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
Hydrated silica an odourless, tasteless, white, gelatinous substance, which is chemically inert. Chemical Formula: SiO · HO Diatomaceous earth, originally mined as "tooth powder" is a naturally occurring hydrated silica. As a fine gel abrasive, frequently combined with softer calcium carbonate (from chalk) it helps to remove plaque. Milled to a slightly larger size, the grains are more aggressive and are used in tooth bleaching formulations. It also has synergetic effects when compounded with traditional flame retardants such as magnesium hydroxide and aluminium hydroxide. Hydrated silica is listed by the US Food and Drug Administration as "Generally Recognized as Safe". Toothpaste: Chemistry: