Formula Mg(ClO4)2 Density 2.21 g/cm³ | Molar mass 223.206 g/mol Melting point 251 °C | |
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Appearance white powder, deliquescent | ||
Magnesium perchlorate is a powerful oxidizing agent, with the formula Mg(ClO4)2. It is also a superior drying agent for gas analysis.
Magnesium perchlorate decomposes at 250 °C. The heat of formation is -568.90 kJ mol−1.
The enthalpy of solution is quite high, so reactions are done in large amounts of water to dilute it.
It is sold under the trade name anhydrone. Manufacture of this product on a semi-industrial scale was first performed by G. Frederick Smith in his garage in Urbana Illinois, but later at a permanent facility in Columbus, OH called G. Frederick Smith Chemical Co. He sold the magnesium perchlorate to A. H. Thomas Co., now Thomas Scientific, under the trade name Dehydrite.
It is used as desiccant to dry gas or air samples, but is no longer advised, for use as a general desiccant, due to hazards inherent in perchlorates. It is dried by heating at 220 °C under vacuum.
Magnesium perchlorate is created by the reaction of magnesium hydroxide and perchloric acid.
In 2011, a study of the Georgia Institute of technology unveils the presence of magnesium perchlorate on Planet Mars. It would be a proof of the presence of water on the planet. Being a drying agent, magnesium perchlorate retains water of the atmosphere to release it when conditions are favorable and temparature is above 250K.