Isotopes of mercury
List of isotopes
Abbreviations: EC: Electron capture IT: Isomeric transition Bold for stable isotopes 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

Isotopes of mercury

Section Title: List of isotopes
Table Section Text: Abbreviations: EC: Electron capture IT: Isomeric transition Bold for stable isotopes 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

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life	decay mode(s)	daughter isotope(s)	nuclear spin and parity	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	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	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)	Stable	0+	0.0997(20)

199Hg	80	119	198.9682799(4)	Stable	1/2−	0.1687(22)

199mHg	532.48(10) keV	42.66(8) min	IT	199Hg	13/2+

200Hg	80	120	199.9683260(4)	Stable	0+	0.2310(19)

201Hg	80	121	200.9703023(6)	Stable	3/2−	0.1318(9)

201mHg	766.22(15) keV	94(3) µs	13/2+

202Hg	80	122	201.9706430(6)	Stable	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)	Stable	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+

Sentence(s)

The longest-living isotopes are ¹⁹⁴Hg with a half-life of 444 years, and ²⁰³Hg.

final_sentence: The longest-living isotopes are ¹⁹⁴Hg with a half-life of 444 years, and ²⁰³Hg.