# Isotopes of tungsten

Naturally occurring tungsten ($_{74}$W) consists of five isotopes. Four are considered stable ($^{182}$W, $^{183}$W, $^{184}$W, and $^{186}$W) and one is slightly radioactive, $^{180}$W, with an extremely long half-life of 1.8 ± 0.2 exayears (10$^{18}$ years). On average, two alpha decays of $^{180}$W occur per gram of natural tungsten per year, so for most practical purposes, $^{180}$W can be considered stable. Theoretically, all five can decay into isotopes of element 72 (hafnium) by alpha emission, but only $^{180}$W has been observed to do so. The other naturally occurring isotopes have not been observed to decay (they are observationally stable), and lower bounds for their half-lives have been established:
    $^{182}$W, t$_{1/2}$ > 7.7×10$^{21}$ years
    $^{183}$W, t$_{1/2}$ > 4.1×10$^{21}$ years
    $^{184}$W, t$_{1/2}$ > 8.9×10$^{21}$ years
    $^{186}$W, t$_{1/2}$ > 8.2×10$^{21}$ years
Thirty-four artificial radioisotopes of tungsten have been characterized with mass numbers ranging from 156 to 194, the most stable of which are $^{181}$W with a half-life of 121.2 days, $^{185}$W with a half-life of 75.1 days, $^{188}$W with a half-life of 69.4 days and $^{178}$W with a half-life of 21.6 days. All of the remaining radioactive isotopes have half-lives of less than 24 hours, and most of these have half-lives that are less than 8 minutes. Tungsten also has twelve known meta states, the most stable being $^{179m1}$W (t$_{1/2}$ 6.4 minutes).

## List of isotopes

| Nuclide | Z | N | Isotopic mass (Da) | Half-life | Decay mode | Daughter isotope | Spin and parity | Natural abundance (mole fraction) | Natural abundance (mole fraction) |
| Nuclide | Excitation energy | Excitation energy | Excitation energy | Half-life | Decay mode | Daughter isotope | Spin and parity | Normal proportion | Range of variation |
| $^{156}$W | 74 | 82 | | 157+57 −34 ms | β$^+$ | $^{156}$Ta | 0+ | | |
| $^{157}$W | 74 | 83 | 156.97886(43)# | 275(40) ms | β$^+$ | $^{157}$Ta | (7/2−) | | |
| $^{158}$W | 74 | 84 | 157.97457(32)# | 1.43(18) ms | α | $^{154}$Hf | 0+ | | |
| $^{158m}$W | 1889(8) keV | 1889(8) keV | 1889(8) keV | 143(19) μs | α | $^{154}$Hf | (8+) | | |
| $^{159}$W | 74 | 85 | 158.97270(32)# | 8.2(7) ms | α (82%) | $^{155}$Hf | 7/2−# | | |
| $^{160}$W | 74 | 86 | 159.96851(16) | 90(5) ms | α (87%) | $^{156}$Hf | 0+ | | |
| $^{160}$W | 74 | 86 | 159.96851(16) | 90(5) ms | β$^+$ (13%) | $^{160}$Ta | 0+ | | |
| $^{161}$W | 74 | 87 | 160.96725(22)# | 409(16) ms | α (73%) | $^{157}$Hf | 7/2−# | | |
| $^{161}$W | 74 | 87 | 160.96725(22)# | 409(16) ms | β$^+$ (27%) | $^{161}$Ta | 7/2−# | | |
| $^{162}$W | 74 | 88 | 161.963500(19) | 1.19(12) s | β$^+$ (54.8%) | $^{162}$Ta | 0+ | | |
| $^{162}$W | 74 | 88 | 161.963500(19) | 1.19(12) s | α (45.2%) | $^{158}$Hf | 0+ | | |
| $^{163}$W | 74 | 89 | 162.962524(63) | 2.63(9) s | β$^+$ (86%) | $^{163}$Ta | 7/2− | | |
| $^{163}$W | 74 | 89 | 162.962524(63) | 2.63(9) s | α (14%) | $^{159}$Hf | 7/2− | | |
| $^{163m}$W | 480.3(7) keV | 480.3(7) keV | 480.3(7) keV | 154(3) ns | IT | $^{163}$W | 13/2+ | | |
| $^{164}$W | 74 | 90 | 163.958952(10) | 6.3(2) s | β$^+$ (96.2%) | $^{164}$Ta | 0+ | | |
| $^{164}$W | 74 | 90 | 163.958952(10) | 6.3(2) s | α (3.8%) | $^{160}$Hf | 0+ | | |
| $^{165}$W | 74 | 91 | 164.958281(28) | 5.1(5) s | β$^+$ | $^{165}$Ta | (5/2−) | | |
| $^{166}$W | 74 | 92 | 165.955032(10) | 19.2(6) s | β$^+$ (99.97%) | $^{166}$Ta | 0+ | | |
| $^{166}$W | 74 | 92 | 165.955032(10) | 19.2(6) s | α (0.035%) | $^{162}$Hf | 0+ | | |
| $^{167}$W | 74 | 93 | 166.954811(20) | 19.9(5) s | β$^+$ (99.96%) | $^{167}$Ta | (5/2−) | | |
| $^{167}$W | 74 | 93 | 166.954811(20) | 19.9(5) s | α (0.04%) | $^{163}$Hf | (5/2−) | | |
| $^{168}$W | 74 | 94 | 167.951805(14) | 50.9(19) s | β$^+$ (99.97%) | $^{168}$Ta | 0+ | | |
| $^{168}$W | 74 | 94 | 167.951805(14) | 50.9(19) s | α (0.032%) | $^{164}$Hf | 0+ | | |
| $^{169}$W | 74 | 95 | 168.951779(17) | 74(6) s | β$^+$ | $^{169}$Ta | 5/2−# | | |
| $^{170}$W | 74 | 96 | 169.949231(14) | 2.42(4) min | β$^+$(99%) | $^{170}$Ta | 0+ | | |
| $^{171}$W | 74 | 97 | 170.949451(30) | 2.38(4) min | β$^+$ | $^{171}$Ta | (5/2−) | | |
| $^{172}$W | 74 | 98 | 171.947292(30) | 6.6(9) min | β$^+$ | $^{172}$Ta | 0+ | | |
| $^{173}$W | 74 | 99 | 172.947689(30) | 7.6(2) min | β$^+$ | $^{173}$Ta | 5/2− | | |
| $^{174}$W | 74 | 100 | 173.946079(30) | 33.2(21) min | β$^+$ | $^{174}$Ta | 0+ | | |
| $^{174m1}$W | 2267.8(4) keV | 2267.8(4) keV | 2267.8(4) keV | 158(3) ns | IT | $^{174}$W | 8− | | |
| $^{174m2}$W | 3515.6(4) keV | 3515.6(4) keV | 3515.6(4) keV | 128(8) ns | IT | $^{174}$W | 12+ | | |
| $^{175}$W | 74 | 101 | 174.946717(30) | 35.2(6) min | β$^+$ | $^{175}$Ta | (1/2−) | | |
| $^{175m}$W | 234.96(15) keV | 234.96(15) keV | 234.96(15) keV | 216(6) ns | IT | $^{175}$W | (7/2+) | | |
| $^{176}$W | 74 | 102 | 175.945634(30) | 2.5(1) h | EC | $^{176}$Ta | 0+ | | |
| $^{177}$W | 74 | 103 | 176.946643(30) | 132.4(20) min | β$^+$ | $^{177}$Ta | 1/2− | | |
| $^{178}$W | 74 | 104 | 177.945886(16) | 21.6(3) d | EC | $^{178}$Ta | 0+ | | |
| $^{178m}$W | 6572.7(3) keV | 6572.7(3) keV | 6572.7(3) keV | 220(10) ns | IT | $^{178}$W | 25+ | | |
| $^{179}$W | 74 | 105 | 178.947079(16) | 37.05(16) min | β$^+$ | $^{179}$Ta | 7/2− | | |
| $^{179m1}$W | 221.91(3) keV | 221.91(3) keV | 221.91(3) keV | 6.40(7) min | IT (99.71%) | $^{179}$W | 1/2− | | |
| $^{179m1}$W | 221.91(3) keV | 221.91(3) keV | 221.91(3) keV | 6.40(7) min | β$^+$ (0.29%) | $^{179}$Ta | 1/2− | | |
| $^{179m2}$W | 1631.90(8) keV | 1631.90(8) keV | 1631.90(8) keV | 390(30) ns | IT | $^{179}$W | 21/2+ | | |
| $^{179m3}$W | 3348.41(14) keV | 3348.41(14) keV | 3348.41(14) keV | 750(80) ns | IT | $^{179}$W | 35/2− | | |
| $^{180}$W | 74 | 106 | 179.9467133(15) | 1.59(5)×10$^{18}$ y | α | $^{176}$Hf | 0+ | 0.0012(1) | |
| $^{180m1}$W | 1529.05(4) keV | 1529.05(4) keV | 1529.05(4) keV | 5.47(9) ms | IT | $^{180}$W | 8− | | |
| $^{180m2}$W | 3264.7(3) keV | 3264.7(3) keV | 3264.7(3) keV | 2.33(19) μs | IT | $^{180}$W | 14− | | |
| $^{181}$W | 74 | 107 | 180.9482187(16) | 120.956(19) d | EC | $^{181}$Ta | 9/2+ | | |
| $^{181m1}$W | 365.55(13) keV | 365.55(13) keV | 365.55(13) keV | 14.59(15) μs | IT | $^{181}$W | 5/2− | | |
| $^{181m2}$W | 1653.0(3) keV | 1653.0(3) keV | 1653.0(3) keV | 200(13) ns | IT | $^{181}$W | 21/2+ | | |
| $^{182}$W | 74 | 108 | 181.94820564(80) | Observationally Stable | Observationally Stable | Observationally Stable | 0+ | 0.2650(16) | |
| $^{182m}$W | 2230.65(14) keV | 2230.65(14) keV | 2230.65(14) keV | 1.3(1) μs | IT | $^{182}$W | 10+ | | |
| $^{183}$W | 74 | 109 | 182.95022442(80) | Observationally Stable | Observationally Stable | Observationally Stable | 1/2− | 0.1431(4) | |
| $^{183m}$W | 309.492(4) keV | 309.492(4) keV | 309.492(4) keV | 5.30(8) s | IT | $^{183}$W | 11/2+ | | |
| $^{184}$W | 74 | 110 | 183.95093318(79) | Observationally Stable | Observationally Stable | Observationally Stable | 0+ | 0.3064(2) | |
| $^{184m1}$W | 1284.997(8) keV | 1284.997(8) keV | 1284.997(8) keV | 8.33(18) μs | IT | $^{184}$W | 5− | | |
| $^{184m2}$W | 4127.7(5) keV | 4127.7(5) keV | 4127.7(5) keV | 188(38) ns | IT | $^{184}$W | (14+) | | |
| $^{185}$W | 74 | 111 | 184.95342121(79) | 75.1(3) d | β$^−$ | $^{185}$Re | 3/2− | | |
| $^{185m}$W | 197.383(23) keV | 197.383(23) keV | 197.383(23) keV | 1.597(4) min | IT | $^{185}$W | 11/2+ | | |
| $^{186}$W | 74 | 112 | 185.9543651(13) | Observationally Stable | Observationally Stable | Observationally Stable | 0+ | 0.2843(19) | |
| $^{186m1}$W | 1517.2(6) keV | 1517.2(6) keV | 1517.2(6) keV | 18(1) μs | IT | $^{186}$W | 7− | | |
| $^{186m2}$W | 3542.8(21) keV | 3542.8(21) keV | 3542.8(21) keV | 2.0(2) s | IT | $^{186}$W | 16+ | | |
| $^{187}$W | 74 | 113 | 186.9571612(13) | 23.809(25) h | β$^−$ | $^{187}$Re | 3/2− | | |
| $^{187m}$W | 410.06(4) keV | 410.06(4) keV | 410.06(4) keV | 1.54(13) μs | IT | $^{187}$W | 11/2+ | | |
| $^{188}$W | 74 | 114 | 187.9584883(33) | 69.77(5) d | β$^−$ | $^{188}$Re | 0+ | | |
| $^{188m}$W | 1926.7(8) keV | 1926.7(8) keV | 1926.7(8) keV | 109.5(35) ns | IT | $^{188}$W | 8− | | |
| $^{189}$W | 74 | 115 | 188.96156(22)# | 11.6(2) min | β$^−$ | $^{189}$Re | 9/2−# | | |
| $^{190}$W | 74 | 116 | 189.963104(38) | 30.0(15) min | β$^−$ | $^{190}$Re | 0+ | | |
| $^{190m1}$W | 1743.6(10) keV | 1743.6(10) keV | 1743.6(10) keV | 111(17) ns | IT | $^{190}$W | 8+ | | |
| $^{190m2}$W | 1840.6(14) keV | 1840.6(14) keV | 1840.6(14) keV | 166(6) μs | IT | $^{190}$W | 10− | | |
| $^{191}$W | 74 | 117 | 190.966531(45) | 14# s [>300 ns] | | | 3/2−# | | |
| $^{191m}$W | 235(10)# keV | 235(10)# keV | 235(10)# keV | 340(14) ns | IT | $^{191}$W | 9/2−# | | |
| $^{192}$W | 74 | 118 | 191.96820(22)# | 40# s [>300 ns] | | | 0+ | | |
| $^{193}$W | 74 | 119 | 192.97188(22)# | 30# s [>300 ns] | | | 1/2−# | | |
| $^{194}$W | 74 | 120 | 193.97380(32)# | 20# s [>300 ns] | | | 0+ | | |
| $^{195}$W | 74 | 121 | 194.97774(32)# | 30# s [>160 ns] | | | 3/2−# | | |
| $^{196}$W | 74 | 122 | 195.97988(43)# | 25# s [>300 ns] | | | 0+ | | |
| $^{197}$W | 74 | 123 | 196.98404(43)# | 1# s [>300 ns] | | | 5/2−# | | |
| This table header & footer: view ||||||||||
* ↑ $^m$W – Excited nuclear isomer.
* ↑ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
* ↑ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
* ↑ Bold half-life – nearly stable, half-life longer than age of universe.
* 1 2 # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
* ↑ Modes of decay: α:Alpha decay β$^+$:Positron emission EC:Electron capture β$^−$:Beta decay IT:Isomeric transition
* ↑ Bold italics symbol as daughter – Daughter product is nearly stable.
* ↑ Bold symbol as daughter – Daughter product is stable.
* ↑ ( ) spin value – Indicates spin with weak assignment arguments.
* ↑ Primordial radionuclide
* ↑ Believed to undergo α decay to $^{178}$Hf with a half-life over 7.7×10$^{21}$ y
* ↑ Believed to undergo α decay to $^{179}$Hf with a half-life over 6.70×10$^{20}$ y
* ↑ Believed to undergo α decay to $^{180}$Hf with a half-life over 8.9×10$^{21}$ y
* ↑ Believed to undergo α decay to $^{182}$Hf or β$^−$β$^−$ decay to $^{186}$Os with a half-life over 4.1×10$^{18}$ y