Isotopes of sulfur
Encyclopedia
Sulfur
(S) has 25 known isotope
s 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 supernovae (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 170 minutes. The shortest-lived is 49S, with a half-life shorter than 200 nanoseconds.
When sulfide mineral
s 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 carbonate
s 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 abundance
s 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.
Standard atomic mass: 32.065(5) u
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
(S) has 25 known isotope
Isotope
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...
s 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 supernovae (see silicon burning).
Other than 35S, the radioactive isotopes of sulfur are all comparatively short-lived. 35S is formed from cosmic ray
Cosmic ray
Cosmic rays are energetic charged subatomic particles, originating from outer space. They may produce secondary particles that penetrate the Earth's atmosphere and surface. The term ray is historical as cosmic rays were thought to be electromagnetic radiation...
spallation
Spallation
In general, spallation is a process in which fragments of material are ejected from a body due to impact or stress. In the context of impact mechanics it describes ejection or vaporization of material from a target during impact by a projectile...
of 40Ar
Argon
Argon is a chemical element represented by the symbol Ar. Argon has atomic number 18 and is the third element in group 18 of the periodic table . Argon is the third most common gas in the Earth's atmosphere, at 0.93%, making it more common than carbon dioxide...
in the atmosphere
Earth's atmosphere
The atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention , and reducing temperature extremes between day and night...
. It has a half-life
Half-life
Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...
of 87 days. The next longest-lived radioisotope is sulfur-38, with a half-life of 170 minutes. The shortest-lived is 49S, with a half-life shorter than 200 nanoseconds.
When sulfide mineral
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
s 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
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
-13 and δS-34 of coexisting carbonate
Carbonate
In chemistry, a carbonate is a salt of carbonic acid, characterized by the presence of the carbonate ion, . The name may also mean an ester of carbonic acid, an organic compound containing the carbonate group C2....
s and sulfides can be used to determine the pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
and oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
fugacity
Fugacity
In chemical thermodynamics, the fugacity of a real gas is an effective pressure which replaces the true mechanical pressure in accurate chemical equilibrium calculations. It is equal to the pressure of an ideal gas which has the same chemical potential as the real gas. For example, nitrogen gas ...
of the ore-bearing fluid during ore formation.
In most forest
Forest
A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...
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
Hydrology
Hydrology is the study of the movement, distribution, and quality of water on Earth and other planets, including the hydrologic cycle, water resources and environmental watershed sustainability...
studies. Differences in the natural abundance
Natural abundance
In chemistry, natural abundance refers to the abundance of isotopes of a chemical element as naturally found on a planet. The relative atomic mass of these isotopes is the atomic weight listed for the element in the periodic table...
s 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.
Standard atomic mass: 32.065(5) u
Table
| nuclide symbol |
Z(p Proton The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number.... ) |
N(n Neutron The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of... ) |
isotopic mass (u) |
half-life | decay mode(s) |
daughter isotope(s)Bold for stable isotopes |
nuclear spin |
representative isotopic composition (mole fraction) |
range of natural variation (mole fraction) |
|---|---|---|---|---|---|---|---|---|---|
| excitation energy | |||||||||
| 26S | 16 | 10 | 26.02788(32)# | 10# ms | 2p Proton emission Proton emission is a type of radioactive decay in which a proton is ejected from a nucleus. Proton emission can occur from high-lying excited states in a nucleus following a beta decay, in which case the process is known as beta-delayed proton emission, or can occur from the ground state of very... |
24Si | 0+ | ||
| 27SHas 2 halo protons | 16 | 11 | 27.01883(22)# | 15.5(15) ms | β+ Beta decay In nuclear physics, beta decay is a type of radioactive decay in which a beta particle is emitted from an atom. There are two types of beta decay: beta minus and beta plus. In the case of beta decay that produces an electron emission, it is referred to as beta minus , while in the case of a... (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+ | ||
| β+, p (20.7%) | 27Si | ||||||||
| 29S | 16 | 13 | 28.99661(5) | 187(4) ms | β+ (53.6%) | 29P | 5/2+ | ||
| β+, p (46.4%) | 28Si | ||||||||
| 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+ | ||
| 32SHeaviest theoretically stable nuclide with equal numbers of protons and neutrons | 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+ | TraceCosmogenic Cosmogenic nuclide See also Environmental radioactivity#NaturalCosmogenic nuclides are rare isotopes created when a high-energy cosmic ray interacts with the nucleus of an in situ solar system atom, causing cosmic ray spallation... |
|
| 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-)# | ||
| β-, n (<.1%) | 40Cl | ||||||||
| 42S | 16 | 26 | 41.98102(13) | 1.013(15) s | β- (96%) | 42Cl | 0+ | ||
| β-, n (4%) | 41Cl | ||||||||
| 43S | 16 | 27 | 42.98715(22) | 260(15) ms | β- (60%) | 43Cl | 3/2-# | ||
| β-, n (40%) | 42Cl | ||||||||
| 43mS | 319(5) keV | 480(50) ns | (7/2-) | ||||||
| 44S | 16 | 28 | 43.99021(42) | 100(1) ms | β- (82%) | 44Cl | 0+ | ||
| β-, n (18%) | 43Cl | ||||||||
| 45S | 16 | 29 | 44.99651(187) | 68(2) ms | β-, n (54%) | 44Cl | 3/2-# | ||
| β- (46%) | 45Cl | ||||||||
| 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-# | ||
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.