Write a short note on silicates.

Explanation

Silicates compounds are formed from the orthosilicic acid. All silicates have the basic structural unit `SiO_4^(4-)` which has tetrahedral structure.
When discrete `SiO_4^(4-)` unit is present in silicates they are called orthosilicates. Different sillicates are formed by joining a number of `SiO_4^(4-)` units through the corners of `SiO_4^(4-)` tehrahedron by sharing 1, 2, 3 or 4 oxygen atoms per silicate unit. Thus chain, ring, sheet or three dimensional silicates are formed depending on the number of oxygen atoms shared. Negative charge on the silicate is neutralised by the positive charged metal ions.