Isotopes of mercury

There are seven stable isotopes of mercury (Hg) 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 thirty-one radioisotopes have half-lives that are less than a day. ¹⁹⁹Hg and ²⁰¹Hg are the most often studied NMR-active nuclei, having spins of 1/2 and 3/2 respectively.

Mercury-180, producible from thallium-180, was found in 2010 to be capable of an unusual form of spontaneous fission.^[1] The fission products are krypton-80 and ruthenium-100.

Relative atomic mass: 200.592(3).

Table

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life	decay mode(s)[2][n 1]	daughter isotope(s)[n 2]	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
	excitation energy
^171Hg	80	91	171.00376(32)#	80(30) µs [59(+36−16) µs]			3/2−#
^172Hg	80	92	171.99883(22)	420(240) µs [0.25(+35−9) ms]			0
^173Hg	80	93	172.99724(22)#	1.1(4) ms [0.6(+5−2) ms]			3/2−#
^174Hg	80	94	173.992864(21)	2.0(4) ms [2.1(+18−7) ms]			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 3]	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 4]			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 5]			0+	0.0997(20)
^199Hg	80	119	198.9682799(4)	Observationally Stable[n 6]			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 7]			0+	0.2310(19)
^201Hg	80	121	200.9703023(6)	Observationally Stable[n 8]			3/2−	0.1318(9)
^201mHg	766.22(15) keV			94(3) µs			13/2+
^202Hg	80	122	201.9706430(6)	Observationally Stable[n 9]			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 10]			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+
^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+

1. Abbreviations:
   EC: Electron capture
   IT: Isomeric transition
2. Bold for stable isotopes
3. When produced from ¹⁸⁰Tl can also undergo fission to ¹⁰⁰Ru and ⁸⁰Kr
4. Believed to undergo α decay to ¹⁹²Pt or β⁺β⁺ decay to ¹⁹⁶Pt with a half-life over 2.5×10¹⁸ years
5. Believed to undergo α decay to ¹⁹⁴Pt
6. Believed to undergo α decay to ¹⁹⁵Pt
7. Believed to undergo α decay to ¹⁹⁶Pt
8. Believed to undergo α decay to ¹⁹⁷Pt
9. Believed to undergo α decay to ¹⁹⁸Pt
10. Believed to undergo α decay to ²⁰⁰Pt or β⁻β⁻ decay to ²⁰⁴Pb

Notes

• Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
• Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC, which use expanded uncertainties.

References

1. Eugenie Samuel Reich (December 1, 2010). "Mercury serves up a nuclear surprise: a new type of fission". Scientific American.
2. "Universal Nuclide Chart". nucleonica. (registration required (help)).

• Isotope masses from:
  • G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.
• Isotopic compositions and standard atomic masses from:
  • J. R. de Laeter; J. K. Böhlke; P. De Bièvre; H. Hidaka; H. S. Peiser; K. J. R. Rosman; P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry 75 (6): 683–800. doi:10.1351/pac200375060683.
  • M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry 78 (11): 2051–2066. doi:10.1351/pac200678112051. Lay summary.
• Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
  • G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.
  • National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. Retrieved September 2005.
  • N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide. CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0-8493-0485-9.