# Isotopes of mercury

There are seven stable isotopes of mercury ($_{80}$Hg) with $^{202}$Hg being the most abundant (29.86%). The longest-lived radioisotopes are $^{194}$Hg with a half-life of 444 years, and $^{203}$Hg with a half-life of 46.612 days. Most of the remaining 40 radioisotopes have half-lives that are less than a day. $^{199}$Hg and $^{201}$Hg are the most often studied NMR-active nuclei, having spin quantum numbers of 1/2 and 3/2 respectively. All isotopes of mercury are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed. These isotopes are predicted to undergo either alpha decay or double beta decay.

## List of isotopes

| Nuclide | Z | N | Isotopic mass (Da) | Half-life | Decay mode | Daughter isotope | Spin and parity | Natural abundance (mole fraction) | Natural abundance (mole fraction) |
| Nuclide | Excitation energy | Excitation energy | Excitation energy | Half-life | Decay mode | Daughter isotope | Spin and parity | Normal proportion | Range of variation |
| $^{170}$Hg | 80 | 90 | 170.00581(32)# | 310(250) μs | α | $^{166}$Pt | 0+ | | |
| $^{171}$Hg | 80 | 91 | 171.00359(33)# | 70(30) μs | α | $^{167}$Pt | 3/2−# | | |
| $^{172}$Hg | 80 | 92 | 171.99886(16) | 231(9) μs | α | $^{168}$Pt | 0+ | | |
| $^{173}$Hg | 80 | 93 | 172.99714(22)# | 800(80) μs | α | $^{169}$Pt | (7/2−) | | |
| $^{174}$Hg | 80 | 94 | 173.992871(21) | 2.0(4) ms | α | $^{170}$Pt | 0+ | | |
| $^{175}$Hg | 80 | 95 | 174.99144(9) | 10.2(3) ms | α | $^{171}$Pt | (7/2−) | | |
| $^{175m}$Hg | 494(2) keV | 494(2) keV | 494(2) keV | 340(30) ns | IT | $^{175}$Hg | (13/2+) | | |
| $^{176}$Hg | 80 | 96 | 175.987349(12) | 20.3(14) ms | α (90%) | $^{172}$Pt | 0+ | | |
| $^{176}$Hg | 80 | 96 | 175.987349(12) | 20.3(14) ms | β$^+$ (10%) | $^{176}$Au | 0+ | | |
| $^{177}$Hg | 80 | 97 | 176.98628(9) | 117(7) ms | α | $^{173}$Pt | 7/2− | | |
| $^{177m}$Hg | 323.2(13) keV | 323.2(13) keV | 323.2(13) keV | 1.50(15) μs | IT | $^{177}$Hg | 13/2+ | | |
| $^{178}$Hg | 80 | 98 | 177.982485(12) | 266.5(24) ms | α (89%) | $^{174}$Pt | 0+ | | |
| $^{178}$Hg | 80 | 98 | 177.982485(12) | 266.5(24) ms | β$^+$ (11%) | $^{178}$Au | 0+ | | |
| $^{179}$Hg | 80 | 99 | 178.98182(3) | 1.05(3) s | α (75%) | $^{175}$Pt | 7/2− | | |
| $^{179}$Hg | 80 | 99 | 178.98182(3) | 1.05(3) s | β$^+$ (25%) | $^{179}$Au | 7/2− | | |
| $^{179}$Hg | 80 | 99 | 178.98182(3) | 1.05(3) s | β$^+$, p (0.15%) | $^{178}$Pt | 7/2− | | |
| $^{179m}$Hg | 171.4(4) keV | 171.4(4) keV | 171.4(4) keV | 6.4(9) μs | IT | $^{179}$Hg | 13/2+ | | |
| $^{180}$Hg | 80 | 100 | 179.978260(14) | 2.59(1) s | β$^+$ (52%) | $^{180}$Au | 0+ | | |
| $^{180}$Hg | 80 | 100 | 179.978260(14) | 2.59(1) s | α (48%) | $^{176}$Pt | 0+ | | |
| $^{181}$Hg | 80 | 101 | 180.977819(17) | 3.6(1) s | β$^+$ (73%) | $^{181}$Au | 1/2− | | |
| $^{181}$Hg | 80 | 101 | 180.977819(17) | 3.6(1) s | α (27%) | $^{177}$Pt | 1/2− | | |
| $^{181}$Hg | 80 | 101 | 180.977819(17) | 3.6(1) s | β$^+$, p (0.014%) | $^{180}$Pt | 1/2− | | |
| $^{181}$Hg | 80 | 101 | 180.977819(17) | 3.6(1) s | β$^+$, α (9×10$^{−6}$%) | $^{177}$Ir | 1/2− | | |
| $^{181m}$Hg | 210(50) keV | 210(50) keV | 210(50) keV | 480(20) μs | IT | $^{181}$Hg | 13/2+ | | |
| $^{182}$Hg | 80 | 102 | 181.974689(11) | 10.83(6) s | β$^+$ (86.2%) | $^{182}$Au | 0+ | | |
| $^{182}$Hg | 80 | 102 | 181.974689(11) | 10.83(6) s | α (13.8%) | $^{178}$Pt | 0+ | | |
| $^{182}$Hg | 80 | 102 | 181.974689(11) | 10.83(6) s | β$^+$, p (<1×10$^{−5}$%) | $^{181}$Pt | 0+ | | |
| $^{183}$Hg | 80 | 103 | 182.974445(8) | 9.4(7) s | β$^+$ (88.3%) | $^{183}$Au | 1/2− | | |
| $^{183}$Hg | 80 | 103 | 182.974445(8) | 9.4(7) s | α (11.7%) | $^{179}$Pt | 1/2− | | |
| $^{183}$Hg | 80 | 103 | 182.974445(8) | 9.4(7) s | β$^+$, p (2.6×10$^{−4}$%) | $^{182}$Pt | 1/2− | | |
| $^{183m}$Hg | 204(14) keV | 204(14) keV | 204(14) keV | >5# μs | | | 13/2+# | | |
| $^{184}$Hg | 80 | 104 | 183.971718(10) | 30.87(26) s | β$^+$ (98.89%) | $^{184}$Au | 0+ | | |
| $^{184}$Hg | 80 | 104 | 183.971718(10) | 30.87(26) s | α (1.11%) | $^{180}$Pt | 0+ | | |
| $^{185}$Hg | 80 | 105 | 184.971891(15) | 49.1(10) s | β$^+$ (94%) | $^{185}$Au | 1/2− | | |
| $^{185}$Hg | 80 | 105 | 184.971891(15) | 49.1(10) s | α (6%) | $^{181}$Pt | 1/2− | | |
| $^{185m}$Hg | 103.7(4) keV | 103.7(4) keV | 103.7(4) keV | 21.6(15) s | IT (54%) | $^{185}$Hg | 13/2+ | | |
| $^{185m}$Hg | 103.7(4) keV | 103.7(4) keV | 103.7(4) keV | 21.6(15) s | β$^+$ (46%) | $^{185}$Au | 13/2+ | | |
| $^{185m}$Hg | 103.7(4) keV | 103.7(4) keV | 103.7(4) keV | 21.6(15) s | α (0.03%) | $^{181}$Pt | 13/2+ | | |
| $^{186}$Hg | 80 | 106 | 185.969362(13) | 1.38(6) min | β$^+$ (99.98%) | $^{186}$Au | 0+ | | |
| $^{186}$Hg | 80 | 106 | 185.969362(13) | 1.38(6) min | α (0.016%) | $^{182}$Pt | 0+ | | |
| $^{186m}$Hg | 2217.3(4) keV | 2217.3(4) keV | 2217.3(4) keV | 82(5) μs | IT | $^{186}$Hg | (8−) | | |
| $^{187}$Hg | 80 | 107 | 186.969814(14) | 1.9(3) min | β$^+$ | $^{187}$Au | 3/2− | | |
| $^{187m}$Hg | 58(14) keV | 58(14) keV | 58(14) keV | 2.4(3) min | β$^+$ | $^{187}$Au | 13/2+ | | |
| $^{188}$Hg | 80 | 108 | 187.967581(7) | 3.25(15) min | β$^+$ | $^{188}$Au | 0+ | | |
| $^{188}$Hg | 80 | 108 | 187.967581(7) | 3.25(15) min | α (3.7×10$^{−5}$%) | $^{184}$Pt | 0+ | | |
| $^{188m}$Hg | 2724.1(4) keV | 2724.1(4) keV | 2724.1(4) keV | 142(14) ns | IT | $^{188}$Hg | 12+ | | |
| $^{189}$Hg | 80 | 109 | 188.96819(3) | 7.6(2) min | β$^+$ | $^{189}$Au | 3/2− | | |
| $^{189m}$Hg | 80(30) keV | 80(30) keV | 80(30) keV | 8.6(2) min | β$^+$ | $^{189}$Au | 13/2+ | | |
| $^{190}$Hg | 80 | 110 | 189.966322(17) | 20.0(5) min | β$^+$ | $^{190}$Au | 0+ | | |
| $^{191}$Hg | 80 | 111 | 190.967158(24) | 49(10) min | β$^+$ | $^{191}$Au | 3/2− | | |
| $^{191m}$Hg | 128(22) keV | 128(22) keV | 128(22) keV | 50.8(15) min | β$^+$ | $^{191}$Au | 13/2+ | | |
| $^{192}$Hg | 80 | 112 | 191.965634(17) | 4.85(20) h | EC | $^{192}$Au | 0+ | | |
| $^{193}$Hg | 80 | 113 | 192.966653(17) | 3.80(15) h | β$^+$ | $^{193}$Au | 3/2− | | |
| $^{193m}$Hg | 140.76(5) keV | 140.76(5) keV | 140.76(5) keV | 11.8(2) h | β$^+$ (92.8%) | $^{193}$Au | 13/2+ | | |
| $^{193m}$Hg | 140.76(5) keV | 140.76(5) keV | 140.76(5) keV | 11.8(2) h | IT (7.2%) | $^{193}$Hg | 13/2+ | | |
| $^{194}$Hg | 80 | 114 | 193.965449(3) | 447(28) y | EC | $^{194}$Au | 0+ | | |
| $^{195}$Hg | 80 | 115 | 194.966706(25) | 10.69(16) h | β$^+$ | $^{195}$Au | 1/2− | | |
| $^{195m}$Hg | 176.07(4) keV | 176.07(4) keV | 176.07(4) keV | 41.60(19) h | IT (54.2%) | $^{195}$Hg | 13/2+ | | |
| $^{195m}$Hg | 176.07(4) keV | 176.07(4) keV | 176.07(4) keV | 41.60(19) h | β$^+$ (45.8%) | $^{195}$Au | 13/2+ | | |
| $^{196}$Hg | 80 | 116 | 195.965833(3) | Observationally Stable | Observationally Stable | Observationally Stable | 0+ | 0.0015(1) | |
| $^{197}$Hg | 80 | 117 | 196.967214(3) | 64.93(7) h | EC | $^{197}$Au | 1/2− | | |
| $^{197m}$Hg | 298.93(8) keV | 298.93(8) keV | 298.93(8) keV | 23.82(4) h | IT (94.68%) | $^{197}$Hg | 13/2+ | | |
| $^{197m}$Hg | 298.93(8) keV | 298.93(8) keV | 298.93(8) keV | 23.82(4) h | EC (5.32%) | $^{197}$Au | 13/2+ | | |
| $^{198}$Hg | 80 | 118 | 197.9667692(5) | Observationally Stable | Observationally Stable | Observationally Stable | 0+ | 0.1004(3) | |
| $^{199}$Hg | 80 | 119 | 198.9682810(6) | Observationally Stable | Observationally Stable | Observationally Stable | 1/2− | 0.1694(12) | |
| $^{199m}$Hg | 532.48(10) keV | 532.48(10) keV | 532.48(10) keV | 42.67(9) min | IT | $^{199}$Hg | 13/2+ | | |
| $^{200}$Hg | 80 | 120 | 199.9683269(6) | Observationally Stable | Observationally Stable | Observationally Stable | 0+ | 0.2314(9) | |
| $^{201}$Hg | 80 | 121 | 200.9703031(8) | Observationally Stable | Observationally Stable | Observationally Stable | 3/2− | 0.1317(9) | |
| $^{201m}$Hg | 766.22(15) keV | 766.22(15) keV | 766.22(15) keV | 94.0(20) μs | IT | $^{201}$Hg | 13/2+ | | |
| $^{202}$Hg | 80 | 122 | 201.9706436(8) | Observationally Stable | Observationally Stable | Observationally Stable | 0+ | 0.2974(13) | |
| $^{203}$Hg | 80 | 123 | 202.9728724(18) | 46.610(10) d | β$^−$ | $^{203}$Tl | 5/2− | | |
| $^{203m1}$Hg | 933.14(23) keV | 933.14(23) keV | 933.14(23) keV | 22.1(10) μs | IT | $^{203}$Hg | (13/2+) | | |
| $^{203m2}$Hg | 8281.3(5) keV | 8281.3(5) keV | 8281.3(5) keV | 146(30) ns | IT | $^{203}$Hg | (53/2+) | | |
| $^{204}$Hg | 80 | 124 | 203.9734940(5) | Observationally Stable | Observationally Stable | Observationally Stable | 0+ | 0.0682(4) | |
| $^{204m}$Hg | 7226.08(17) keV | 7226.08(17) keV | 7226.08(17) keV | ~485 ns | IT | $^{204}$Hg | 22+ | | |
| $^{205}$Hg | 80 | 125 | 204.976073(4) | 5.14(9) min | β$^−$ | $^{205}$Tl | 1/2− | | |
| $^{205m1}$Hg | 1556.4(3) keV | 1556.4(3) keV | 1556.4(3) keV | 1.09(4) ms | IT | $^{205}$Hg | 13/2+ | | |
| $^{205m2}$Hg | 3316.6(8) keV | 3316.6(8) keV | 3316.6(8) keV | 5.89(18) μs | IT | $^{205}$Hg | (23/2−) | | |
| $^{206}$Hg | 80 | 126 | 205.977514(22) | 8.32(7) min | β$^−$ | $^{206}$Tl | 0+ | Trace | |
| $^{206m1}$Hg | 2102.4(3) keV | 2102.4(3) keV | 2102.4(3) keV | 2.088(17) μs | IT | $^{206}$Hg | 5− | | |
| $^{206m2}$Hg | 3722.3(10) keV | 3722.3(10) keV | 3722.3(10) keV | 106(3) ns | IT | $^{206}$Hg | (10+) | | |
| $^{207}$Hg | 80 | 127 | 206.98230(3) | 2.9(2) min | β$^−$ | $^{207}$Tl | 9/2+ | | |
| $^{208}$Hg | 80 | 128 | 207.98576(3) | 135(10) s | β$^−$ | $^{208}$Tl | 0+ | | |
| $^{208m}$Hg | 1338(24) keV | 1338(24) keV | 1338(24) keV | 99(14) ns | IT | $^{208}$Hg | (8+) | | |
| $^{209}$Hg | 80 | 129 | 208.99076(16)# | 6.3(11) s | β$^−$ | $^{209}$Tl | 9/2+# | | |
| $^{210}$Hg | 80 | 130 | 209.99431(22)# | 64(12) s | β$^−$ (97.8%) | $^{210}$Tl | 0+ | | |
| $^{210}$Hg | 80 | 130 | 209.99431(22)# | 64(12) s | β$^−$, n (2.2%) | $^{209}$Tl | 0+ | | |
| $^{210m1}$Hg | 663(2) keV | 663(2) keV | 663(2) keV | 2.1(7) μs | IT | $^{210}$Hg | (3−) | | |
| $^{210m2}$Hg | 1406(23) keV | 1406(23) keV | 1406(23) keV | 2(1) μs | IT | $^{210}$Hg | 8+# | | |
| $^{211}$Hg | 80 | 131 | 210.99958(22)# | 26.4(81) s | β$^−$ (93.7%) | $^{211}$Tl | 9/2+# | | |
| $^{211}$Hg | 80 | 131 | 210.99958(22)# | 26.4(81) s | β$^−$, n (6.3%) | $^{210}$Tl | 9/2+# | | |
| $^{212}$Hg | 80 | 132 | 212.00324(32)# | 30# s [>300 ns] | | | 0+ | | |
| $^{213}$Hg | 80 | 133 | 213.00880(32)# | 15# s [>300 ns] | | | 9/2+# | | |
| $^{214}$Hg | 80 | 134 | 214.01264(43)# | 8# s [>300 ns] | | | 0+ | | |
| $^{215}$Hg | 80 | 135 | 215.01837(43)# | 600# ms [>300 ns] | | | 9/2+# | | |
| $^{216}$Hg | 80 | 136 | 216.02246(43)# | 2# s [>300 ns] | | | 0+ | | |
| This table header & footer: view ||||||||||
* ↑ $^m$Hg – 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
* ↑ Bold symbol as daughter – Daughter product is stable.
* ↑ ( ) spin value – Indicates spin with weak assignment arguments.
* ↑ Believed to undergo β$^+$β$^+$ decay to $^{196}$Pt with a half-life over 2.5×10$^{18}$ years; also theorized to undergo α decay to $^{192}$Pt
* ↑ Believed to undergo α decay to $^{194}$Pt
* ↑ Believed to undergo α decay to $^{195}$Pt
* ↑ Believed to undergo α decay to $^{196}$Pt
* ↑ Believed to undergo α decay to $^{197}$Pt
* ↑ Believed to undergo α decay to $^{198}$Pt
* ↑ Believed to undergo β$^−$β$^−$ decay to $^{204}$Pb
* ↑ Intermediate decay product of $^{238}$U