Search results
Results from the WOW.Com Content Network
The molecular SiO 2 has a linear structure like CO 2. It has been produced by combining silicon monoxide (SiO) with oxygen in an argon matrix. 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 ...
Silicate anions ([SiO 2+n] 2n−) are invariably colorless, or when crushed to a fine powder, white. The colors of silicate minerals arise from the metal component, commonly iron. The colors of silicate minerals arise from the metal component, commonly iron.
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 O) x · SiO 2 + x H 2 O. Sodium silicates can also be obtained by dissolving silica SiO 2 (whose melting point is 1713 °C) in molten sodium carbonate (that melts with decomposition at 851 °C): [17] x Na 2 CO 3 + SiO 2 → (Na 2 O) x · SiO 2 + CO 2. The material can be obtained also from sodium sulfate (melting point 884 °C) with carbon as ...
Structure of the orthosilicate anion SiO 4− 4. A silicate is any member of a family of polyatomic anions consisting of silicon and oxygen, usually with the general formula [SiO (4-2x)− 4−x] 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 ...
3 SiO 2 + 4 H 2 O → H 8 Si 3 O 10 4 SiO 2 + 1 H 2 O → H 2 Si 4 O 9 Hydrated silicas exhibit a trend of decreasing bonded water molecules as the crystallinity of the silica molecule increases, with microcrystalline quartz's typically containing the least water content and macrocrystaline quartz having negligible water.
The exhibited hydrophobicity is a result of the chemical reaction occurring between the silica particles and the TMCS. When the original SiO 2-OH groups are replaced with hydrolytically stable Si(CH 3) groups, this hydrophobicity occurs due to the prevention of the silica particles from interacting with water. [8]
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.