Allotropes Of Carbon

Allotropes are different structural forms of the same element, and their properties depend on how the atoms are bonded. In graphite, each carbon atom is sp^2 hybridised and bonded to three others within flat hexagonal layers, leaving one electron per atom delocalised over the layer. These delocalised electrons are free to move along the layers, so graphite conducts electricity, making it useful as an electrode. Diamond, by contrast, has each carbon sp^3 hybridised and bonded to four others in a rigid three-dimensional network with no free electrons, so it is an electrical insulator. Fullerene conducts only under special conditions and is not the standard conducting allotrope. Amorphous carbon lacks the ordered conducting layers of graphite. The structure-property relationship of carbon allotropes is a standard NCERT topic. Plausibility check: graphite is used in electrodes and as a lubricant precisely because of its mobile delocalised electrons and layered slipping planes, confirming its conductivity.