Calcium bromide
| Calcium bromide | |
|---|---|
 | |
| IUPAC name Calcium bromide | |
| Other names Calcium dibromide | |
| Identifiers | |
| CAS number | 7789-41-5  , 22208-73-7 (dihydrate) |
| PubChem | 24608 |
| ChemSpider | 23010 |
| UNII | 87CNY2EEBH |
| ChEBI | CHEBI:31338 |
| RTECS number | EV9328000 |
| Jmol-3D images | {{#if:[Ca+2].[Br-].[Br-]|Image 1 |
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| Properties | |
| Molecular formula | CaBr2 |
| Molar mass | 199.89 g/mol (anhydrous) 235.98 g/mol (dihydrate) |
| Appearance | Odorless, very hygroscopic colorless crystals sharp saline taste |
| Density | 3.353 g/cm3 |
| Melting point | 730 °C |
| Boiling point | 1935 °C (anhydrous) 810 °C (dihydrate) |
| Solubility in water | 125 g/100 mL (0 °C) 143 g/100 ml (20°C) 312 g/100 mL (100 °C) |
| Solubility in alcohol, acetone | soluble |
| Acidity (pKa) | 9 |
| Structure | |
| Crystal structure | rhomboid |
| Hazards | |
| Main hazards | Decomposes on heating at high temperature producing toxic and corrosive fumes |
| NFPA 704 |
 0
1
0
|
| LD50 | 4100 mg/kg (rat, oral) 1580 mg/kg (mouse, subcutaneous) |
| Related compounds | |
| Other anions | Calcium fluoride Calcium chloride Calcium iodide |
| Other cations | Beryllium bromide Magnesium bromide Strontium bromide Barium bromide Radium bromide |
(verify) (what is: / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa) | |
| Infobox references | |
Calcium bromide is the calcium salt of hydrobromic acid with the chemical formula of CaBr2. It is a white powder that reacts with water to form the hexahydrate. CaBr2 is mainly used in drilling fluid.[1]
Synthesis, structure, and reactions
It is produced by the reaction of calcium oxide, calcium carbonate with hydrobromic acid or the reaction of calcium metal with elemental bromine.[1]
It adopts the rutile structure, featuring octahedral Ca centres bound to six bromide anions, which also bridge to other Ca centres.
When strongly heated in air, calcium bromide will produce calcium oxide and bromine:
- 2 CaBr2 + O2 → 2 CaO + 2 Br2
In this reaction the oxygen oxidizes the bromide to bromine.
Uses
It is mainly used as dense aqueous solutions for drilling fluids.[1] It is also used in neuroses medication, freezing mixtures, food preservatives, photography and fire retardants.[2]
References
- ↑ 1.0 1.1 1.2 Michael J. Dagani, Henry J. Barda, Theodore J. Benya, David C. Sanders “Bromine Compounds” Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. doi:10.1002/14356007.a04_405
- ↑ "Chemical Land 21". Retrieved 25 December 2008.