Isotopes of gold

Gold (₇₉Au) has one stable isotope, ¹⁹⁷Au, and 37 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 ^[n 4]	Decay mode ^[n 5]	Daughter isotope ^[n 6]^[n 7]	Spin and parity ^[n 8]^[n 4]	Natural abundance (mole fraction)
	Excitation energy^[n 4]							Normal proportion	Range of variation
^169Au^[6]	79	90	168.99808(32)#	1.16+0.50 −0.47 μs	p (~94%)	^168Pt	(11/2−)
					α (~6%)	^165mIr
^170Au^[7]	79	91	169.99602(22)#	286+50 −40 μs	p (89%)	^169Pt	(2−)
					α (11%)	^166Ir
^170mAu^[7]	282(10) keV			617+50 −40 μs	p (58%)	^169Pt	(9+)
					α (42%)	^166mIr
^171Au	79	92	170.991882(22)	22+3 −2 μs^[7]	p (100%)	^170Pt	(1/2+)
					α (rare)	^167Ir
^171mAu	258(13) keV			1.014(19) ms	α (66%)	^167mIr	11/2−
					p (34%)	^170Pt
^172Au	79	93	171.99000(6)	4.7(11) ms	α (98%)	^168Ir	high
					p (2%)	^171Pt
^173Au	79	94	172.986224(24)	25(1) ms	α	^169Ir	(1/2+)
					β^+ (rare)	^173Pt
^173mAu	214(23) keV			14.0(9) ms	α (96%)	^169Ir	(11/2−)
					β^+ (4%)	^173Pt
^174Au	79	95	173.98491(11)#	139(3) ms	α	^170Ir	low
					β^+ (rare)	^174Pt
^174mAu	360(70)# keV			171(29) ms			high
^175Au	79	96	174.98132(4)	100# ms	α (82%)	^171Ir	1/2+#
					β^+ (18%)	^175Pt
^175mAu	200(30)# keV			156(3) ms	α	^171Ir	11/2−#
					β^+	^175Pt
^176Au	79	97	175.98012(4)	1.08(17) s [0.84(+17−14) s]	α (60%)	^172Ir	(5−)
					β^+ (40%)	^176Pt
^176mAu	150(100)# keV			860(160) ms			(7+)
^177Au	79	98	176.976870(11)	1.462(32) s	β^+ (60%)	^177Pt	(1/2+, 3/2+)
					α (40%)	^173Ir
^177mAu	216(26) keV			1.180(12) s			11/2−
^178Au	79	99	177.976057(11)	2.6(5) s	β^+ (60%)	^178Pt
					α (40%)	^174Ir
^179Au	79	100	178.973174(13)	7.1(3) s	β^+ (78%)	^179Pt	5/2−#
					α (22%)	^175Ir
^179mAu	99(16) keV						(11/2−)
^180Au	79	101	179.972490(5)	8.1(3) s	β^+ (98.2%)	^180Pt
					α (1.8%)	^176Ir
^181Au	79	102	180.970079(21)	13.7(14) s	β^+ (97.3%)	^181Pt	(3/2−)
					α (2.7%)	^177Ir
^182Au	79	103	181.969614(20)	15.5(4) s	β^+ (99.87%)	^182Pt	(2+)
					α (.13%)	^178Ir
^183Au	79	104	182.967588(10)	42.8(10) s	β^+ (99.2%)	^183Pt	(5/2)−
					α (.8%)	^179Ir
^183m1Au	73.3(4) keV			>1 μs			(1/2)+
^183m2Au	230.6(6) keV			<1 μs			(11/2)−
^184Au	79	105	183.967452(24)	20.6(9) s	β^+	^184Pt	5+
^184mAu	68.46(1) keV			47.6(14) s	β^+ (70%)	^184Pt	2+
					IT (30%)	^184Au
					α (.013%)	^180Ir
^185Au	79	106	184.9657989(28)	4.25(6) min	β^+ (99.74%)	^185Pt	5/2−
					α (.26%)	^181Ir
^185mAu	100(100)# keV			6.8(3) min			1/2+#
^186Au	79	107	185.965953(23)	10.7(5) min	β^+ (99.9992%)	^186Pt	3−
					α (8×10^−4%)	^182Ir
^186mAu	227.77(7) keV			110(10) ns			2+
^187Au	79	108	186.964542(24)	8.4(3) min	β^+ (99.997%)	^187Pt	1/2+
					α (.003%)	^183Ir
^187mAu	120.51(16) 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(3) min	β^+ (99.9997%)	^189Pt	1/2+
					α (3×10^−4%)	^185Ir
^189m1Au	247.23(16) keV			4.59(11) min	β^+	^189Pt	11/2−
					IT (rare)	^189Au
^189m2Au	325.11(16) keV			190(15) ns			9/2−
^189m3Au	2554.7(12) keV			242(10) ns			31/2+
^190Au	79	111	189.964752(4)	42.8(10) min	β^+	^190Pt	1−
					α (<10^−6%)	^186Ir
^190mAu	200(150)# keV			125(20) ms	IT	^190Au	11−#
					β^+ (rare)	^190Pt
^191Au	79	112	190.963716(5)	3.18(8) h	β^+	^191Pt	3/2+
^191m1Au	266.2(5) keV			920(110) ms	IT	^191Au	(11/2−)
^191m2Au	2490(1) keV			>400 ns
^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			(11−)
^193Au	79	114	192.964138(9)	17.65(15) h	β^+^[n 9]	^193Pt	3/2+
^193m1Au	290.19(3) keV			3.9(3) s	IT (99.97%)	^193Au	11/2−
					β^+ (.03%)	^193Pt
^193m2Au	2486.5(6) keV			150(50) ns			(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			(11−)
^195Au	79	116	194.9650378(12)	186.098(47) d	EC	^195Pt	3/2+
^195mAu	318.58(4) keV			30.5(2) s	IT	^195Au	11/2−
^196Au	79	117	195.966571(3)	6.1669(6) d	β^+ (93.05%)	^196Pt	2−
					β^− (6.95%)	^196Hg
^196m1Au	84.660(20) keV			8.1(2) s	IT	^196Au	5+
^196m2Au	595.66(4) keV			9.6(1) h			12−
^197Au^[n 10]	79	118	196.9665701(6)	Observationally Stable^[n 11]			3/2+	1.0000
^197mAu	409.15(8) keV			7.73(6) s	IT	^197Au	11/2−
^198Au	79	119	197.9682437(6)	2.69517(21) d	β^−	^198Hg	2−
^198m1Au	312.2200(20) keV			124(4) ns			5+
^198m2Au	811.7(15) keV			2.27(2) d	IT	^198Au	(12−)
^199Au	79	120	198.9687666(6)	3.139(7) d	β^−	^199Hg	3/2+
^199mAu	548.9368(21) keV			440(30) μs			(11/2)−
^200Au	79	121	199.970757(29)	48.4(3) min	β^−	^200Hg	1(−)
^200mAu	970(70) keV			18.7(5) h	β^− (82%)	^200Hg	12−
					IT (18%)	^200Au
^201Au	79	122	200.971658(3)	26(1) min	β^−	^201Hg	3/2+
^201m1Au	594(5) keV			730(630) μs			(11/2-)
^201m2Au	1610(5) keV			5.6(2.4) μs			(11/2-)
^202Au	79	123	201.973856(25)	28.8(19) s	β^−	^202Hg	(1−)
^203Au	79	124	202.975154(3)	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(1.3) s	β^−	^204Hg	(2−)
^204mAu	3816(1000)# keV			2.1(0.3) μs	IT	^204Au	16+#
^205Au	79	126	204.98006(22)#	32.5(1.4) s	β^−	^205Hg	3/2+#
^205m1Au	907(5) keV			6(2) s			11/2−#
^205m2Au	2850(5) keV			163(5) ns			19/2+#
^206Au	79	127	205.98477(32)#	47(11) s	β^−	^206Hg	(5+, 6+)
^207Au	79	128	206.98858(32)#	3# s			3/2+#
^208Au	79	129	207.99366(32)#	20# s			6+#
^209Au	79	130	208.99761(43)#	1# s			3/2+#
^210Au	79	131	210.00288(43)#	10# s			6+#
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. Theoretically capable of α decay to ¹⁸⁹Ir^[1]
10. Potential material for salted bombs
11. 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. Hilton, Joshua Ben. "Decays of new nuclides 169Au, 170Hg, 165Pt and the ground state of 165Ir discovered using MARA" (PDF). University of Liverpool. Retrieved 11 June 2023.
7. 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.