Question

what is allotropes of carbon and silicon

Answer 1

the allotropes of carbon include diamond (the carbon atoms are bonded together in a tetrahedral lattice arrangement), graphite (the carbon atoms are bonded together in sheets of a hexagonal lattice), graphene (single sheets of graphite), and fullerenes (the carbon atoms are bonded together in spherical, ...

Answer 2

In crystallography crystals are described as isomorphous if they are closely similar in shape. Both carbon and silicon belong to same group. The C atom in diamond and Si atom in crystalline silicon is coordinated to 4 other atoms which results in tetrahedral structure which continues over a large range.