Magnesium sulfide reacts with oxygen to form the corresponding sulfate, magnesium sulfate. MgS reacts with water to give hydrogen sulfide and magnesium hydroxide. In the BOS steelmaking process, sulfur is the first element to be removed. Sulfur is removed from the impure blast furnace iron by the addition of several hundred kilograms of magnesium powder by a lance. Magnesium sulfide is formed, which then floats on the molten iron and is removed. MgS is a wide band-gap direct semiconductor of interest as a blue-green emitter, a property that has been known since the early 1900s. The wide-band gap property also allows the
Magnesium carbonate sulfate) is treated with aqueous sodium carbonate, a precipitate of basic magnesium carbonate—a hydrated complex of magnesium carbonate and magnesium hydroxide—rather than magnesium carbonate itself is formed: High purity industrial routes include a path through magnesium bicarbonate, which can be formed by combining a slurry of magnesium hydroxide and carbon dioxide at high pressure and moderate temperature. The bicarbonate is then vacuum dried, causing it to lose carbon dioxide and a molecule of water: Like many common group 2 metal carbonates, magnesium carbonate reacts with aqueous acids to release carbon dioxide and water: At high temperatures MgCO decomposes to magnesium