Isotopes of zirconium

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 t_1/2 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 1.53×10^6 y β^− ^93Nb ^94Zr 17.38% stable ^96Zr 2.80% 2.0×10^19 y[1] β^−β^− ^96Mo
Standard atomic weight Ar, standard(Zr)	91.224(2)[2]

List of isotopes

Nuclide [n 1]	Z	N	Isotopic mass (Da) [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)×10^6 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)×10^18 y	β^−β^−[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. # – 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. Fission product
10. Long-lived fission product
11. Believed to decay by β⁻β⁻ 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-88

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-89

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-93

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	?

Long-lived fission products

Nuclide	t​^1⁄2	Yield	Decay energy[a 1]	Decay mode
	(Ma)	(%)[a 2]	(keV)
^99Tc	0.211	6.1385	294	β
^126Sn	0.230	0.1084	4050[a 3]	βγ
^79Se	0.327	0.0447	151	β
^93Zr	1.53	5.4575	91	βγ
^135Cs	2.3	6.9110[a 4]	269	β
^107Pd	6.5	1.2499	33	β
^129I	15.7	0.8410	194	βγ
Decay energy is split among β, neutrino, and γ if any. Per 65 thermal-neutron fissions of U-235 and 35 of Pu-239. Has decay energy 380 keV, but decay product Sb-126 has decay energy 3.67 MeV. Lower in thermal reactor because predecessor absorbs neutrons.

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.

References

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. Bibcode:2016NIMPA.806...70F. 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. Bibcode:2019Natur.565..328S. 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. PMID 29557435.
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. PMID 19734052.
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.

• Isotope masses from:
  • Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
• Isotopic compositions and standard atomic masses from:
  • de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
  • Wieser, Michael E. (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051. Lay summary.
• Half-life, spin, and isomer data selected from the following sources.
  • Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
  • National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory.
  • Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.