Thiosulfuric acid

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Thiosulfuric acid [1]
H2S2O3Steudel.svg
Names
IUPAC name
Sulfurothioic O-acid [2]
Systematic IUPAC name
Dihydroxidooxidosulfidosulfur [2]
Other names
Thiosulfuric acid
Sulfurothioic O,O-acid [3]
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
PubChem CID
UNII
  • InChI=1S/H2O3S2/c1-5(2,3)4/h(H2,1,2,3,4) Yes check.svgY
    Key: DHCDFWKWKRSZHF-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/H2O3S2/c1-5(2,3)4/h(H2,1,2,3,4)
  • O=S(=S)(O)O
Properties [1] [4]
H2S2O3
Molar mass 114.13 g·mol−1
Melting point decomposes below 0 °C
decomposes
Acidity (pKa)pKa1 = 0.6
pKa2 = 1.74
Conjugate base Thiosulfate
Related compounds
Other cations
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Thiosulfuric acid is the inorganic compound with the formula H2S2O3. It has attracted academic interest as a simple, easily accessed compound that is labile. It has few practical uses.

Contents

Preparation and degradation

The acid cannot be made by acidifying aqueous thiosulfate salt solutions 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 reaction conditions. [5] Anhydrous methods of producing the acid were developed by Max Schmidt: [5] [6]

H2S + SO3 → H2S2O3
Na2S2O3 + 2 HCl → 2 NaCl + H2S2O3
HSO3Cl + H2S → HCl + H2S2O3

The anhydrous acid also decomposes above −5 °C: [5]

H2S2O3 → H2S + SO3

Structure

The structure of the conjugate base of thiosulfuric acid. HS2O3anion.svg
The structure of the conjugate base of thiosulfuric acid.

The isomer (O=)2S(−OH)(−SH) is more stable than the isomer (O=)(S=)S(−OH)2 as established by Hartree–Fock/ab initio calculations with a 6-311 G** basis set and MP2 to MP4 refinements. [7] [ clarification needed ] The theoretically predicted structure conforms with the double bond rule.

An isomer of thiosulfuric acid is the adduct of hydrogen sulfide and sulfur trioxide, H2S·SO3, which can also be prepared at low temperature. It is a white crystalline solid. [5]

Related Research Articles

Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. Sulfide also refers to large families of inorganic and organic compounds, e.g. lead sulfide and dimethyl sulfide. Hydrogen sulfide (H2S) and bisulfide (SH) are the conjugate acids of sulfide.

Sulfur trioxide (alternative spelling sulphur trioxide, also known as nisso sulfan) is the chemical compound with the formula SO3. It has been described as "unquestionably the most [economically important]" sulfur oxide. It is prepared on an industrial scale as a precursor to sulfuric acid.

In chemistry, disproportionation, sometimes called dismutation, is a redox reaction in which one compound of intermediate oxidation state converts to two compounds, one of higher and one of lower oxidation states. The reverse of disproportionation, such as when a compound in an intermediate oxidation state is formed from precursors of lower and higher oxidation states, is called comproportionation, also known as synproportionation.

<span class="mw-page-title-main">Calcium sulfide</span> Chemical compound of formula CaS

Calcium sulfide is the chemical compound with the formula CaS. This white material crystallizes in cubes like rock salt. CaS has been studied as a component in a process that would recycle gypsum, a product of flue-gas desulfurization. Like many salts containing sulfide ions, CaS typically has an odour of H2S, which results from small amount of this gas formed by hydrolysis of the salt.

<span class="mw-page-title-main">Ammonium hydrosulfide</span> Chemical compound

Ammonium hydrosulfide is the chemical compound with the formula [NH4]SH.

<span class="mw-page-title-main">Perrhenic acid</span> Chemical compound

Perrhenic acid is the chemical compound with the formula Re2O7(H2O)2. It is obtained by evaporating aqueous solutions of Re2O7. Conventionally, perrhenic acid is considered to have the formula HReO4, and a species of this formula forms when rhenium(VII) oxide sublimes in the presence of water or steam. When a solution of Re2O7 is kept for a period of months, it breaks down and crystals of HReO4·H2O are formed, which contain tetrahedral ReO−4. For most purposes, perrhenic acid and rhenium(VII) oxide are used interchangeably. Rhenium can be dissolved in nitric or concentrated sulfuric acid to produce perrhenic acid.

An oxyacid, oxoacid, or ternary acid is an acid that contains oxygen. Specifically, it is a compound that contains hydrogen, oxygen, and at least one other element, with at least one hydrogen atom bonded to oxygen that can dissociate to produce the H+ cation and the anion of the acid.

<span class="mw-page-title-main">Chlorosulfuric acid</span> Chemical compound

Chlorosulfuric acid (IUPAC name: sulfurochloridic acid) is the inorganic compound with the formula HSO3Cl. It is also known as chlorosulfonic acid, being the sulfonic acid of chlorine. It is a distillable, colorless liquid which is hygroscopic and a powerful lachrymator. Commercial samples usually are pale brown or straw colored.

<span class="mw-page-title-main">Disulfur dichloride</span> Chemical compound

Disulfur dichloride is the inorganic compound of sulfur and chlorine with the formula S2Cl2. It is an amber oily liquid.

A polysulfane is a chemical compound of formula H2Sn, where n > 1. Compounds containing 2 – 8 sulfur atoms have been isolated, longer chain compounds have been detected, but only in solution. H2S2 is colourless, higher members are yellow with the colour increasing with the sulfur content. In the chemical literature the term polysulfanes is sometimes used for compounds containing −(S)n, e.g. organic polysulfanes R1−(S)n−R2.

Selenium monochloride or diselenium dichloride is an inorganic compound with the formula Se2Cl2. Although a common name for the compound is selenium monochloride, reflecting its empirical formula, IUPAC does not recommend that name, instead preferring the more descriptive diselenium dichloride.

<span class="mw-page-title-main">Polythionic acid</span>

Polythionic acid is an oxoacid which has a straight chain of sulfur atoms and has the chemical formula Sn(SO3H)2 (n > 2). Trithionic acid (H2S3O6), tetrathionic acid (H2S4O6) are simple examples. They are the conjugate acids of polythionates. The compounds of n < 80 are expected to exist, and those of n < 20 have already been synthesized. Dithionic acid (H2S2O6) does not belong to the polythionic acids due to strongly different properties.

<span class="mw-page-title-main">Thiosulfurous acid</span> Chemical compound

Thiosulfurous acid is a hypothetical chemical compound with the formula HS−S(=O)−OH or HO−S(=S)−OH. Attempted synthesis leads to polymers. It is a low oxidation state (+1) sulfur acid. It is the Arrhenius acid for disulfur monoxide. Salts derived from thiosulfurous acid, which are also unknown, are named "thiosulfites" or "sulfurothioites". The ion is S=SO2−
2
.

Tellurium compounds are compounds containing the element tellurium (Te). Tellurium belongs to the chalcogen family of elements on the periodic table, which also includes oxygen, sulfur, selenium and polonium: Tellurium and selenium compounds are similar. Tellurium exhibits the oxidation states −2, +2, +4 and +6, with +4 being most common.

<span class="mw-page-title-main">Sulfoxylic acid</span> Chemical compound

Sulfoxylic acid (H2SO2) (also known as hyposulfurous acid or sulfur dihydroxide) is an unstable oxoacid of sulfur in an intermediate oxidation state between hydrogen sulfide and dithionous acid. It consists of two hydroxy groups attached to a sulfur atom. Sulfoxylic acid contains sulfur in an oxidation state of +2. Sulfur monoxide (SO) can be considered as a theoretical anhydride for sulfoxylic acid, but it is not actually known to react with water.

Dihydroxydisulfane or hypodithionous acid is a reduced sulfur oxyacid with sulfur in a formal oxidation state of +1, but the valence of sulfur is 2. The structural formula is HO−S−S−OH, with all atoms arranged in a chain. It is an isomer of thiosulfurous acid but is lower in energy. Other isomers include HOS(=O)SH, HOS(=S)OH, and HS(=O)2SH. Disulfur monoxide, S2O, can be considered as the anhydride. Unlike many of these other reduced sulfur acids, dihydroxydisulfane can be formed in a pure state by reacting hydrogen sulfide with sulfur dioxide at −70 °C in dichlorodifluoromethane.

Gold(III) sulfide or auric sulfide is an inorganic compound with the formula Au2S3. Auric sulfide has been described as a black and amorphous solid. Only the amorphous phase has been produced, and the only evidence of existence is based on thermal analysis.

Tungsten trisulfide is an inorganic compound of tungsten and sulfur with the chemical formula WS3. The compound looks like chocolate-brown powder.

Polonium sulfide is an inorganic compound of polonium and sulfur with the chemical formula PoS. The compound is radioactive and forms black crystals.

Gallium compounds are compounds containing the element gallium. These compounds are found primarily in the +3 oxidation state. The +1 oxidation state is also found in some compounds, although it is less common than it is for gallium's heavier congeners indium and thallium. For example, the very stable GaCl2 contains both gallium(I) and gallium(III) and can be formulated as GaIGaIIICl4; in contrast, the monochloride is unstable above 0 °C, disproportionating into elemental gallium and gallium(III) chloride. Compounds containing Ga–Ga bonds are true gallium(II) compounds, such as GaS (which can be formulated as Ga24+(S2−)2) and the dioxan complex Ga2Cl4(C4H8O2)2. There are also compounds of gallium with negative oxidation states, ranging from -5 to -1, most of these compounds being magnesium gallides (MgxGay).

References

  1. 1 2 Macintyre, Jane Elizabeth, ed. (1992), Dictionary of Inorganic Compounds, Chapman & Hall, p. 3362, ISBN   0-412-30120-2
  2. 1 2 International Union of Pure and Applied Chemistry (2005). Nomenclature of Inorganic Chemistry (IUPAC Recommendations 2005). Cambridge (UK): RSCIUPAC. ISBN   0-85404-438-8. p. 139. Electronic version.
  3. ACD Chemsketch Name Free
  4. Page, F. M. (1953), "The dissociation constants of thiosulphuric acid", J. Chem. Soc.: 1719–24, doi:10.1039/JR9530001719
  5. 1 2 3 4 Greenwood, Norman N.; Earnshaw, Alan (1984). Chemistry of the Elements. Oxford: Pergamon Press. pp. 846–48. ISBN   978-0-08-022057-4..
  6. Schmidt, Max (1957), "Über Säuren des Schwefels. I. Zur Kenntnis der wasserfreien Thioschwefelsäure", Z. Anorg. Allg. Chem., 289 (1–4): 141–57, doi:10.1002/zaac.19572890113
  7. 1 2 Miaskiewicz, Karol; Steudel, Ralf (1992), "The Structures of Thiosulfuric Acid H
    2
    S
    2
    O
    3
    and Its Monoanion HS
    2
    O
    3
    ", Angew. Chem. Int. Ed. Engl., 31 (1): 58–59, doi:10.1002/anie.199200581