White powder or tablets.
It is made by bubbling chlorine gas through a solution of calcium hydroxide.
Calcium hypochlorite is the main ingredient in swimming pool chlorine tablets.
Calcium hypochlorite is one of the best disinfectants known, killing bacteria, yeasts, fungus, spores, even viruses.
Calcium hypochlorite is used to disinfect water supplies and swimming pools more than its sodium cousin sodium hypochlorite (household bleach), because it can be sold as a solid (it does not attract moisture from the air and clump up like sodium hypochlorite powder does).
calcium hypochlorite: InChI=1/Ca.2ClO/c;2*1-2/q+2;2*-1
sodium hypochlorite: InChI=1/ClO.Na/c1-2;/q-1;+1