Disulfur
Encyclopedia
Disulfur is the diatomic molecule with the formula S2. It is analogous to the dioxygen molecule but rarely occurs at room temperature. This violet gas is commonly generated by heating sulfur above 720 °C and comprises 99% of vapor species at low pressure (1 mm Hg) at 530 °C. S2 is one of minor components of the atmosphere of Io’s
, which is dominantly composed of SO2
. Diatomic molecules are common containing C, O, N and F, but for heavier elements they are often only stable at high temperatures.
is irradiated with UV light using a mercury photosensitizer or when CS2, H2S2, S2Cl2 or C2H4S are photolyzed. Singlet S2 is also formed when sulfur compounds such as H2S, PSF3 or COS are photolyzed. S2 can be generated by heating various organosulfur precursors.
like O2, i.e. both are diradicals. It has S-S double bond length of 189 pm, much shorter than the S-S single bonds in S8, which are 206 pm. In its Raman spectrum, the S-S vibrational band is observed at 715 cm−1. The corresponding vibrational band of O-O is found at 1122 cm−1. The S-S bond energy
is 265 kJ/mol compared to 498 kJ/mol for O2.
Sulfur has a large number of allotropes, perhaps as many as thirty. Their specific properties are distinguishable by various types of spectroscopy. The only stable form of sulfur at normal condition is S8.
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....
, which is dominantly composed of 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...
. Diatomic molecules are common containing C, O, N and F, but for heavier elements they are often only stable at high temperatures.
Production
Disulfur results when an atmosphere of COSCarbonyl 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...
is irradiated with UV light using a mercury photosensitizer or when CS2, H2S2, S2Cl2 or C2H4S are photolyzed. Singlet S2 is also formed when sulfur compounds such as H2S, PSF3 or COS are photolyzed. S2 can be generated by heating various organosulfur precursors.
Properties
S2 exists in the triplet stateTriplet state
A spin triplet is a set of three quantum states of a system, each with total spin S = 1 . The system could consist of a single elementary massive spin 1 particle such as a W or Z boson, or be some multiparticle state with total spin angular momentum of one.In physics, spin is the angular momentum...
like O2, i.e. both are diradicals. It has S-S double bond length of 189 pm, much shorter than the S-S single bonds in S8, which are 206 pm. In its Raman spectrum, the S-S vibrational band is observed at 715 cm−1. The corresponding vibrational band of O-O is found at 1122 cm−1. The S-S bond energy
Bond energy
In chemistry, bond energy is the measure of bond strength in a chemical bond. It is the heat required to break one Mole of molecules into their individual atoms. For example, the carbon-hydrogen bond energy in methane E is the enthalpy change involved with breaking up one molecule of methane into...
is 265 kJ/mol compared to 498 kJ/mol for O2.
Sulfur has a large number of allotropes, perhaps as many as thirty. Their specific properties are distinguishable by various types of spectroscopy. The only stable form of sulfur at normal condition is S8.