Isotopes of gold

Gold (₇₉Au) has one stable isotope, ¹⁹⁷Au, and 40 radioisotopes, with ¹⁹⁵Au being the most stable with a half-life of 186 days. Gold is currently considered the heaviest monoisotopic element. Bismuth formerly held that distinction until alpha-decay of the ²⁰⁹Bi isotope was observed. All isotopes of gold are either radioactive or, in the case of ¹⁹⁷Au, observationally stable, meaning that ¹⁹⁷Au is predicted to be radioactive but no actual decay has been observed.^[4]

Isotopes of gold (₇₉Au)

Main isotopes[1] Decay abun­dance half-life (t1/2) mode pro­duct 195Au synth 186.01 d ε 195Pt 196Au synth 6.165 d β+ 196Pt β− 196Hg 197Au 100% stable 198Au synth 2.69464 d β− 198Hg 199Au synth 3.139 d β− 199Hg
Standard atomic weight Ar°(Au)
	196.966570±0.000004[2] 196.97±0.01 (abridged)[3]
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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][n 7]	Spin and parity[1] [n 8][n 4]	Isotopic abundance
	Excitation energy[n 4]
170Au[6]	79	91	169.99602(22)#	286+50 −40 μs	p (89%)	169Pt	(2)−
					α (11%)	166Ir
170mAu[6]	282(10) keV			617+50 −40 μs	p (58%)	169Pt	(9)+
					α (42%)	166mIr
171Au[6]	79	92	170.991882(22)	22+3 −2 μs	p	170Pt	1/2+
					α?	167Ir
171mAu[6]	258(13) keV			1.09(3) ms	α (66%)	167mIr	11/2−
					p (34%)	170Pt
172Au	79	93	171.99000(6)	28(4) ms	α (98%)	168Ir	(2)−
					p (2%)	171Pt
					β+	172Pt
172mAu[n 9]	160(250) keV			11.0(10) ms	α	168Ir	(9,10)+
					p?	171Pt
173Au	79	94	172.986224(24)	25.5(8) ms	α (86%)	169Ir	(1/2+)
					β+ (14%)	173Pt
173mAu	214(21) keV			12.2(1) ms	α (89%)	169Ir	(11/2−)
					β+ (11%)	173Pt
174Au	79	95	173.98491(11)#	139(3) ms	α (90%)	170Ir	(3−)
					β+ (10%)	174Pt
174mAu	130(50)# keV			162(2) ms	α?	170Ir	(9+)
					β+?	174Pt
175Au	79	96	174.98132(4)	200(3) ms	α (88%)	171Ir	1/2+
					β+ (12%)	175Pt
175mAu	164(11)# keV			136(1) ms	α (75%)	171Ir	(11/2−)
					β+ (25%)	175Pt
176Au	79	97	175.98012(4)	1.05(1) s	α (75%)	172Ir	(3−,4−)
					β+ (25%)	176Pt
176mAu[n 9]	139(13) keV			1.36(2) s	α?	172Ir	(8+,9+)
					β+?	176Pt
177Au	79	98	176.976870(11)	1.501(20) s	β+ (60%)	177Pt	1/2+
					α (40%)	173Ir
177mAu	190(7) keV			1.193(13) s	α (60%)	173Ir	11/2−
					β+ (40%)	177Pt
178Au	79	99	177.976057(11)	3.4(5) s	β+ (84%)	178Pt	(2+,3−)
					α (16%)	174Ir
178m1Au	50.3(2) keV			300(10) ns	IT	178Au	(4−,5+)
178m2Au	186(14) keV			2.7(5) s	β+ (82%)	178Pt	(7+,8−)
					α (18%)	174Ir
178m3Au	243(14) keV			390(10) ns	IT	178Au	(5+,6)
179Au	79	100	178.973174(13)	7.1(3) s	β+ (78.0%)	179Pt	1/2+
					α (22.0%)	175Ir
179mAu	89.5(3) keV			327(5) ns	IT	179Au	(3/2−)
180Au	79	101	179.9724898(51)	7.9(3) s	β+ (99.42%)	180Pt	(1+)
					α (0.58%)	176Ir
181Au	79	102	180.970079(21)	13.7(14) s	β+ (97.3%)	181Pt	(5/2−)
					α (2.7%)	177Ir
182Au	79	103	181.969614(20)	15.5(4) s	β+ (99.87%)	182Pt	(2+)
					α (0.13%)	178Ir
183Au	79	104	182.967588(10)	42.8(10) s	β+ (99.45%)	183Pt	5/2−
					α (0.55%)	179Ir
183mAu	73.10(1) keV			>1 μs	IT	183Au	(1/2)+
184Au	79	105	183.967452(24)	20.6(9) s	β+ (99.99%)	184Pt	5+
					α (0.013%)	180Ir
184mAu	68.46(4) keV			47.6(14) s	β+ (70%)	184Pt	2+
					IT (30%)	184Au
					α (0.013%)	180Ir
185Au	79	106	184.9657989(28)	4.25(6) min	β+ (99.74%)	185Pt	5/2−
					α (0.26%)	181Ir
185mAu[n 9]	50(50)# keV			6.8(3) min	β+	185Pt	1/2+#
					IT?	185Au
186Au	79	107	185.965953(23)	10.7(5) min	β+	186Pt	3−
					α (8×10−4%)	182Ir
186mAu	227.77(7) keV			110(10) ns	IT	186Au	2+
187Au	79	108	186.964542(24)	8.3(2) min	β+	187Pt	1/2+
					α?	183Ir
187mAu	120.33(14) keV			2.3(1) s	IT	187Au	9/2−
188Au	79	109	187.9652480(29)	8.84(6) min	β+	188Pt	1−
189Au	79	110	188.963948(22)	28.7(4) min	β+	189Pt	1/2+
					α? (<3×10−5%)	185Ir
189m1Au	247.25(16) keV			4.59(11) min	β+	189Pt	11/2−
					IT?	189Au
189m2Au	325.12(16) keV			190(15) ns	IT	189Au	9/2−
189m3Au	2554.8(8) keV			242(10) ns	IT	189Au	31/2+
190Au	79	111	189.964752(4)	42.8(10) min	β+	190Pt	1−
					α? (<10−6%)	186Ir
190mAu[n 9]	200(150)# keV			125(20) ms	IT	190Au	11−#
					β+?	190Pt
191Au	79	112	190.963716(5)	3.18(8) h	β+	191Pt	3/2+
191m1Au	266.2(7) keV			920(110) ms	IT	191Au	11/2−
191m2Au	2489.6(9) keV			402(20) ns	IT	191Au	31/2+
192Au	79	113	191.964818(17)	4.94(9) h	β+	192Pt	1−
192m1Au	135.41(25) keV			29 ms	IT	192Au	5+
192m2Au	431.6(5) keV			160(20) ms	IT	192Au	11−
193Au	79	114	192.964138(9)	17.65(15) h	β+[n 10]	193Pt	3/2+
193m1Au	290.20(4) keV			3.9(3) s	IT (99.97%)	193Au	11/2−
					β+ (0.03%)	193Pt
193m2Au	2486.7(6) keV			150(50) ns	IT	193Au	31/2+
194Au	79	115	193.9654191(23)	38.02(10) h	β+	194Pt	1−
194m1Au	107.4(5) keV			600(8) ms	IT	194Au	5+
194m2Au	475.8(6) keV			420(10) ms	IT	194Au	11−
195Au	79	116	194.9650378(12)	186.01(6) d	EC	195Pt	3/2+
195m1Au	318.58(4) keV			30.5(2) s	IT	195Au	11/2−
195m2Au	2501(20)# keV			12.89(21) μs	IT	195Au	31/2(−)
196Au	79	117	195.966571(3)	6.165(11) d	β+ (93.0%)	196Pt	2−
					β− (7.0%)	196Hg
196m1Au	84.656(20) keV			8.1(2) s	IT	196Au	5+
196m2Au	595.66(4) keV			9.603(22) h	IT	196Au	12−
197Au[n 11]	79	118	196.9665701(6)	Observationally Stable[n 12]			3/2+	1.0000
197m1Au	409.15(8) keV			7.73(6) s	IT	197Au	11/2−
197m2Au	2532.5(10) keV			150(5) ns	IT	197Au	27/2+#
198Au	79	119	197.9682437(6)	2.69464(14) d	β−	198Hg	2−
198m1Au	312.2227(20) keV			124(4) ns	IT	198Au	5+
198m2Au	811.9(15) keV			2.272(16) d	IT	198Au	12−
199Au	79	120	198.9687666(6)	3.139(7) d	β−	199Hg	3/2+
199mAu	548.9405(21) keV			440(30) μs	IT	199Au	11/2−
200Au	79	121	199.970757(29)	48.4(3) min	β−	200Hg	(1−)
200mAu	1010(40) keV			18.7(5) h	β− (84%)	200Hg	12−
					IT (16%)	200Au
201Au	79	122	200.971658(3)	26.0(8) min	β−	201Hg	3/2+
201m1Au	594(5) keV			730(630) μs	IT	201Au	11/2-
201m2Au	1610(5) keV			5.6(24) μs	IT	201Au	19/2+#
202Au	79	123	201.973856(25)	28.4(12) s	β−	202Hg	(1−)
203Au	79	124	202.9751545(33)	60(6) s	β−	203Hg	3/2+
203mAu	641(3) keV			140(44) μs	IT	203Au	11/2−#
204Au	79	125	203.97811(22)#	38.3(13) s	β−	204Hg	(2−)
204mAu	3816(500)# keV			2.1(3) μs	IT	204Au	16+#
205Au	79	126	204.98006(22)#	32.0(14) s	β−	205Hg	3/2+#
205m1Au	907(5) keV			6(2) s	IT?	205Au	11/2−#
					β−?	205Hg
205m2Au	2849.7(4) keV			163(5) ns	IT	205Au	19/2+#
206Au	79	127	205.98477(32)#	47(11) s	β−	206Hg	6+#
207Au	79	128	206.98858(32)#	3# s [>300 ns]	β−?	207Hg	3/2+#
					β−, n?	206Hg
208Au	79	129	207.99366(32)#	20# s [>300 ns]	β−?	208Hg	6+#
					β−, n?	207Hg
209Au	79	130	208.99761(43)#	1# s [>300 ns]	β−?	209Hg	3/2+#
					β−, n?	210Hg
210Au	79	131	210.00288(43)#	10# s [>300 ns]	β−?	210Hg	6+#
					β−, n?	209Hg
This table header & footer: view

1. ^mAu – 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 italics symbol as daughter – Daughter product is nearly stable.
7. Bold symbol as daughter – Daughter product is stable.
8. ( ) spin value – Indicates spin with weak assignment arguments.
9. Order of ground state and isomer is uncertain.
10. Theoretically capable of α decay to ¹⁸⁹Ir
11. Potential material for salted bombs
12. Theoretically predicted to undergo α decay to ¹⁹³Ir

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. "Standard Atomic Weights: Gold". CIAAW. 2017.
3. 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.
4. Belli, P.; Bernabei, R.; Danevich, F. A.; et al. (2019). "Experimental searches for rare alpha and beta decays". European Physical Journal A. 55 (8): 140–1–140–7. arXiv:1908.11458. Bibcode:2019EPJA...55..140B. doi:10.1140/epja/i2019-12823-2. ISSN 1434-601X. S2CID 201664098.
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. Kettunen, H.; Enqvist, T.; Grahn, T.; Greenlees, P. T.; Jones, P.; Julin, R.; Juutinen, S.; Keenan, A.; Kuusiniemi, P.; Leino, M.; Leppänen, A.-P.; Nieminen, P.; Pakarinen, J.; Rahkila, P.; Uusitalo, J. (28 May 2004). "Decay studies of Au 170 , 171 , Hg 171 – 173 , and Tl 176". Physical Review C. 69 (5): 054323. doi:10.1103/PhysRevC.69.054323. ISSN 0556-2813. Retrieved 11 June 2023.

• 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.