L1 /
12
CH3041
SILICATES I
• Quartz has the empirical formula SiO2.
• A form of silica.
• O
/ Si ratio = 2: 1
• Bonding is by the
3-D interconnection
of SiO44- tetrahedra.
3-D interconnection
of SiO44- tetrahedra.
Network (framework)
Silicates
Aluminosilicates
• O / Si ratio > 2
• Network
interconnected SiO44- tetrahedra
• Some Si4+ (tetrahedral
sites) substituted by
Al3+ Þ net -ve charge. ie. AlO4-5
Al3+ Þ net -ve charge. ie. AlO4-5
