Question

write the characters of Covalent network crystals​

Answer 1

Explanation:

Covalent (or network) solids are extended-lattice compounds, in which each atom is covalently bonded to its nearest neighbors. Because there are no delocalized electrons, covalent solids do not conduct electricity.

The rearranging or breaking of covalent bonds requires large amounts of energy; therefore, covalent solids have high melting points.

Covalent bonds are extremely strong, so covalent solids are very hard. Generally, covalent solids are insoluble due to the difficulty of solvating very large molecules.

Diamond is the hardest material known, while cubic boron nitride (BN) is the second-hardest. Silicon carbide (SiC) is very structurally complex and has at least 70 crystalline forms.

Answer 2

Answer : -

Characteristics of covalent network crystals are as follows :

i. The constituent particles in covalent network solids are atoms.

ii. The atoms in these crystals are linked by a continous system of covalent bonds. The result is a rigid three dimensional network that forms a giant molecule. The entire crystal is a single molecule.

iii. As a result of rigid and strongly bonded structure, covalent network crystals are very hard. In fact they are the hardest and most incompressible of all the materials. These crystals have high melting and boiling points.

iv. The electrons are localised in covalent bonds and hence are not mobile. As a result, covalent solids are poor conductors of heat and electricity.

For example : diamond, quartz (SiO_2), boron nitride, carborandum are covalent network solids