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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

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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)
nuclide symbol	excitation energy			half-life	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
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
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Categories: Isotopes | Silicon

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.