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Silicalite is an inorganic compound with the formula SiO 2. It is one of several forms of silicon dioxide. It is a white solid. It consists of tetrahedral silicon centers and two-coordinate oxides. It is prepared by hydrothermal reaction using tetrapropylammonium hydroxide followed by calcining to remove residual ammonium salts.
The dimeric silicon dioxide, (SiO 2) 2 has been obtained by reacting O 2 with matrix isolated dimeric silicon monoxide, (Si 2 O 2). In dimeric silicon dioxide there are two oxygen atoms bridging between the silicon atoms with an Si–O–Si angle of 94° and bond length of 164.6 pm and the terminal Si–O bond length is 150.2 pm.
Two-dimensional silica (2D silica) is a layered polymorph of silicon dioxide. Two varieties of 2D silica, both of hexagonal crystal symmetry, have been grown so far on various metal substrates. One is based on SiO 4 tetrahedra, which are covalently bonded to the substrate.
Unlike other silica polymorphs, the crystal structure of stishovite resembles that of rutile (TiO 2). The silicon in stishovite adopts an octahedral coordination geometry, being bound to six oxides. Similarly, the oxides are three-connected, unlike low-pressure forms of SiO 2. In most silicates, silicon is tetrahedral, being bound to four ...
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 ...
n, where 0 ≤ x < 2. The family includes orthosilicate SiO 4− 4 ( x = 0 ), metasilicate SiO 2− 3 ( x = 1 ), and pyrosilicate Si 2 O 6− 7 ( x = 0.5 , n = 2 ). The name is also used for any salt of such anions, such as sodium metasilicate ; or any ester containing the corresponding chemical group , such as tetramethyl orthosilicate . [ 1 ]
The phosphorus atoms can be shared to form different patterns e.g. [Si 2 P 6] 10− which forms pairs, and [Si 3 P 7] 3− which contains two-dimensional double layer sheets. [1] SiP 4 ] 8− with isolated tetrahedra , and [SiP 2 ] 2− with a three dimensional network with shared tetrahedron corners. [ 2 ]
Silicon disulfide is the inorganic compound with the formula Si S 2. Like silicon dioxide, this material is polymeric, but it adopts a 1-dimensional structure quite different from the usual forms of SiO 2.