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 carbonate ammonia. All forms of magnesium carbonate react in acids. Magnesium carbonate crystallizes in the calcite structure where in Mg is surrounded by six oxygen atoms. The dihydrate one has a triclinic structure, while the trihydrate has a monoclinic structure. References to 'light' and 'heavy' magnesium carbonates actually refer to the magnesium hydroxy carbonates hydromagnesite and dypingite (respectively). Magnesium carbonate is ordinarily obtained by mining the mineral magnesite. Seventy percent of the world's supply is mined and prepared in China. Magnesium carbonate can be prepared in laboratory by reaction between any soluble magnesium salt and sodium bicarbonate: If magnesium chloride (or