silice cristalline

CONT: La silice ou dioxyde de silicium (formule moléculaire : SiO[indice 2]) peut exister sous forme de silice cristalline ou de silice amorphe. La silice cristalline, peut se présenter sous plusieurs formes (polymorphes : même formule chimique mais structure cristalline différente). Le quartz (CAS : 14808-60-7) [...] La cristobalite (CAS : 14464-46-1) [...] Le tripoli (CAS : 1317-95-9) [et la] tridymite (CAS : 15468-32-3) [...]
OBS: Formules chimiques : O[indice 2]Si ou SiO[indice 2]

CONT: Crystalline silica is the scientific name for a group of minerals composed of silicon and oxygen. The term crystalline refers to the fact that the oxygen and silicon atoms are arranged in a three dimensional repeating pattern. ... Because oxygen is the most abundant element in the Earth's crust and silicon is the second most abundant, the formation of silica is quite common in nature. … quartz, … is the most common form of silica found in nature. Silica can also be biological in origin, produced by tiny organisms. The most significant of these are diatoms (plants) and radiolarians (animals) ... Thus, silica can be found in more than one state—amorphous as in the remains from a diatom and crystalline as in a quartz crystal … Both are SiO[subscript 2], but they are quite different physically.
CONT: Crystalline silica is a basic component of soil, sand, granite, and many other minerals. Quartz is the most common form of crystalline silica. Cristobalite and tridymite are two other forms of crystalline silica. All three forms may become respirable size particles when workers chip, cut, drill, or grind objects that contain crystalline silica.
OBS: Chemical formulas: O[subscript 2]Si or SiO[subscript 2]