Which statement correctly describes the structure, bonding, and properties of the allotropes of carbon and silicon dioxide?
Buckminsterfullerene (C60\text{C}_{60}C60) has a higher melting point than diamond because its spherical molecules are held together by a dense network of covalent bonds.
In silicon dioxide (SiO2\text{SiO}_2SiO2), each silicon atom is bonded to two oxygen atoms by double covalent bonds, forming a simple molecular structure with low electrical conductivity.
Graphene is a single layer of graphite in which each carbon atom forms three σ\sigmaσ-bonds in a trigonal planar arrangement, leaving a delocalised π\piπ-system that allows electrical conduction.
Silicon has a giant metallic structure similar to graphite, allowing it to conduct electricity efficiently at room temperature.