|Calcium hypochlorite or Calcium oxychloride|
|Jmol-3D images||Image 1|
|Molar mass||142.98 g/mol|
|Density||2.35 g/cm3 (20 °C)|
175 °C, decomposes
|Solubility in water||21 g/100 mL, reacts|
|Solubility||reacts in alcohol|
|EU classification||Oxidant (O)
Dangerous for the environment (N)
|R-phrases||R8, R22, R31, R34, R50|
|S-phrases||(S1/2), S26, S36/37/39, S45, S61|
|LD50||850 mg/kg (oral, rat)|
|Other anions||Calcium chloride|
|Other cations||Sodium hypochlorite|
| (what is: / ?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Calcium hypochlorite is a chemical compound with formula Ca(ClO)2. It is widely used for water treatment and as a bleaching agent (bleaching powder). This chemical is considered to be relatively stable and has greater available chlorine than sodium hypochlorite (liquid bleach).
It is manufactured by the calcium process:
Calcium hypochlorite is a yellow white solid which has a strong smell of chlorine. It is not highly soluble in water, and is more preferably used in soft to medium-hard water. It has two forms: a dry form and a hydrated form. The hydrated form is safer to handle.
A calcium hypochlorite solution is basic. This is due to the hydrolysis performed by the hypochlorite ion, as hypochlorous acid is weak, but calcium hydroxide is a strong base. As a result, the hypochlorite ion is a strong conjugate base, and the calcium ion is a weak conjugate acid:
- ClO− + H2O → HClO + OH−
- Ca(OCl)2 + 4 HCl → CaCl2 + 2 H2O + 2 Cl2
Calcium hypochlorite is used for the disinfection of drinking water or swimming pool water. It is used as a sanitizer in outdoor swimming pools in combination with a cyanuric acid stabilizer, which reduces the loss of chlorine due to ultraviolet radiation. The calcium content hardens the water and tends to clog up some filters; hence, some products containing calcium hypochlorite also contain anti-scaling agents.
Calcium hypochlorite is also an ingredient in bleaching powder, used for bleaching cotton and linen. It is also used in bathroom cleaners, household disinfectant sprays, moss and algae removers, and weedkillers.
In addition, calcium hypochlorite may be used to manufacture chloroform.
Bleaching powder is used also in sugar industry for bleaching sugar cane juice before its crystallization.
Calcium hypochlorite is best kept in a cool dry place away from any organic material. It is known to undergo self heating and rapid decomposition accompanied by the release of toxic chlorine gas.
- Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8