Isotopes of dysprosium

Isotopes of dysprosium (₆₆Dy)

Main isotopes[1] Decay abun­dance half-life (t1/2) mode pro­duct ^154Dy synth 1.40×10^6 y[2] α ^150Gd ^156Dy 0.056% stable ^158Dy 0.095% stable ^160Dy 2.33% stable ^161Dy 18.9% stable ^162Dy 25.5% stable ^163Dy 24.9% stable ^164Dy 28.3% stable ^165Dy synth 2.334 h β^− ^165Ho
Standard atomic weight Ar°(Dy)
	162.500±0.001[3] 162.50±0.01 (abridged)[4]

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)[5] [n 2][n 3]	Half-life[1] [n 4]	Decay mode[1] [n 5]	Daughter isotope [n 6]	Spin and parity[1] [n 7][n 4]	Natural abundance (mole fraction)
	Excitation energy							Normal proportion[1]	Range of variation
^139Dy	66	73	138.95953(54)#	600(200) ms	β^+ (~89%)	^139Tb	(7/2+)
					β^+, p (~11%)	^138Gd
^140Dy	66	74	139.95402(43)#	700# ms	β^+?	^140Tb	0+
					β^+, p?	^139Gd
^140mDy	2166.1(5) keV			7.0(5) μs	IT	^140Dy	8−
^141Dy	66	75	140.95128(32)#	0.90(14) s	β^+	^141Tb	(9/2−)
					β^+, p?	^140Gd
^142Dy	66	76	141.94619(78)#	2.3(3) s	β^+ (90%)	^142Tb	0+
					EC (10%)
					β^+, p (0.06%)	^141Gd
^143Dy	66	77	142.943994(14)	5.6(10) s	β^+	^143Tb	(1/2+)
					β^+, p?	^142Gd
^143m1Dy	310.7(6) keV			3.0(3) s	β^+	^143Tb	(11/2−)
					β^+, p?	^142Gd
^143m2Dy	406.3(8) keV			1.2(3) μs	IT	^143Dy	(7/2−)
^144Dy	66	78	143.9392695(77)	9.1(4) s	β^+	^144Tb	0+
					β^+, p?	^143Gd
^145Dy	66	79	144.9374740(70)	9.5(10) s	β^+	^145Tb	(1/2+)
					β^+, p?	^144Gd
^145mDy	118.2(2) keV			14.1(7) s	β^+	^145Tb	(11/2−)
					β^+, p (~50%)	^144Gd
^146Dy	66	80	145.9328445(72)	33.2(7) s	β^+	^146Tb	0+
^146mDy	2934.5(4) keV			150(20) ms	IT	^146Dy	10+
^147Dy	66	81	146.9310827(95)	67(7) s	β^+ (99.95%)	^147Tb	(1/2+)
					β^+, p (0.05%)	^146Tb
^147m1Dy	750.5(4) keV			55.2(5) s	β^+ (68.9%)	^147Tb	(11/2−)
					IT (31.1%)	^147Dy
^147m2Dy	3407.2(8) keV			0.40(1) μs	IT	^147Dy	(27/2−)
^148Dy	66	82	147.9271499(94)	3.3(2) min	β^+	^148Tb	0+
^148mDy	2919.1(10) keV			471(20) ns	IT	^148Dy	10+
^149Dy	66	83	148.9273275(99)	4.20(14) min	β^+	^149Tb	7/2−
^149mDy	2661.1(4) keV			490(15) ms	IT (99.3%)	^149Dy	27/2−
					β^+ (0.7%)	^149Tb
^150Dy	66	84	149.9255931(46)	7.17(5) min	β^+ (66.4%)	^150Tb	0+
					α (33.6%)	^146Gd
^151Dy	66	85	150.9261913(35)	17.9(3) min	β^+ (94.4%)	^151Tb	7/2−
					α (5.6%)	^147Gd
^152Dy	66	86	151.9247253(49)	2.38(2) h	EC (99.90%)	^152Tb	0+
					α (0.100%)	^148Gd
^153Dy	66	87	152.9257717(43)	6.4(1) h	β^+ (99.99%)	^153Tb	7/2−
					α (0.0094%)	^149Gd
^154Dy	66	88	153.9244289(80)	1.40(8)×10^6 y[6]	α[n 8]	^150Gd	0+
^155Dy	66	89	154.925758(10)	9.9(2) h	β^+	^155Tb	3/2−
^155mDy	234.33(3) keV			6(1) μs	IT	^155Dy	11/2−
^156Dy	66	90	155.9242836(11)	Observationally Stable[n 9]			0+	5.6(3)×10^−4
^157Dy	66	91	156.9254696(55)	8.14(4) h	β^+	^157Tb	3/2−
^157m1Dy	161.99(3) keV			1.3(2) μs	IT	^157Dy	9/2+
^157m2Dy	199.38(7) keV			21.6(16) ms	IT	^157Dy	11/2−
^158Dy	66	92	157.9244148(25)	Observationally Stable[n 10]			0+	9.5(3)×10^−4
^159Dy	66	93	158.9257459(15)	144.4(2) d	EC	^159Tb	3/2−
^159mDy	352.77(14) keV			122(3) μs	IT	^159Dy	11/2−
^160Dy	66	94	159.92520358(75)	Observationally Stable[n 11]			0+	0.02329(18)
^161Dy	66	95	160.92693943(75)	Observationally Stable[n 12]			5/2+	0.18889(42)
^161mDy	485.56(16) keV			0.76(17) μs	IT	^161Dy	11/2−
^162Dy	66	96	161.92680451(75)	Observationally Stable[n 13]			0+	0.25475(36)
^162mDy	2188.1(3) keV			8.3(3) μs	IT	^162Dy	8+
^163Dy	66	97	162.92873722(74)	Stable[n 14]			5/2−	0.24896(42)
^164Dy[n 15]	66	98	163.92918082(75)	Stable			0+	0.28260(54)
^165Dy	66	99	164.93170940(75)	2.332(4) h	β^−	^165Ho	7/2+
^165mDy	108.1552(13) keV			1.257(6) min	IT (97.76%)	^165Dy	1/2−
					β^− (2.24%)	^165Ho
^166Dy	66	100	165.93281281(86)	81.6(1) h	β^−	^166Ho	0+
^167Dy	66	101	166.9356824(43)	6.20(8) min	β^−	^167Ho	(1/2−)
^168Dy	66	102	167.93713(15)	8.7(3) min	β^−	^168Ho	0+
^168mDy	1378.2(6) keV			0.57(7) μs	IT	^168Dy	(4−)
^169Dy	66	103	168.94032(32)	39(8) s	β^−	^169Ho	(5/2)−
^169mDy	166.1(5) keV			1.26(17) μs	IT	^169Dy	(1/2−)
^170Dy	66	104	169.94234(22)#	54.9(80) s	β^−	^170Ho	0+
^170mDy	1643.8(3) keV			0.99(4) μs	IT	^170Dy	(6+)
^171Dy	66	105	170.94631(22)#	4.07(40) s	β^−	^171Ho	7/2−#
^172Dy	66	106	171.94873(32)#	3.4(2) s	β^−	^172Ho	0+
^172mDy	1278(1) keV			710(50) ms	IT (81%)	^172Dy	(8−)
					β^− (19%)	^172Ho
^173Dy	66	107	172.95304(43)#	1.43(20) s	β^−	^173Ho	9/2+#
					β^−, n?	^172Ho
^174Dy	66	108	173.95585(54)#	1# s [>300 ns]	β^−?	^174Ho	0+
					β^−, n?	^173Ho
^175Dy	66	109	174.96057(54)#	390# ms [>550 ns]	β^−?	^175Ho	1/2-#
					β^−, n?	^174Ho
^176Dy	66	110	175.96392(54)#	440# ms [>550 ns]	β^−?	^176Ho	0+
					β^−, n?	^175Ho
This table header & footer: view

1. ^mDy – 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. # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
5. Modes of decay:

   EC:	Electron capture
   IT:	Isomeric transition
   p:	Proton emission

6. Bold symbol as daughter – Daughter product is stable.
7. ( ) spin value – Indicates spin with weak assignment arguments.
8. Theorized to also undergo β^+β^+ decay to ^154Gd
9. Believed to undergo α decay to ^152Gd or β^+β^+ decay to ^156Gd with a half-life over 10^18 years
10. Believed to undergo α decay to ^154Gd or β^+β^+ decay to ^158Gd
11. Believed to undergo α decay to ^156Gd
12. Believed to undergo α decay to ^157Gd
13. Believed to undergo α decay to ^158Gd
14. Can undergo bound-state β^− decay to ^163Ho^66+ with a half-life of 47 days when fully ionized[7]
15. Heaviest theoretically stable nuclide

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.[8]

References

1. Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
2. Chiera, Nadine Mariel; Dressler, Rugard; Sprung, Peter; Talip, Zeynep; Schumann, Dorothea (2022-05-28). "High precision half-life measurement of the extinct radio-lanthanide Dysprosium-154". Scientific Reports. 12 (1). Springer Science and Business Media LLC. doi:10.1038/s41598-022-12684-6. ISSN 2045-2322.
3. "Standard Atomic Weights: Dysprosium". CIAAW. 2001.
4. Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
5. Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.
6. Chiera, Nadine Mariel; Dressler, Rugard; Sprung, Peter; Talip, Zeynep; Schumann, Dorothea (2022-05-28). "High precision half-life measurement of the extinct radio-lanthanide Dysprosium-154". Scientific Reports. 12 (1). Springer Science and Business Media LLC: 8988. Bibcode:2022NatSR..12.8988C. doi:10.1038/s41598-022-12684-6. ISSN 2045-2322. PMC 9148308. PMID 35643721.
7. M. Jung; et al. (1992-10-12). "First observation of bound-state β^− decay". Physical Review Letters. 69 (15): 2164–2167. Bibcode:1992PhRvL..69.2164J. doi:10.1103/PhysRevLett.69.2164. PMID 10046415.
8. Hnatowich, D. J.; Kramer, R. I.; Sledge, C. B.; Noble, J.; Shortkroff, S. (1978-03-01). "Dysprosium-165 ferric hydroxide macroaggregates for radiation synovectomy. [Rabbits]". J. Nucl. Med.; (United States). 19 (3). OSTI 5045140.

• 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.