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Isotopes of silicon



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 argon decay. 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

Additional recommended knowledge

Table

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(13) a 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+

Notes

  • The precision of the isotope abundances and atomic mass is limited through variations. The given ranges should be applicable to any normal terrestrial material.
  • Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
  • Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which use expanded uncertainties.

References

  • Isotope masses from Ame2003 Atomic Mass Evaluation by G. Audi, A.H. Wapstra, C. Thibault, J. Blachot and O. Bersillon in Nuclear Physics A729 (2003).
  • Isotopic compositions and standard atomic masses from Atomic weights of the elements. Review 2000 (IUPAC Technical Report). Pure Appl. Chem. Vol. 75, No. 6, pp. 683-800, (2003) and Atomic Weights Revised (2005).
  • Half-life, spin, and isomer data selected from these sources. Editing notes on this article's talk page.
    • Audi, Bersillon, Blachot, Wapstra. The Nubase2003 evaluation of nuclear and decay properties, Nuc. Phys. A 729, pp. 3-128 (2003).
    • National Nuclear Data Center, Brookhaven National Laboratory. Information extracted from the NuDat 2.1 database (retrieved Sept. 2005).
    • David R. Lide (ed.), Norman E. Holden in CRC Handbook of Chemistry and Physics, 85th Edition, online version. CRC Press. Boca Raton, Florida (2005). Section 11, Table of the Isotopes.


Isotopes of aluminium Isotopes of silicon Isotopes of phosphorus
Index to isotope pages
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Isotopes_of_silicon". A list of authors is available in Wikipedia.
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