Calcium iodide (chemical formula CaI2) is the ionic compound of calcium and iodine. This colourless deliquescent solid is a salt that is highly soluble in water. Its properties are similar to those for related salts, such as calcium chloride.
Molar mass：293.887 g/mol (anhydrous)
365.95 g/mol (tetrahydrate)
Density：3.956 g/cm3 (anhydrous)
Melting point：779 °C (1,434 °F; 1,052 K) (anhydrous)
Boiling point：1,100 °C (2,010 °F; 1,370 K)
Solubility in water：64.6 g/100 mL (0 °C)
66 g/100 mL (20 °C)
81 g/100 mL (100 °C)
Solubility：soluble in acetone and alcohols
Magnetic susceptibility (χ)：-109.0·10−6 cm3/mol
Crystal structure：Rhombohedral, hP3
It is used in photography. It is also used in cat food as a source of iodine.