Calcium chlorate
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3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.030.331 |
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CompTox Dashboard (EPA)
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| Properties | |
| Ca(ClO3)2 | |
| Molar mass | 206.98 g/mol |
| Appearance | white solid deliquescent |
| Odor | odorless |
| Density | 2.71 g/cm3 |
| Melting point | 150°C (dihydrate, decomp) 325°C |
| 209 g/100mL (20 °C) 197 g/100mL (25 °C) | |
| Structure | |
| monoclinic | |
| Hazards | |
| NFPA 704 (fire diamond) | |
| Related compounds | |
Other anions
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calcium chloride calcium bromate calcium bromide |
Other cations
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potassium chlorate sodium chlorate barium chlorate magnesium chlorate |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Calcium chlorate is the calcium salt of chloric acid, with the chemical formula Ca(ClO3)2. Like other chlorates, it is a strong oxidizer.
Production
[edit]Calcium chlorate is produced by passing chlorine gas through a hot suspension of calcium hydroxide in water, producing calcium hypochlorite, which disproportionates when heated with excess chlorine to give calcium chlorate and calcium chloride:[1]
- 6 Ca(OH)2 + 6 Cl2 → Ca(ClO3)2 + 5 CaCl2 + 6 H2O
This is also the first step of the Liebig process for the manufacture of potassium chlorate.[citation needed]
In theory, electrolysis of hot calcium chloride solution will produce the chlorate salt,[citation needed] analogous to the process used for the manufacture of sodium chlorate. In practice, electrolysis is complicated by calcium hydroxide depositing on the cathode, preventing the flow of current.
Reactions
[edit]When concentrated solutions of calcium chlorate and potassium chloride are combined, potassium chlorate precipitates:[1][2]
- Ca(ClO3)2 + 2 KCl → 2 KClO3 + CaCl2
This is the second step of the Liebig process for the manufacture of potassium chlorate.[2]
Solutions of calcium chlorate react with solutions of alkali carbonates to give a precipitate of calcium carbonate and the alkali chlorate in solution:
- Ca(ClO3)2 + Na2CO3 → 2 NaClO3 + CaCO3
On strong heating, calcium chlorate decomposes to give oxygen and calcium chloride:
- Ca(ClO3)2 → CaCl2 + 3 O2
Cold, dilute solutions of calcium chlorate and sulfuric acid react to give a precipitate of calcium sulfate and chloric acid in solution:[3]
- Ca(ClO3)2 + H2SO4 → 2 HClO3 + CaSO4
Contact with strong sulfuric acid can result in explosions[4] due to the instability of concentrated chloric acid. Contact with ammonium compounds can also cause violent decomposition due to the formation of unstable ammonium chlorate.[4]
Uses
[edit]Calcium chlorate has been used as an herbicide,[citation needed] like sodium chlorate.
Calcium chlorate is occasionally used in pyrotechnics,[citation needed] as an oxidizer and pink flame colorant. Its hygroscopic nature and incompatibility with other common pyrotechnic materials (such as sulfur) limit its utility in these applications.
References
[edit]- ^ a b Samuel P. Sadtler, Virgil Coblentz and Jeannot Hostmann (1918). A textbook of chemistry, intended for the use of pharmaceutical and medical students. p. 329.
- ^ a b Mellor, Joseph William (1917). Modern Inorganic Chemistry. p. 287.
- ^ Ira Remsen, Charles August Rouillu (1883). "American Chemical Journal". 4: 309.
Solution of pure calcium chlorate, treated by sulphuric acid, would of course give a solution of chloric acid
{{cite journal}}: Cite journal requires|journal=(help) - ^ a b PubChem - Calcium Chlorate: Experimental Properties