Calcium iodide

Cadmium-iodide-3D-balls

Calcium iodide is an inorganic compound that is made of calcium and iodine. It has the chemical formula CaI2. This compound is used in various applications, including photography, cat food, and as a source of iodine in animal feed to prevent and treat iodine deficiencies. It is also utilized in some types of lamps, such as metal halide lamps, where it contributes to the generation of light.

Properties

Calcium iodide is a white solid at room temperature and is highly soluble in water. Its solubility increases with temperature, making it easy to dissolve in water at higher temperatures. The compound can also dissolve in other solvents such as ethanol and acetone. When exposed to moist air, calcium iodide is deliquescent, meaning it can absorb water from the air and dissolve in it, eventually turning into a solution.

Preparation

Calcium iodide can be prepared by the direct combination of elemental calcium and iodine. Another method involves reacting calcium carbonate (CaCO3) or calcium oxide (CaO) with hydroiodic acid (HI):

CaCO3 + 2HI → CaI2 + CO2 + H2O

CaO + 2HI → CaI2 + H2O

Applications

Photography

In photography, calcium iodide is used in the preparation of emulsions. It acts as a stabilizer and increases the sensitivity of the photographic film to light.

Animal Feed

Calcium iodide serves as a source of iodine in animal feed. Iodine is an essential element for the thyroid gland to produce thyroid hormones, which are critical for regulating metabolism in animals and humans. Adding calcium iodide to animal feed helps prevent iodine deficiency, which can lead to various health issues, including goiter.

Lamps

In the production of metal halide lamps, calcium iodide is mixed with other metal halides to improve the quality and spectrum of light produced. These lamps are widely used in public lighting, automotive headlights, and for growing plants in greenhouses.

Safety

Calcium iodide should be handled with care, as it can cause irritation to the skin, eyes, and respiratory system. Proper protective equipment, such as gloves and goggles, should be worn when handling this chemical. It is also important to work in a well-ventilated area to avoid inhalation of dust or vapors.