Isotopes of gold

Gold (Au) has one stable isotope, ¹⁹⁷Au, and 18 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, but bismuth-209 has been found to be slightly radioactive).

Relative atomic mass: 196.966569(5).^[1]

Radioactive particle tracking

Inside coker units at oil refineries, gold-198 is used to study the hydrodynamic behavior of solids in fluidized beds and can also be used to quantify the degree of fouling of bed internals.^[2]

Nuclear medicine

Gold-198 is a beta emitter with range in tissue of about 11 mm and half life 2.7 days. It is used in some cancer treatments and for treating other diseases.^[3][4] Gold-198 nanoparticles are being investigated as an injectable treatment for prostate cancer.^[5]

Nuclear weapons

Gold has been proposed as a material for creating a salted nuclear weapon (cobalt is another, better-known salting material). A jacket of natural ¹⁹⁷Au, irradiated by the intense high-energy neutron flux from an exploding thermonuclear weapon, would transmute into the radioactive isotope ¹⁹⁸Au with a half-life of 2.697 days and produce approximately .411 MeV of gamma radiation, significantly increasing the radioactivity of the weapon's fallout for several days. Such a weapon is not known to have ever been built, tested, or used.^[6] Gold has been used in thermonuclear weapons as radiation mirrors within the secondary assembly. Ivy Mike used a thin layer of gold on the secondary casing walls to enhance the blackbody effect, trapping more energy in the foam to enhance the implosion.^[7]

The highest amount of ¹⁹⁸Au detected in any United States nuclear test was in shot "Sedan" detonated at Nevada Test Site on July 6, 1962.^[8]

Table

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life	decay mode(s)[9][n 1]	daughter isotope(s)[n 2]	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
	excitation energy
^169Au	79	90	168.99808(32)#	150# µs			1/2+#
^170Au	79	91	169.99612(22)#	310(50) µs [286(+50−40) µs]			(2−)
^170mAu	275(14) keV			630(60) µs [0.62(+6−5) ms]			(9+)
^171Au	79	92	170.991879(28)	30(5) µs	p	^170Pt	(1/2+)
					α (rare)	^167Ir
^171mAu	250(16) keV			1.014(19) ms	α (54%)	^167Ir	11/2−
					p (46%)	^170Pt
^172Au	79	93	171.99004(17)#	4.7(11) ms	α (98%)	^168Ir	high
					p (2%)	^171Pt
^173Au	79	94	172.986237(28)	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	173.98476(11)#	139(3) ms	α	^170Ir	low
					β^+ (rare)	^174Pt
^174mAu	360(70)# keV			171(29) ms			high
^175Au	79	96	174.98127(5)	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	175.98010(11)#	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	176.976865(14)	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	177.97603(6)	2.6(5) s	β^+ (60%)	^178Pt
					α (40%)	^174Ir
^179Au	79	100	178.973213(18)	7.1(3) s	β^+ (78%)	^179Pt	5/2−#
					α (22%)	^175Ir
^179mAu	99(16) keV						(11/2−)
^180Au	79	101	179.972521(23)	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	181.969618(22)	15.5(4) s	β^+ (99.87%)	^182Pt	(2+)
					α (.13%)	^178Ir
^183Au	79	104	182.967593(11)	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	184.965789(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	186.964568(27)	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	187.965324(22)	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	189.964700(17)	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	190.96370(4)	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	191.964813(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	192.964150(11)	17.65(15) h	β^+ (100%)	^193Pt	3/2+
					α (10^−5%)	^189Ir
^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	193.965365(11)	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	194.9650346(14)	186.098(47) d	EC	^195Pt	3/2+
^195mAu	318.58(4) keV			30.5(2) s	IT	^195Au	11/2−
^196Au	79	117	195.966570(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 3]	79	118	196.9665687(6)	Observationally Stable[n 4]			3/2+	1.0000
^197mAu	409.15(8) keV			7.73(6) s	IT	^197Au	11/2−
^198Au	79	119	197.9682423(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	198.9687652(6)	3.139(7) d	β^−	^199Hg	3/2+
^199mAu	548.9368(21) keV			440(30) µs			(11/2)−
^200Au	79	121	199.97073(5)	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	200.971657(3)	26(1) min	β^−	^201Hg	3/2+
^202Au	79	123	201.97381(18)	28.8(19) s	β^−	^202Hg	(1−)
^203Au	79	124	202.975155(3)	53(2) s	β^−	^203Hg	3/2+
^204Au	79	125	203.97772(22)#	39.8(9) s	β^−	^204Hg	(2−)
^205Au	79	126	204.97987(32)#	31(2) s	β^−	^205Hg	3/2+

1. Abbreviations:
   EC: Electron capture
   IT: Isomeric transition
2. Bold for stable isotopes, bold italics for nearly-stable isotopes (half-life longer than the age of the universe)
3. Potential material for salted bombs
4. Believed to undergo α decay to ¹⁹³Ir

Notes

• Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
• Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC, which use expanded uncertainties.

References

1. Table of Standard Atomic Weights 2013 – CIAAW
2. Sanchez, Francisco J.; Granovskiy, Mikhail (2012). "Application of radioactive particle tracking to indicate shed fouling in the stripper section of a fluid coker". Canadian Journal of Chemical Engineering. doi:10.1002/cjce.21740.
3. "Nanoscience and Nanotechnology in Nanomedicine: Hybrid Nanoparticles In Imaging and Therapy of Prostate Cancer". Radiopharmaceutical Sciences Institute, University of Missouri-Columbia. Archived from the original on March 14, 2009.
4. Hainfeld, James F.; Dilmanian, F. Avraham; Slatkin, Daniel N.; Smilowitz, Henry M. (2008). "Radiotherapy enhancement with gold nanoparticles". Journal of Pharmacy and Pharmacology 60 (8): 977–85. doi:10.1211/jpp.60.8.0005. PMID 18644191.
5. "Green Tea and Gold Nanoparticles Destroy Prostate Tumors". 2012.
6. D. T. Win; M. Al Masum (2003). "Weapons of Mass Destruction" (PDF). Assumption University Journal of Technology 6 (4): 199–219.
7. Rhodes, Richard (1995). Dark sun: The making of the hydrogen bomb. New York: Simon & Schuster. ISBN 0-684-80400-X.
8. R. L. Miller (2002). U.S. Atlas of Nuclear Fallout, 1951–1970 1 (Abridged General Reader ed.). Two Sixty Press. p. 340. ISBN 1-881043-13-4.
9. "Universal Nuclide Chart". nucleonica. (registration required (help)).

• Isotope masses from:
  • G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A 729 (1): 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.
• Isotopic compositions and standard atomic masses from:
  • J. R. de Laeter; J. K. Böhlke; P. De Bièvre; H. Hidaka; H. S. Peiser; K. J. R. Rosman; P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry 75 (6): 683–800. doi:10.1351/pac200375060683.
  • M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry 78 (11): 2051–2066. doi:10.1351/pac200678112051. Lay summary.
• Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
  • G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A 729 (1): 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.
  • National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. Retrieved September 2005.
  • N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide. CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0-8493-0485-9.