Isotopes of mercury
There are seven stable isotopes of mercury (80Hg) with 202Hg being the most abundant (29.86%). The longest-lived radioisotopes are 194Hg with a half-life of 444 years, and 203Hg with a half-life of 46.612 days. Most of the remaining 40 radioisotopes have half-lives that are less than a day. 199Hg and 201Hg 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.
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Standard atomic weight Ar°(Hg) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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180Hg, producible from 180Tl, was found in 2010 to be capable of an unusual form of spontaneous fission.[4] The fission products are 80Kr and 100Ru.
List of isotopes
Nuclide [n 1] |
Z | N | Isotopic mass (Da) [n 2][n 3] |
Half-life [n 4] |
Decay mode [n 5] |
Daughter isotope [n 6] |
Spin and parity [n 7][n 4] |
Natural abundance (mole fraction) | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Excitation energy[n 4] | Normal proportion | Range of variation | |||||||||||||||||
170Hg[5] | 80 | 90 | 80(+400-40) μs | α | 166Pt | 0+ | |||||||||||||
171Hg | 80 | 91 | 171.00376(32)# | 80(30) μs [59(+36−16) μs] |
α | 167Pt | 3/2−# | ||||||||||||
172Hg | 80 | 92 | 171.99883(22) | 420(240) μs [0.25(+35−9) ms] |
α | 168Pt | 0+ | ||||||||||||
173Hg | 80 | 93 | 172.99724(22)# | 1.1(4) ms [0.6(+5−2) ms] |
α | 169Pt | 3/2−# | ||||||||||||
174Hg | 80 | 94 | 173.992864(21) | 2.0(4) ms [2.1(+18−7) ms] |
α | 170Pt | 0+ | ||||||||||||
175Hg | 80 | 95 | 174.99142(11) | 10.8(4) ms | α | 171Pt | 5/2−# | ||||||||||||
176Hg | 80 | 96 | 175.987355(15) | 20.4(15) ms | α (98.6%) | 172Pt | 0+ | ||||||||||||
β+ (1.4%) | 176Au | ||||||||||||||||||
177Hg | 80 | 97 | 176.98628(8) | 127.3(18) ms | α (85%) | 173Pt | 5/2−# | ||||||||||||
β+ (15%) | 177Au | ||||||||||||||||||
178Hg | 80 | 98 | 177.982483(14) | 0.269(3) s | α (70%) | 174Pt | 0+ | ||||||||||||
β+ (30%) | 178Au | ||||||||||||||||||
179Hg | 80 | 99 | 178.981834(29) | 1.09(4) s | α (53%) | 175Pt | 5/2−# | ||||||||||||
β+ (47%) | 179Au | ||||||||||||||||||
β+, p (.15%) | 178Pt | ||||||||||||||||||
180Hg[n 8] | 80 | 100 | 179.978266(15) | 2.58(1) s | β+ (52%) | 180Au | 0+ | ||||||||||||
α (48%) | 176Pt | ||||||||||||||||||
SF | 100Ru, 80Kr | ||||||||||||||||||
181Hg | 80 | 101 | 180.977819(17) | 3.6(1) s | β+ (64%) | 181Au | 1/2(−) | ||||||||||||
α (36%) | 177Pt | ||||||||||||||||||
β+, p (.014%) | 180Pt | ||||||||||||||||||
β+, α (9×10−6%) | 177Ir | ||||||||||||||||||
181mHg | 210(40)# keV | 13/2+ | |||||||||||||||||
182Hg | 80 | 102 | 181.97469(1) | 10.83(6) s | β+ (84.8%) | 182Au | 0+ | ||||||||||||
α (15.2%) | 178Pt | ||||||||||||||||||
β+, p (10−5%) | 181Pt | ||||||||||||||||||
183Hg | 80 | 103 | 182.974450(9) | 9.4(7) s | β+ (74.5%) | 183Au | 1/2− | ||||||||||||
α (25.5%) | 179Pt | ||||||||||||||||||
β+, p (5.6×10−4%) | 182Pt | ||||||||||||||||||
183m1Hg | 198(14) keV | 13/2+# | |||||||||||||||||
183m2Hg | 240(40)# keV | 5# s | β+ | 183Au | 13/2+# | ||||||||||||||
184Hg | 80 | 104 | 183.971713(11) | 30.6(3) s | β+ (98.89%) | 184Au | 0+ | ||||||||||||
α (1.11%) | 180Pt | ||||||||||||||||||
185Hg | 80 | 105 | 184.971899(17) | 49.1(10) s | β+ (94%) | 185Au | 1/2− | ||||||||||||
α (6%) | 181Pt | ||||||||||||||||||
185mHg | 99.3(5) keV | 21.6(15) s | IT (54%) | 185Hg | 13/2+ | ||||||||||||||
β+ (46%) | 185Au | ||||||||||||||||||
α (.03%) | 181Pt | ||||||||||||||||||
186Hg | 80 | 106 | 185.969362(12) | 1.38(6) min | β+ (99.92%) | 186Au | 0+ | ||||||||||||
α (.016%) | 182Pt | ||||||||||||||||||
186mHg | 2217.3(4) keV | 82(5) μs | (8−) | ||||||||||||||||
187Hg | 80 | 107 | 186.969814(15) | 1.9(3) min | β+ | 187Au | 3/2− | ||||||||||||
α (1.2×10−4%) | 183Pt | ||||||||||||||||||
187mHg | 59(16) keV | 2.4(3) min | β+ | 187Au | 13/2+ | ||||||||||||||
α (2.5×10−4%) | 183Pt | ||||||||||||||||||
188Hg | 80 | 108 | 187.967577(12) | 3.25(15) min | β+ | 188Au | 0+ | ||||||||||||
α (3.7×10−5%) | 184Pt | ||||||||||||||||||
188mHg | 2724.3(4) keV | 134(15) ns | (12+) | ||||||||||||||||
189Hg | 80 | 109 | 188.96819(4) | 7.6(1) min | β+ | 189Au | 3/2− | ||||||||||||
α (3×10−5%) | 185Pt | ||||||||||||||||||
189mHg | 80(30) keV | 8.6(1) min | β+ | 189Au | 13/2+ | ||||||||||||||
α (3×10−5%) | 185Pt | ||||||||||||||||||
190Hg | 80 | 110 | 189.966322(17) | 20.0(5) min | β+ | 190Au | 0+ | ||||||||||||
α (5×10−5%) | 186Pt | ||||||||||||||||||
191Hg | 80 | 111 | 190.967157(24) | 49(10) min | β+ | 191Au | 3/2(−) | ||||||||||||
191mHg | 128(22) keV | 50.8(15) min | β+ | 191Au | 13/2+ | ||||||||||||||
192Hg | 80 | 112 | 191.965634(17) | 4.85(20) h | EC | 192Au | 0+ | ||||||||||||
α (4×10−6%) | 188Pt | ||||||||||||||||||
193Hg | 80 | 113 | 192.966665(17) | 3.80(15) h | β+ | 193Au | 3/2− | ||||||||||||
193mHg | 140.76(5) keV | 11.8(2) h | β+ (92.9%) | 193Au | 13/2+ | ||||||||||||||
IT (7.1%) | 193Hg | ||||||||||||||||||
194Hg | 80 | 114 | 193.965439(13) | 444(77) y | EC | 194Au | 0+ | ||||||||||||
195Hg | 80 | 115 | 194.966720(25) | 10.53(3) h | β+ | 195Au | 1/2− | ||||||||||||
195mHg | 176.07(4) keV | 41.6(8) h | IT (54.2%) | 195Hg | 13/2+ | ||||||||||||||
β+ (45.8%) | 195Au | ||||||||||||||||||
196Hg | 80 | 116 | 195.965833(3) | Observationally Stable[n 9] | 0+ | 0.0015(1) | |||||||||||||
197Hg | 80 | 117 | 196.967213(3) | 64.14(5) h | EC | 197Au | 1/2− | ||||||||||||
197mHg | 298.93(8) keV | 23.8(1) h | IT (91.4%) | 197Hg | 13/2+ | ||||||||||||||
EC (8.6%) | 197Au | ||||||||||||||||||
198Hg | 80 | 118 | 197.9667690(4) | Observationally Stable[n 10] | 0+ | 0.0997(20) | |||||||||||||
199Hg | 80 | 119 | 198.9682799(4) | Observationally Stable[n 11] | 1/2− | 0.1687(22) | |||||||||||||
199mHg | 532.48(10) keV | 42.66(8) min | IT | 199Hg | 13/2+ | ||||||||||||||
200Hg | 80 | 120 | 199.9683260(4) | Observationally Stable[n 12] | 0+ | 0.2310(19) | |||||||||||||
201Hg | 80 | 121 | 200.9703023(6) | Observationally Stable[n 13] | 3/2− | 0.1318(9) | |||||||||||||
201mHg | 766.22(15) keV | 94(3) μs | 13/2+ | ||||||||||||||||
202Hg | 80 | 122 | 201.9706430(6) | Observationally Stable[n 14] | 0+ | 0.2986(26) | |||||||||||||
203Hg | 80 | 123 | 202.9728725(18) | 46.595(6) d | β− | 203Tl | 5/2− | ||||||||||||
203mHg | 933.14(23) keV | 24(4) μs | (13/2+) | ||||||||||||||||
204Hg | 80 | 124 | 203.9734939(4) | Observationally Stable[n 15] | 0+ | 0.0687(15) | |||||||||||||
205Hg | 80 | 125 | 204.976073(4) | 5.14(9) min | β− | 205Tl | 1/2− | ||||||||||||
205mHg | 1556.40(17) keV | 1.09(4) ms | IT | 205Hg | 13/2+ | ||||||||||||||
206Hg | 80 | 126 | 205.977514(22) | 8.15(10) min | β− | 206Tl | 0+ | Trace[n 16] | |||||||||||
207Hg | 80 | 127 | 206.98259(16) | 2.9(2) min | β− | 207Tl | (9/2+) | ||||||||||||
208Hg | 80 | 128 | 207.98594(32)# | 42(5) min [41(+5−4) min] |
β− | 208Tl | 0+ | ||||||||||||
209Hg | 80 | 129 | 208.99104(21)# | 37(8) s | 9/2+# | ||||||||||||||
210Hg | 80 | 130 | 209.99451(32)# | 10# min [>300 ns] |
0+ | ||||||||||||||
211Hg | 80 | 131 | 210.99380(200)# | 26(8) s | 9/2+# | ||||||||||||||
212Hg | 80 | 132 | 212.02760(300)# | 1# min [>300 ns] |
0+ | ||||||||||||||
213Hg | 80 | 133 | 213.07670(300)# | 1# s [>300 ns] |
5/2+# | ||||||||||||||
214Hg | 80 | 134 | 214.11180(400)# | 1# s [>300 ns] |
0+ | ||||||||||||||
215Hg | 80 | 135 | 215.16210(400)# | 1# s [>300 ns] |
3/2+# | ||||||||||||||
216Hg | 80 | 136 | 216.19860(400)# | 100# ms [>300 ns] |
0+ | ||||||||||||||
This table header & footer: |
- mHg – 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).
- # – 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 SF: Spontaneous fission - Bold symbol as daughter – Daughter product is stable.
- ( ) spin value – Indicates spin with weak assignment arguments.
- When produced from 180Tl can also undergo fission to 100Ru and 80Kr
- Believed to undergo β+β+ decay to 196Pt with a half-life over 2.5×1018 years
- Believed to undergo α decay to 194Pt
- Believed to undergo α decay to 195Pt
- Believed to undergo α decay to 196Pt
- Believed to undergo α decay to 197Pt
- Believed to undergo α decay to 198Pt
- Believed to undergo β−β− decay to 204Pb
- Intermediate decay product of 238U
Particular Isotopes
Hg-196
While it is the rarest stable isotope of Mercury, at a proportion lower than that of 235
U in natural uranium, Hg-196 is of some theoretical interest in the synthesis of precious metals via nuclear transmutation since it could - in theory - be transmutated into the only stable gold isotope 197
Au via neutron absorption and subsequent decay via electron capture. However, given that a costly step of isotope separation would have to precede the already costly process of transmutation, this has (as of 2022) mostly remained a theoretical curiosity rather than an actual area of research.
Hg-198
At roughly 10% of natural Mercury, Hg-198 is neither particularly abundant nor particularly rare. It has a non-negligible gamma ray cross section for the (γ, n) reaction with 10 Mega-Electronvolt Gamma Rays. This reaction, in addition to serving as a potential neutron source could also be used to produce Hg-197 and via electron capture produce 197
Au - stable gold. Given that it is roughly two orders of magnitude more abundant that Hg-196, the required isotopic separation, even it required a further step of separating the lighter Hg-196 from the heavier Hg-198 could be achieved with a better yield for any given effort than for Hg-196.
References
- 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.
- "Standard Atomic Weights: Mercury". CIAAW. 2011.
- Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; et al. (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.
- Eugenie Samuel Reich (December 1, 2010). "Mercury serves up a nuclear surprise: a new type of fission". Scientific American.
- Hilton, J.; et al. (2019). "α-spectroscopy studies of the new nuclides 165Pt and 170Hg". Physical Review C. 100 (1): 014305. Bibcode:2019PhRvC.100a4305H. doi:10.1103/PhysRevC.100.014305. S2CID 199118719.
- Isotope masses from:
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
- Audi, G.; Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S. (2017). "The NUBASE2016 evaluation of nuclear properties" (PDF). Chinese Physics C. 41 (3): 030001. Bibcode:2017ChPhC..41c0001A. doi:10.1088/1674-1137/41/3/030001.
- Isotopic compositions and standard atomic masses from:
- de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
- Wieser, Michael E. (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051.
- "News & Notices: Standard Atomic Weights Revised". International Union of Pure and Applied Chemistry. 19 October 2005.
- Half-life, spin, and isomer data selected from the following sources.
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
- Audi, G.; Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S. (2017). "The NUBASE2016 evaluation of nuclear properties" (PDF). Chinese Physics C. 41 (3): 030001. Bibcode:2017ChPhC..41c0001A. doi:10.1088/1674-1137/41/3/030001.
- National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory.
- Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.