Magnesium sulfate decomposes into magnesium oxide (MgO) and sulfur trioxide (SO). The heptahydrate can be prepared by neutralizing sulfuric acid with magnesium carbonate or oxide, but it is usually obtained directly from natural sources. It is on the WHO Model List of Essential Medicines, the most important medications needed in a basic health system. Magnesium sulfate is a common mineral pharmaceutical preparation of magnesium, commonly known as Epsom salt, used both externally and internally. Magnesium sulfate is highly water-soluble and solubility is inhibited with lipids typically used in lotions. Lotions often employ the use of emulsions or suspensions to include both oil
Magnesium oxychloride It can be prepared by calcination of magnesium hydroxycarbonate ·4 at about 600 °C. (Higher temperatures increase particle size leading to lower reaction rate.) It is believed that, during the reaction, the magnesium oxide is continuously hydrated and dissolved, helped by the slightly acidic character of the magnesium chloride solution. The acidity is attributed to hydrolysis of the magnesium hexahydrate cations: The protons (which are actually hydrated, e.g. as ) make the solution acidic; the pH varies from 6.5 to 4.7 as the concentration of increases from 30% to 70% (weight basis). The protons then react with and dissolve the