What are molecular solids ? Explain the types of molecular solids.

Explanation

Molecular solids `:` In molecular solids, the constituents are neutral molecules. They are held together by weak vander Waals forces. Genergally molecular solids are soft and they do not conduct electricity. These molecular solids are further classified into three types .
(i) Non - polar molecular solids `:`
( a) In non-polar molecular solids constituent molecules are held together by weak dispersion force or London forces.
(b) They have low melting points and are usually in liquids or gaseous state at room temperature.
Ex `:` Naphthalene, anthreacene etc.,
(ii) Polar molecular solids `:`
(a) The constituents are molecules formed by polar covalent bonds.
(b) They are held together by relatively strong dipole-dipole interactions .
(c ) They have higher melting points than the nonpolar molecular solids.
Ex `:` Solid `CO_(2)` , solid `NH_(3)` etc.

(iii) Hydrogen bonded molecular solids `:`
( a) The constituents are held together by hydrogen bonds.
( b ) They are generally soft slids under room temperature.
(c ) Examples `:` solid ice `( H_(2)O)` , glucose, urea etc.