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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 synthetic product.
The mass-to-charge ratio (m/Q) is a physical quantity relating the mass (quantity of matter) and the electric charge of a given particle, expressed in units of kilograms per coulomb (kg/C). It is most widely used in the electrodynamics of charged particles , e.g. in electron optics and ion optics .
In silicon (Si) the electron mobility is of the order of 1,000, in germanium around 4,000, and in gallium arsenide up to 10,000 cm 2 /(V⋅s). Hole mobilities are generally lower and range from around 100 cm 2 /(V⋅s) in gallium arsenide, to 450 in silicon, and 2,000 in germanium.
The process first forms silicon metal and magnesium oxide, and, if an excess of SiO 2 is used, then elemental silicon is formed: 2 Mg + SiO 2 → 2 MgO + Si. If an excess of Mg is present, Mg 2 Si is formed from the reaction of the remaining magnesium with the silicon: 2 Mg + Si → Mg 2 Si. These reactions proceed exothermically, [4] even ...
Silica gel is an amorphous and porous form of silicon dioxide (silica), consisting of an irregular tridimensional framework of alternating silicon and oxygen atoms with nanometer-scale voids and pores. The voids may contain water or some other liquids, or may be filled by gas or vacuum.
Silicon tetrachloride is manufactured on a huge scale as a precursor to the production of pure silicon, silicon dioxide, and some silicon esters. [11] The silicon tetrahalides hydrolyse readily in water, unlike the carbon tetrahalides, again because of the larger size of the silicon atom rendering it more open to nucleophilic attack and the ...
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.
2.4 Silicon Dioxide production. 3 Safety. 4 See also. ... Molar mass: 154.279 g·mol −1 Appearance ... The most common potassium silicate has the formula K 2 SiO 3, ...