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)
  • OS(=O)(=O)S
Properties [1] [4]
H2S2O3
Molar mass 114.13 g·mol−1
Melting point decomposes below 0 °C
decomposes
Acidity (pKa)
  • pKa1 = 0.6 [5]
  • pKa2 = 1.74 [5]
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. [6] Anhydrous methods of producing the acid were developed by Max Schmidt: [6] [7]

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

The anhydrous acid also decomposes above −5 °C: [6]

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. [8] [ 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. [6]

Related Research Articles

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

Sulfuric(IV) acid, also known as sulfurous (UK: sulphurous) acid and thionic acid, is the chemical compound with the formula H2SO3.

Sulfide (also sulphide in British English ) 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.

<span class="mw-page-title-main">Hydrogen bromide</span> Chemical compound

Hydrogen bromide is the inorganic compound with the formula HBr. It is a hydrogen halide consisting of hydrogen and bromine. A colorless gas, it dissolves in water, forming hydrobromic acid, which is saturated at 68.85% HBr by weight at room temperature. Aqueous solutions that are 47.6% HBr by mass form a constant-boiling azeotrope mixture that boils at 124.3 °C (255.7 °F). Boiling less concentrated solutions releases H2O until the constant-boiling mixture composition is reached.

<span class="mw-page-title-main">Cobalt(II) chloride</span> Chemical compound

Cobalt(II) chloride is an inorganic compound, a salt of cobalt and chlorine, with the formula CoCl
2
. The compound forms several hydrates CoCl
2
·nH
2
O
, for n = 1, 2, 6, and 9. Claims of the formation of tri- and tetrahydrates have not been confirmed. The anhydrous form is a blue crystalline solid; the dihydrate is purple and the hexahydrate is pink. Commercial samples are usually the hexahydrate, which is one of the most commonly used cobalt salts in the lab.

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">Peroxymonosulfuric acid</span> Powerful oxidizing agent

Peroxymonosulfuric acid, H
2
SO
5
, is also known as persulfuric acid, peroxysulfuric acid, or Caro's acid. In this acid, the S(VI) center adopts its characteristic tetrahedral geometry; the connectivity is indicated by the formula HO–O–S(O)2–OH. It is one of the strongest oxidants known (E0 = +2.51 V) and is highly explosive.

<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.

<span class="mw-page-title-main">Sodium thioantimoniate</span> Chemical compound

Sodium thioantimoniate or sodium tetrathioantimonate(V) is an inorganic compound with the formula Na3SbS4. The nonahydrate of this chemical, Na3SbS4·9H2O, is known as Schlippe's salt, named after Johann Karl Friedrich von Schlippe (1799–1867). These compounds are examples of sulfosalts. They were once of interest as species generated in qualitative inorganic analysis.

<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.

Hyponitrous acid is a chemical compound with formula H
2
N
2
O
2
or HON=NOH. It is an isomer of nitramide, H2N−NO2; and a formal dimer of azanone, HNO.

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.

<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 > 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", "thionosulfites" or "sulfurothioites". The ion is S=SO2−
2
.

<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.

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 Perrin, D. D., ed. (1982) [1969]. Ionisation Constants of Inorganic Acids and Bases in Aqueous Solution. IUPAC Chemical Data (2nd ed.). Oxford: Pergamon (published 1984). Entry 239. ISBN   0-08-029214-3. LCCN   82-16524.
  6. 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..
  7. 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
  8. 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