Which of the following best explains why diamond is extremely hard whereas graphite…
CHEMISTRY · Single correct · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
Which of the following best explains why diamond is extremely hard whereas graphite is soft enough to serve as a dry lubricant?
(a) Diamond contains ionic C–C bonds formed by complete electron transfer, whereas graphite contains purely covalent C–C bonds.
(b) All of diamond's valence electrons are delocalized throughout the lattice, markedly strengthening bonding; graphite lacks such electron delocalization.
(c) Diamond possesses a three-dimensional network of strong σ bonds, whereas in graphite the strong covalent bonds are restricted to individual planar sheets separated by weak intermolecular forces.
(d) Diamond's hardness arises from very strong London dispersion forces within its lattice, whereas only weak dispersion forces act between the layers in graphite.