Isotopes of dysprosium

Isotopes of dysprosium (₆₆Dy)
Standard atomic weight Ar°(Dy)
	162.500±0.001; 162.50±0.01 (abridged);
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Naturally occurring dysprosium (₆₆Dy) is composed of 7 stable isotopes, ¹⁵⁶Dy, ¹⁵⁸Dy, ¹⁶⁰Dy, ¹⁶¹Dy, ¹⁶²Dy, ¹⁶³Dy and ¹⁶⁴Dy, with ¹⁶⁴Dy being the most abundant (28.18% natural abundance). Twenty-nine radioisotopes have been characterized, with the most stable being ¹⁵⁴Dy with a half-life of 1.4 million years, ¹⁵⁹Dy with a half-life of 144.4 days, and ¹⁶⁶Dy with a half-life of 81.6 hours. All of the remaining radioactive isotopes have half-lives that are less than 10 hours, and the majority of these have half-lives that are less than 30 seconds. This element also has 12 meta states, with the most stable being ^165mDy (half-life 1.257 minutes), ^147mDy (half-life 55.7 seconds) and ^145mDy (half-life 13.6 seconds).

The primary decay mode before the most abundant stable isotope, ¹⁶⁴Dy, is electron capture, and the primary mode after is beta decay. The primary decay products before ¹⁶⁴Dy are terbium isotopes, and the primary products after are holmium isotopes. Dysprosium is the heaviest element to have isotopes that are predicted to be stable rather than observationally stable isotopes that are predicted to be radioactive.

List of isotopes

Nuclide ^{[n 1]}	Z	N	Isotopic mass (Da) ^{[n 2]}^{[n 3]}	Half-life ^{[n 4]}	Decay mode ^{[n 5]}	Daughter isotope ^{[n 6]}	Spin and parity ^{[n 7]}^{[n 4]}	Natural abundance (mole fraction)
Nuclide ^{[n 1]}	Excitation energy			Half-life ^{[n 4]}	Decay mode ^{[n 5]}	Daughter isotope ^{[n 6]}	Spin and parity ^{[n 7]}^{[n 4]}	Normal proportion	Range of variation
¹³⁸Dy	66	72	137.96249(64)#	200# ms			0+
¹³⁹Dy	66	73	138.95954(54)#	600(200) ms			7/2+#
¹⁴⁰Dy	66	74	139.95401(54)#	700# ms	β⁺	¹⁴⁰Tb	0+
^140mDy	2166.1(5) keV			7.0(5) μs			(8−)
¹⁴¹Dy	66	75	140.95135(32)#	0.9(2) s	β⁺	¹⁴¹Tb	(9/2−)
¹⁴¹Dy	66	75	140.95135(32)#	0.9(2) s	β⁺, p (rare)	¹⁴⁰Gd	(9/2−)
¹⁴²Dy	66	76	141.94637(39)#	2.3(3) s	β⁺ (90(4)%)	¹⁴²Tb	0+
					EC (10(4)%)	¹⁴²Tb
					β⁺, p (.06%)	¹⁴¹Gd
¹⁴³Dy	66	77	142.94383(21)#	5.6(10) s	β⁺	¹⁴³Tb	(1/2+)
¹⁴³Dy	66	77	142.94383(21)#	5.6(10) s	β⁺, p (rare)	¹⁴²Gd	(1/2+)
^143mDy	310.7(6) keV			3.0(3) s			(11/2−)
¹⁴⁴Dy	66	78	143.93925(3)	9.1(4) s	β⁺	¹⁴⁴Tb	0+
¹⁴⁴Dy	66	78	143.93925(3)	9.1(4) s	β⁺, p (rare)	¹⁴³Gd	0+
¹⁴⁵Dy	66	79	144.93743(5)	9.5(10) s	β⁺	¹⁴⁵Tb	(1/2+)
¹⁴⁵Dy	66	79	144.93743(5)	9.5(10) s	β⁺, p (rare)	¹⁴⁴Gd	(1/2+)
^145mDy	118.2(2) keV			14.1(7) s	β⁺	¹⁴⁵Tb	(11/2−)
¹⁴⁶Dy	66	80	145.932845(29)	33.2(7) s	β⁺	¹⁴⁶Tb	0+
^146mDy	2935.7(6) keV			150(20) ms	IT	¹⁴⁶Dy	(10+)#
¹⁴⁷Dy	66	81	146.931092(21)	40(10) s	β⁺ (99.95%)	¹⁴⁷Tb	1/2+
¹⁴⁷Dy	66	81	146.931092(21)	40(10) s	β⁺, p (.05%)	¹⁴⁶Tb	1/2+
^147m1Dy	750.5(4) keV			55(1) s	β⁺ (65%)	¹⁴⁷Tb	11/2−
^147m1Dy	750.5(4) keV			55(1) s	IT (35%)	¹⁴⁷Dy	11/2−
^147m2Dy	3407.2(8) keV			0.40(1) μs			(27/2−)
¹⁴⁸Dy	66	82	147.927150(11)	3.3(2) min	β⁺	¹⁴⁸Tb	0+
¹⁴⁹Dy	66	83	148.927305(9)	4.20(14) min	β⁺	¹⁴⁹Tb	7/2(−)
^149mDy	2661.1(4) keV			490(15) ms	IT (99.3%)	¹⁴⁹Dy	(27/2−)
^149mDy	2661.1(4) keV			490(15) ms	β⁺ (.7%)	¹⁴⁹Tb	(27/2−)
¹⁵⁰Dy	66	84	149.925585(5)	7.17(5) min	β⁺ (64%)	¹⁵⁰Tb	0+
¹⁵⁰Dy	66	84	149.925585(5)	7.17(5) min	α (36%)	¹⁴⁶Gd	0+
¹⁵¹Dy	66	85	150.926185(4)	17.9(3) min	β⁺ (94.4%)	¹⁵¹Tb	7/2(−)
¹⁵¹Dy	66	85	150.926185(4)	17.9(3) min	α (5.6%)	¹⁴⁷Gd	7/2(−)
¹⁵²Dy	66	86	151.924718(6)	2.38(2) h	EC (99.9%)	¹⁵²Tb	0+
¹⁵²Dy	66	86	151.924718(6)	2.38(2) h	α (.1%)	¹⁴⁸Gd	0+
¹⁵³Dy	66	87	152.925765(5)	6.4(1) h	β⁺ (99.99%)	¹⁵³Tb	7/2(−)
¹⁵³Dy	66	87	152.925765(5)	6.4(1) h	α (.00939%)	¹⁴⁹Gd	7/2(−)
¹⁵⁴Dy	66	88	153.924424(8)	1.40(8)×10⁶ y^[5]	α^{[n 8]}	¹⁵⁰Gd	0+
¹⁵⁵Dy	66	89	154.925754(13)	9.9(2) h	β⁺	¹⁵⁵Tb	3/2−
^155mDy	234.33(3) keV			6(1) μs			11/2−
¹⁵⁶Dy	66	90	155.924283(7)	Observationally Stable^{[n 9]}			0+	5.6(3)×10⁻⁴
¹⁵⁷Dy	66	91	156.925466(7)	8.14(4) h	β⁺	¹⁵⁷Tb	3/2−
^157m1Dy	161.99(3) keV			1.3(2) μs			9/2+
^157m2Dy	199.38(7) keV			21.6(16) ms	IT	¹⁵⁷Dy	11/2−
¹⁵⁸Dy	66	92	157.924409(4)	Observationally Stable^{[n 10]}			0+	9.5(3)×10⁻⁴
¹⁵⁹Dy	66	93	158.9257392(29)	144.4(2) d	EC	¹⁵⁹Tb	3/2−
^159mDy	352.77(14) keV			122(3) μs			11/2−
¹⁶⁰Dy	66	94	159.9251975(27)	Observationally Stable^{[n 11]}			0+	0.02329(18)
¹⁶¹Dy	66	95	160.9269334(27)	Observationally Stable^{[n 12]}			5/2+	0.18889(42)
¹⁶²Dy	66	96	161.9267984(27)	Observationally Stable^{[n 13]}			0+	0.25475(36)
¹⁶³Dy	66	97	162.9287312(27)	Stable^{[n 14]}^[6]			5/2−	0.24896(42)
¹⁶⁴Dy^{[n 15]}	66	98	163.9291748(27)	Stable			0+	0.28260(54)
¹⁶⁵Dy	66	99	164.9317033(27)	2.334(1) h	β⁻	¹⁶⁵Ho	7/2+
^165mDy	108.160(3) keV			1.257(6) min	IT (97.76%)	¹⁶⁵Dy	1/2−
^165mDy	108.160(3) keV			1.257(6) min	β⁻ (2.24%)	¹⁶⁵Ho	1/2−
¹⁶⁶Dy	66	100	165.9328067(28)	81.6(1) h	β⁻	¹⁶⁶Ho	0+
¹⁶⁷Dy	66	101	166.93566(6)	6.20(8) min	β⁻	¹⁶⁷Ho	(1/2−)
¹⁶⁸Dy	66	102	167.93713(15)	8.7(3) min	β⁻	¹⁶⁸Ho	0+
¹⁶⁹Dy	66	103	168.94031(32)	39(8) s	β⁻	¹⁶⁹Ho	(5/2−)
¹⁷⁰Dy	66	104	169.94239(21)#	30# s	β⁻	¹⁷⁰Ho	0+
¹⁷¹Dy	66	105	170.94620(32)#	6# s	β⁻	¹⁷¹Ho	7/2−#
¹⁷²Dy	66	106	171.94876(43)#	3# s	β⁻	¹⁷²Ho	0+
¹⁷³Dy	66	107	172.95300(54)#	2# s	β⁻	¹⁷³Ho	9/2+#
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Geologically exceptional samples are found associated with the Oklo natural nuclear fission reactor, in which the isotopic composition lies outside the reported range. The uncertainty in the atomic mass may exceed the stated value for such specimens.

Dysprosium-165

The radioactive isotope ¹⁶⁵Dy, with a half-life of 2.334 hours, has radiopharmaceutical uses in radiation synovectomy of the knee. It had been previously performed with colloidal-sized particles containing longer-lived isotopes such as ¹⁹⁸Au and ⁹⁰Y. The major problem with the usage of those isotopes was radiation leakage out of the knee. ¹⁶⁵Dy, with its shorter half-life and thus shorter period of potential radiation leakage, is more suitable for the procedure.^[7]

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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