Isotopes of sulfur

Main isotopes of sulfur

Isotope			Decay
	abundance	half-life (t_1/2)	mode	product
³²S	94.99%	stable
³³S	0.75%	stable
³⁴S	4.25%	stable
³⁵S	trace	87.32 d	β⁻	³⁵Cl
³⁶S	0.01%	stable

Standard atomic weight (A_r)

[32.059, 32.076]^[1]
Conventional: 32.06

Sulfur (₁₆S) has 24 known isotopes with mass numbers ranging from 26 to 49, four of which are stable: ³²S (95.02%), ³³S (0.75%), ³⁴S (4.21%), and ³⁶S (0.02%). The preponderance of sulfur-32 is explained by its production from carbon-12 plus successive fusion capture of five helium nuclei, in the so-called alpha process of exploding type II supernovas (see silicon burning).

Other than ³⁵S, the radioactive isotopes of sulfur are all comparatively short-lived. ³⁵S is formed from cosmic ray spallation of ⁴⁰Ar in the atmosphere. It has a half-life of 87 days. The next longest-lived radioisotope is sulfur-38, with a half-life of 17 minutes. The shortest-lived is ⁴⁹S, with a half-life shorter than 200 nanoseconds.

When sulfide minerals are precipitated, isotopic equilibration among solids and liquid may cause small differences in the δS-64 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 oceans believed to be dominated by watershed sources of sulfate.

List of isotopes

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life	decay mode(s)^[2]	daughter isotope(s)^{[n 1]}	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
nuclide symbol	excitation energy			half-life	decay mode(s)^[2]	daughter isotope(s)^{[n 1]}	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
²⁶S	16	10	26.02788(32)#	10# ms	2p	²⁴Si	0+
²⁷S^{[n 2]}	16	11	27.01883(22)#	15.5(15) ms	β⁺ (98.0%)	²⁷P	(5/2+)
					β⁺, 2p (2.0%)	²⁵Al
					β⁺, p (<.1%)	²⁶Si
²⁸S	16	12	28.00437(17)	125(10) ms	β⁺ (79.3%)	²⁸P	0+
²⁸S	16	12	28.00437(17)	125(10) ms	β⁺, p (20.7%)	²⁷Si	0+
²⁹S	16	13	28.99661(5)	187(4) ms	β⁺ (53.6%)	²⁹P	5/2+
²⁹S	16	13	28.99661(5)	187(4) ms	β⁺, p (46.4%)	²⁸Si	5/2+
³⁰S	16	14	29.984903(3)	1.178(5) s	β⁺	³⁰P	0+
³¹S	16	15	30.9795547(16)	2.572(13) s	β⁺	³¹P	1/2+
³²S^{[n 3]}	16	16	31.97207100(15)	Stable			0+	0.9493(31)	0.94454-0.95281
³³S	16	17	32.97145876(15)	Stable			3/2+	0.0076(2)	0.00730-0.00793
³⁴S	16	18	33.96786690(12)	Stable			0+	0.0429(28)	0.03976-0.04734
³⁵S	16	19	34.96903216(11)	87.51(12) d	β⁻	³⁵Cl	3/2+	Trace^{[n 4]}
³⁶S	16	20	35.96708076(20)	Stable			0+	2(1)×10⁻⁴	1.3×10⁻⁴-2.7×10⁻⁴
³⁷S	16	21	36.97112557(21)	5.05(2) min	β⁻	³⁷Cl	7/2−
³⁸S	16	22	37.971163(8)	170.3(7) min	β⁻	³⁸Cl	0+
³⁹S	16	23	38.97513(5)	11.5(5) s	β⁻	³⁹Cl	(3/2,5/2,7/2)−
⁴⁰S	16	24	39.97545(15)	8.8(22) s	β⁻	⁴⁰Cl	0+
⁴¹S	16	25	40.97958(13)	1.99(5) s	β⁻ (>99.9%)	⁴¹Cl	(7/2−)#
⁴¹S	16	25	40.97958(13)	1.99(5) s	β⁻, n (<.1%)	⁴⁰Cl	(7/2−)#
⁴²S	16	26	41.98102(13)	1.013(15) s	β⁻ (96%)	⁴²Cl	0+
⁴²S	16	26	41.98102(13)	1.013(15) s	β⁻, n (4%)	⁴¹Cl	0+
⁴³S	16	27	42.98715(22)	260(15) ms	β⁻ (60%)	⁴³Cl	3/2−#
⁴³S	16	27	42.98715(22)	260(15) ms	β⁻, n (40%)	⁴²Cl	3/2−#
^43mS	319(5) keV			480(50) ns			(7/2−)
⁴⁴S	16	28	43.99021(42)	100(1) ms	β⁻ (82%)	⁴⁴Cl	0+
⁴⁴S	16	28	43.99021(42)	100(1) ms	β⁻, n (18%)	⁴³Cl	0+
⁴⁵S	16	29	44.99651(187)	68(2) ms	β⁻, n (54%)	⁴⁴Cl	3/2−#
⁴⁵S	16	29	44.99651(187)	68(2) ms	β⁻ (46%)	⁴⁵Cl	3/2−#
⁴⁶S	16	30	46.00075(75)#	50(8) ms	β⁻	⁴⁶Cl	0+
⁴⁷S	16	31	47.00859(86)#	20# ms [>200 ns]	β⁻	⁴⁷Cl	3/2−#
⁴⁸S	16	32	48.01417(97)#	10# ms [>200 ns]	β⁻	⁴⁸Cl	0+
⁴⁹S	16	33	49.02362(102)#	<200 ns	n	⁴⁸S	3/2−#

↑ Bold for stable isotopes
↑ Has 2 halo protons
↑ Heaviest theoretically stable nuclide with equal numbers of protons and neutrons
↑ Cosmogenic

Facts

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.
Abundance updated from Nubase data.

References

Isotope masses from:
- G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001. Archived from the original (PDF) on 2008-09-23.
Isotopic compositions and standard atomic masses from:
- J. R. de Laeter; J. K. Böhlke; P. De Bièvre; H. Hidaka; H. S. Peiser; K. J. R. Rosman; P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
- M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051. Lay summary.
Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
- G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001. Archived from the original (PDF) on 2008-09-23.
- National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. Retrieved September 2005. Check date values in: |access-date= (help)
- N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide. CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0-8493-0485-9.

↑ Meija, J.; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure Appl. Chem. 88 (3): 265–91. doi:10.1515/pac-2015-0305.
↑ "Universal Nuclide Chart". nucleonica. (Registration required (help)).

External links

Sulfur isotopes data from The Berkeley Laboratory Isotopes Project's

Isotopes of phosphorus	Isotopes of sulfur	Isotopes of chlorine
Table of nuclides

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