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 β+ 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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List of isotopes

Nuclide [n 1]	Z	N	Isotopic mass (Da)[4] [n 2][n 3]	Half-life[1] [n 4]	Decay mode[1] [n 5]	Daughter isotope [n 6]	Spin and parity[1] [n 7][n 4]	Natural abundance (mole fraction)
	Excitation energy[n 4]							Normal proportion[1]	Range of variation
170Hg	80	90	170.00581(32)#	310(250) μs	α	166Pt	0+
171Hg	80	91	171.00359(33)#	70(30) μs	α	167Pt	3/2−#
172Hg	80	92	171.99886(16)	231(9) μs	α	168Pt	0+
173Hg	80	93	172.99714(22)#	800(80) μs	α	169Pt	(7/2−)
174Hg	80	94	173.992871(21)	2.0(4) ms	α	170Pt	0+
175Hg	80	95	174.99144(9)	10.2(3) ms	α	171Pt	(7/2−)
175mHg	494(2) keV			340(30) ns	IT	175Hg	(13/2+)
176Hg	80	96	175.987349(12)	20.3(14) ms	α (90%)	172Pt	0+
					β+ (10%)	176Au
177Hg	80	97	176.98628(9)	117(7) ms	α	173Pt	7/2−
177mHg	323.2(13) keV			1.50(15) μs	IT	177Hg	13/2+
178Hg	80	98	177.982485(12)	266.5(24) ms	α (89%)	174Pt	0+
					β+ (11%)	178Au
179Hg	80	99	178.98182(3)	1.05(3) s	α (75%)	175Pt	7/2−
					β+ (25%)	179Au
					β+, p (0.15%)	178Pt
179mHg	171.4(4) keV			6.4(9) μs	IT	179Hg	13/2+
180Hg	80	100	179.978260(14)	2.59(1) s	β+ (52%)	180Au	0+
					α (48%)	176Pt
181Hg	80	101	180.977819(17)	3.6(1) s	β+ (73%)	181Au	1/2−
					α (27%)	177Pt
					β+, p (0.014%)	180Pt
					β+, α (9×10−6%)	177Ir
181mHg	210(50) keV			480(20) μs	IT	181Hg	13/2+
182Hg	80	102	181.974689(11)	10.83(6) s	β+ (86.2%)	182Au	0+
					α (13.8%)	178Pt
					β+, p (<1×10−5%)	181Pt
183Hg	80	103	182.974445(8)	9.4(7) s	β+ (88.3%)	183Au	1/2−
					α (11.7%)	179Pt
					β+, p (2.6×10−4%)	182Pt
183mHg	204(14) keV			>5# μs			13/2+#
184Hg	80	104	183.971718(10)	30.87(26) s	β+ (98.89%)	184Au	0+
					α (1.11%)	180Pt
185Hg	80	105	184.971891(15)	49.1(10) s	β+ (94%)	185Au	1/2−
					α (6%)	181Pt
185mHg	103.7(4) keV			21.6(15) s	IT (54%)	185Hg	13/2+
					β+ (46%)	185Au
					α (0.03%)	181Pt
186Hg	80	106	185.969362(13)	1.38(6) min	β+ (99.98%)	186Au	0+
					α (0.016%)	182Pt
186mHg	2217.3(4) keV			82(5) μs	IT	186Hg	(8−)
187Hg	80	107	186.969814(14)	1.9(3) min	β+	187Au	3/2−
187mHg	58(14) keV			2.4(3) min	β+	187Au	13/2+
188Hg	80	108	187.967581(7)	3.25(15) min	β+	188Au	0+
					α (3.7×10−5%)	184Pt
188mHg	2724.1(4) keV			142(14) ns	IT	188Hg	12+
189Hg	80	109	188.96819(3)	7.6(2) min	β+	189Au	3/2−
189mHg	80(30) keV			8.6(2) min	β+	189Au	13/2+
190Hg	80	110	189.966322(17)	20.0(5) min	β+	190Au	0+
191Hg	80	111	190.967158(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+
193Hg	80	113	192.966653(17)	3.80(15) h	β+	193Au	3/2−
193mHg	140.76(5) keV			11.8(2) h	β+ (92.8%)	193Au	13/2+
					IT (7.2%)	193Hg
194Hg	80	114	193.965449(3)	447(28) y	EC	194Au	0+
195Hg	80	115	194.966706(25)	10.69(16) h	β+	195Au	1/2−
195mHg	176.07(4) keV			41.60(19) h	IT (54.2%)	195Hg	13/2+
					β+ (45.8%)	195Au
196Hg	80	116	195.965833(3)	Observationally Stable[n 8]			0+	0.0015(1)
197Hg	80	117	196.967214(3)	64.93(7) h	EC	197Au	1/2−
197mHg	298.93(8) keV			23.82(4) h	IT (94.68%)	197Hg	13/2+
					EC (5.32%)	197Au
198Hg	80	118	197.9667692(5)	Observationally Stable[n 9]			0+	0.1004(3)
199Hg	80	119	198.9682810(6)	Observationally Stable[n 10]			1/2−	0.1694(12)
199mHg	532.48(10) keV			42.67(9) min	IT	199Hg	13/2+
200Hg	80	120	199.9683269(6)	Observationally Stable[n 11]			0+	0.2314(9)
201Hg	80	121	200.9703031(8)	Observationally Stable[n 12]			3/2−	0.1317(9)
201mHg	766.22(15) keV			94.0(20) μs	IT	201Hg	13/2+
202Hg	80	122	201.9706436(8)	Observationally Stable[n 13]			0+	0.2974(13)
203Hg	80	123	202.9728724(18)	46.610(10) d	β−	203Tl	5/2−
203m1Hg	933.14(23) keV			22.1(10) μs	IT	203Hg	(13/2+)
203m2Hg	8281.3(5) keV			146(30) ns	IT	203Hg	(53/2+)
204Hg	80	124	203.9734940(5)	Observationally Stable[n 14]			0+	0.0682(4)
204mHg	7226.08(17) keV			~485 ns	IT	204Hg	22+
205Hg	80	125	204.976073(4)	5.14(9) min	β−	205Tl	1/2−
205m1Hg	1556.4(3) keV			1.09(4) ms	IT	205Hg	13/2+
205m2Hg	3316.6(8) keV			5.89(18) μs	IT	205Hg	(23/2−)
206Hg	80	126	205.977514(22)	8.32(7) min	β−	206Tl	0+	Trace[n 15]
206m1Hg	2102.4(3) keV			2.088(17) μs	IT	206Hg	5−
206m2Hg	3722.3(10) keV			106(3) ns	IT	206Hg	(10+)
207Hg	80	127	206.98230(3)	2.9(2) min	β−	207Tl	9/2+
208Hg	80	128	207.98576(3)	135(10) s	β−	208Tl	0+
208mHg	1338(24) keV			99(14) ns	IT	208Hg	(8+)
209Hg	80	129	208.99076(16)#	6.3(11) s	β−	209Tl	9/2+#
210Hg	80	130	209.99431(22)#	64(12) s	β− (97.8%)	210Tl	0+
					β−, n (2.2%)	209Tl
210m1Hg	663(2) keV			2.1(7) μs	IT	210Hg	(3−)
210m2Hg	1406(23) keV			2(1) μs	IT	210Hg	8+#
211Hg	80	131	210.99958(22)#	26.4(81) s	β− (93.7%)	211Tl	9/2+#
					β−, n (6.3%)	210Tl
212Hg	80	132	212.00324(32)#	30# s [>300 ns]			0+
213Hg	80	133	213.00880(32)#	15# s [>300 ns]			9/2+#
214Hg	80	134	214.01264(43)#	8# s [>300 ns]			0+
215Hg	80	135	215.01837(43)#	600# ms [>300 ns]			9/2+#
216Hg	80	136	216.02246(43)#	2# s [>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

6. Bold symbol as daughter – Daughter product is stable.
7. ( ) spin value – Indicates spin with weak assignment arguments.
8. 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
9. Believed to undergo α decay to ¹⁹⁴Pt
10. Believed to undergo α decay to ¹⁹⁵Pt
11. Believed to undergo α decay to ¹⁹⁶Pt
12. Believed to undergo α decay to ¹⁹⁷Pt
13. Believed to undergo α decay to ¹⁹⁸Pt
14. Believed to undergo β⁻β⁻ decay to ²⁰⁴Pb
15. Intermediate decay product of ²³⁸U