Isotopes of gold

Isotopes of gold  (₇₉Au)

Main isotopes [1] Decay Isotope 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 2.6946 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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Gold (₇₉Au) has one stable isotope, ¹⁹⁷Au, and known radioisotopes ranging from ¹⁶⁹Au to ²¹⁰Au, with the most stable ¹⁹⁵Au being the most stable with a half-life of 186.01 days, followed by ¹⁹⁶Au at 6.165 days. Isotopes heavier than the stable mass number 197 generally decay by beta emission to mercury isotopes, while those lighter decay by electron capture to platinum isotopes or alpha emission to iridium isotopes; 196 decays both to platinum and to mercury. Of the meta states the most stable is ^198m2Au at 2.27 days.

Gold is currently the heaviest monoisotopic element (and is also mononuclidic). 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]

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]
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 [7]	79	92	170.991882(22)	22+3 −2 μs	p	170Pt	1/2+
					α?	167Ir
171mAu [7]	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+	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 10]	79	118	196.9665701(6)	Observationally Stable [n 11]			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?	208Hg
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. Potential material for salted bombs
11. Theoretically predicted to undergo α decay to ¹⁹³Ir

See also

Daughter products other than gold

• Isotopes of mercury
• Isotopes of platinum
• Isotopes of iridium

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.