Silicon (14 Si) has 25 knownisotopes , withmass number ranging from 22 to 46.28 Si (the most abundant isotope, at 92.24%),29 Si (4.67%), and30 Si (3.07%) are stable. The longest-lived radioisotope is32 Si, which occurs naturally in tiny quantities fromcosmic ray spallation ofargon . Itshalf-life has been determined to be approximately 157 years; itbeta decays with energy 0.21 MeV to32 P , which in turn beta-decays, with half-life 14.269 days to32 S ; neither step hasgamma emission. After32 Si,31 Si has the second longest half-life at 157.2 minutes. All others have half-lives under 7 seconds.
A chart showing the relative abundances of the naturally occurring isotopes of silicon. Nuclide[ n 1] Z N Isotopic mass (Da ) [ 4] [ n 2] [ n 3] Half-life [ 1] [ n 4] Decay [ 1] [ n 5] Daughter [ n 6] Spin andparity [ 1] [ n 7] [ n 4] Natural abundance (mole fraction) Excitation energy Normal proportion[ 1] Range of variation 22 Si14 8 22.03611(54)# 28.7(11) ms β+ ,p (62%)21 Mg0+ β+ (37%) 22 Alβ+ , 2p (0.7%) 20 Na23 Si14 9 23.02571(54)# 42.3(4) ms β+ , p (88%) 22 Mg3/2+# β+ (8%) 23 Alβ+ , 2p (3.6%) 21 Na24 Si14 10 24.011535(21) 143.2 (21) ms β+ (65.5%) 24 Al0+ β+ , p (34.5%) 23 Mg25 Si14 11 25.004109(11) 220.6(10) ms β+ (65%) 25 Al5/2+ β+ , p (35%) 24 Mg26 Si14 12 25.99233382(12) 2.2453(7) s β+ 26 Al0+ 27 Si14 13 26.98670469(12) 4.117(14) s β+ 27 Al5/2+ 28 Si14 14 27.97692653442(55) Stable 0+ 0.92223(19) 0.92205–0.92241 29 Si14 15 28.97649466434(60) Stable 1/2+ 0.04685(8) 0.04678–0.04692 30 Si14 16 29.973770137(23) Stable 0+ 0.03092(11) 0.03082–0.03102 31 Si14 17 30.975363196(46) 157.16(20) min β− 31 P3/2+ 32 Si14 18 31.97415154(32) 157(7) y β− 32 P0+ trace cosmogenic 33 Si14 19 32.97797696(75) 6.18(18) s β− 33 P3/2+ 34 Si14 20 33.97853805(86) 2.77(20) s β− 34 P0+ 34m Si4256.1(4) keV <210 ns IT 34 Si(3−) 35 Si14 21 34.984550(38) 780(120) ms β− 35 P7/2−# β− ,n ? 34 P36 Si14 22 35.986649(77) 503(2) ms β− (88%) 36 P0+ β− ,n (12%) 35 P37 Si14 23 36.99295(12) 141.0(35) ms β− (83%) 37 P(5/2−) β− , n (17%) 36 Pβ− , 2n? 35 P38 Si14 24 37.99552(11) 63(8) ms β− (75%) 38 P0+ β− , n (25%) 37 P39 Si14 25 39.00249(15) 41.2(41) ms β− (67%) 39 P(5/2−) β− , n (33%) 38 Pβ− , 2n? 37 P40 Si14 26 40.00608(13) 31.2(26) ms β− (62%) 40 P0+ β− , n (38%) 39 Pβ− , 2n? 38 P41 Si14 27 41.01417(32)# 20.0(25) ms β− , n (>55%) 40 P7/2−# β− (<45%) 41 Pβ− , 2n? 39 P42 Si14 28 42.01808(32)# 15.5(4 (stat ), 16 (sys )) ms[ 5] β− (51%) 42 P0+ β− , n (48%) 41 Pβ− , 2n (1%) 40 P43 Si14 29 43.02612(43)# 13(4 (stat ), 2 (sys )) ms[ 5] β− , n (52%) 42 P3/2−# β− (27%) 43 Pβ− , 2n (21%) 41 P44 Si14 30 44.03147(54)# 4# ms [>360 ns] β− ? 44 P0+ β− , n? 43 Pβ− , 2n? 42 P45 Si[ 6] 14 31 45.03982(64)# 4# ms 3/2−# 46 Si[ 6] 14 32 This table header & footer:
^ m Si – Excitednuclear 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). ^a b # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN). ^ Modes of decay: ^ Bold symbol as daughter – Daughter product is stable.^ ( ) spin value – Indicates spin with weak assignment arguments. Silicon-28, the most abundant isotope of silicon, is of particular interest in the construction ofquantum computers when highly enriched, as the presence of29 Si in a sample of silicon contributes toquantum decoherence .[ 7] 28 Si can be produced through selectiveionization anddeposition of28 Si fromsilane gas.[ 8] Avogadro project sought to develop a new definition of thekilogram by making a 93.75 mm (3.691 in) sphere of the isotope and determining the exact number of atoms in the sample.[ 9] [ 10]
Silicon-28 is produced in stars during thealpha process and theoxygen-burning process , and drives thesilicon-burning process in massive stars shortly before they gosupernova .[ 11] [ 12]
Silicon-29 is of note as the only stable silicon isotope with a nonzeronuclear spin (I = 1/2).[ 13] nuclear magnetic resonance andhyperfine transition studies, for example to study the properties of the so-calledA-center defect in pure silicon.[ 14]
Silicon-34 is a radioactive isotope with a half-life of 2.8 seconds.[ 1] N = 20 closed shell, the nucleus also shows a strongZ = 14 shell closure, making it behave like adoubly magic spherical nucleus, except that it is also located two protons above anisland of inversion .[ 15] s 1/2 proton orbital is almost unoccupied in the ground state, unlike in36 S[ 16] [ 17] cluster decay emission particles; it is produced in the decay of242 Cm× 10−16 [ 18]
Daughter products other than silicon
^a b c d e f Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021)."The NUBASE2020 evaluation of nuclear properties" (PDF) .Chinese Physics C .45 (3) 030001.doi :10.1088/1674-1137/abddae . ^ "Standard Atomic Weights: Silicon" .CIAAW . 2009.^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04)."Standard atomic weights of the elements 2021 (IUPAC Technical Report)" .Pure and Applied Chemistry .doi :10.1515/pac-2019-0603 .ISSN 1365-3075 . ^ Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*".Chinese Physics C .45 (3) 030003.doi :10.1088/1674-1137/abddaf . ^a b Crawford, H. L.; Tripathi, V.; Allmond, J. M.; et al. (2022)."CrossingN = 28 toward the neutron drip line: first measurement of half-lives at FRIB" .Physical Review Letters .129 (212501) 212501.Bibcode :2022PhRvL.129u2501C .doi :10.1103/PhysRevLett.129.212501 PMID 36461950 .S2CID 253600995 . ^a b Yoshimoto, Masahiro; Suzuki, Hiroshi; Fukuda, Naoki; Takeda, Hiroyuki; Shimizu, Yohei; Yanagisawa, Yoshiyuki; Sato, Hiromi; Kusaka, Kensuke; Ohtake, Masao; Yoshida, Koichi; Michimasa, Shin'ichiro (2024)."Discovery of Neutron-Rich Silicon Isotopes45,46 Si" .Progress of Theoretical and Experimental Physics .2024 (10). Oxford University Press (OUP).doi :10.1093/ptep/ptae155 ISSN 2050-3911 . ^ "Beyond Six Nines: Ultra-enriched Silicon Paves the Road to Quantum Computing" .NIST . 2014-08-11.^ Dwyer, K J; Pomeroy, J M; Simons, D S; Steffens, K L; Lau, J W (2014-08-30)."Enriching 28 Si beyond 99.9998 % for semiconductor quantum computing" Journal of Physics D: Applied Physics .47 (34) 345105.doi :10.1088/0022-3727/47/34/345105 .ISSN 0022-3727 . ^ Powell, Devin (1 July 2008)."Roundest Objects in the World Created" .New Scientist ^ Keats, Jonathon."The Search for a More Perfect Kilogram" .Wired . Vol. 19, no. 10. Retrieved16 December 2023 . ^ Woosley, S.; Janka, T. (2006). "The physics of core collapse supernovae".Nature Physics .1 (3):147– 154.arXiv :astro-ph/0601261 Bibcode :2005NatPh...1..147W .CiteSeerX 10.1.1.336.2176 doi :10.1038/nphys172 .S2CID 118974639 . ^ Narlikar, Jayant V. (1995).From Black Clouds to Black Holes World Scientific . p. 94.ISBN 978-981-02-2033-4 ^ Greenwood, Norman N.; Earnshaw, Alan (1997).Chemistry of the Elements (2nd ed.). Butterworth-Heinemann.ISBN 978-0-08-037941-8 ^ Watkins, G. D.; Corbett, J. W. (1961-02-15)."Defects in Irradiated Silicon. I. Electron Spin Resonance of the Si- A Center" Physical Review .121 (4):1001– 1014.Bibcode :1961PhRv..121.1001W .doi :10.1103/PhysRev.121.1001 .ISSN 0031-899X . ^ Lică, R.; Rotaru, F.; Borge, M. J. G.; Grévy, S.; Negoiţă, F.; Poves, A.; Sorlin, O.; Andreyev, A. N.; Borcea, R.; Costache, C.; De Witte, H.; Fraile, L. M.; Greenlees, P. T.; Huyse, M.; Ionescu, A.; Kisyov, S.; Konki, J.; Lazarus, I.; Madurga, M.; Mărginean, N.; Mărginean, R.; Mihai, C.; Mihai, R. E.; Negret, A.; Nowacki, F.; Page, R. D.; Pakarinen, J.; Pucknell, V.; Rahkila, P.; Rapisarda, E.; Şerban, A.; Sotty, C. O.; Stan, L.; Stănoiu, M.; Tengblad, O.; Turturică, A.; Van Duppen, P.; Warr, N.; Dessagne, Ph.; Stora, T.; Borcea, C.; Călinescu, S.; Daugas, J. M.; Filipescu, D.; Kuti, I.; Franchoo, S.; Gheorghe, I.; Morfouace, P.; Morel, P.; Mrazek, J.; Pietreanu, D.; Sohler, D.; Stefan, I.; Şuvăilă, R.; Toma, S.; Ur, C. A. (11 September 2019)."Normal and intruder configurations in Si 34 populated in the β − decay of Mg 34 and Al 34" .Physical Review C .100 (3) 034306.arXiv :1908.11626 doi :10.1103/PhysRevC.100.034306 ^ "Physicists find atomic nucleus with a 'bubble' in the middle" . 24 October 2016. Retrieved26 December 2023 .^ Mutschler, A.; Lemasson, A.; Sorlin, O.; Bazin, D.; Borcea, C.; Borcea, R.; Dombrádi, Z.; Ebran, J.-P.; Gade, A.; Iwasaki, H.; Khan, E.; Lepailleur, A.; Recchia, F.; Roger, T.; Rotaru, F.; Sohler, D.; Stanoiu, M.; Stroberg, S. R.; Tostevin, J. A.; Vandebrouck, M.; Weisshaar, D.; Wimmer, K. (February 2017). "A proton density bubble in the doubly magic 34Si nucleus".Nature Physics .13 (2):152– 156.arXiv :1707.03583 doi :10.1038/nphys3916 . ^ Bonetti, R.; Guglielmetti, A. (2007)."Cluster radioactivity: an overview after twenty years" (PDF) .Romanian Reports in Physics .59 :301– 310. Archived fromthe original (PDF) on 19 September 2016.
Group 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Period Hydrogen and Alkaline Pnictogens Chalcogens Halogens Noble gases ① 1 2 ② 3 4 5 6 7 8 9 10 ③ 11 12 13 14 15 16 17 18 ④ 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 ⑤ 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 ⑥ 55 56 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 ⑦ 87 88 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 ⑧ 119 120 57 58 59 60 61 62 63 64 65 66 67 68 69 70 89 90 91 92 93 94 95 96 97 98 99 100 101 102
