Thiosulfuric acid
Encyclopedia
Thiosulfuric acid is a sulfur
oxoacid
. The acid cannot be made by acidifying thiosulfate
salts as the acid readily decomposes in water. The decomposition products can include sulfur
, sulfur dioxide
, hydrogen sulfide
, polysulfanes, sulfuric acid
and polythionates, depending on the exact reaction conditions. Anhydrous methods of producing the acid were developed by Schmidt:
The anhydrous acid also decomposes below 0 °C:
The S-acid isomer is believed to be more stable than the O-acid isomer based on Hartree–Fock/ab initio calculations with a 6-311 G** basis set
and MP2 to MP4 refinements. There is another isomeric form, a white crystalline adduct of hydrogen sulfide
and sulfur trioxide
, H2S·SO3, which can also be prepared at low temperature.
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...
oxoacid
Oxoacid
An oxoacid is an acid that contains oxygen. To be more specific, it is an acid that:#contains oxygen#contains at least one other element#has at least one hydrogen atom bound to oxygen#forms an ion by the loss of one or more protons....
. The acid cannot be made by acidifying thiosulfate
Thiosulfate
Thiosulfate is an oxyanion of sulfur. The prefix thio indicates that thiosulfate ion is a sulfate ion with one oxygen replaced by a sulfur. Thiosulfate occurs naturally and is produced by certain biochemical processes...
salts as the acid readily decomposes in water. The decomposition products can include sulfur
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...
, sulfur dioxide
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...
, 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...
, polysulfanes, 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...
and polythionates, depending on the exact reaction conditions. Anhydrous methods of producing the acid were developed by Schmidt:
- H2S + SO3 → H2S2O3·nEt2O (in diethyl etherDiethyl etherDiethyl ether, also known as ethyl ether, simply ether, or ethoxyethane, is an organic compound in the ether class with the formula . It is a colorless, highly volatile flammable liquid with a characteristic odor...
at −78 °C ) - Na2S2O3 + 2HCl → 2NaCl + H2S2O3·2Et2O (in diethyl etherDiethyl etherDiethyl ether, also known as ethyl ether, simply ether, or ethoxyethane, is an organic compound in the ether class with the formula . It is a colorless, highly volatile flammable liquid with a characteristic odor...
at −78 °C ) - HSO3Cl + H2S → HCl + H2S2O3 (low temperature)
The anhydrous acid also decomposes below 0 °C:
- H2S2O3 → H2S + SO3
The S-acid isomer is believed to be more stable than the O-acid isomer based on Hartree–Fock/ab initio calculations with a 6-311 G** basis set
Basis set (chemistry)
A basis set in chemistry is a set of functions used to create the molecular orbitals, which are expanded as a linear combination of such functions with the weights or coefficients to be determined. Usually these functions are atomic orbitals, in that they are centered on atoms. Otherwise, the...
and MP2 to MP4 refinements. There is another isomeric form, a white crystalline adduct of 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 sulfur trioxide
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...
, H2S·SO3, which can also be prepared at low temperature.