There are seven stable isotope

Isotope

Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...

s of mercury

Mercury (element)

Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...

(Hg) with ²⁰²Hg being the most abundant (29.86%). The longest-lived radioisotopes are ¹⁹⁴Hg with a half-life

Half-life

Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...

 of 444 years, and ²⁰³Hg with a half-life of 46.612 days. Most of the remaining radioisotopes have half-lives that are less than a day. ¹⁹⁹Hg and ²⁰¹Hg are the most often studied NMR

Nuclear magnetic resonance

Nuclear magnetic resonance is a physical phenomenon in which magnetic nuclei in a magnetic field absorb and re-emit electromagnetic radiation...

-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

Spontaneous fission

Spontaneous fission is a form of radioactive decay characteristic of very heavy isotopes. Because the nuclear binding energy reaches a maximum at a nuclear mass greater than about 60 atomic mass units , spontaneous breakdown into smaller nuclei and single particles becomes possible at heavier masses...

.

Standard atomic mass: 200.59(2) u

Table

nuclide symbol	Z(p Proton The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number.... )	N(n Neutron The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of... )	isotopic mass (u)	half-life	decay mode(s)Abbreviations: EC: Electron capture Electron capture Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino... IT: Isomeric transition Isomeric transition An isomeric transition is a radioactive decay process that involves emission of a gamma ray from an atom where the nucleus is in an excited metastable state, referred to in its excited state, as a nuclear isomer....	daughter isotope(s)Bold for stable isotopes	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 Alpha decay Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle and thereby transforms into an atom with a mass number 4 less and atomic number 2 less...	171Pt	5/2-#
176Hg	80	96	175.987355(15)	20.4(15) ms	α (98.6%)	172Pt	0+
					β+ Beta decay In nuclear physics, beta decay is a type of radioactive decay in which a beta particle is emitted from an atom. There are two types of beta decay: beta minus and beta plus. In the case of beta decay that produces an electron emission, it is referred to as beta minus , while in the case of a...  (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 Proton emission Proton emission is a type of radioactive decay in which a proton is ejected from a nucleus. Proton emission can occur from high-lying excited states in a nucleus following a beta decay, in which case the process is known as beta-delayed proton emission, or can occur from the ground state of very...  (.15%)	178Pt
180HgWhen produced from 180Tl can also undergo fission to 100Ru and 80Kr	80	100	179.978266(15)	2.58(1) s	β+ (52%)	180Au	0+
					α (48%)	176Pt
80Kr	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 Isomeric transition An isomeric transition is a radioactive decay process that involves emission of a gamma ray from an atom where the nucleus is in an excited metastable state, referred to in its excited state, as a nuclear isomer....  (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 Electron capture Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino...	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) a	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 StableBelieved to undergo α decay to 192Pt or β+β+ decay to 196Pt with a half-life over 2.5×1018 years			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 StableBelieved to undergo α decay to 194Pt			0+	0.0997(20)
199Hg	80	119	198.9682799(4)	Observationally StableBelieved to undergo α decay to 195Pt			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 StableBelieved to undergo α decay to 196Pt			0+	0.2310(19)
201Hg	80	121	200.9703023(6)	Observationally StableBelieved to undergo α decay to 197Pt			3/2-	0.1318(9)
201mHg	766.22(15) keV			94(3) µs			13/2+
202Hg	80	122	201.9706430(6)	Observationally StableBelieved to undergo α decay to 198Pt			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 StableBelieved to undergo α decay to 200Pt or β-β- decay to 204Pb			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+

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