Calcium diiodide

  • Formula: CaI2
  • Hill system formula: Ca1I2
  • CAS registry number: [10102-68-8]
  • Formula weight: 293.887
  • Class: iodide
  • Colour: pale yellow
  • Appearance: crystalline solid
  • Melting point: 779°C
  • Boiling point: 1100°C
  • Density: 4520 kg m-3

The following are some synonyms of calcium diiodide:

  • calcium diiodide
  • calcium(II) iodide
  • calcium iodide

The oxidation number of calcium in calcium diiodide is 2.


Small pure smaples of calcum iodide may be made through the reaction of calcium metal in liquid ammonia with ammonium iodide.

Ca(NH3) + 2NH4I → CaI2 + 2NH3 + H2(g)

Solid state structure

  • Geometry of calcium: 6 coordinate: octahedral
  • Prototypical structure:
Crystal structure of calcium diiodide.
Crystal structure of calcium diiodide.

Element analysis

The table shows element percentages for CaI2 (calcium diiodide).

Element %
Ca 13.64
I 86.36

Isotope pattern for CaI2

The chart below shows the calculated isotope pattern for the formula CaI2 with the most intense ion set to 100%.


The data on these compounds pages are assembled and adapted from the primary literature and several other sources including the following.

  • R.T. Sanderson in Chemical Periodicity, Reinhold, New York, USA, 1960.
  • N.N. Greenwood and A. Earnshaw in Chemistry of the Elements, 2nd edition, Butterworth, UK, 1997.
  • F.A. Cotton, G. Wilkinson, C.A. Murillo, and M. Bochmann, in Advanced Inorganic Chemistry, John Wiley & Sons, 1999.
  • A.F. Trotman-Dickenson, (ed.) in Comprehensive Inorganic Chemistry, Pergamon, Oxford, UK, 1973.
  • R.W.G. Wyckoff, in Crystal Structures, volume 1, Interscience, John Wiley & Sons, 1963.
  • A.R.West in Basic solid state chemistry Chemistry, John Wiley & Sons, 1999.
  • A.F. Wells in Structural inorganic chemistry, 4th edition, Oxford, UK, 1975.
  • J.D.H. Donnay, (ed.) in Crystal data determinative tables, ACA monograph number 5, American Crystallographic Association, USA, 1963.
  • D.R. Lide, (ed.) in Chemical Rubber Company handbook of chemistry and physics, CRC Press, Boca Raton, Florida, USA, 77th edition, 1996.
  • J.W. Mellor in A comprehensive treatise on inorganic and theoretical chemistry, volumes 1-16, Longmans, London, UK, 1922-1937.
  • J.E. Macintyre (ed.) in Dictionary of inorganic compounds, volumes 1-3, Chapman & Hall, London, UK, 1992.

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