Cobalt (II) chloride . Its chemical formula is (CoCl 2 ), although the same term is used for the (hexa) hydrated compound. It is a crystalline solid of blue color , and the CoCl 2 · 6H 2 O is pinkish.
Summary
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- 1 Physical properties
- 2 Chemical properties
- 3 Reactivity
- 4 Uses
- 1 Information on health hazards
- 5 First aid
- 6 Related link
- 7 Sources
Physical properties
Cobalt (II) Chloride Anhydride
The aqueous solutions of CoCl 2 and its hydrated namesake contain the species [Co (H 2 O) 6 ] 2+ (that is, the cobalt surrounded by six waters , and this set with two positive charges).
In the solid state the CoCl 2 · 6H 2 O contains trans- [CoCl 2 (H 2 O) 4] · 2H 2 O (that is, the cobalt surrounded by alternating waters and chlorides, and all this with two more waters), These two more waters is water of crystallization. This species dissolves easily in water and alcohol. It has the interesting property that at a high aqueous solution concentration it is red at room temperature, but turns blue when heated. CoCl 2 · 6H 2 O is deliquescent (that is, it has the capacity to absorb water from the outside in such a marked way that it is even capable of forming aqueous solutions ), whereas the anhydrous salt is hygroscopic (that is, it has a tendency to incorporate water molecules in its structure), easily converting into hydrated salt.
Chemical properties
CoCl 2 · 6H 2 O and CoCl 2 are weak Lewis acids that form many other coordinated compounds . These cobalt (II) complexes are normally octahedral or tetrahedral. This includes octahedral complexes with pyridine (C 5 H 5 N) (one hex with five carbon tips and one nitrogen tip): CoCl_ 2 · 6H 2 O + 4 C 5 H 5 N = CoCl_ 2 [C 5 H 5 N] 4 + 6H2 O.
The complex tetrahedral with triphenylphosphine (P (C 6 H 5 ) 3 ) (three phenyl groups ( benzene ) with one atom of phosphorus ): CoCl 2 · 6H 2 O + 2 P (C 6 H 5 ) 3 = CoCl 2 [ [P (C 6 H 5 ) 3 ] 2 + 6H 2 O AND the anion complex (with negative charges ) CoCl 2- 4 : CoCl_ 2 + 2 [(C 2 H5 ) 4 N] Cl = [(C 2 H 5 ) 4 N] 2 [CoCl 4 ]
In other cases, aqueous solutions of cobalt (II) chloride behave like other cobalt (II) salts, for example precipitating CoS ( cobalt (II) sulfide when treated with H 2 S ( hydrogen sulfide ).
In the laboratory, cobalt (II) chloride is used as a standard precursor for the synthesis of other cobalt compounds. For example, the reaction of 1-nobornyl lithium with CoCl 2 produces brown, thermally stable tetrabalkyl cobalt (IV) ; the only compound of its kind whose detailed structure is completely known.
Reaction of anhydrous CoCl 2 with sodium cyclopentadienylide in THF (TetraHydroFuran, solvent) results in a black compound , cobaltocene. This species of 19 electrons is a good reducing agent (gives electrons), easily oxidized to the cobaltocene cation yellow color , which has the same electrons as ferrocene.
Reactivity
Dangerous substance for the environment . Conditions that contribute to chemical stability : Moderate. Incompatibilities: In contact with strong oxidizing agents, strong mineral acids, alkali metals such as Sodium and Potassium . Hazardous decomposition products: Hydrochloric Acid Gas and Cobalt Oxides. Conditions to Avoid: High temperatures (decomposes).
Applications
Because of the very visible change from pinkish to blue, and the ease of hydration / dehydration reaction, cobalt (II) chloride is used as an indicator of water / humidity, its frequent use is for the detection of humidity, for example in drying agents such as silica gel (used for chromatography, for example), in addition to being used to make sympathetic inks and to produce recreational instruments that forecast the weather. Paper impregnated with cobalt chloride, whose use is the same, detects the presence of water in a similar way.
Hexahydrate is one of the most common compounds in the laboratory.
Information on health hazards
- Exposure route
CoCl 2 · 6H 2 O can affect the body if it is inhaled or comes into contact with the skin or eyes. It can also affect the body if ingested. Effects of overexposure.
Cobalt (II) chloride is corrosive if contacted with any tissue. The effects due to inhalation range from severe irritations to the respiratory tract, causing cough, respiratory distress, as well as respiratory hypersensitivity – asthma. Nausea, dizziness and headache. Inhalation of Cobalt fumes and powders is associated with an increasing incidence of lung damage, possible pulmonary edema. Contact with skin or eyes can cause severe irritation, redness, itching and pain.
Ingestion of cobalt (II) chloride is very harmful, it can cause abdominal pain, nausea, vertigo, vomiting and diarrhea, it can have cumulative toxic action, muscular paralysis, it reduces the activity of the thyroid and, if the exposure is greater, May cause depression of red blood cell production, damage to kidneys, pancreas, heart, .DL50 (oral – rat): 80 mg / kg.
Currently there is evidence that it has carcinogenic effects at the level of animal experiences. there is no evidence that it has teratogenic effects, and the mutagenic effect is under study.
Indicative symptoms: A doctor should be consulted if signs or symptoms are observed or observed and if they are suspected to be caused by exposure to cobalt (II) chloride.
First aid
In case of:
- Inhalation:Move the person where there is fresh air, in case of respiratory arrest, use cardiopulmonary resuscitation method. :
If breathing is difficult, oxygen should be supplied , get medical help immediately.
- Skin contact:Wash with abundant and fast water , for at least 5 minutes, use an emergency shower, remove contaminated clothing and then wash or discard it.
If the injury continues, seek medical assistance immediately.
- Eye Contact:Wash with abundant and rapid water in an eye wash, between 5 and 10 minutes minimum, separating the eyelids. If the damage persists, refer to a medical attention center quickly.
- Ingestion:Wash mouth with plenty of water , give plenty of water to drink. Induce vomiting, only if the person is conscious.
Send to a medical service immediately.
