Silica amorphous helical

Amorphous helical silica nanosprings, 80-140nm in diameter, up to 8 microns in length Asymmetric Yes (Fe) Chemical vapor deposition technique [22]... 

Crystalline silica can exist as quartz, cristobalite, and tridymite, with quartz being the form most commonly used in adsorption studies. Many studies also use amorphous silicon oxides. The quartz crystal consists of silica tetrahedra with die silicon ions located in the center and the oiq gen ions located at the comers. The tetrahedra are arranged to form interlinked helical chains [5]. The different forms of quartz are distinguished by the differences between the angles formed by the Si—O—Si bond, with the a-form being the most common. 

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