Calcium chlorite

Description

Calcium chlorite is an oxysalt with a molecular formula of Ca(ClO2)2. It is a white, crystalline material that is soluble in water. It is a strong oxidizer and a fire risk in contact with organic materials. The four-digit UN identification number is 1453. Hypochlorites have two less oxygen atoms than the base-state compounds. They can cause combustion in high concentrations when in contact with organic materials. When heated or in contact with water, they can give off oxygen gas. At ordinary temperatures, they can give off chlorine and oxygen when in contact with moisture and acids. They are commonly used as bleaches and swimming pool disinfectants.

Chemical properties

White crystals. Decomposes in water.

Physical properties

Calcium chlorite, Ca(ClO2)2, has the molecular weight of 174.98 g/mol. Its density is 2.71 g/cm3. Its CAS number is 14674-72-7. Calcium chlorite can be prepared by reaction of chlorous acid with calcium carbonate:
CaCO3 (solid)＋ 2HClO2 (aq)→Ca(ClO2)2·6H2O
It is a white granular solid and if formed in solution, crystallizes as the hexahydrate. Calcium hypochlorite, hydrated, is a white granular solid having an odor of chlorine. It is noncombustible and accelerates the burning of combustible materials. It is decomposed by water with evolution of chlorine gas and heat. Prolonged exposure to fire or heat may result in an explosion. It is decomposed by water to form calcium hydroxide and chlorine dioxide, an explosive oxidizing gas:
Ca(ClO2)2＋H2O→Ca(OH)2＋ 2ClO2
Calcium chlorite is a strong oxidizing agent. It ignites on contact with potassium thiocyanate and reaction with chlorine yields explosive chlorine dioxide gas. Reaction with ammonia produces ammonium chlorite, which is shock sensitive and explodes. If mixed with finely divided metallic or organic substances, the combination is highly flammable and may be ignited by friction.
Currently, no manufacturer is registered for the product CALCIUM CHLORITE. There is a paucity of data concerning the physical properties of this salt and they are not easily accessible.

General Description

White granular solid. Prolonged exposure to fire or heat may result in an explosion and the rupturing of the containers.

Air & Water Reactions

Decomposed by water to calcium hydroxide and chlorine dioxide, an explosive oxidizing gas.

Reactivity Profile

A strong oxidizing agent. Accelerate the burning of combustible materials. Ignites on contact with potassium thiocyanate [Lewis]. Reaction with chlorine yields explosive chlorine dioxide gas. Reaction with ammonia produces ammonium chlorite, which is shock-sensitive. Finely divided mixtures with metallic or organic substances are highly flammable and may be ignited by friction (Lab. Gov. Chemist 1965).

Hazard

Strong oxidizer, fire risk in contact with organic materials.

Health Hazard

Inhalation, ingestion or contact (skin, eyes) with vapors or substance may cause severe injury, burns or death. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may cause pollution.

Fire Hazard

These substances will accelerate burning when involved in a fire. Some may decompose explosively when heated or involved in a fire. May explode from heat or contamination. Some will react explosively with hydrocarbons (fuels). May ignite combustibles (wood, paper, oil, clothing, etc.). Containers may explode when heated. Runoff may create fire or explosion hazard.

Safety Profile

A strong oxidizer. Ignites on contact with potassium thiocyanate. Reaction with Cl2 yields explosive Cl0~. When heated to decomposition it emits toxic fumes of Cl-. See also CHLORITES and CALCIUM COMPOUNDS.