cobalt ii chloride hexahydrate
| Formula | CoCl2 *6H2O |
| Chemical formula | CoCl2 *6H2O |
| Molar mass | 237.93 g/mol |
| CAS number | 7791-13-1 |
| HS Code | 28273400 |
| EC number | 231-589-4 |
| Storage | Without limitation |
| SDS | available |
| RTECS | GG0200000 |
| R phrase | R 49-E22-42/43-50/53 |
| S phrase | S 53-22-45-60-61 |
| Odour | odourless |
| Form | solid |
| Color | violet |
| p H value | ~4.9 (50 g/l 25°c) |
| Solubility in water | 76 g/l (20°c) |
| Melting point | 56 °C |
| Assay | 97.0 -102.0 | % | |
| Description | Conforms | ||
| Identification | Conforms | ||
| Solubility | Conforms | ||
| Nitrate | Conforms | ||
| Sulfate | ≤ | 0/007 | % |
| Iron | ≤ | 0/005 | % |
| Nickel | ≤ | 0/15 | % |
| Lead | ≤ | 0/002 | % |
| Zinc | ≤ | 0/05 | % |
| Substances not precipated by | ≤ | 0/3 | % |
| ammonium sulfide |
Cobalt(II) chloride hexahydrate is a deep pink to red crystalline compound that is highly hygroscopic and commonly used as an indicator for moisture. It is the hydrated form of cobalt(II) chloride and is widely used in laboratories and industry due to its distinct color change properties and solubility.
🏭⚗️ Production
Cobalt(II) chloride hexahydrate is produced by reacting cobalt metal or cobalt oxide with hydrochloric acid, followed by crystallization from aqueous solution. The resulting crystals incorporate six water molecules per cobalt(II) ion, forming the hexahydrate. It is commercially available and typically prepared under controlled humidity and temperature conditions to ensure consistent hydration.
🔬 Properties
The chemical formula of cobalt(II) chloride hexahydrate is CoCl₂·6H₂O, with a molar mass of approximately 237.93 g/mol. It appears as pink to red crystals that are soluble in water and alcohol. Upon heating, it loses water molecules and gradually converts to the blue anhydrous form (CoCl₂). It has a melting point of about 86 °C (with decomposition of the hydrate), and is sensitive to air and humidity, changing color as it gains or loses water. It is ionic in nature and exhibits paramagnetic behavior due to unpaired electrons in the cobalt ion.
🧪 Applications
Cobalt(II) chloride hexahydrate is commonly used as a humidity indicator, changing from blue (anhydrous) to pink (hydrated) in response to moisture. It is also used in analytical chemistry, in the preparation of other cobalt compounds, and as a catalyst in various chemical reactions. In biochemical applications, it may be used as a source of cobalt ions. Additionally, it finds use in colorimetric assays and educational demonstrations involving reversible hydration and dehydration.
⚠️ Safety
Cobalt(II) chloride hexahydrate is toxic and should be handled with care. It may cause skin and eye irritation and is classified as a carcinogen and reproductive toxin with chronic exposure. Inhalation or ingestion should be avoided, and handling requires protective gloves, goggles, and proper lab ventilation. It should be stored in tightly sealed containers in a dry environment away from incompatible substances such as strong oxidizers and acids.
