+ 89Y 9/2+
89mZr 587.82(10) keV 4.161(17) min IT (93.77%) 89Zr 1/2−
β+ (6.23%) 89Y
90Zr[n 9] 40 50 89.9047044(25) Stable 0+ 0.5145(40)
90m1Zr 2319.000(10) keV 809.2(20) ms IT 90Zr 5-
90m2Zr 3589.419(16) keV 131(4) ns 8+
91Zr[n 9] 40 51 90.9056458(25) Stable 5/2+ 0.1122(5)
91mZr 3167.3(4) keV 4.35(14) µs (21/2+)
92Zr[n 9] 40 52 91.9050408(25) Stable 0+ 0.1715(8)
93Zr[n 10] 40 53 92.9064760(25) 1.53(10)×106 y β (73%) 93mNb 5/2+
β (27%) 93Nb
94Zr[n 9] 40 54 93.9063152(26) Observationally Stable[n 11] 0+ 0.1738(28)
95Zr[n 9] 40 55 94.9080426(26) 64.032(6) d β 95Nb 5/2+
96Zr[n 12][n 9] 40 56 95.9082734(30) 20(4)×1018 y ββ[n 13] 96Mo 0+ 0.0280(9)
97Zr 40 57 96.9109531(30) 16.744(11) h β 97mNb 1/2+
98Zr 40 58 97.912735(21) 30.7(4) s β 98Nb 0+
99Zr 40 59 98.916512(22) 2.1(1) s β 99mNb 1/2+
100Zr 40 60 99.91776(4) 7.1(4) s β 100Nb 0+
101Zr 40 61 100.92114(3) 2.3(1) s β 101Nb 3/2+
102Zr 40 62 101.92298(5) 2.9(2) s β 102Nb 0+
103Zr 40 63 102.92660(12) 1.3(1) s β 103Nb (5/2−)
104Zr 40 64 103.92878(43)# 1.2(3) s β 104Nb 0+
105Zr 40 65 104.93305(43)# 0.6(1) s β (>99.9%) 105Nb
β, n (<.1%) 104Nb
106Zr 40 66 105.93591(54)# 200# ms
[>300 ns]
β 106Nb 0+
107Zr 40 67 106.94075(32)# 150# ms
[>300 ns]
β 107Nb
108Zr 40 68 107.94396(64)# 80# ms
[>300 ns]
β 108Nb 0+
109Zr 40 69 108.94924(54)# 60# ms
[>300 ns]
110Zr 40 70 109.95287(86)# 30# ms
[>300 ns]
0+
  1. ^ mZr – 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. ^ Bold half-life – nearly stable, half-life longer than age of universe.
  5. ^ a b # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  6. ^ Bold symbol as daughter – Daughter product is stable.
  7. ^ ( ) spin value – Indicates spin with weak assignment arguments.
  8. ^ Second most powerful known neutron absorber
  9. ^ a b c d e f Fission product
  10. ^ Long-lived fission product
  11. ^ Believed to decay by ββ to 94Mo with a half-life over 1.1×1017 years
  12. ^ Primordial radionuclide
  13. ^ Theorized to also undergo β decay to 96Nb with a partial half-life greater than 2.4×1019 y[5]

Zirconium-88Edit

88Zr is a radioisotope of zirconium with a half-life of 83.4 days. In January 2019, this isotope was discovered to have a neutron capture cross section of approximately 861,000 barns; this is several orders of magnitude greater than predicted, and greater than that of any other nuclide except xenon-135.[6]

Zirconium-89Edit

89Zr is a radioisotope of zirconium with a half-life of 78.41 hours. It is produced by proton irradiation of natural yttrium-89. Its most prominent gamma photon has an energy of 909 keV.

Zirconium-89 is employed in specialized diagnostic applications using positron emission tomography[7] imaging, for example, with zirconium-89 labeled antibodies (immuno-PET).[8] For a decay table, see Maria Vosjan. "Zirconium-89 (89Zr)". Cyclotron.nl.

Zirconium-93Edit

Yield, % per fission[9]
Thermal Fast 14 MeV
232Th not fissile 6.70 ± 0.40 5.58 ± 0.16
233U 6.979 ± 0.098 6.94 ± 0.07 5.38 ± 0.32
235U 6.346 ± 0.044 6.25 ± 0.04 5.19 ± 0.31
238U not fissile 4.913 ± 0.098 4.53 ± 0.13
239Pu 3.80 ± 0.03 3.82 ± 0.03 3.0 ± 0.3
241Pu 2.98 ± 0.04 2.98 ± 0.33 ?


93Zr is a radioisotope of zirconium with a half-life of 1.53 million years, decaying through emission of a low-energy beta particle. 73% of decays populate an excited state of niobium-93, which decays with a halflife of 14 years and a low-energy gamma ray to the stable ground state of 93Nb, while the remaining 27% of decays directly populate the ground state.[10] It is one of only 7 long-lived fission products. The low specific activity and low energy of its radiations limit the radioactive hazards of this isotope.

Nuclear fission produces it at a fission yield of 6.3% (thermal neutron fission of 235U), on a par with the other most abundant fission products. Nuclear reactors usually contain large amounts of zirconium as fuel rod cladding (see zircaloy), and neutron irradiation of 92Zr also produces some 93Zr, though this is limited by 92Zr's low neutron capture cross section of 0.22 barns.

93Zr also has a low neutron capture cross section of 0.7 barns.[11][12] Most fission zirconium consists of other isotopes; the other isotope with a significant neutron absorption cross section is 91Zr with a cross section of 1.24 barns. 93Zr is a less attractive candidate for disposal by nuclear transmutation than are 99Tc and 129I. Mobility in soil is relatively low, so that geological disposal may be an adequate solution.

ReferencesEdit

  1. ^ Pritychenko, Boris; Tretyak, V. "Adopted Double Beta Decay Data". National Nuclear Data Center. Retrieved 2008-02-11.
  2. ^ Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.
  3. ^ "List of Adopted Double Beta (ββ) Decay Values". National Nuclear Data Center, Brookhaven National Laboratory.
  4. ^ H Heiskanen; M T Mustonen; J Suhonen (30 March 2007). "Theoretical half-life for beta decay of 96Zr". Journal of Physics G: Nuclear and Particle Physics. 34 (5).
  5. ^ Finch, S.W.; Tornow, W. (2016). "Search for the β decay of 96Zr". Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 806: 70–74. doi:10.1016/j.nima.2015.09.098.
  6. ^ Shusterman, J.A.; Scielzo, N.D.; Thomas, K.J.; Norman, E.B.; Lapi, S.E.; Loveless, C.S.; Peters, N.J.; Robertson, J.D.; Shaughnessy, D.A.; Tonchev, A.P. (2019). "The surprisingly large neutron capture cross-section of 88Zr". Nature. 565 (7739): 328–330. doi:10.1038/s41586-018-0838-z. PMID 30617314.
  7. ^ Dilworth, Jonathan R.; Pascu, Sofia I. (2018). "The chemistry of PET imaging with zirconium-89". Chemical Society Reviews. 47 (8): 2554–2571. doi:10.1039/C7CS00014F.
  8. ^ Van Dongen, GA; Vosjan, MJ (August 2010). "Immuno-positron emission tomography: shedding light on clinical antibody therapy". Cancer Biotherapy and Radiopharmaceuticals. 25 (4): 375–85.
  9. ^ M. B. Chadwick et al, "ENDF/B-VII.1: Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data", Nucl. Data Sheets 112(2011)2887. (accessed at www-nds.iaea.org/exfor/endf.htm)
  10. ^ Cassette, P.; Chartier, F.; Isnard, H.; Fréchou, C.; Laszak, I.; Degros, J.P.; Bé, M.M.; Lépy, M.C.; Tartes, I. (2010). "Determination of 93Zr decay scheme and half-life". Applied Radiation and Isotopes. 68: 122–130. doi:10.1016/j.apradiso.2009.08.011.
  11. ^ "ENDF/B-VII.1 Zr-93(n,g)". National Nuclear Data Center, Brookhaven National Laboratory. 2011-12-22. Retrieved 2014-11-20.
  12. ^ S. Nakamura; et al. (2007). "Thermal neutron capture cross-sections of Zirconium-91 and Zirconium-93 by prompt gamma-ray spectroscopy". Journal of Nuclear Science and Technology. 44 (1): 21–28. doi:10.1080/18811248.2007.9711252.