Sulfanyl
Encyclopedia
Sulfanyl also known as the mercapto radical, hydrosulfide radical, or hydridosulfur, is a simple radical
molecule consisting of one hydrogen and one sulfur atom. The radical appears in metabolism in organisms as H2S is detoxified. Sulfanyl is one of the top three sulfur containing gasses in gas giant
s such as Jupiter and is very likely to be found in brown dwarf
s and cool stars. It was originally discovered by Margaret N. Lewis and John U. White at University of California in 1939. They observed molecular absorption bands around 325 nm belonging to the system designated by 2Σ+ ← 2Πi. They generated the radical by means of a radio frequency discharge in hydrogen sulfide
. HS* is formed during the degradation of hydrogen sulfide in the atmosphere of the Earth. This may be a deliberate action to destroy odours or a natural phenomena.
Sulfanyl has been detected in interstellar gas.
It is possibly present in comets.
Various theoretical studies have examined HS in atmospheres. In Earth's atmosphere
HS reacts with NO2 to make two products HSNO2 and HSONO. HSONO decomposes to HSO and NO
Also HS reacts with O2 and N2O. HS can also react with Cl2 producing HSCl and a Cl. atom. HS* destroys ozone producing HSO* and oxygen. HS* is formed in the Earth's atmosphere by the reaction of HO*, the hydroxyl radical, on carbon disulfide
, carbon oxysulfide and hydrogen sulfide
and side products of carbon dioxide and water. Photodissociation of hydrogen sulfide also produces the radical in air.
In an atmosphere that contains H2S, HS will be formed if the temperature and pressure are high enough.
The ratio of H2S and HS is given by: log(XH2S/XHS)=-3.37+8785/T+0.5log PT+0.5 log XH2
For a hydrogen dominated atmosphere in a gas giant or star: H2S has the same level as HS at log PT = 6.82-17570/T.
At higher temperatures HS breaks up into sulfur vapour and H2. The line of equal S and HS concentration follows the line
log PT = 4.80 - 14522/T. The lines of equal concentration cross at 1509K and 1.51 Pa, with HS being left out of the mix at lower temperatures and pressures. SH is expected to be the second or third most common sulfur containing gas in gas giants or brown dwarfs.
The radical can be formed by the action of ultraviolet radiation on hydrogen sulfide, which splits off a hydrogen atom. A wavelength of 190 nm gives maximum absorption.
In humans superoxide dismutase [Cu-Zn
] converts the hydrosulfide ion (HS−) to •. This happens as the Cu2+ ion in the enzyme is converted to Cu+.
Sulfide dehydrogenase as found in sulfur bacteria catalyses the oxidation of HS− to •, by removing a single electron.
When sulfur minerals are leached with ferric ions HS· is formed in this way: MS + Fe3+ + 2H+ → M2+ + Fe2+ + H2S·+ with the H2S·+ radical then passing a proton to water to make the HS· radical. M is a metal such as zinc or copper. This has potential for bioleaching
in metallic ore extraction.
The hydrosulfide ion HS- can be oxidized to HS* with cerium (IV) sulfate.
O2-. In water HS has an equilibrium with S- and H+. The hydroxyl radical *OH combines with H2S to form HS* and water. Other reactions investigated by J. J. Tiee in 1981 are HS·+ethylene, HS·+O2→HO·+SO
, and reactions with itself HS· + HS· → H2S2
or H2 and S. The disulfide can further react with HS· to make the disulfide radical HSS· and H2S.
The interatomic distance between sulfur and hydrogen in the radical is 0.134 nm.
HS* reacts with carboxylic acids to make carbonyl sulfide
(COS) and probably is the main source of this substance in the atmosphere of Earth.
HS+ is known as sulfanylium, and the common hydrosulfide ion HS- is also known as sulfanido for a ligand or sulfanide as an anion. Further down the periodic table, HSe* is known as selanyl, and HTe* is termed tellanyl.
Radical (chemistry)
Radicals are atoms, molecules, or ions with unpaired electrons on an open shell configuration. Free radicals may have positive, negative, or zero charge...
molecule consisting of one hydrogen and one sulfur atom. The radical appears in metabolism in organisms as H2S is detoxified. Sulfanyl is one of the top three sulfur containing gasses in gas giant
Gas giant
A gas giant is a large planet that is not primarily composed of rock or other solid matter. There are four gas giants in the Solar System: Jupiter, Saturn, Uranus, and Neptune...
s such as Jupiter and is very likely to be found in brown dwarf
Brown dwarf
Brown dwarfs are sub-stellar objects which are too low in mass to sustain hydrogen-1 fusion reactions in their cores, which is characteristic of stars on the main sequence. Brown dwarfs have fully convective surfaces and interiors, with no chemical differentiation by depth...
s and cool stars. It was originally discovered by Margaret N. Lewis and John U. White at University of California in 1939. They observed molecular absorption bands around 325 nm belonging to the system designated by 2Σ+ ← 2Πi. They generated the radical by means of a radio frequency discharge in hydrogen sulfide
Hydrogen sulfide
Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...
. HS* is formed during the degradation of hydrogen sulfide in the atmosphere of the Earth. This may be a deliberate action to destroy odours or a natural phenomena.
Natural occurrence
Absorption lines of sulfanyl in space were first detected in the infrared by Yamamura in 2000 in a star R And. In the sun SH was detected at several ultraviolet wavelengths: 326.0459 327.5468 328.9749 330.0892 and 330.1112 nm.Sulfanyl has been detected in interstellar gas.
It is possibly present in comets.
Various theoretical studies have examined HS in atmospheres. In Earth's atmosphere
HS reacts with NO2 to make two products HSNO2 and HSONO. HSONO decomposes to HSO and NO
Also HS reacts with O2 and N2O. HS can also react with Cl2 producing HSCl and a Cl. atom. HS* destroys ozone producing HSO* and oxygen. HS* is formed in the Earth's atmosphere by the reaction of HO*, the hydroxyl radical, on carbon disulfide
Carbon disulfide
Carbon disulfide is a colorless volatile liquid with the formula CS2. The compound is used frequently as a building block in organic chemistry as well as an industrial and chemical non-polar solvent...
, carbon oxysulfide and hydrogen sulfide
Hydrogen sulfide
Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...
and side products of carbon dioxide and water. Photodissociation of hydrogen sulfide also produces the radical in air.
In an atmosphere that contains H2S, HS will be formed if the temperature and pressure are high enough.
The ratio of H2S and HS is given by: log(XH2S/XHS)=-3.37+8785/T+0.5log PT+0.5 log XH2
For a hydrogen dominated atmosphere in a gas giant or star: H2S has the same level as HS at log PT = 6.82-17570/T.
At higher temperatures HS breaks up into sulfur vapour and H2. The line of equal S and HS concentration follows the line
log PT = 4.80 - 14522/T. The lines of equal concentration cross at 1509K and 1.51 Pa, with HS being left out of the mix at lower temperatures and pressures. SH is expected to be the second or third most common sulfur containing gas in gas giants or brown dwarfs.
Formation
Thermal decompostion of mercaptans, such as ethyl mercaptan yields •.The radical can be formed by the action of ultraviolet radiation on hydrogen sulfide, which splits off a hydrogen atom. A wavelength of 190 nm gives maximum absorption.
In humans superoxide dismutase [Cu-Zn
SOD1
Superoxide dismutase [Cu-Zn] also known as superoxide dismutase 1 or SOD1 is an enzyme that in humans is encoded by the SOD1 gene. SOD1 is one of three human superoxide dismutases.- Function :...
] converts the hydrosulfide ion (HS−) to •. This happens as the Cu2+ ion in the enzyme is converted to Cu+.
Sulfide dehydrogenase as found in sulfur bacteria catalyses the oxidation of HS− to •, by removing a single electron.
When sulfur minerals are leached with ferric ions HS· is formed in this way: MS + Fe3+ + 2H+ → M2+ + Fe2+ + H2S·+ with the H2S·+ radical then passing a proton to water to make the HS· radical. M is a metal such as zinc or copper. This has potential for bioleaching
Bioleaching
Bioleaching is the extraction of specific metals from their ores through the use of living organisms. This is much cleaner than the traditional heap leaching using cyanide...
in metallic ore extraction.
The hydrosulfide ion HS- can be oxidized to HS* with cerium (IV) sulfate.
Reactions
Being a radical HS* is quite reactive. In water HS can react with O2 producing SO2- and H+. SO2- reacts further with O2 to make SO2 and superoxideSuperoxide
A superoxide, also known by the obsolete name hyperoxide, is a compound that possesses the superoxide anion with the chemical formula O2−. The systematic name of the anion is dioxide. It is important as the product of the one-electron reduction of dioxygen O2, which occurs widely in nature...
O2-. In water HS has an equilibrium with S- and H+. The hydroxyl radical *OH combines with H2S to form HS* and water. Other reactions investigated by J. J. Tiee in 1981 are HS·+ethylene, HS·+O2→HO·+SO
Sulfur monoxide
Sulfur monoxide is an inorganic compound with formula . It is only found as a dilute gas phase. When concentrated or condensed, it converts to S2O2 . It has been detected in space but is rarely encountered intact otherwise.-Structure and bonding:The SO molecule has a triplet ground state similar...
, and reactions with itself HS· + HS· → H2S2
Hydrogen disulfide
Hydrogen disulfide is an inorganic compound. This mal-odorous oil decomposes readily to hydrogen sulfide .-Structure:The structure of hydrogen disulfide is similar to that of hydrogen peroxide, with two central sulfur atoms and two outer hydrogen atoms...
or H2 and S. The disulfide can further react with HS· to make the disulfide radical HSS· and H2S.
Properties
The ionization energy of HS is 10.4219 eV. The reduction potential to go to HS- is 0.92 eV. HS* in water can ionize to S*- and H+. The S*- can catalyze a cis-trans conversion in lipids.The interatomic distance between sulfur and hydrogen in the radical is 0.134 nm.
HS* reacts with carboxylic acids to make carbonyl sulfide
Carbonyl sulfide
Carbonyl sulfide is the chemical compound with the formula OCS. Commonly written as COS, it is a colourless flammable gas with an unpleasant odor. It is a linear molecule consisting of a carbonyl group double bonded to a sulfur atom...
(COS) and probably is the main source of this substance in the atmosphere of Earth.
Related molecules
HSS* is called disufanyl with lengthening chains as trisulfanyl, tetrasulfanyl and pentasulfanyl HSSSSS*. S-* is termed sufanidyl.HS+ is known as sulfanylium, and the common hydrosulfide ion HS- is also known as sulfanido for a ligand or sulfanide as an anion. Further down the periodic table, HSe* is known as selanyl, and HTe* is termed tellanyl.
External links
- Mercapto radical from NIST