Silicon (Si) has numerous known isotopes, with mass numbers ranging from 22 to 44. 28Si (the most abundant isotope, at 92.23%), 29Si (4.67%), and 30Si (3.1%) are stable; 32Si is a radioactive isotope produced by cosmic ray spallation of argon. Its half-life has been determined to be approximately 170 years (0.21 MeV), and it decays by beta emission to 32P (which has a 14.28 day half-life [1]) and then to 32S. The standard atomic mass is 28.0855(3) u
Contents |
| nuclide symbol |
Z(p) | N(n) | isotopic mass (u) |
half-life | nuclear spin |
representative isotopic composition (mole fraction) |
range of natural variation (mole fraction) |
|---|---|---|---|---|---|---|---|
| excitation energy | |||||||
| 22Si | 14 | 8 | 22.03453(22)# | 29(2) ms | 0+ | ||
| 23Si | 14 | 9 | 23.02552(21)# | 42.3(4) ms | 3/2+# | ||
| 24Si | 14 | 10 | 24.011546(21) | 140(8) ms | 0+ | ||
| 25Si | 14 | 11 | 25.004106(11) | 220(3) ms | 5/2+ | ||
| 26Si | 14 | 12 | 25.992330(3) | 2.234(13) s | 0+ | ||
| 27Si | 14 | 13 | 26.98670491(16) | 4.16(2) s | 5/2+ | ||
| 28Si | 14 | 14 | 27.9769265325(19) | STABLE | 0+ | 0.92223(19) | 0.92205-0.92241 |
| 29Si | 14 | 15 | 28.976494700(22) | STABLE | 1/2+ | 0.04685(8) | 0.04678-0.04692 |
| 30Si | 14 | 16 | 29.97377017(3) | STABLE | 0+ | 0.03092(11) | 0.03082-0.03102 |
| 31Si | 14 | 17 | 30.97536323(4) | 157.3(3) min | 3/2+ | ||
| 32Si | 14 | 18 | 31.97414808(5) | 170 y | 0+ | ||
| 33Si | 14 | 19 | 32.978000(17) | 6.18(18) s | (3/2+) | ||
| 34Si | 14 | 20 | 33.978576(15) | 2.77(20) s | 0+ | ||
| 35Si | 14 | 21 | 34.98458(4) | 780(120) ms | 7/2-# | ||
| 36Si | 14 | 22 | 35.98660(13) | 0.45(6) s | 0+ | ||
| 37Si | 14 | 23 | 36.99294(18) | 90(60) ms | (7/2-)# | ||
| 38Si | 14 | 24 | 37.99563(15) | 90# ms [>1 µs] | 0+ | ||
| 39Si | 14 | 25 | 39.00207(36) | 47.5(20) ms | 7/2-# | ||
| 40Si | 14 | 26 | 40.00587(60) | 33.0(10) ms | 0+ | ||
| 41Si | 14 | 27 | 41.01456(198) | 20.0(25) ms | 7/2-# | ||
| 42Si | 14 | 28 | 42.01979(54)# | 13(4) ms | 0+ | ||
| 43Si | 14 | 29 | 43.02866(75)# | 15# ms [>260 ns] | 3/2-# | ||
| 44Si | 14 | 30 | 44.03526(86)# | 10# ms | 0+ | ||
| Isotopes of aluminium | Isotopes of silicon | Isotopes of phosphorus |
| Index to isotope pages · Table of nuclides | ||