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Isotopes of sulfur



Sulfur (S) has 18 isotopes, four of which are stable: 32S (95.02%), 33S (0.75%), 34S (4.21%), and 36S (0.02%). Other than 35S, the radioactive isotopes of sulfur are all short lived. 35S is formed from cosmic ray spallation of 40Ar in the atmosphere. It has a half-life of 87 days. Standard atomic mass: 32.065(5) u

Additional recommended knowledge

When sulfide minerals are precipitated, isotopic equilibration among solids and liquid may cause small differences in the δS-34 values of co-genetic minerals. The differences between minerals can be used to estimate the temperature of equilibration. The δC-13 and δS-34 of coexisting carbonates and sulfides can be used to determine the pH and oxygen fugacity of the ore-bearing fluid during ore formation.

In most forest ecosystems, sulfate is derived mostly from the atmosphere; weathering of ore minerals and evaporites also contribute some sulfur. Sulfur with a distinctive isotopic composition has been used to identify pollution sources, and enriched sulfur has been added as a tracer in hydrologic studies. Differences in the natural abundances can also be used in systems where there is sufficient variation in the 34S of ecosystem components. Rocky Mountain lakes thought to be dominated by atmospheric sources of sulfate have been found to have different δS-34 values from lakes believed to be dominated by watershed sources of sulfate.

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
26S 16 10 26.02788(32)# 10# ms 0+
27S 16 11 27.01883(22)# 15.5(15) ms (5/2+)
28S 16 12 28.00437(17) 125(10) ms 0+
29S 16 13 28.99661(5) 187(4) ms 5/2+
30S 16 14 29.984903(3) 1.178(5) s 0+
31S 16 15 30.9795547(16) 2.572(13) s 1/2+
32S 16 16 31.97207100(15) STABLE 0+ 0.9499(26) 0.94454-0.95281
33S 16 17 32.97145876(15) STABLE 3/2+ 0.0075(2) 0.00730-0.00793
34S 16 18 33.96786690(12) STABLE 0+ 0.0425(24) 0.03976-0.04734
35S 16 19 34.96903216(11) 87.51(12) d 3/2+
36S 16 20 35.96708076(20) STABLE 0+ 0.0001(1) 0.00013-0.00019
37S 16 21 36.97112557(21) 5.05(2) min 7/2-
38S 16 22 37.971163(8) 170.3(7) min 0+
39S 16 23 38.97513(5) 11.5(5) s (3/2,5/2,7/2)-
40S 16 24 39.97545(15) 8.8(22) s 0+
41S 16 25 40.97958(13) 1.99(5) s (7/2-)#
42S 16 26 41.98102(13) 1.013(15) s 0+
43S 16 27 42.98715(22) 260(15) ms 3/2-#
43mS 319(5) keV 480(50) ns (7/2-)
44S 16 28 43.99021(42) 100(1) ms 0+
45S 16 29 44.99651(187) 68(2) ms 3/2-#
46S 16 30 46.00075(75)# 50(8) ms 0+
47S 16 31 47.00859(86)# 20# ms [>200 ns] 3/2-#
48S 16 32 48.01417(97)# 10# ms [>200 ns] 0+
49S 16 33 49.02362(102)# <200 ns 3/2-#

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 phosphorus Isotopes of sulfur Isotopes of chlorine
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This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Isotopes_of_sulfur". A list of authors is available in Wikipedia.
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