   #copyright

Calcium chloride

2007 Schools Wikipedia Selection. Related subjects: Chemical compounds

                          Calcium chloride
                          Calcium chloride
                               General
       Systematic name                               calcium chloride
           Other names                          calcium(II) chloride,
                                                   calcium dichloride
     Molecular formula                                        CaCl[2]
            Molar mass             110.99 g/mol, anhydrous
                                   147.02 g/mol, dihydrate
                                   182.04 g/mol, tetrahydrate
                                            219.08 g/mol, hexahydrate
            Appearance                      white or colourless solid
            CAS number             [10043-52-4], anhydrous
                                   [10035-04-8], dihydrate
                                   [25094-02-4], tetrahydrate
                                             [7774-34-7], hexahydrate
                             Properties
     Density and phase       2.15 g/cm^3, anhydrous
                                        0.835 g/cm^3, dihydrate
                                             1.71 g/cm^3, hexahydrate
   Solubility in water                          74.5 g/100 ml (20 °C)
            In ethanol
            In acetone
        In acetic acid                                        soluble
         Melting point                             772 °C (anhydrous)
         Boiling point                                       >1600 °C
       Vapour Pressure                                         11 hPa
                              Structure
 Coordination geometry                       octahedral, 6-coordinate
     Crystal structure                                deformed rutile
                               Hazards
                  MSDS                                  External MSDS
     EU classification                                  Irritant (Xi)
              NFPA 704

                       0
                       1
                       0

             R-phrases                                            R36
             S-phrases                                   S2, S22, S24
          RTECS number              EV9800000, anhydrous
                                    EV9810000, dihydrate
                                               EV9830000, hexahydrate
                       Supplementary data page
Structure & properties                                  n, ε[r], etc.
    Thermodynamic data                                Phase behaviour
                                                   Solid, liquid, gas
         Spectral data                                UV, IR, NMR, MS
                          Related compounds
          Other anions                  calcium fluoride
                                        calcium bromide
                                                       calcium iodide
         Other cations                             magnesium chloride
                                                   strontium chloride
          Except where noted otherwise, data are given for
                materials in their standard state (at 25°C, 100 kPa)
                                    Infobox disclaimer and references

   Calcium chloride is a chemical compound of calcium and chlorine. It is
   highly soluble in water and it is deliquescent. It is a salt that is
   solid at room temperature, and it behaves as a typical ionic halide. It
   has several common applications such as brine for refrigeration plants,
   ice and dust control on roads, and in cement. It can be produced
   directly from limestone, but large amounts are also produced as a
   by-product of the Solvay process. Because of its hygroscopic nature, it
   must be kept in tightly-sealed containers.

Chemical properties

   Calcium chloride can serve as a source of calcium ions in solution, for
   instance for precipitation because many calcium compounds are
   insoluble:

   3 CaCl[2]( aq) + 2 K[3]PO[4]( aq) → Ca[3](PO[4])[2]( s) + 6 KCl( aq)

   Molten CaCl[2] can be electrolysed to give calcium metal:

   CaCl[2]( l) → Ca( s) + Cl[2](g)

Preparation

   Calcium chloride is a by-product of the Solvay process used for the
   manufacture of sodium carbonate. It can also be produced by the action
   of hydrochloric acid on calcium carbonate CaCO[3]( s) + 2 HCl →
   CaCl[2](aq) + H[2]O( l) + CO[2](g)

Uses

   Millions of tonnes of calcium chloride are made each year in the US
   alone, and in 1990 the bulk price there was $182 per tonne. It has a
   variety of applications:
     * Because it is strongly hygroscopic, air or other gases may be
       channeled through a column of calcium chloride to remove moisture.
       In particular, calcium chloride is usually used to pack drying
       tubes to exclude atmospheric moisture from a reaction set-up while
       allowing gases to escape. It can also be added to liquids to remove
       suspended or dissolved water. In this capacity, it is known as a
       drying agent or desiccant. It is converted to a brine as it absorbs
       the water or water vapor from the substance to be dried:

          CaCl[2] + 2 H[2]O → CaCl[2]·2H[2]O

          The dissolving process is highly exothermic and rapidly produces
          temperatures of around 60° C (140° F). This can result in burns
          if humans or other animals eat dry calcium chloride pellets.
          Small children are more susceptible to burns than adults, and
          calcium chloride pellets should be kept out of their reach.

     * Aided by the intense heat evolved during its dissolution, calcium
       chloride is also used as an ice-melting compound. Unlike the
       more-common sodium chloride (rock salt or halite), it is relatively
       harmless to plants and soil. It is also more effective at lower
       temperatures than sodium chloride. When distributed for this use,
       it usually takes the form of small white balls a few millimetres in
       diameter, called prills (see picture at top of page).

     * It is used in concrete mixes to help speed up the initial setting.
       However chloride ion leads to corrosion of steel rebars, so it
       should not be used in reinforced concrete.

     * It is used for dust control on some highways, as its hygroscopic
       nature keeps a liquid layer on the surface of the roadway, which
       holds dust down.

     * Calcium chloride tastes extremely salty and is used an ingredient
       in some foods, especially pickles, to give a salty taste while not
       increasing the food's sodium content.

     * It's also used as an ingredient in canned vegetables to maintain
       firmness.

     * Used as an additive in plastics.

     * Used as a drainage aid for wastewater treatment.

     * Aqueous Calcium Chloride is used in genetic transformation of cells
       by increasing the cell membrane permeability. This allows DNA
       fragments to enter the cell more readily.

     * Tire ballast
     * Additive in fire extinguishers
     * Additive to control scaffolding in blast furnaces

     * It can be used to make ersatz caviar from vegetable or fruit
       juices.

     * It is used in Smartwater and some sports drinks as an Electrolyte

Precautions

   Calcium chloride is an irritant; wear gloves and goggles to protect
   hands and eyes; avoid inhalation.

   Although calcium chloride is relatively safe to handle, care should be
   taken that it is not ingested. Calcium chloride reacts exothermically
   with water and can burn the mouth and esophagus.
   Retrieved from " http://en.wikipedia.org/wiki/Calcium_chloride"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
