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
Read more about this topic: Calcium Iodide
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—George Orwell (1903–1950)
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—Cathy Rindner Tempelsman (20th century)