Magnesium perchlorate is a powerful

oxidizing agent An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or "Electron acceptor, accepts"/"receives" an electron from a (called the , , or ). In ot ...

, with the formula Mg(ClO₄)₂. The salt 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 In thermochemistry, the enthalpy of solution ( heat of solution or enthalpy of solvation) is the enthalpy change associated with the dissolution of a substance in a solvent at constant pressure resulting in infinite dilution. The enthalpy of sol ...

is quite high, so reactions are done in large amounts of water to dilute it. It is sold under the

trade name A trade name, trading name, or business name, is a pseudonym used by companies that do not operate under their registered company name. The term for this type of alternative name is a "fictitious" business name. Registering the fictitious name w ...

anhydrone. Manufacture of this product on a semi-industrial scale was first performed by

G. Frederick Smith George Frederick Smith (1891–1976) was an early American researcher and advocate of the use of perchloric acid and perchlorate salts in analytical chemistry.Tracings Quarterly, pg 1-10, 1966 He authored and co-authored many scholarly papers and t ...

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., no
Thomas Scientific
under the trade name Dehydrite.

Uses

It is used as

desiccant A desiccant is a hygroscopic substance that is used to induce or sustain a state of dryness (desiccation) in its vicinity; it is the opposite of a humectant. Commonly encountered pre-packaged desiccants are solids that absorb water. 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 and other

perchlorates A perchlorate is a chemical compound containing the perchlorate ion, . The majority of perchlorates are commercially produced salts. They are mainly used as oxidizers for pyrotechnic devices and to control static electricity in food packaging. Pe ...

have been found on

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...

. Being a drying agent, magnesium perchlorate retains water from the atmosphere and may release it when conditions are favorable and temperature is above 273 K. Briny solutions that contain salts such as magnesium perchlorate have a lower melting point than that of pure water. Therefore the abundance of magnesium and other perchlorate salts on Mars could support the theory that liquid aqueous solutions might exist on or below the surface, where temperature and pressure conditions would ordinarily cause the water to freeze.

Production

Magnesium perchlorate is produced by the reaction of

magnesium hydroxide Magnesium hydroxide is the inorganic compound with the chemical formula Mg(OH)2. It occurs in nature as the mineral brucite. It is a white solid with low solubility in water (). Magnesium hydroxide is a common component of antacids, such as milk ...

and

perchloric acid Perchloric acid is a mineral acid with the formula H Cl O4. Usually found as an aqueous solution, this colorless compound is a stronger acid than sulfuric acid, nitric acid and hydrochloric acid. It is a powerful oxidizer when hot, but aqueous sol ...

References

Perchlorates Magnesium compounds {{inorganic-compound-stub