Cobalt(II) chloride
Cobalt dichloride
Blue crystalline solid (anhydrous), as hexahydrate red - violet solid
Fixed
3.356 g · cm -3
735 ° C
1049 ° C
- Slightly soluble in water ( 529 g · l-1 at 20 ° C)
- Soluble in methanol, ethanol, acetone, pyridine and diethyl ether
Risk
Not determined, as carcinogenic
Template: Infobox chemical / molecular formula search available
Cobalt (II ) chloride is a chemical compound of cobalt and chlorine. It is in the anhydrous state blue, pink as hexahydrate salt.
Production and representation
Cobalt (II ) chloride can be obtained from the elements or by heating the hexahydrate in the presence of thionyl chloride or phosgene or hydrogen chloride stream.
The latter can be obtained by reaction of the cobalt ( II) hydroxide and cobalt (II ) carbonate with hydrochloric acid again.
Also possible is the representation of cobalt (II ) acetate tetrahydrate, and acetyl chloride.
Properties
Anhydrous cobalt ( II ) chloride is very hygroscopic and readily absorbs water. This is very characteristic changes its color from blue to pink. The opposite color change from pink to blue is also possible, by heating the hexahydrate to temperatures above 35 ° C.
Cobalt (II ) chloride hexahydrate
It sublimes in hydrogen chloride atmosphere at 500 ° C to loose Kristallflittern. Its crystal structure is hexagonal and corresponds to the cadmium (II ) chloride with the space group R 3 ¯ m (a = 354.4 pm, c = 1743 pm ).
Use
Because of the typical color change, it served as a moisture indicator in desiccants such as silica gel. With the help of cobalt (II ) chloride can be detected in other solutions of water.
Also it is used as a so-called invisible ink, as it is barely visible as hexahydrate in aqueous solution on the paper, but when it is heated (eg a candle ), emerges deep blue font.
Furthermore, it may be used as an additive to the electrolyte (sulfuric acid) in the lead-acid accumulators, in order to increase battery life and performance.
Safety
Cobalt (II ) chloride is considered to be carcinogenic and teratogenic and may be mutagenic. The material was recorded on 28 October 2008 in the Kanditatenliste the SVHC ' Substance of very high concern ( SVHC ) '. The entry has been added on June 20, 2011, at the reproductive toxicity properties.
Cobalt (II ) chloride promotes the production of red blood cells ( erythrocytes ). There is therefore concern that cobalt ( II ) chloride is abused in sports as doping substance.