Isotopes of zirconium

Isotopes of zirconium (₄₀Zr)
γ	–
β+	89Y
γ	–
Standard atomic weight Ar°(Zr)
	91.224±0.002; 91.224±0.002 (abridged);
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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;^[5] 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.^[6] The second most stable radioisotope is ⁹³Zr, which has a half-life of 1.53 million years. Thirty 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.

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)
Nuclide ^{[n 1]}	Excitation energy			Half-life ^{[n 4]}^{[n 5]}	Decay mode	Daughter isotope ^{[n 6]}	Spin and parity ^{[n 7]}^{[n 5]}	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+#
⁷⁹Zr	40	39	78.94916(43)#	56(30) ms	β⁺	⁷⁹Y	5/2+#
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−)#
⁸¹Zr	40	41	80.93721(18)	5.5(4) s	β⁺, p (<.1%)	⁸⁰Sr	(3/2−)#
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−)#
⁸³Zr	40	43	82.92865(10)	41.6(24) s	β⁺, p (<.1%)	⁸²Sr	(1/2−)#
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−)
^85mZr	292.2(3) keV			10.9(3) s	β⁺ (8%)	⁸⁵Y	(1/2−)
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−
^89mZr	587.82(10) keV			4.161(17) min	β⁺ (6.23%)	⁸⁹Y	1/2−
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+
⁹³Zr^{[n 10]}	40	53	92.9064760(25)	1.53(10)×10⁶ y	β⁻ (27%)	⁹³Nb	5/2+
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]}^{[n 13]}	40	56	95.9082734(30)	2.0(4)×10¹⁹ y	β⁻β⁻^{[n 14]}	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
¹⁰⁵Zr	40	65	104.93305(43)#	0.6(1) s	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+
¹¹¹Zr^[8]	40	71
¹¹²Zr^[8]	40	72					0+
¹¹³Zr^[9]	40	73
¹¹⁴Zr^[10]	40	74					0+
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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.^[11]

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^[12] imaging, for example, with zirconium-89 labeled antibodies (immuno-PET).^[13] For a decay table, see Maria Vosjan. "Zirconium-89 (⁸⁹Zr)". Cyclotron.nl.

Zirconium-93

Yield, % per fission^[14]
	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
v
t
e
Nuclide	t_1⁄2	Yield	Q^{[a 1]}	βγ
	(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
¹³⁵Cs	1.33	6.9110^{[a 4]}	269	β
⁹³Zr	1.53	5.4575	91	βγ
¹⁰⁷Pd	6.5	1.2499	33	β
¹²⁹I	15.7	0.8410	194	βγ

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.^[15] 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. Indeed, one of the primary reasons for using zirconium in fuel rod cladding is its low cross section.

⁹³Zr also has a low neutron capture cross section of 0.7 barns.^[16]^[17] 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. Alternatively, if the effect on the neutron economy of ⁹³
Zr's higher cross section is deemed acceptable, irradiated cladding and fission product Zirconium (which are mixed together in most current nuclear reprocessing methods) could be used to form new zircalloy cladding. Once the cladding is inside the reactor, the relatively low level radioactivity can be tolerated, but transport and manufacturing might require special precautions.

References

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.
"News & Notices: Standard Atomic Weights Revised". International Union of Pure and Applied Chemistry. 19 October 2005.
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.

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