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Other names
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| Identifiers | |
3D model (JSmol) | |
| ChEBI | |
| ChEMBL | |
| ChemSpider |
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| ECHA InfoCard | 100.029.007 |
| EC Number |
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| KEGG | |
| RTECS number |
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| UNII | |
| UN number | 1748 2208 |
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| Properties | |
| Ca(OCl)2 | |
| Molar mass | 142.98 g·mol−1 |
| Appearance | white/gray powder |
| Density | 2.35 g/cm3 (20 °C) |
| Melting point | 100 °C (212 °F; 373 K) |
| Boiling point | 175 °C (347 °F; 448 K) decomposes |
| 21 g/(100 mL) at 25 °C | |
| Solubility | reacts inalcohol |
| Hazards | |
| GHS labelling: | |
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| Danger | |
| H272,H302,H314,H400 | |
| P210,P220,P221,P260,P264,P270,P273,P280,P301+P312,P301+P330+P331,P303+P361+P353,P304+P340,P305+P351+P338,P310,P321,P330,P363,P370+P378,P391,P405,P501 | |
| NFPA 704 (fire diamond) | |
| Flash point | Non-flammable |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) | 850 mg/kg (oral, rat) |
| Safety data sheet (SDS) | ICSC 0638 |
| Related compounds | |
Otheranions | |
Othercations | |
Related compounds | |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Calcium hypochlorite is aninorganic compound withchemical formulaCa(ClO)2, also written asCa(OCl)2. It is a white solid, although commercial samples appear yellow. It strongly smells of chlorine, owing to its slowdecomposition in moist air. This compound is relatively stable as a solid and solution and has greater availablechlorine thansodium hypochlorite.[1] "Pure" samples have 99.2%active chlorine. Given common industrial purity, an active chlorine content of 65-70% is typical.[2] It is the main active ingredient of commercial products calledbleaching powder,[a] used forwater treatment and as ableaching agent.[3]
Charles Tennant andCharles Macintosh developed an industrial process in the late 18th century for the manufacture of chloride of lime, patenting it in 1799.[4] Tennant's process is essentially still used today,[4][3] and became of military importance duringWorld War I, because calcium hypochlorite was the active ingredient intrench disinfectant.[4]
Calcium hypochlorite is commonly used tosanitize public swimming pools anddisinfect drinking water. Generally the commercial substances are sold with a purity of 65% to 73% with other chemicals present, such as calcium chloride and calcium carbonate, resulting from the manufacturing process. In solution, calcium hypochlorite could be used as a general purpose sanitizer,[5] but due to calcium residue (makingthe water harder),sodium hypochlorite (bleach) is usually preferred.
Calcium hypochlorite is a generaloxidizing agent and therefore finds some use inorganic chemistry.[6] For instance the compound is used tocleaveglycols,α-hydroxy carboxylic acids andketo acids to yield fragmentedaldehydes orcarboxylic acids.[7] Calcium hypochlorite can also be used in thehaloform reaction to manufacturechloroform.[8]Calcium hypochlorite can be used to oxidizethiol andsulfide byproducts in organic synthesis and thereby reduce their odour and make them safe to dispose of.[9] The reagent used in organic chemistry is similar to the sanitizer at ~70% purity.[10]
Calcium hypochlorite is produced industrially by reaction of moist slakedcalcium hydroxide withchlorine gas. The one-step reaction is shown below:[3]
Industrial setups allow for the reaction to be conducted in stages to give various compositions, each producing different ratios of calcium hypochlorite, unconverted lime, andcalcium chloride.[3] In one process, the chloride-rich first stage water is discarded, while the solid precipitate is dissolved in a mixture of water andlye for another round of chlorination to reach the target purity.[2] Commercial calcium hypochlorite consists of anhydrousCa(OCl)2, dibasic calcium hypochloriteCa3(OCl)2(OH)4 (also written asCa(OCl)2·2Ca(OH)2), and dibasic calcium chlorideCa3Cl2(OH)4 (also written asCaCl2·2Ca(OH)2).[11][12]
Calcium hypochlorite reacts rapidly with acids producingcalcium chloride, chlorine gas, and water:[citation needed]
It is a strongoxidizing agent, as it contains ahypochlorite ion at the valence +1 (redox state: Cl+1).[citation needed]
Calcium hypochlorite should not be stored wet and hot, or near any acid, organic materials, or metals. The unhydrated form is safer to handle.[citation needed]
Assay (iodometric): 67.0 - 75.0 %
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