water is a mineral present in igneous rocks, calculating the amount of molecules it takes to prepare 513 g. Its chemical formula is Ca (Mg, Fe, Al) Si2O6 Ca=40, Mg=24, Fe=56, Al=27, Si=28, O=16
Answers
Answer: The single chain silicates have a basic structural unit consisting of linked SiO4 tetrahedra that each share 2 of their oxygens in such a way as to build long chains of SiO4. The basic structural group is thus Si2O6 with an Si:O ratio of 1:3. The most important inosilicates are the pyroxenes. These have a general structural formula of:
XYZ2O6
where X = Na+, Ca+2, Mn+2, Fe+2, or Mg+2 filling octahedral sites called M2
Y = Mn+2, Fe+2, Mg+2 , Al+3, Cr+3, or Ti+4 filling smaller octahedral sites called M1
Z = Si+4 or Al+3 in tetrahedral coordination.
The pyroxenes can be divided into several groups based on chemistry and crystallography:
Orthorhombic Pyroxenes (Orthopyroxenes - Opx)
These consist of a range of compositions between enstatite - MgSiO3 and ferrosilite - FeSiO3
Monoclinic Pyroxenes (Clinopyroxenes - Cpx)
The Diopside- Hedenbergite series - Diopside (CaMgSi2O6) - Ferrohedenbergite (CaFeSi2O6)
The Sodic Pyroxenes - Jadeite (NaAlSi2O6) and Aegerine (NaFe+3Si2O6)
Augite is closely related to the diopside - Hedenbergite series with addition of Al and minor Na substitution - (Ca,Na)(Mg,Fe,Al)(Si,Al)2O6
Pigeonite is also a monoclinic pyroxene with a composition similar to the orthopyroxenes with more Ca substituting for Fe, and Mg.