Search results
Results from the WOW.Com Content Network
In mineralogy, silica (silicon dioxide, SiO 2) is usually considered a silicate mineral rather than an oxide mineral. Silica is found in nature as the mineral quartz , and its polymorphs . On Earth, a wide variety of silicate minerals occur in an even wider range of combinations as a result of the processes that have been forming and re-working ...
Silylation is the introduction of one or more (usually) substituted silyl groups (R 3 Si) to a molecule. Silylations are core methods for production of organosilicon chemistry.
At very high pressure, such as exists in the majority of the Earth's rock, even SiO 2 adopts the six-coordinated octahedral geometry in the mineral stishovite, a dense polymorph of silica found in the lower mantle of the Earth and also formed by shock during meteorite impacts.
The grouping of the New Dana Classification and of the mindat.org is similar only, and so this classification is an overview only. Consistency is missing too on the group name endings (group, subgroup, series) between New Dana Classification and mindat.org. Category, class and supergroup name endings are used as layout tools in the list as well.
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula SiO 2, commonly found in nature as quartz. [5] [6] In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundant families of materials, existing as a compound of several minerals and as a
Hydrated silica is a form of silicon dioxide, which has a variable amount of water in the formula. When dissolved in water, it is usually known as silicic acid . It is found in nature as opal [ 2 ] (which has been mined as a gemstone for centuries), and in the cell walls of diatoms .
The silica cycle plays an important role in long term global climate regulation. The global silica cycle also has large effects on the global carbon cycle through the carbonate-silicate cycle. [43] The process of silicate mineral weathering transfers atmospheric CO 2 to the hydrologic cycle through the chemical reaction displayed above. [4]
Precipitated silica is an amorphous form of silica (silicon dioxide, SiO 2); it is a white, powdery material. Precipitated silica is produced by precipitation from a solution containing silicate salts. The three main classes of amorphous silica are pyrogenic silica, precipitated silica and silica gel.