Isotopes of zirconium

Naturally occurring zirconium (Zr) 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;^[1] it can also undergo single beta decay which is not yet observed, but the theoretically predicted value of T_½ is 2.4×10²⁰ years.^[2] 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 (63.4 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.

Zirconium is the heaviest element that can be formed from symmetric fusion, from either ⁴⁵Sc, or ⁴⁶Ca producing ⁹⁰Zr (after two beta-plus decays from ⁹⁰Mo) and ⁹²Zr respectively. All heavier elements are formed either through asymmetric fusion or during the collapse of supernovae. As most of these are energy-absorbing processes, most nuclides of elements heavier than zirconium are theoretically unstable to spontaneous fission, although in many cases, the half-life for this is too long to have been observed. See list of nuclides for a tabulation.

Standard atomic mass: 91.224(2) u.

1 Zirconium-89
2 Zirconium-93
3 Table
- 3.1 Notes
4 References

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 imaging, for example, with zirconium-89 labeled antibodies (immuno-PET).^[3] For a decay table, see the Zirconium 89 decay Table

Zirconium-93

Long-lived
fission products
Prop: Unit:	t^½ Ma	Yield %	Q * KeV	βγ *
⁹⁹Tc	0.211	6.1385	294	β
¹²⁶Sn	0.230	0.1084	4050	βγ
⁷⁹Se	0.327	0.0447	151	β
⁹³Zr	1.53	5.4575	91	βγ
¹³⁵Cs	2.3	6.9110	269	β
¹⁰⁷Pd	6.5	1.2499	33	β
¹²⁹I	15.7	0.8410	194	βγ

Chain yield, % per fission^[4]
	Thermal	Fast	14 MeV
²³²Th	not fissile	6.46 ± 0.48	5.75 ± 0.23
²³³U	6.950 ± 0.076	7.04 ± 0.38	5.66 ± 0.64
²³⁵U	6.435 ± 0.089	6.06 ± 0.13	5.40 ± 0.58
²³⁸U	not fissile	5.38 ± 0.26	4.59 ± 0.12
²³⁹Pu	3.91 ± 0.13	3.92 ± 0.19	?
²⁴¹Pu	2.95 ± 0.15	3.101 ± 0.078	?

⁹³Zr is a radioisotope of zirconium with a half-life of 1.53 million years, decaying with a low-energy beta particle to Niobium-93m, which decays with a halflife of 14 years and a low-energy gamma ray to ordinary ⁹³Nb. 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 6.2956%, 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 2.70 barns. 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 Tc-99 and I-129. Mobility in soil is relatively low, so that geological disposal may be an adequate solution.

ANL fact sheet

Table

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life^{[n 1]}	decay mode(s)^[5]^{[n 2]}	daughter isotope(s)^{[n 3]}	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
nuclide symbol	excitation energy			half-life^{[n 1]}	decay mode(s)^[5]^{[n 2]}	daughter isotope(s)^{[n 3]}	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
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⁺	⁸⁶Y	(9/2)+
^87mZr	335.84(19) keV			14.0(2) s	IT	⁸⁷Zr	(1/2)-
⁸⁸Zr	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 4]}	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 4]}	40	51	90.9056458(25)	Stable			5/2+	0.1122(5)
^91mZr	3167.3(4) keV			4.35(14) µs			(21/2+)
⁹²Zr^{[n 4]}	40	52	91.9050408(25)	Stable^{[n 5]}			0+	0.1715(8)
⁹³Zr^{[n 6]}	40	53	92.9064760(25)	1.53(10)×10⁶ a	β^-	⁹³Nb	5/2+
⁹⁴Zr^{[n 4]}	40	54	93.9063152(26)	Observationally Stable^{[n 7]}			0+	0.1738(28)
⁹⁵Zr^{[n 4]}	40	55	94.9080426(26)	64.032(6) d	β^-	⁹⁵Nb	5/2+
⁹⁶Zr^{[n 8]}^{[n 4]}	40	56	95.9082734(30)	20(4)×10¹⁸ a	β^-β^-^{[n 9]}	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+

^ Bold for isotopes with half-lives longer than the age of the universe (nearly stable)
^ Abbreviations:
EC: Electron capture
IT: Isomeric transition
^ Bold for stable isotopes
^ ^a ^b ^c ^d ^e ^f Fission product
^ Heaviest theoretically stable nuclide
^ Long-lived fission product
^ Believed to decay by β^-β^- to ⁹⁴Mo with a half-life over 1.1×10¹⁷ years
^ Primordial radionuclide
^ Theorized to also undergo β^- decay to ⁹⁶Nb

Notes

Geologically exceptional samples are known in which the isotopic composition lies outside the reported range. The uncertainty in the atomic mass may exceed the stated value for such specimens.
Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which use expanded uncertainties.

References

^ http://www.nndc.bnl.gov/bbdecay/list.html
^ http://www.iop.org/EJ/abstract/0954-3899/34/5/005/
^ Van Dongen GA, Vosjan MJ. Immuno-positron emission tomography: shedding light on clinical antibody therapy. Cancer Biother Radiopharm. 2010 Aug;25(4):375-85.
^ http://www-nds.iaea.org/sgnucdat/c1.htm Chain Fission Yields, IAEA
^ http://www.nucleonica.net/unc.aspx

Isotope masses from:
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (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. http://www.nndc.bnl.gov/amdc/nubase/Nubase2003.pdf.
Isotopic compositions and standard atomic masses from:
- J. R. de Laeter, J. K. Böhlke, P. De Bièvre, H. Hidaka, H. S. Peiser, K. J. R. Rosman and P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry 75 (6): 683–800. doi:10.1351/pac200375060683. http://www.iupac.org/publications/pac/75/6/0683/pdf/.
- M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry 78 (11): 2051–2066. doi:10.1351/pac200678112051. http://iupac.org/publications/pac/78/11/2051/pdf/. Lay summary.
Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (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. http://www.nndc.bnl.gov/amdc/nubase/Nubase2003.pdf.
- National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. http://www.nndc.bnl.gov/nudat2/. Retrieved September 2005.
- N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide. CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0849304859.

Isotopes of yttrium	Isotopes of zirconium	Isotopes of niobium
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