Isotopes of gold

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Gold (79Au) has one stable isotope, 197Au, and known radioisotopes ranging from 169Au to 210Au, with 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.

Quick facts Main isotopes, Decay ...
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)
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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


More information Nuclide, Z ...
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:
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  1. [1]
    mAu – Excited nuclear isomer.
  2. [2]
    ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
  3. [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. [4]
    # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  5. [5]
    Modes of decay:
    EC:Electron capture
    IT:Isomeric transition
    p:Proton emission
  6. [6]
    Bold italics symbol as daughter – Daughter product is nearly stable.
  7. [7]
    Bold symbol as daughter – Daughter product is stable.
  8. [8]
    ( ) spin value – Indicates spin with weak assignment arguments.
  9. [9]
    Order of ground state and isomer is uncertain.
  10. [10]
    Potential material for salted bombs
  11. [11]
    Theoretically predicted to undergo α decay to 193Ir

See also

Daughter products other than gold

References

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