# Isotopes of gold

Gold ($_{79}$Au) has one stable isotope, $^{197}$Au, and 40 radioisotopes, with $^{195}$Au 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 $^{209}$Bi isotope was observed. All isotopes of gold are either radioactive or, in the case of $^{197}$Au, observationally stable, meaning that $^{197}$Au is predicted to be radioactive but no actual decay has been observed.

## List of isotopes

| Nuclide | Z | N | Isotopic mass (Da) | Half-life | Decay mode | Daughter isotope | Spin and parity | Isotopic abundance |
| Isotopic abundance |||
| $^{170}$Au | 79 | 91 | 169.99602(22)# | 286+50 −40 μs | p (89%) | $^{169}$Pt | (2)− | |
| $^{170}$Au | 79 | 91 | 169.99602(22)# | 286+50 −40 μs | α (11%) | $^{166}$Ir | (2)− | |
| $^{170m}$Au | 282(10) keV | 282(10) keV | 282(10) keV | 617+50 −40 μs | p (58%) | $^{169}$Pt | (9)+ | |
| $^{170m}$Au | 282(10) keV | 282(10) keV | 282(10) keV | 617+50 −40 μs | α (42%) | $^{166m}$Ir | (9)+ | |
| $^{171}$Au | 79 | 92 | 170.991882(22) | 22+3 −2 μs | p | $^{170}$Pt | 1/2+ | |
| $^{171}$Au | 79 | 92 | 170.991882(22) | 22+3 −2 μs | α? | $^{167}$Ir | 1/2+ | |
| $^{171m}$Au | 258(13) keV | 258(13) keV | 258(13) keV | 1.09(3) ms | α (66%) | $^{167m}$Ir | 11/2− | |
| $^{171m}$Au | 258(13) keV | 258(13) keV | 258(13) keV | 1.09(3) ms | p (34%) | $^{170}$Pt | 11/2− | |
| $^{172}$Au | 79 | 93 | 171.99000(6) | 28(4) ms | α (98%) | $^{168}$Ir | (2)− | |
| $^{172}$Au | 79 | 93 | 171.99000(6) | 28(4) ms | p (2%) | $^{171}$Pt | (2)− | |
| $^{172}$Au | 79 | 93 | 171.99000(6) | 28(4) ms | β$^+$ | $^{172}$Pt | (2)− | |
| $^{172m}$Au | 160(250) keV | 160(250) keV | 160(250) keV | 11.0(10) ms | α | $^{168}$Ir | (9,10)+ | |
| $^{172m}$Au | 160(250) keV | 160(250) keV | 160(250) keV | 11.0(10) ms | p? | $^{171}$Pt | (9,10)+ | |
| $^{173}$Au | 79 | 94 | 172.986224(24) | 25.5(8) ms | α (86%) | $^{169}$Ir | (1/2+) | |
| $^{173}$Au | 79 | 94 | 172.986224(24) | 25.5(8) ms | β$^+$ (14%) | $^{173}$Pt | (1/2+) | |
| $^{173m}$Au | 214(21) keV | 214(21) keV | 214(21) keV | 12.2(1) ms | α (89%) | $^{169}$Ir | (11/2−) | |
| $^{173m}$Au | 214(21) keV | 214(21) keV | 214(21) keV | 12.2(1) ms | β$^+$ (11%) | $^{173}$Pt | (11/2−) | |
| $^{174}$Au | 79 | 95 | 173.98491(11)# | 139(3) ms | α (90%) | $^{170}$Ir | (3−) | |
| $^{174}$Au | 79 | 95 | 173.98491(11)# | 139(3) ms | β$^+$ (10%) | $^{174}$Pt | (3−) | |
| $^{174m}$Au | 130(50)# keV | 130(50)# keV | 130(50)# keV | 162(2) ms | α? | $^{170}$Ir | (9+) | |
| $^{174m}$Au | 130(50)# keV | 130(50)# keV | 130(50)# keV | 162(2) ms | β$^+$? | $^{174}$Pt | (9+) | |
| $^{175}$Au | 79 | 96 | 174.98132(4) | 200(3) ms | α (88%) | $^{171}$Ir | 1/2+ | |
| $^{175}$Au | 79 | 96 | 174.98132(4) | 200(3) ms | β$^+$ (12%) | $^{175}$Pt | 1/2+ | |
| $^{175m}$Au | 164(11)# keV | 164(11)# keV | 164(11)# keV | 136(1) ms | α (75%) | $^{171}$Ir | (11/2−) | |
| $^{175m}$Au | 164(11)# keV | 164(11)# keV | 164(11)# keV | 136(1) ms | β$^+$ (25%) | $^{175}$Pt | (11/2−) | |
| $^{176}$Au | 79 | 97 | 175.98012(4) | 1.05(1) s | α (75%) | $^{172}$Ir | (3−,4−) | |
| $^{176}$Au | 79 | 97 | 175.98012(4) | 1.05(1) s | β$^+$ (25%) | $^{176}$Pt | (3−,4−) | |
| $^{176m}$Au | 139(13) keV | 139(13) keV | 139(13) keV | 1.36(2) s | α? | $^{172}$Ir | (8+,9+) | |
| $^{176m}$Au | 139(13) keV | 139(13) keV | 139(13) keV | 1.36(2) s | β$^+$? | $^{176}$Pt | (8+,9+) | |
| $^{177}$Au | 79 | 98 | 176.976870(11) | 1.501(20) s | β$^+$ (60%) | $^{177}$Pt | 1/2+ | |
| $^{177}$Au | 79 | 98 | 176.976870(11) | 1.501(20) s | α (40%) | $^{173}$Ir | 1/2+ | |
| $^{177m}$Au | 190(7) keV | 190(7) keV | 190(7) keV | 1.193(13) s | α (60%) | $^{173}$Ir | 11/2− | |
| $^{177m}$Au | 190(7) keV | 190(7) keV | 190(7) keV | 1.193(13) s | β$^+$ (40%) | $^{177}$Pt | 11/2− | |
| $^{178}$Au | 79 | 99 | 177.976057(11) | 3.4(5) s | β$^+$ (84%) | $^{178}$Pt | (2+,3−) | |
| $^{178}$Au | 79 | 99 | 177.976057(11) | 3.4(5) s | α (16%) | $^{174}$Ir | (2+,3−) | |
| $^{178m1}$Au | 50.3(2) keV | 50.3(2) keV | 50.3(2) keV | 300(10) ns | IT | $^{178}$Au | (4−,5+) | |
| $^{178m2}$Au | 186(14) keV | 186(14) keV | 186(14) keV | 2.7(5) s | β$^+$ (82%) | $^{178}$Pt | (7+,8−) | |
| $^{178m2}$Au | 186(14) keV | 186(14) keV | 186(14) keV | 2.7(5) s | α (18%) | $^{174}$Ir | (7+,8−) | |
| $^{178m3}$Au | 243(14) keV | 243(14) keV | 243(14) keV | 390(10) ns | IT | $^{178}$Au | (5+,6) | |
| $^{179}$Au | 79 | 100 | 178.973174(13) | 7.1(3) s | β$^+$ (78.0%) | $^{179}$Pt | 1/2+ | |
| $^{179}$Au | 79 | 100 | 178.973174(13) | 7.1(3) s | α (22.0%) | $^{175}$Ir | 1/2+ | |
| $^{179m}$Au | 89.5(3) keV | 89.5(3) keV | 89.5(3) keV | 327(5) ns | IT | $^{179}$Au | (3/2−) | |
| $^{180}$Au | 79 | 101 | 179.9724898(51) | 7.9(3) s | β$^+$ (99.42%) | $^{180}$Pt | (1+) | |
| $^{180}$Au | 79 | 101 | 179.9724898(51) | 7.9(3) s | α (0.58%) | $^{176}$Ir | (1+) | |
| $^{181}$Au | 79 | 102 | 180.970079(21) | 13.7(14) s | β$^+$ (97.3%) | $^{181}$Pt | (5/2−) | |
| $^{181}$Au | 79 | 102 | 180.970079(21) | 13.7(14) s | α (2.7%) | $^{177}$Ir | (5/2−) | |
| $^{182}$Au | 79 | 103 | 181.969614(20) | 15.5(4) s | β$^+$ (99.87%) | $^{182}$Pt | (2+) | |
| $^{182}$Au | 79 | 103 | 181.969614(20) | 15.5(4) s | α (0.13%) | $^{178}$Ir | (2+) | |
| $^{183}$Au | 79 | 104 | 182.967588(10) | 42.8(10) s | β$^+$ (99.45%) | $^{183}$Pt | 5/2− | |
| $^{183}$Au | 79 | 104 | 182.967588(10) | 42.8(10) s | α (0.55%) | $^{179}$Ir | 5/2− | |
| $^{183m}$Au | 73.10(1) keV | 73.10(1) keV | 73.10(1) keV | >1 μs | IT | $^{183}$Au | (1/2)+ | |
| $^{184}$Au | 79 | 105 | 183.967452(24) | 20.6(9) s | β$^+$ (99.99%) | $^{184}$Pt | 5+ | |
| $^{184}$Au | 79 | 105 | 183.967452(24) | 20.6(9) s | α (0.013%) | $^{180}$Ir | 5+ | |
| $^{184m}$Au | 68.46(4) keV | 68.46(4) keV | 68.46(4) keV | 47.6(14) s | β$^+$ (70%) | $^{184}$Pt | 2+ | |
| $^{184m}$Au | 68.46(4) keV | 68.46(4) keV | 68.46(4) keV | 47.6(14) s | IT (30%) | $^{184}$Au | 2+ | |
| $^{184m}$Au | 68.46(4) keV | 68.46(4) keV | 68.46(4) keV | 47.6(14) s | α (0.013%) | $^{180}$Ir | 2+ | |
| $^{185}$Au | 79 | 106 | 184.9657989(28) | 4.25(6) min | β$^+$ (99.74%) | $^{185}$Pt | 5/2− | |
| $^{185}$Au | 79 | 106 | 184.9657989(28) | 4.25(6) min | α (0.26%) | $^{181}$Ir | 5/2− | |
| $^{185m}$Au | 50(50)# keV | 50(50)# keV | 50(50)# keV | 6.8(3) min | β$^+$ | $^{185}$Pt | 1/2+# | |
| $^{185m}$Au | 50(50)# keV | 50(50)# keV | 50(50)# keV | 6.8(3) min | IT? | $^{185}$Au | 1/2+# | |
| $^{186}$Au | 79 | 107 | 185.965953(23) | 10.7(5) min | β$^+$ | $^{186}$Pt | 3− | |
| $^{186}$Au | 79 | 107 | 185.965953(23) | 10.7(5) min | α (8×10$^{−4}$%) | $^{182}$Ir | 3− | |
| $^{186m}$Au | 227.77(7) keV | 227.77(7) keV | 227.77(7) keV | 110(10) ns | IT | $^{186}$Au | 2+ | |
| $^{187}$Au | 79 | 108 | 186.964542(24) | 8.3(2) min | β$^+$ | $^{187}$Pt | 1/2+ | |
| $^{187}$Au | 79 | 108 | 186.964542(24) | 8.3(2) min | α? | $^{183}$Ir | 1/2+ | |
| $^{187m}$Au | 120.33(14) keV | 120.33(14) keV | 120.33(14) keV | 2.3(1) s | IT | $^{187}$Au | 9/2− | |
| $^{188}$Au | 79 | 109 | 187.9652480(29) | 8.84(6) min | β$^+$ | $^{188}$Pt | 1− | |
| $^{189}$Au | 79 | 110 | 188.963948(22) | 28.7(4) min | β$^+$ | $^{189}$Pt | 1/2+ | |
| $^{189}$Au | 79 | 110 | 188.963948(22) | 28.7(4) min | α? (<3×10$^{−5}$%) | $^{185}$Ir | 1/2+ | |
| $^{189m1}$Au | 247.25(16) keV | 247.25(16) keV | 247.25(16) keV | 4.59(11) min | β$^+$ | $^{189}$Pt | 11/2− | |
| $^{189m1}$Au | 247.25(16) keV | 247.25(16) keV | 247.25(16) keV | 4.59(11) min | IT? | $^{189}$Au | 11/2− | |
| $^{189m2}$Au | 325.12(16) keV | 325.12(16) keV | 325.12(16) keV | 190(15) ns | IT | $^{189}$Au | 9/2− | |
| $^{189m3}$Au | 2554.8(8) keV | 2554.8(8) keV | 2554.8(8) keV | 242(10) ns | IT | $^{189}$Au | 31/2+ | |
| $^{190}$Au | 79 | 111 | 189.964752(4) | 42.8(10) min | β$^+$ | $^{190}$Pt | 1− | |
| $^{190}$Au | 79 | 111 | 189.964752(4) | 42.8(10) min | α? (<10$^{−6}$%) | $^{186}$Ir | 1− | |
| $^{190m}$Au | 200(150)# keV | 200(150)# keV | 200(150)# keV | 125(20) ms | IT | $^{190}$Au | 11−# | |
| $^{190m}$Au | 200(150)# keV | 200(150)# keV | 200(150)# keV | 125(20) ms | β$^+$? | $^{190}$Pt | 11−# | |
| $^{191}$Au | 79 | 112 | 190.963716(5) | 3.18(8) h | β$^+$ | $^{191}$Pt | 3/2+ | |
| $^{191m1}$Au | 266.2(7) keV | 266.2(7) keV | 266.2(7) keV | 920(110) ms | IT | $^{191}$Au | 11/2− | |
| $^{191m2}$Au | 2489.6(9) keV | 2489.6(9) keV | 2489.6(9) keV | 402(20) ns | IT | $^{191}$Au | 31/2+ | |
| $^{192}$Au | 79 | 113 | 191.964818(17) | 4.94(9) h | β$^+$ | $^{192}$Pt | 1− | |
| $^{192m1}$Au | 135.41(25) keV | 135.41(25) keV | 135.41(25) keV | 29 ms | IT | $^{192}$Au | 5+ | |
| $^{192m2}$Au | 431.6(5) keV | 431.6(5) keV | 431.6(5) keV | 160(20) ms | IT | $^{192}$Au | 11− | |
| $^{193}$Au | 79 | 114 | 192.964138(9) | 17.65(15) h | β$^+$ | $^{193}$Pt | 3/2+ | |
| $^{193m1}$Au | 290.20(4) keV | 290.20(4) keV | 290.20(4) keV | 3.9(3) s | IT (99.97%) | $^{193}$Au | 11/2− | |
| $^{193m1}$Au | 290.20(4) keV | 290.20(4) keV | 290.20(4) keV | 3.9(3) s | β$^+$ (0.03%) | $^{193}$Pt | 11/2− | |
| $^{193m2}$Au | 2486.7(6) keV | 2486.7(6) keV | 2486.7(6) keV | 150(50) ns | IT | $^{193}$Au | 31/2+ | |
| $^{194}$Au | 79 | 115 | 193.9654191(23) | 38.02(10) h | β$^+$ | $^{194}$Pt | 1− | |
| $^{194m1}$Au | 107.4(5) keV | 107.4(5) keV | 107.4(5) keV | 600(8) ms | IT | $^{194}$Au | 5+ | |
| $^{194m2}$Au | 475.8(6) keV | 475.8(6) keV | 475.8(6) keV | 420(10) ms | IT | $^{194}$Au | 11− | |
| $^{195}$Au | 79 | 116 | 194.9650378(12) | 186.01(6) d | EC | $^{195}$Pt | 3/2+ | |
| $^{195m1}$Au | 318.58(4) keV | 318.58(4) keV | 318.58(4) keV | 30.5(2) s | IT | $^{195}$Au | 11/2− | |
| $^{195m2}$Au | 2501(20)# keV | 2501(20)# keV | 2501(20)# keV | 12.89(21) μs | IT | $^{195}$Au | 31/2(−) | |
| $^{196}$Au | 79 | 117 | 195.966571(3) | 6.165(11) d | β$^+$ (93.0%) | $^{196}$Pt | 2− | |
| $^{196}$Au | 79 | 117 | 195.966571(3) | 6.165(11) d | β$^−$ (7.0%) | $^{196}$Hg | 2− | |
| $^{196m1}$Au | 84.656(20) keV | 84.656(20) keV | 84.656(20) keV | 8.1(2) s | IT | $^{196}$Au | 5+ | |
| $^{196m2}$Au | 595.66(4) keV | 595.66(4) keV | 595.66(4) keV | 9.603(22) h | IT | $^{196}$Au | 12− | |
| $^{197}$Au | 79 | 118 | 196.9665701(6) | Observationally Stable | Observationally Stable | Observationally Stable | 3/2+ | 1.0000 |
| $^{197m1}$Au | 409.15(8) keV | 409.15(8) keV | 409.15(8) keV | 7.73(6) s | IT | $^{197}$Au | 11/2− | |
| $^{197m2}$Au | 2532.5(10) keV | 2532.5(10) keV | 2532.5(10) keV | 150(5) ns | IT | $^{197}$Au | 27/2+# | |
| $^{198}$Au | 79 | 119 | 197.9682437(6) | 2.69464(14) d | β$^−$ | $^{198}$Hg | 2− | |
| $^{198m1}$Au | 312.2227(20) keV | 312.2227(20) keV | 312.2227(20) keV | 124(4) ns | IT | $^{198}$Au | 5+ | |
| $^{198m2}$Au | 811.9(15) keV | 811.9(15) keV | 811.9(15) keV | 2.272(16) d | IT | $^{198}$Au | 12− | |
| $^{199}$Au | 79 | 120 | 198.9687666(6) | 3.139(7) d | β$^−$ | $^{199}$Hg | 3/2+ | |
| $^{199m}$Au | 548.9405(21) keV | 548.9405(21) keV | 548.9405(21) keV | 440(30) μs | IT | $^{199}$Au | 11/2− | |
| $^{200}$Au | 79 | 121 | 199.970757(29) | 48.4(3) min | β$^−$ | $^{200}$Hg | (1−) | |
| $^{200m}$Au | 1010(40) keV | 1010(40) keV | 1010(40) keV | 18.7(5) h | β$^−$ (84%) | $^{200}$Hg | 12− | |
| $^{200m}$Au | 1010(40) keV | 1010(40) keV | 1010(40) keV | 18.7(5) h | IT (16%) | $^{200}$Au | 12− | |
| $^{201}$Au | 79 | 122 | 200.971658(3) | 26.0(8) min | β$^−$ | $^{201}$Hg | 3/2+ | |
| $^{201m1}$Au | 594(5) keV | 594(5) keV | 594(5) keV | 730(630) μs | IT | $^{201}$Au | 11/2- | |
| $^{201m2}$Au | 1610(5) keV | 1610(5) keV | 1610(5) keV | 5.6(24) μs | IT | $^{201}$Au | 19/2+# | |
| $^{202}$Au | 79 | 123 | 201.973856(25) | 28.4(12) s | β$^−$ | $^{202}$Hg | (1−) | |
| $^{203}$Au | 79 | 124 | 202.9751545(33) | 60(6) s | β$^−$ | $^{203}$Hg | 3/2+ | |
| $^{203m}$Au | 641(3) keV | 641(3) keV | 641(3) keV | 140(44) μs | IT | $^{203}$Au | 11/2−# | |
| $^{204}$Au | 79 | 125 | 203.97811(22)# | 38.3(13) s | β$^−$ | $^{204}$Hg | (2−) | |
| $^{204m}$Au | 3816(500)# keV | 3816(500)# keV | 3816(500)# keV | 2.1(3) μs | IT | $^{204}$Au | 16+# | |
| $^{205}$Au | 79 | 126 | 204.98006(22)# | 32.0(14) s | β$^−$ | $^{205}$Hg | 3/2+# | |
| $^{205m1}$Au | 907(5) keV | 907(5) keV | 907(5) keV | 6(2) s | IT? | $^{205}$Au | 11/2−# | |
| $^{205m1}$Au | 907(5) keV | 907(5) keV | 907(5) keV | 6(2) s | β$^−$? | $^{205}$Hg | 11/2−# | |
| $^{205m2}$Au | 2849.7(4) keV | 2849.7(4) keV | 2849.7(4) keV | 163(5) ns | IT | $^{205}$Au | 19/2+# | |
| $^{206}$Au | 79 | 127 | 205.98477(32)# | 47(11) s | β$^−$ | $^{206}$Hg | 6+# | |
| $^{207}$Au | 79 | 128 | 206.98858(32)# | 3# s [>300 ns] | β$^−$? | $^{207}$Hg | 3/2+# | |
| $^{207}$Au | 79 | 128 | 206.98858(32)# | 3# s [>300 ns] | β$^−$, n? | $^{206}$Hg | 3/2+# | |
| $^{208}$Au | 79 | 129 | 207.99366(32)# | 20# s [>300 ns] | β$^−$? | $^{208}$Hg | 6+# | |
| $^{208}$Au | 79 | 129 | 207.99366(32)# | 20# s [>300 ns] | β$^−$, n? | $^{207}$Hg | 6+# | |
| $^{209}$Au | 79 | 130 | 208.99761(43)# | 1# s [>300 ns] | β$^−$? | $^{209}$Hg | 3/2+# | |
| $^{209}$Au | 79 | 130 | 208.99761(43)# | 1# s [>300 ns] | β$^−$, n? | $^{210}$Hg | 3/2+# | |
| $^{210}$Au | 79 | 131 | 210.00288(43)# | 10# s [>300 ns] | β$^−$? | $^{210}$Hg | 6+# | |
| $^{210}$Au | 79 | 131 | 210.00288(43)# | 10# s [>300 ns] | β$^−$, n? | $^{209}$Hg | 6+# | |
| This table header & footer: view |||||||||
* ↑ $^m$Au – Excited nuclear isomer.
* ↑ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
* ↑ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
* 1 2 3 # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
* ↑ Modes of decay: EC:Electron capture IT:Isomeric transition p:Proton emission
* ↑ Bold italics symbol as daughter – Daughter product is nearly stable.
* ↑ Bold symbol as daughter – Daughter product is stable.
* ↑ ( ) spin value – Indicates spin with weak assignment arguments.
* 1 2 3 4 Order of ground state and isomer is uncertain.
* ↑ Theoretically capable of α decay to $^{189}$Ir
* ↑ Potential material for salted bombs
* ↑ Theoretically predicted to undergo α decay to $^{193}$Ir