Isotopes of dysprosium

Isotopes of dysprosium  (₆₆Dy)

Main isotopes [1] Decay Isotope abun­dance half-life (t1/2) mode pro­duct 154Dy synth 1.40×106 y [2] α 150Gd 156Dy 0.056% stable 158Dy 0.095% stable 159Dy synth 144.4 d ε 159Tb 160Dy 2.33% stable 161Dy 18.9% stable 162Dy 25.5% stable 163Dy 24.9% stable 164Dy 28.3% stable 165Dy synth 2.332 h β− 165Ho 166Dy synth 3.40 d β− 166Ho
Standard atomic weight Ar°(Dy)
	162.500±0.001 [3] 162.50±0.01 (abridged) [4]
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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 (28.26% 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 to isotopes of terbium, and after beta decay to those of holmium. Dysprosium is the heaviest element to have isotopes that are theoretically stable (163, 164), rather than only ones that are observationally stable and predicted to be radioactive. ¹⁶⁴Dy has a surprisingly large thermal neutron absorption and the product isotope ¹⁶⁵Dy has found medical use (see below).

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%)	146Gd
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)×106 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 [n 12]	66	95	160.92693943(75)	Observationally Stable [n 13]			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 14]			0+	0.25475(36)
162mDy	2188.1(3) keV			8.3(3) μs	IT	162Dy	8+
163Dy	66	97	162.92873722(74)	Stable [n 15]			5/2−	0.24896(42)
164Dy [n 16]	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 with a half-life over 10¹⁸ years or β⁺β⁺ decay to ¹⁵⁶Gd
10. Believed to undergo α decay to ¹⁵⁴Gd or β⁺β⁺ decay to ¹⁵⁸Gd
11. Believed to undergo α decay to ¹⁵⁶Gd
12. Fission product
13. Believed to undergo α decay to ¹⁵⁷Gd
14. Believed to undergo α decay to ¹⁵⁸Gd
15. Can undergo bound-state β⁻ decay to ¹⁶³Ho⁶⁶⁺ with a half-life of 47 days when fully ionized ^[7]
16. Heaviest theoretically stable nuclide

Dysprosium-165

The radioactive isotope ¹⁶⁵Dy, with a half-life of 2.332 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]

See also

Daughter products other than dysprosium

• Isotopes of holmium
• Isotopes of terbium
• Isotopes of gadolinium

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.