Silicates (also known as phyllosilicates) are formed in a process similar to chain silicates
. Three of the four oxygens are shared with other tetrahedra: only the upper
oxygens remain charged and not connected to a Silicon atom.
Sheet silicates tend to follow their namesake
and form sheets or layers
of minerals. This gives very strong intramolecular
bonds, but extremely weak intermolecular
bonds. The bonds between molecules in a sheet silicate are a very good representation of Van Der Waals forces
Muscovite or any of the micas.
For more general information, see silicon tetrahedra.