Synthetic magnesium silicate Synthetic magnesium silicate Synthetic magnesium silicates are white, odorless, finely divided powders formed by the precipitation reaction of water-soluble sodium silicate (water glass) and a water-soluble magnesium salt such as magnesium chloride, magnesium nitrate or magnesium sulfate. The composition of the precipitate depends on the ratio of the components in the reaction medium, the addition of the correcting substances, and the way in which they are precipitated. The molecular formula is typically written as MgO:XSiO, where X denotes the average mole ratio of SiO to MgO. The product is hydrated and the formula is sometimes written MgO:XSiO•HO to show 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