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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. In the last case, the material is properly called silica ...
Fused quartz, fused silica or quartz glass is a glass consisting of almost pure silica (silicon dioxide, SiO 2) in amorphous (non- crystalline) form. This differs from all other commercial glasses, such as soda-lime glass, lead glass, or borosilicate glass, in which other ingredients are added which change the glasses' optical and physical ...
Precipitated silica. 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.
Silicon dioxide is a relatively inert material (hence its widespread occurrence as a mineral). Silica is often used as inert containers for chemical reactions. At high temperatures, it is converted to silicon by reduction with carbon.
Santa Barbara Amorphous-15. SBA-15, an acronym for Santa Barbara Amorphous-15, is a silica-based ordered mesoporous material that was first synthesized by researchers at the university of California Santa Barbra in 1998. [1] This material proved important for scientists in various fields such as material sciences, [2] drug delivery, [3 ...
Colloidal silicas are most often prepared in a multi-step process where an alkali-silicate solution is partially neutralized, leading to the formation of silica nuclei. The subunits of colloidal silica particles are typically in the range of 1 to 5 nm. Whether or not these subunits are joined depends on the conditions of polymerization.
Stöber process. The Stöber process is a chemical process used to prepare silica (SiO. 2) particles [1] of controllable and uniform size [2] for applications in materials science. It was pioneering [3] when it was reported by Werner Stöber and his team in 1968, [1] and remains today the most widely used wet chemistry synthetic approach to ...
Stishovite may also be synthesized by duplicating these conditions in the laboratory, either isostatically or through shock (see shocked quartz). [12] At 4.287 g/cm 3, it is the second densest polymorph of silica, after seifertite. It has tetragonal crystal symmetry, P4 2 /mnm, No. 136, Pearson symbol tP6. [13]