Magnesium arsenic reduces its corrosion rate in a salt solution by a factor of nearly ten. Research showed that magnesium's tendency to creep at high-temperatures is eliminated by the addition of scandium and gadolinium. Flammability is greatly reduced by a small amount of calcium in the alloy. Magnesium forms a variety of compounds important to industry and biology, including magnesium carbonate, magnesium chloride, magnesium citrate, magnesium hydroxide (milk of magnesia), magnesium oxide, magnesium sulfate, and magnesium sulfate heptahydrate (Epsom salts). Magnesium has three stable isotopes: , and . All are present in significant amounts (see table of isotopes above). About 79%
Magnesium oxychloride at about 23 °C, the completely liquid region has vertices at the following triple equilibrium points (as mass fractions, not molar fractions): The other vertices are pure water, magnesium chloride hexahydrate, and the saturated solution (0.0044 MgO + 0.9956 by mass). The anhydrous forms decompose when heated above 450-500 °C by decomposition of the hydroxide and chloride anions, releasing water and hydrogen chloride and leaving a magnesium oxide residue, by the reactions: Extended exposure of magnesium oxychlorides to water leaches out the soluble , leaving hydrated brucite . On exposure to the atmosphere, the oxychlorides will slowly react with carbon