Calcium iodide

Calcium iodide

Names
IUPAC name calcium iodide
Identifiers
CAS Number	10102-68-8 Y 13640-62-5 (tetrahydrate) N
ChemSpider	59629 Y
Jmol 3D model	Interactive image
PubChem	66244
RTECS number	EV1300000
UNII	8EKI9QEE2H Y
InChI InChI=1S/Ca.2HI/h;2*1H/q+2;;/p-2 Y Key: UNMYWSMUMWPJLR-UHFFFAOYSA-L Y InChI=1/Ca.2HI/h;2*1H/q+2;;/p-2 Key: UNMYWSMUMWPJLR-NUQVWONBAC
SMILES [Ca+2].[I-].[I-]
Properties
Chemical formula	CaI2
Molar mass	293.887 g/mol (anhydrous) 365.95 g/mol (tetrahydrate)
Appearance	white solid
Density	3.956 g/cm3
Melting point	779 °C (1,434 °F; 1,052 K) (tetrahydrate) with decomposition
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
Structure
Crystal structure	Rhombohedral, hP3
Space group	P-3m1, No. 164
Coordination geometry	octahedral
Vapor pressure	{{{value}}}
Related compounds
Other anions	calcium fluoride calcium chloride calcium bromide
Other cations	beryllium iodide magnesium iodide strontium iodide barium iodide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

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. It is used in photography. It is also used in cat food as a source of iodine.

Reactions

Henri Moissan first isolated pure calcium in 1898 by reducing calcium iodide with pure sodium metal:

CaI₂ + 2 Na → 2 NaI + Ca

Calcium iodide can be formed by treating calcium carbonate, calcium oxide, or calcium hydroxide with hydroiodic acid:

CaCO₃ + 2 HI → CaI₂ + H₂O + CO₂

Calcium iodide slowly reacts with oxygen and carbon dioxide in the air, liberating iodine, which is responsible for the faint yellow color of impure samples.

2 CaI₂ + 2 CO₂ + O₂ → 2 CaCO₃ + 2 I₂