Sulfur monoxide
Encyclopedia
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 (sometimes called disulfur dioxide or sulfur peroxide). It has been detected in space but is rarely encountered intact otherwise.
(e.g. S8O, S−O = 148 pm) but is longer than the S−O bond in gaseous S2O (146 pm), SO2
(143.1 pm) and SO3
(142 pm).
The molecule is excited with near infrared radiation to the singlet state (with no unpaired electrons). The singlet state is believed be more reactive than the ground state triplet state, in the same way that singlet oxygen
is more reactive than the triplet oxygen
.
: as well as more complex examples, such as a trisulfide oxide, C10H6S3O,
The SO molecule is thermodynamically unstable, converting initially to S2O2.
SO inserts into alkenes, alkynes and diene
s producing molecules with three membered rings containing sulfur.
of concentrated sulfuric acid
containing some dissolved noble gas.
A chemiluminescence detector for sulfur has been reported that is based on the reactions:
, one of Jupiter
's moons, both in the atmosphere and in the plasma
torus
. It has also been found in the atmosphere of Venus, in the Hale-Bopp comet and in the interstellar medium
.
On Io
, SO is thought to be produced both by volcanic and photochemical
routes. The principal photochemical reactions are proposed as follows:
SO converts to disulfur dioxide (S2O2). Disulfur dioxide is planar molecule with C2v symmetry
. The S-O bond length is 145.8 pm, shorter than in the monomer, and the S-S bond length is 202.45 pm. The OSS angle is 112.7°. S2O2 has a dipole moment of 3.17 D.
Inorganic compound
Inorganic compounds have traditionally been considered to be of inanimate, non-biological origin. In contrast, organic compounds have an explicit biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists,...
with formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
. It is only found as a dilute gas phase. When concentrated or condensed, it converts to S2O2 (sometimes called disulfur dioxide or sulfur peroxide). It has been detected in space but is rarely encountered intact otherwise.
Structure and bonding
The SO molecule has a triplet ground state similar to O2, i.e. each molecule has two unpaired electrons. The S−O bond length of 148.1 pm is similar to that found in lower sulfur oxidesLower sulfur oxides
The lower sulfur oxides are a group of chemical compounds consisting of :*SO, sulfur monoxide and its dimer S2O2*S2O*sulfur monoxides, SnO, based on cyclic Sn rings where n is 5-10*S7O2*polymeric oxides, polysulfuroxides sometimes termed PSO's...
(e.g. S8O, S−O = 148 pm) but is longer than the S−O bond in gaseous S2O (146 pm), SO2
Sulfur dioxide
Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...
(143.1 pm) and SO3
Sulfur trioxide
Sulfur trioxide is the chemical compound with the formula SO3. In the gaseous form, this species is a significant pollutant, being the primary agent in acid rain. It is prepared on massive scales as a precursor to sulfuric acid.-Structure and bonding:Gaseous SO3 is a trigonal planar molecule of...
(142 pm).
The molecule is excited with near infrared radiation to the singlet state (with no unpaired electrons). The singlet state is believed be more reactive than the ground state triplet state, in the same way that singlet oxygen
Singlet oxygen
Singlet oxygen is the common name used for the diamagnetic form of molecular oxygen , which is less stable than the normal triplet oxygen. Because of its unusual properties, singlet oxygen can persist for over an hour at room temperature, depending on the environment...
is more reactive than the triplet oxygen
Triplet oxygen
Triplet oxygen is the ground state of the oxygen molecule. The electron configuration of the molecule has two unpaired electrons occupying two degenerate molecular orbitals...
.
Production and reactions
Production of SO as a reagent in organic syntheses has centred on using compounds that "extrude" SO. Examples include the decomposition of the relatively simple molecule thiirane 1-oxideThiirane
Thiirane, more commonly known as ethylene sulfide, is the cyclic chemical compound with the formula C2H4S. It is the smallest sulfur-containing heterocycle. Like many organosulfur compounds, this species has a stench. Thiirane is also used to describe any derivative of the parent ethylene...
: as well as more complex examples, such as a trisulfide oxide, C10H6S3O,
- C2H4OS → C2H4 + SO
The SO molecule is thermodynamically unstable, converting initially to S2O2.
SO inserts into alkenes, alkynes and diene
Diene
In organic chemistry a diene or diolefin is a hydrocarbon that contains two carbon double bonds.Conjugated dienes are functional groups, with a general formula of CnH2n-2. Dienes and alkynes are functional isomers...
s producing molecules with three membered rings containing sulfur.
Generation under extreme conditions
In the laboratory sulfur monoxide can be produced by treating sulfur dioxide with sulfur vapour in a glow discharge. It has been detected in single bubble sonoluminescenceSonoluminescence
Sonoluminescence is the emission of short bursts of light from imploding bubbles in a liquid when excited by sound.-History:The effect was first discovered at the University of Cologne in 1934 as a result of work on sonar. H. Frenzel and H. Schultes put an ultrasound transducer in a tank of...
of concentrated sulfuric acid
Sulfuric acid
Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...
containing some dissolved noble gas.
A chemiluminescence detector for sulfur has been reported that is based on the reactions:
- SO + O3 → SO2(excited) + O2
- SO2(excited) → SO2 + hν
Ligand for transition metals
As a ligand SO can bond in a number different ways:- a terminal ligand, with a bent M-S-O arrangement, analogous to bent nitrosyl
- bridging across 2 or 3 metal centres (via sulfur), as in Fe3S(SO)(CO)9
Astrochemistry
Sulfur monoxide has been detected around IoIo (moon)
Io ) is the innermost of the four Galilean moons of the planet Jupiter and, with a diameter of , the fourth-largest moon in the Solar System. It was named after the mythological character of Io, a priestess of Hera who became one of the lovers of Zeus....
, one of Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
's moons, both in the atmosphere and in the plasma
Plasma (physics)
In physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...
torus
Torus
In geometry, a torus is a surface of revolution generated by revolving a circle in three dimensional space about an axis coplanar with the circle...
. It has also been found in the atmosphere of Venus, in the Hale-Bopp comet and in the interstellar medium
Interstellar medium
In astronomy, the interstellar medium is the matter that exists in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, dust, and cosmic rays. It fills interstellar space and blends smoothly into the surrounding intergalactic space...
.
On Io
Io (moon)
Io ) is the innermost of the four Galilean moons of the planet Jupiter and, with a diameter of , the fourth-largest moon in the Solar System. It was named after the mythological character of Io, a priestess of Hera who became one of the lovers of Zeus....
, SO is thought to be produced both by volcanic and photochemical
Photochemistry
Photochemistry, a sub-discipline of chemistry, is the study of chemical reactions that proceed with the absorption of light by atoms or molecules.. Everyday examples include photosynthesis, the degradation of plastics and the formation of vitamin D with sunlight.-Principles:Light is a type of...
routes. The principal photochemical reactions are proposed as follows:
- O + S2 → S + SO
- SO2 → SO + O
Biological chemistry
Sulfur monoxide may have some biological activity, the formation of transient SO in porcine coronary artery has been inferred from the reaction products.Disulfur dioxide
Symmetry group
The symmetry group of an object is the group of all isometries under which it is invariant with composition as the operation...
. The S-O bond length is 145.8 pm, shorter than in the monomer, and the S-S bond length is 202.45 pm. The OSS angle is 112.7°. S2O2 has a dipole moment of 3.17 D.