# Isotopes of sulfur

Sulfur ($_{16}$S) has 23 known isotopes with mass numbers ranging from 27 to 49, four of which are stable: $^{32}$S (95.02%), $^{33}$S (0.75%), $^{34}$S (4.21%), and $^{36}$S (0.02%). The preponderance of sulfur-32 is explained by its production from carbon-12 plus successive fusion capture of five helium-4 nuclei, in the so-called alpha process of exploding type II supernovas (see silicon burning).
Other than $^{35}$S, the radioactive isotopes of sulfur are all comparatively short-lived. $^{35}$S is formed from cosmic ray spallation of $^{40}$Ar in the atmosphere. It has a half-life of 87 days. The next longest-lived radioisotope is sulfur-38, with a half-life of 170 minutes. Isotopes lighter than $^{32}$S mostly decay to isotopes of phosphorus or silicon, while $^{35}$S and heavier radioisotopes decay to isotopes of chlorine.
The beams of several radioactive isotopes (such as those of $^{44}$S) have been studied theoretically within the framework of the synthesis of superheavy elements, especially those ones in the vicinity of island of stability.
When sulfide minerals are precipitated, isotopic equilibration among solids and liquid may cause small differences in the δ$^{34}$S values of co-genetic minerals. The differences between minerals can be used to estimate the temperature of equilibration. The δ$^{13}$C and δ$^{34}$S 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 $^{34}$S of ecosystem components. Rocky Mountain lakes thought to be dominated by atmospheric sources of sulfate have been found to have different δ$^{34}$S values from oceans believed to be dominated by watershed sources of sulfate.

## List of isotopes

| Nuclide | Z | N | Isotopic mass (Da) | Half-life | Decay mode | Daughter isotope | Spin and parity | Natural abundance (mole fraction) | Natural abundance (mole fraction) |
| Nuclide | Excitation energy | Excitation energy | Excitation energy | Half-life | Decay mode | Daughter isotope | Spin and parity | Normal proportion | Range of variation |
| $^{27}$S | 16 | 11 | 27.01878(43)# | 16.3(2) ms | β$^+$, p (61%) | $^{26}$Si | (5/2+) | | |
| $^{27}$S | 16 | 11 | 27.01878(43)# | 16.3(2) ms | β$^+$ (36%) | $^{27}$P | (5/2+) | | |
| $^{27}$S | 16 | 11 | 27.01878(43)# | 16.3(2) ms | β$^+$, 2p (3.0%) | $^{25}$Al | (5/2+) | | |
| $^{28}$S | 16 | 12 | 28.00437(17) | 125(10) ms | β$^+$ (79.3%) | $^{28}$P | 0+ | | |
| $^{28}$S | 16 | 12 | 28.00437(17) | 125(10) ms | β$^+$, p (20.7%) | $^{27}$Si | 0+ | | |
| $^{29}$S | 16 | 13 | 28.996678(14) | 188(4) ms | β$^+$ (53.6%) | $^{29}$P | 5/2+# | | |
| $^{29}$S | 16 | 13 | 28.996678(14) | 188(4) ms | β$^+$, p (46.4%) | $^{28}$Si | 5/2+# | | |
| $^{30}$S | 16 | 14 | 29.98490677(22) | 1.1798(3) s | β$^+$ | $^{30}$P | 0+ | | |
| $^{31}$S | 16 | 15 | 30.97955700(25) | 2.5534(18) s | β$^+$ | $^{31}$P | 1/2+ | | |
| $^{32}$S | 16 | 16 | 31.9720711735(14) | Stable | Stable | Stable | 0+ | 0.9485(255) | |
| $^{33}$S | 16 | 17 | 32.9714589086(14) | Stable | Stable | Stable | 3/2+ | 0.00763(20) | |
| $^{34}$S | 16 | 18 | 33.967867011(47) | Stable | Stable | Stable | 0+ | 0.04365(235) | |
| $^{35}$S | 16 | 19 | 34.969032321(43) | 87.37(4) d | β$^−$ | $^{35}$Cl | 3/2+ | Trace | |
| $^{36}$S | 16 | 20 | 35.96708069(20) | Stable | Stable | Stable | 0+ | 1.58(17)×10$^{−4}$ | |
| $^{37}$S | 16 | 21 | 36.97112550(21) | 5.05(2) min | β$^−$ | $^{37}$Cl | 7/2− | | |
| $^{38}$S | 16 | 22 | 37.9711633(77) | 170.3(7) min | β$^−$ | $^{38}$Cl | 0+ | | |
| $^{39}$S | 16 | 23 | 38.975134(54) | 11.5(5) s | β$^−$ | $^{39}$Cl | (7/2)− | | |
| $^{40}$S | 16 | 24 | 39.9754826(43) | 8.8(22) s | β$^−$ | $^{40}$Cl | 0+ | | |
| $^{41}$S | 16 | 25 | 40.9795935(44) | 1.99(5) s | β$^−$ | $^{41}$Cl | 7/2−# | | |
| $^{42}$S | 16 | 26 | 41.9810651(30) | 1.016(15) s | β$^−$ (>96%) | $^{42}$Cl | 0+ | | |
| $^{42}$S | 16 | 26 | 41.9810651(30) | 1.016(15) s | β$^−$, n (<1%) | $^{41}$Cl | 0+ | | |
| $^{43}$S | 16 | 27 | 42.9869076(53) | 265(13) ms | β$^−$ (60%) | $^{43}$Cl | 3/2− | | |
| $^{43}$S | 16 | 27 | 42.9869076(53) | 265(13) ms | β$^−$, n (40%) | $^{42}$Cl | 3/2− | | |
| $^{43m}$S | 320.7(5) keV | 320.7(5) keV | 320.7(5) keV | 415.0(26) ns | IT | $^{43}$S | (7/2−) | | |
| $^{44}$S | 16 | 28 | 43.9901188(56) | 100(1) ms | β$^−$ (82%) | $^{44}$Cl | 0+ | | |
| $^{44}$S | 16 | 28 | 43.9901188(56) | 100(1) ms | β$^−$, n (18%) | $^{43}$Cl | 0+ | | |
| $^{44m}$S | 1365.0(8) keV | 1365.0(8) keV | 1365.0(8) keV | 2.619(26) μs | IT | $^{44}$S | 0+ | | |
| $^{45}$S | 16 | 29 | 44.99641(32)# | 68(2) ms | β$^−$, n (54%) | $^{44}$Cl | 3/2−# | | |
| $^{45}$S | 16 | 29 | 44.99641(32)# | 68(2) ms | β$^−$ (46%) | $^{45}$Cl | 3/2−# | | |
| $^{46}$S | 16 | 30 | 46.00069(43)# | 50(8) ms | β$^−$ | $^{46}$Cl | 0+ | | |
| $^{47}$S | 16 | 31 | 47.00773(43)# | 24# ms [>200 ns] | | | 3/2−# | | |
| $^{48}$S | 16 | 32 | 48.01330(54)# | 10# ms [>200 ns] | | | 0+ | | |
| $^{49}$S | 16 | 33 | 49.02189(63)# | 4# ms [>400 ns] | | | 1/2−# | | |
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* ↑ $^m$S – 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).
* ↑ 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.
* ↑ # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
* ↑ Heaviest theoretically stable nuclide with equal numbers of protons and neutrons
* ↑ Cosmogenic