Silicon (14Si) has 25 known isotopes, with mass numbers ranging from 22 to 46. 28Si (the most abundant isotope, at 92.23%), 29Si (4.67%), and 30Si (3.1%) are stable. The longest-lived radioisotope is 32Si, which is produced by cosmic ray spallation of argon. Its half-life has been determined to be approximately 150 years (with decay energy 0.21 MeV), and it decays by beta emission to 32P (which has a 14.27-day half-life)[1] and then to 32S. After 32Si, 31Si has the second longest half-life at 157.3 minutes. All others have half-lives under 7 seconds.
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| Standard atomic weight Ar°(Si) | ||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
List of isotopes
edit| Nuclide [n 1] |
Z | N | Isotopic mass (Da)[4] [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 | Normal proportion[1] | Range of variation | |||||||||||||||||
| 22Si | 14 | 8 | 22.03611(54)# | 28.7(11) ms | β+, p (62%) | 21Mg | 0+ | ||||||||||||
| β+ (37%) | 22Al | ||||||||||||||||||
| β+, 2p (0.7%) | 20Na | ||||||||||||||||||
| 23Si | 14 | 9 | 23.02571(54)# | 42.3(4) ms | β+, p (88%) | 22Mg | 3/2+# | ||||||||||||
| β+ (8%) | 23Al | ||||||||||||||||||
| β+, 2p (3.6%) | 21Na | ||||||||||||||||||
| 24Si | 14 | 10 | 24.011535(21) | 143.2 (21) ms | β+ (65.5%) | 24Al | 0+ | ||||||||||||
| β+, p (34.5%) | 23Mg | ||||||||||||||||||
| 25Si | 14 | 11 | 25.004109(11) | 220.6(10) ms | β+ (65%) | 25Al | 5/2+ | ||||||||||||
| β+, p (35%) | 24Mg | ||||||||||||||||||
| 26Si | 14 | 12 | 25.99233382(12) | 2.2453(7) s | β+ | 26Al | 0+ | ||||||||||||
| 27Si | 14 | 13 | 26.98670469(12) | 4.117(14) s | β+ | 27Al | 5/2+ | ||||||||||||
| 28Si | 14 | 14 | 27.97692653442(55) | Stable | 0+ | 0.92223(19) | 0.92205–0.92241 | ||||||||||||
| 29Si | 14 | 15 | 28.97649466434(60) | Stable | 1/2+ | 0.04685(8) | 0.04678–0.04692 | ||||||||||||
| 30Si | 14 | 16 | 29.973770137(23) | Stable | 0+ | 0.03092(11) | 0.03082–0.03102 | ||||||||||||
| 31Si | 14 | 17 | 30.975363196(46) | 157.16(20) min | β− | 31P | 3/2+ | ||||||||||||
| 32Si | 14 | 18 | 31.97415154(32) | 157(7) y | β− | 32P | 0+ | trace | cosmogenic | ||||||||||
| 33Si | 14 | 19 | 32.97797696(75) | 6.18(18) s | β− | 33P | 3/2+ | ||||||||||||
| 34Si | 14 | 20 | 33.97853805(86) | 2.77(20) s | β− | 34P | 0+ | ||||||||||||
| 34mSi | 4256.1(4) keV | <210 ns | IT | 34Si | (3−) | ||||||||||||||
| 35Si | 14 | 21 | 34.984550(38) | 780(120) ms | β− | 35P | 7/2−# | ||||||||||||
| β−, n? | 34P | ||||||||||||||||||
| 36Si | 14 | 22 | 35.986649(77) | 503(2) ms | β− (88%) | 36P | 0+ | ||||||||||||
| β−, n (12%) | 35P | ||||||||||||||||||
| 37Si | 14 | 23 | 36.99295(12) | 141.0(35) ms | β− (83%) | 37P | (5/2−) | ||||||||||||
| β−, n (17%) | 36P | ||||||||||||||||||
| β−, 2n? | 35P | ||||||||||||||||||
| 38Si | 14 | 24 | 37.99552(11) | 63(8) ms | β− (75%) | 38P | 0+ | ||||||||||||
| β−, n (25%) | 37P | ||||||||||||||||||
| 39Si | 14 | 25 | 39.00249(15) | 41.2(41) ms | β− (67%) | 39P | (5/2−) | ||||||||||||
| β−, n (33%) | 38P | ||||||||||||||||||
| β−, 2n? | 37P | ||||||||||||||||||
| 40Si | 14 | 26 | 40.00608(13) | 31.2(26) ms | β− (62%) | 40P | 0+ | ||||||||||||
| β−, n (38%) | 39P | ||||||||||||||||||
| β−, 2n? | 38P | ||||||||||||||||||
| 41Si | 14 | 27 | 41.01417(32)# | 20.0(25) ms | β−, n (>55%) | 40P | 7/2−# | ||||||||||||
| β− (<45%) | 41P | ||||||||||||||||||
| β−, 2n? | 39P | ||||||||||||||||||
| 42Si | 14 | 28 | 42.01808(32)# | 15.5(4 (stat), 16 (sys)) ms[5] | β− (51%) | 42P | 0+ | ||||||||||||
| β−, n (48%) | 41P | ||||||||||||||||||
| β−, 2n (1%) | 40P | ||||||||||||||||||
| 43Si | 14 | 29 | 43.02612(43)# | 13(4 (stat), 2 (sys)) ms[5] | β−, n (52%) | 42P | 3/2−# | ||||||||||||
| β− (27%) | 43P | ||||||||||||||||||
| β−, 2n (21%) | 41P | ||||||||||||||||||
| 44Si | 14 | 30 | 44.03147(54)# | 4# ms [>360 ns] | β−? | 44P | 0+ | ||||||||||||
| β−, n? | 43P | ||||||||||||||||||
| β−, 2n? | 42P | ||||||||||||||||||
| 45Si[6] | 14 | 31 | 45.03982(64)# | 4# ms | 3/2−# | ||||||||||||||
| 46Si[6] | 14 | 32 | |||||||||||||||||
| This table header & footer: | |||||||||||||||||||
- ^ mSi – 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).
- ^ a b # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
- ^
Modes of decay:
IT: Isomeric transition n: Neutron emission p: Proton emission - ^ Bold symbol as daughter – Daughter product is stable.
- ^ ( ) spin value – Indicates spin with weak assignment arguments.
Silicon-28
editSilicon-28, the most abundant isotope of silicon, is of particular interest in the construction of quantum computers when highly enriched, as the presence of 29Si in a sample of silicon contributes to quantum decoherence.[7] Extremely pure (>99.9998%) samples of 28Si can be produced through selective ionization and deposition of 28Si from silane gas.[8] Due to the extremely high purity that can be obtained in this manner, the Avogadro project sought to develop a new definition of the kilogram 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 the alpha process and the oxygen-burning process, and drives the silicon-burning process in massive stars shortly before they go supernova.[11][12]
Silicon-29
editSilicon-29 is of note as the only stable silicon isotope with a nuclear spin (I = 1/2).[13] As such, it can be employed in nuclear magnetic resonance and hyperfine transition studies, for example to study the properties of the so-called A-center defect in pure silicon.[14]
Silicon-34
editSilicon-34 is a radioactive isotope with a half-life of 2.8 seconds.[1] In addition to the usual N = 20 closed shell, the nucleus also shows a strong Z = 14 shell closure, making it behave like a doubly magic spherical nucleus, except that it is also located two protons above an island of inversion.[15] Silicon-34 has an unusual "bubble" structure where the proton distribution is less dense at the center than near the surface, as the 2s1/2 proton orbital is almost unoccupied in the ground state, unlike in 36S where it is almost full.[16][17] Silicon-34 is one of the known cluster decay emission particles; it is produced in the decay of 242Cm with a branching ratio of approximately 1×10−16.[18]
References
edit- ^ a b c d e f g 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). "Crossing N = 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 Isotopes 45,46Si". 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. Retrieved 16 June 2015.
- ^ Keats, Jonathon. "The Search for a More Perfect Kilogram". Wired. Vol. 19, no. 10. Retrieved 16 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 978-9810220334.
- ^ 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. Retrieved 26 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 from the original (PDF) on 19 September 2016.