Cobalt (II) thiocyanate

Crystal structure
General
Surname	Cobalt (II) thiocyanate
other names	Bis (thiocyanic acid) cobalt (II) salt Cobalt thiocyanate Cobalt rhodanide Isothiocyanic acid cobalt (II) salt
Ratio formula	Co (SCN) 2
Brief description	yellow-brown solid
External identifiers / databases
CAS number 3017-60-5 97126-35-7 (trihydrate) PubChem 18174 Wikidata Q4457907
properties
Molar mass	175.10 g mol −1
Physical state	firmly
density	1.786 g cm −3 (trihydrate)
solubility	soluble in water (50 g l −1 at 25 ° C) soluble in methanol, ethanol and acetone
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 302-312-332-410 P: 273-280-501
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Cobalt (II) thiocyanate is an inorganic chemical compound of cobalt from the group of thiocyanates .

Extraction and presentation

Cobalt (II) thiocyanate can be obtained by reacting cobalt (II) sulfate with barium thiocyanate .

${\displaystyle \mathrm {CoSO_{4}+Ba(SCN)_{2}\longrightarrow BaSO_{4}\downarrow +Co(SCN)_{2}} }$

It is also possible to produce it by reacting thiocyanic acid with cobalt (II) carbonate or by reacting ammonium thiocyanate and cobalt salts in neutral solution.

properties

Cobalt (II) thiocyanate from cobalt (II) chloride and potassium thiocyanate (above in acetone, below in water)

Cobalt (II) thiocyanate is a yellow-brown solid that is soluble in water. The solution is reddish in color. The trihydrate has a purple to brown color that looks red in transmitted light and dissolves in water to turn blue. It converts to anhydrate from 105 ° C. The trihydrate has a monoclinic crystal structure with the space group C 2 / c (space group no. 15) .

use

Cobalt (II) thiocyanate can be used to detect alkaloids , methadone , ephedrine , cocaine and other drugs. If these are added to a 2 percent solution of cobalt (II) thiocyanate, a blue or blue-green precipitate forms, depending on the compound. This is called the Scott test (with the addition of chloroform ). The trihydrate is used as a humidity indicator. An aqueous solution of the compound can be used to determine nonionic surfactants based on ethoxylates in water.

Individual evidence

1. ↑ ^{a b c d} Dale L. Perry: Handbook of Inorganic Compounds . CRC Press, 1995, ISBN 978-0-8493-8671-8 , pp. 131 ( limited preview in Google Book search).
2. ↑ ^{a b c} data sheet cobalt (II) thiocyanate, 99.9% trace metals basis from Sigma-Aldrich , accessed on December 10, 2015 ( PDF ).
3. ↑ ^{a b c} F. H. Cano, S. García-Blanco, AG Laverat: The crystal structure of cobalt (II) thiocyanate trihydrate. In: Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry. 32, p. 1526, doi : 10.1107 / S0567740876005694 .
4. ^ William M. Haynes: CRC Handbook of Chemistry and Physics, 96th Edition . CRC Press, 2015, ISBN 978-1-4822-6097-7 , pp. 60 ( limited preview in Google Book search).
5. ^ Philipp Kurz, Norbert Stock: Synthetic Inorganic Chemistry Basic Course . Walter de Gruyter, 2013, ISBN 978-3-11-025875-2 , p. 73 ( limited preview in Google Book search).
6. ^ Helmut Hofmann, Gerhart Jander: Qualitative analysis . Walter de Gruyter, 1972, ISBN 978-3-11-003653-4 , p. 123 ( limited preview in Google Book search).
7. ^ David E. Newton: Forensic Chemistry . Infobase Publishing, 2007, ISBN 978-1-4381-0976-3 , pp. 86 ( limited preview in Google Book search).
8. ↑ Rick Houghton: Field Confirmation Testing for Suspicious Substances . CRC Press, 2009, ISBN 978-1-4200-8616-4 , pp. 174 ( limited preview in Google Book search).
9. ↑ Rolf Pohling: Chemical reactions in water analysis . Springer-Verlag, 2015, ISBN 978-3-642-36354-2 , pp. 344 ( limited preview in Google Book search).