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CH3041
SILICATES III
O / Si ratio = 2:1
Isolated SiO44- tetrahedra,
Ionic bonding to cations
® charge neutrality
® charge neutrality
eg. Olivine
(forsterite)
Mg2+...SiO44-... Mg2+.
Mg2+...SiO44-... Mg2+.
O / Si ratio = 3:1
2
oxygens of SiO44- shared
eg. Pyroxene (enstatite)
MgSiO3
MgSiO3
Chain Silicates [SiO3]2-
Monomer Silicates [SiO4]4-
