Question

The resistivity (a measure of electrical resistance) of graphite is (0.4 to $5.0)\times {10}^{-4}ohm\times cm$ in the basal plane. (The basal plane is the plane of the six-member rings of carbon atoms.) The resistivity is 0.2 to$1.0ohm\times cm$ along the axis perpendicular to the plane. The resistivity of diamond is${10}^{14}$ to${10}^{16}ohm\times cm$ and is independent of direction. How can you account for this behaviour in terms of the structures of graphite and diamond?

Short answer

The delocalized electrons are linked to resistivity. There are no delocalized electrons in diamond, thus the resistivity is highest in each layer. There are delocalized electrons in diamond, so the resistivity is lowest, and electron transfer between two layers is restricted but still possible.

Step-by-step solution

Definition of Delocalized electron

A delocalized electron is one that is not associated with any particular atom or covalent link in an atom, ion, or molecule. Instead of single and double bonds, delocalized electrons in a ring structure are represented by a circle.

Determine the behaviour in terms of the structure of graphite and diamond

• Graphite is made up of six layers that are represented as rings in planes. Because the localised electron model reveals delocalized electrons slightly below or above that plane, the smallest resistivity has a basal plane (through one layer), implying that electricity can easily be transferred through this layer (layer).
• Although electrons can be moved from one layer to another, the distance between them is too great for this to happen.
• As a result, the resistivity is larger than the resistivity of a single layer.
• Because there are no delocalized electrons in the tetrahedral Diamond structure, electron transport is nearly impossible, resulting in the highest resistance.
• The delocalized electrons are linked to resistivity. There are no delocalized electrons in diamond, thus the resistivity is highest in each layer.
• There are delocalized electrons in diamond, so the resistivity is lowest, and electron transfer between two layers is restricted but still possible.