Isotopes of tin

Tin (₅₀Sn) is the element with the greatest number of stable isotopes (ten; three of them are potentially radioactive but have not been observed to decay). This is probably related to the fact that 50 is a "magic number" of protons. In addition, 32 unstable tin isotopes are known, including tin-100 (¹⁰⁰Sn) (discovered in 1994)^[4] and tin-132 (¹³²Sn), which are both "doubly magic". The longest-lived tin radioisotope is tin-126 (¹²⁶Sn), with a half-life of 230,000 years. The other 28 radioisotopes have half-lives of less than a year.

Isotopes of tin (₅₀Sn)

Main isotopes[1] Decay Isotope abun­dance half-life (t1/2) mode pro­duct 112Sn 0.970% stable 113Sn synth 115.08 d ε 113In 114Sn 0.66% stable 115Sn 0.34% stable 116Sn 14.5% stable 117Sn 7.68% stable 118Sn 24.2% stable 119Sn 8.59% stable 120Sn 32.6% stable 121mSn synth 43.9 y IT77.6% 121Sn β−22.4% 121Sb 122Sn 4.63% stable 123Sn synth 129.2 d β− 123Sb 124Sn 5.79% stable 126Sn trace 2.3×105 y β− 126Sb
Standard atomic weight Ar°(Sn)
	118.710±0.007[2] 118.71±0.01 (abridged)[3]
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List of isotopes

Nuclide [n 1]	Z	N	Isotopic mass (Da)[5] [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
98Sn[6]	50	48					0+
99Sn[n 8]	50	49	98.94850(63)#	24(4) ms	β+ (95%)	99In	9/2+#
					β+, p (5%)	98Cd
100Sn[n 9]	50	50	99.93865(26)	1.18(8) s	β+ (>83%)	100In	0+
					β+, p (<17%)	99Cd
101Sn	50	51	100.93526(32)	2.22(5) s	β+	101In	(7/2+)
					β+, p?	100Cd
102Sn	50	52	101.93029(11)	3.8(2) s	β+	102In	0+
102mSn	2017(2) keV			367(8) ns	IT	102Sn	(6+)
103Sn	50	53	102.92797(11)#	7.0(2) s	β+ (98.8%)	103In	5/2+#
					β+, p (1.2%)	102Cd
104Sn	50	54	103.923105(6)	20.8(5) s	β+	104In	0+
105Sn	50	55	104.921268(4)	32.7(5) s	β+	105In	(5/2+)
					β+, p (0.011%)	104Cd
106Sn	50	56	105.916957(5)	1.92(8) min	β+	106In	0+
107Sn	50	57	106.915714(6)	2.90(5) min	β+	107In	(5/2+)
108Sn	50	58	107.911894(6)	10.30(8) min	β+	108In	0+
109Sn	50	59	108.911293(9)	18.1(2) min	β+	109In	5/2+
110Sn	50	60	109.907845(15)	4.154(4) h	EC	110In	0+
111Sn	50	61	110.907741(6)	35.3(6) min	β+	111In	7/2+
111mSn	254.71(4) keV			12.5(10) μs	IT	111Sn	1/2+
112Sn	50	62	111.9048249(3)	Observationally Stable[n 10]			0+	0.0097(1)
113Sn	50	63	112.9051759(17)	115.08(4) d	β+	113In	1/2+
113mSn	77.389(19) keV			21.4(4) min	IT (91.1%)	113Sn	7/2+
					β+ (8.9%)	113In
114Sn	50	64	113.90278013(3)	Stable			0+	0.0066(1)
114mSn	3087.37(7) keV			733(14) ns	IT	114Sn	7−
115Sn[n 11]	50	65	114.903344695(16)	Stable			1/2+	0.0034(1)
115m1Sn	612.81(4) keV			3.26(8) μs	IT	115Sn	7/2+
115m2Sn	713.64(12) keV			159(1) μs	IT	115Sn	11/2−
116Sn	50	66	115.90174283(10)	Stable			0+	0.1454(9)
116m1Sn	2365.975(21) keV			348(19) ns	IT	116Sn	5−
116m2Sn	3547.16(17) keV			833(30) ns	IT	116Sn	10+
117Sn[n 11]	50	67	116.90295404(52)	Stable			1/2+	0.0768(7)
117m1Sn[n 11]	314.58(4) keV			13.939(24) d	IT	117Sn	11/2−
117m2Sn	2406.4(4) keV			1.75(7) μs	IT	117Sn	(19/2+)
118Sn[n 11]	50	68	117.90160663(54)	Stable			0+	0.2422(9)
118m1Sn	2574.91(4) keV			230(10) ns	IT	118Sn	7−
118m2Sn	3108.06(22) keV			2.52(6) μs	IT	118Sn	(10+)
119Sn[n 11]	50	69	118.90331127(78)	Stable			1/2+	0.0859(4)
119m1Sn[n 11]	89.531(13) keV			293.1(7) d	IT	119Sn	11/2−
119m2Sn	2127.0(10) keV			9.6(12) μs	IT	119Sn	(19/2+)
119m3Sn	2369.0(3) keV			96(9) ns	IT	119Sn	23/2+
120Sn[n 11]	50	70	119.90220256(99)	Stable			0+	0.3258(9)
120m1Sn	2481.63(6) keV			11.8(5) μs	IT	120Sn	7−
120m2Sn	2902.22(22) keV			6.26(11) μs	IT	120Sn	10+
121Sn[n 11]	50	71	120.9042435(11)	27.03(4) h	β−	121Sb	3/2+
121m1Sn[n 11]	6.31(6) keV			43.9(5) y	IT (77.6%)	121Sn	11/2−
					β− (22.4%)	121Sb
121m2Sn	1998.68(13) keV			5.3(5) μs	IT	121Sn	19/2+
121m3Sn	2222.0(2) keV			520(50) ns	IT	121Sn	23/2+
121m4Sn	2833.9(2) keV			167(25) ns	IT	121Sn	27/2−
122Sn[n 11]	50	72	121.9034455(26)	Observationally Stable[n 12]			0+	0.0463(3)
122m1Sn	2409.03(4) keV			7.5(9) μs	IT	122Sn	7−
122m2Sn	2765.5(3) keV			62(3) μs	IT	122Sn	10+
122m3Sn	4721.2(3) keV			139(9) ns	IT	122Sn	15−
123Sn[n 11]	50	73	122.9057271(27)	129.2(4) d	β−	123Sb	11/2−
123m1Sn	24.6(4) keV			40.06(1) min	β−	123Sb	3/2+
123m2Sn	1944.90(12) keV			7.4(26) μs	IT	123Sn	19/2+
123m3Sn	2152.66(19) keV			6 μs	IT	123Sn	23/2+
123m4Sn	2712.47(21) keV			34 μs	IT	123Sn	27/2−
124Sn[n 11]	50	74	123.9052796(14)	Observationally Stable[n 13]			0+	0.0579(5)
124m1Sn	2204.620(23) keV			270(60) ns	IT	124Sn	5-
124m2Sn	2324.96(4) keV			3.1(5) μs	IT	124Sn	7−
124m3Sn	2656.6(3) keV			51(3) μs	IT	124Sn	10+
124m4Sn	4552.4(3) keV			260(25) ns	IT	124Sn	15−
125Sn[n 11]	50	75	124.9077894(14)	9.634(15) d	β−	125Sb	11/2−
125m1Sn	27.50(14) keV			9.77(25) min	β−	125Sb	3/2+
125m2Sn	1892.8(3) keV			6.2(2) μs	IT	125Sn	19/2+
125m3Sn	2059.5(4) keV			650(60) ns	IT	125Sn	23/2+
125m4Sn	2623.5(5) keV			230(17) ns	IT	125Sn	27/2−
126Sn[n 14]	50	76	125.907658(11)	2.30(14)×105 y	β−	126Sb	0+	< 10−14[7]
126m1Sn	2218.99(8) keV			6.1(7) μs	IT	126Sn	7−
126m2Sn	2564.5(5) keV			7.6(3) μs	IT	126Sn	10+
126m3Sn	4347.4(4) keV			114(2) ns	IT	126Sn	15−
127Sn	50	77	126.9103917(99)	2.10(4) h	β−	127Sb	11/2−
127m1Sn	5.07(6) keV			4.13(3) min	β−	127Sb	3/2+
127m2Sn	1826.67(16) keV			4.52(15) μs	IT	127Sn	19/2+
127m3Sn	1930.97(17) keV			1.26(15) μs	IT	127Sn	(23/2+)
127m4Sn	2552.4(10) keV			250(30) ns	IT	127Sn	(27/2−)
128Sn	50	78	127.910508(19)	59.07(14) min	β−	128Sb	0+
128m1Sn	2091.50(11) keV			6.5(5) s	IT	128Sn	7−
128m2Sn	2491.91(17) keV			2.91(14) μs	IT	128Sn	10+
128m3Sn	4099.5(4) keV			220(30) ns	IT	128Sn	(15−)
129Sn	50	79	128.913482(19)	2.23(4) min	β−	129Sb	3/2+
129m1Sn	35.15(5) keV			6.9(1) min	β−	129Sb	11/2−
129m2Sn	1761.6(10) keV			3.49(11) μs	IT	129Sn	(19/2+)
129m3Sn	1802.6(10) keV			2.22(13) μs	IT	129Sn	23/2+
129m4Sn	2552.9(11) keV			221(18) ns	IT	129Sn	(27/2−)
130Sn	50	80	129.9139745(20)	3.72(7) min	β−	130Sb	0+
130m1Sn	1946.88(10) keV			1.7(1) min	β−	130Sb	7−
130m2Sn	2434.79(12) keV			1.501(17) μs	IT	130Sn	(10+)
131Sn	50	81	130.917053(4)	56.0(5) s	β−	131Sb	3/2+
131m1Sn	65.1(3) keV			58.4(5) s	β−	131Sb	11/2−
					IT?	131Sn
131m2Sn	4670.0(4) keV			316(5) ns	IT	131Sn	(23/2−)
132Sn	50	82	131.9178239(21)	39.7(8) s	β−	132Sb	0+
132mSn	4848.52(20) keV			2.080(16) μs	IT	132Sn	8+
133Sn	50	83	132.9239138(20)	1.37(7) s	β− (99.97%)	133Sb	7/2−
					β−n (.0294%)	132Sb
134Sn	50	84	133.928680(3)	0.93(8) s	β− (83%)	134Sb	0+
					β−n (17%)	133Sb
134mSn	1247.4(5) keV			87(8) ns	IT	134Sn	6+
135Sn	50	85	134.934909(3)	515(5) ms	β− (79%)	135Sb	7/2−#
					β−n (21%)	134Sb
					β−2n?	133Sb
136Sn	50	86	135.93970(22)#	355(18) ms	β− (72%)	136Sb	0+
					β−n (28%)	135Sb
					β−2n?	134Sb
137Sn	50	87	136.94616(32)#	249(15) ms	β− (52%)	137Sb	5/2−#
					β−n (48%)	136Sb
					β−2n?	135Sb
138Sn	50	88	137.95114(43)#	148(9) ms	β− (64%)	138Sb	0+
					β−n (36%)	137Sb
					β−2n?	136Sb
138mSn	1344(2) keV			210(45) ns	IT	138Sn	(6+)
139Sn	50	89	138.95780(43)#	120(38) ms	β−	139Sb	5/2−#
					β−n?	138Sb
					β−2n?	137Sb
140Sn	50	90	139.96297(32)#	50# ms [>550 ns]	β−?	140Sb	0+
					β−n?	139Sb
					β−2n?	138Sb
This table header & footer: view

1. ^mSn – 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
   n:	Neutron emission
   p:	Proton emission

6. Bold symbol as daughter – Daughter product is stable.
7. ( ) spin value – Indicates spin with weak assignment arguments.
8. Heaviest known nuclide with more protons than neutrons
9. Heaviest nuclide with equal numbers of protons and neutrons with no observed α decay
10. Believed to decay by β⁺β⁺ to ¹¹²Cd
11. Fission product
12. Believed to undergo β⁻β⁻ decay to ¹²²Te
13. Believed to undergo β⁻β⁻ decay to ¹²⁴Te with a half-life over 1×10¹⁷ years
14. Long-lived fission product

Tin-117m

Tin-117m is a radioisotope of tin. One of its uses is in a particulate suspension to treat canine synovitis (radiosynoviorthesis).^[8]

Tin-121m

Tin-121m (^121mSn) is a radioisotope and nuclear isomer of tin with a half-life of 43.9 years.

In a normal thermal reactor, it has a very low fission product yield; thus, this isotope is not a significant contributor to nuclear waste. Fast fission or fission of some heavier actinides will produce tin-121 at higher yields. For example, its yield from uranium-235 is 0.0007% per thermal fission and 0.002% per fast fission.^[9]

Tin-126

Yield, % per fission^[9]

	Thermal	Fast	14 MeV
232Th	not fissile	0.0481 ± 0.0077	0.87 ± 0.20
233U	0.224 ± 0.018	0.278 ± 0.022	1.92 ± 0.31
235U	0.056 ± 0.004	0.0137 ± 0.001	1.70 ± 0.14
238U	not fissile	0.054 ± 0.004	1.31 ± 0.21
239Pu	0.199 ± 0.016	0.26 ± 0.02	2.02 ± 0.22
241Pu	0.082 ± 0.019	0.22 ± 0.03	?

Tin-126 is a radioisotope of tin and one of the only seven long-lived fission products of uranium and plutonium. While tin-126's half-life of 230,000 years translates to a low specific activity of gamma radiation, its short-lived decay products, two isomers of antimony-126, emit a cascade of hard gamma radiation - at least 3 photons over 400 keV per decay - before reaching stable tellurium-126, making external exposure to tin-126 a potential concern.

Tin-126 is in the middle of the mass range for fission products. Thermal reactors, which make up almost all current nuclear power plants, produce it at only low yield, since slow neutrons almost always fission ²³⁵U or ²³⁹Pu into unequal halves. Fast fission in a fast reactor or nuclear weapon, or fission of some heavy minor actinides such as californium, will produce it at higher yields.

• ANL factsheet

See also

Daughter products other than tin

• Isotopes of antimony
• Isotopes of indium
• Isotopes of cadmium