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.

Isotopes of mercury (₈₀Hg)

Main isotopes^[1] Decay abun­dance half-life (t1/2) mode pro­duct ^194Hg synth 444 y ε ^194Au ^195Hg synth 9.9 h ε ^195Au ^196Hg 0.15% stable ^197Hg synth 64.14 h ε ^197Au ^198Hg 10.0% stable ^199Hg 16.9% stable ^200Hg 23.1% stable ^201Hg 13.2% stable ^202Hg 29.7% stable ^203Hg synth 46.612 d β^− ^203Tl ^204Hg 6.82% stable
Standard atomic weight Ar°(Hg)
	200.592±0.003^[2] 200.59±0.01 (abridged)^[3]
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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^+^[n 9]	^190Au	0+
^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^[n 10]	^192Au	0+
^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 11]			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 12]			0+	0.0997(20)
^199Hg	80	119	198.9682799(4)	Observationally Stable^[n 13]			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 14]			0+	0.2310(19)
^201Hg	80	121	200.9703023(6)	Observationally Stable^[n 15]			3/2−	0.1318(9)
^201mHg	766.22(15) keV			94(3) μs			13/2+
^202Hg	80	122	201.9706430(6)	Observationally Stable^[n 16]			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 17]			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 18]
^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: view

1. ^mHg – Excited nuclear isomer.
2. ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
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. # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
5. Modes of decay:

   EC:	Electron capture
   IT:	Isomeric transition
   SF:	Spontaneous fission

6. Bold symbol as daughter – Daughter product is stable.
7. ( ) spin value – Indicates spin with weak assignment arguments.
8. When produced from ¹⁸⁰Tl can also undergo fission to ¹⁰⁰Ru and ⁸⁰Kr
9. Theoretically capable of α decay to ¹⁸⁶Pt^[1]
10. Theoretically capable of α decay to ¹⁸⁸Pt^[1]
11. Believed to undergo β⁺β⁺ decay to ¹⁹⁶Pt with a half-life over 2.5×10¹⁸ years; also theorized to undergo α decay to ¹⁹²Pt
12. Believed to undergo α decay to ¹⁹⁴Pt
13. Believed to undergo α decay to ¹⁹⁵Pt
14. Believed to undergo α decay to ¹⁹⁶Pt
15. Believed to undergo α decay to ¹⁹⁷Pt
16. Believed to undergo α decay to ¹⁹⁸Pt
17. Believed to undergo β⁻β⁻ decay to ²⁰⁴Pb
18. Intermediate decay product of ²³⁸U

References

1. 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.
2. "Standard Atomic Weights: Mercury". CIAAW. 2011.
3. Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (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.
4. Eugenie Samuel Reich (December 1, 2010). "Mercury serves up a nuclear surprise: a new type of fission". Scientific American.
5. 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.