Disulfates

The chemical structure of the disulfate anion

Disulfates (also: pyrosulfates ) are the salts of disulfuric acid . Disulfates have the general formula Me ^I ₂ S ₂ O ₇ . Disulfates have a dichromate- like structure, with sulfur in an oxidation state of +6.

Some pyrosulfates are for example:

• Sodium disulfate
• Potassium disulfate

properties

Disulfates are moisture-sensitive salts that react strongly acidic with water , releasing sulfuric acid .

${\displaystyle \mathrm {S_{2}O_{7}\,_{(aq)}^{2-}+H_{2}O_{(l)}\ \longrightarrow \ SO_{4}\,_{(aq)}^{2-}+H_{2}SO_{4(aq)}} }$

Manufacturing

Disulfates are produced by heating hydrogen sulfates with elimination of water:

${\displaystyle \mathrm {2\ HSO_{4}^{-}\longrightarrow \ S_{2}O_{7}^{2-}\ +\ H_{2}O} }$

Disulfates can also be produced by reacting sulfur trioxide with a sulfate:

${\displaystyle \mathrm {SO_{4}^{2-}\ +\ SO_{3}\longrightarrow \ S_{2}O_{7}^{2-}} }$

If the temperature is too high, disulfates can decompose again in the reverse reaction:

${\displaystyle \mathrm {S_{2}O_{7}^{2-}\longrightarrow \ SO_{4}^{2-}\ +\ SO_{3}} }$

use

Disulfates have properties that make them useful for special fields of application. Potassium disulfate is used, for example, in the synthesis of new composite ion conductors . It is also used in the catalytic conversion of diethyl tartaric acid ester to pyruvic acid .

Individual evidence

1. ^ Disulfate - Lexicon of Chemistry. In: www.spektrum.de. Retrieved May 19, 2016 . 
2. ↑ Kenny Ståhl, Tonci Balic-Zunic, Francisco da Silva, K. Michael Eriksen, Rolf W. Berg, Rasmus Fehrmann: The crystal structure determinations and refinements of K ₂ S ₂ O ₇ , KNaS ₂ O ₇ and Na ₂ S ₂ O ₇ from X-ray powder and single crystal diffraction data . In: Journal of Solid State Chemistry . tape 178 , no. 5 , 2005, p. 1697–1704 , doi : 10.1016 / j.jssc.2005.03.022 .
3. ↑ Entry on Potassium Disulfate at Toronto Research Chemicals , accessed on May 21, 2016 ( PDF ).