Calcium bromide

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Calcium bromide
Hydrophilite.GIF
Identifiers
CAS number 7789-41-5 YesY
22208-73-7 (dihydrate)
PubChem 24608
ChemSpider 23010 YesY
UNII 87CNY2EEBH YesY
EC number 232-164-6
ChEBI CHEBI:31338 YesY
RTECS number EV9328000
Jmol-3D images Image 1
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 (1,350 °F; 1,000 K)
Boiling point 1,935 °C (3,515 °F; 2,208 K) (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
Thermochemistry
Specific
heat capacity
C
75 J/mol K
Std molar
entropy
So298
130 J/mol K
Std enthalpy of
formation
ΔfHo298
-647.9 kJ/mol
Gibbs free energy ΔG -656.1 kJ/mol
Hazards
Main hazards Decomposes on heating at high temperature producing toxic and corrosive fumes
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
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
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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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[edit]

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[edit]

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[edit]

  1. ^ a b c 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
  2. ^ "Chemical Land 21". Retrieved 25 December 2008. 

External links[edit]