What is the chemical bond of CaOCl2

Chlorinated lime

Chlorinated lime (also Lime) is a technical mixture of mostly 35% calcium hypochlorite Ca (OCl)2, 30% calcium chloride (CaCl2) and 13% calcium hydroxide Ca (OH)2.[1] Occasionally, chlorinated lime with the semi-structural formula 3CaCl (OCl) Ca (OH)2 · 5 H2O described.

Chlorinated lime was first made by Charles Tennant in 1799.[2]


Chlorinated lime is formed in the cold by the action of chlorine gas on moist slaked lime (calcium hydroxide):[2]

$ \ mathrm {Ca (OH) _2 + Cl_2 \ longrightarrow CaCl (OCl) + H_2O} $

The conversion to calcium hypochlorite described by the reaction equation does not take place completely, however, so a mixture is formed which also contains calcium chloride and calcium hydroxide.


Chlorinated lime is a white powder or granulate that smells of chlorine. It is only sparingly soluble in water.[1] The density becomes 1.5 g · cm−3 specified.[1]

In the presence of acids, even with the carbon dioxide from the air, chlorine gas is generated. An example of this is the reaction of sulfuric acid with chlorinated lime:

$ \ mathrm {CaCl (OCl) + H_2SO_4 \ longrightarrow CaSO_4 + H_2O + Cl_2} $

When standing and with some metal oxides, oxygen is released (especially when exposed to light).


Chlorinated lime was first used successfully as a disinfectant by the physician Ignaz Semmelweis; this enabled the mortality of women who have recently given birth to be reduced considerably. However, chlorinated lime not only attacks bacteria and viruses, but also the skin. Therefore, the tolerance is not very good and the willingness to use it regularly is low. Alcohol-based hand disinfectants are more widely accepted today. It is also used as an algaecide (algae control agent) and for the decontamination of warfare agents (e.g. sarin or mustard gas). In the military field it is therefore also under the NATO abbreviation C8 known.

In technology, chlorinated lime or calcium hypochlorite is used as a bleaching agent for cellulose, paper and textiles, but for environmental reasons they are increasingly being replaced by other chlorine-free bleaching processes.


Commercially available preparations of chlorinated lime are provided with the same safety instructions as the main component calcium hypochlorite. It is classified as oxidizing, corrosive and hazardous to the environment. The lethal dose of LD50 is 850 mg kg−1 for oral ingestion in rats.[1]

Individual evidence

  1. 1,01,11,21,3Safety data sheet (Hedinger)
  2. 2,02,1Römpp CD 2006, Georg Thieme Verlag 2006