Potassium thiosulfate

Structural formula
General
Surname	Potassium thiosulfate
other names	Dipotassium thiosulfate Potassium hyposulfite
Molecular formula	K 2 S 2 O 3
Brief description	white solid
External identifiers / databases
CAS number 10294-66-3 EC number 233-666-8 ECHA InfoCard 100.030.593 PubChem 61501 ChemSpider 55421 Wikidata Q4457892
properties
Molar mass	190.31 g mol −1
Physical state	firmly
density	2.37 g cm −3
Melting point	> 600 ° C
solubility	very easily soluble in water (1650 g l −1 at 25 ° C) practically insoluble in ethanol
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Potassium thiosulphate is an inorganic chemical compound of potassium from the group of thiosulphates .

Extraction and presentation

Potassium thiosulphate can be obtained by reacting potassium carbonate with sulfur .

${\displaystyle {\ce {3 K2CO3 + 8 S -> K2S2O3 + 2 K2S3 + 3 CO2}}}$

The representation by reaction of potassium hydroxide with sulfur and subsequent oxidation of the resulting potassium polysulfide is also possible .

properties

Potassium thiosulfate is a white solid that is very easily soluble in water. Potassium thiosulfate is pH sensitive and becomes unstable at pH below 5.5 and above 8.5. The crystal structure of anhydrous potassium thiosulfate is monoclinic with the space group P 2 ₁ / c (space group no. 14) (a = 1010.15 (14), b = 910.65 (12), c = 1329.4 (2) pm , β = 111.984 ° (11), Z = 8, R1 = 0.0665). It has two crystallographically different thiosulfate anions, coordinated by 9/10 potassium cations. Their arrangement in the structure leads to a complex structure with a pseudo- orthorhombic unit cell . The crystal structure of the even more complex 1/3 hydrate is also monoclinic with the P 2 ₁ / c (No. 14) (a = 938.27 (6), b = 602.83 (4), c = 3096.0) (2) pm, β = 98.415 ° (6), Z = 12, R1 = 0.0327).

use

Potassium thiosulfate is used as a liquid fertilizer that provides potassium and sulfur.

Individual evidence

1. ↑ ^{a b c d e f g h} Entry on potassium thiosulfate in the GESTIS substance database of the IFA , accessed on April 10, 2019(JavaScript required) .
2. ^ William M. Haynes: CRC Handbook of Chemistry and Physics . CRC Press, 2016, ISBN 978-1-4987-5429-3 , pp. 81 ( limited preview in Google Book search).
3. ↑ Max Biechele: Pharmaceutical Exercise Preparations Instructions for the representation, recognition, testing and stoichiometric calculation of official chemical-pharmaceutical preparations . Springer-Verlag, 2013, ISBN 978-3-662-32756-2 , pp. 162 ( limited preview in Google Book search).
4. ↑ Google Patents: EP3208234A1 - Oxidation process for producing potassium thiosulfate - Google Patents , accessed April 10, 2019
5. ↑ Western Plant Health Association: Western Fertilizer Handbook Third Horticulture Edition . Waveland Press, 2018, ISBN 1-4786-3884-2 , pp. 186 ( limited preview in Google Book search).
6. ↑ Anna J. Lehner, Lisa V. Schindler, Caroline Röhr: Crystal structures of the alkali metal thiosulfates A2S2O3 nH2O (A / n = K / 0, K / ⅓, Rb = 1) / Crystal Structures of the Alkali Thiosulfates A2S2O3 - nH2O (A. / n = K / 0, K / ⅓, Rb = 1). In: Zeitschrift für Naturforschung B. 68, 2013, p. 323, doi : 10.5560 / ZNB.2013-3089 .
7. ↑ FIFA: Australian Soil Fertility Manual . Csiro Publishing, 2006, ISBN 978-0-643-09021-7 , pp. 59 ( limited preview in Google Book search).