---
title: "A student compares the structures and conductivities of three carbon allotropes. In a solid, electrical current requires mobile charged particles, whereas thermal energy can be transferred by mobile electrons or by vibrations transmitted through a bonded lattice.  | Allotrope | Simplified bonding model | Electrical conductivity | Thermal conductivity | |—|—|—|—| | Diamond | Each \\(\\text{C}\\) atom forms \\(4\\) localized \\(\\sigma\\) bonds in a continuous network. | Very low | High throughout the crystal | | Graphene | Each \\(\\text{C}\\) atom forms \\(3\\) localized \\(\\sigma\\) bonds in a planar sheet, and the remaining valence electrons form a delocalized \\(\\pi\\) system within the sheet. | High along the sheet | High along the sheet | | Graphite | Graphene-like sheets are stacked with weak attractions between sheets; the \\(\\pi\\) electrons are delocalized primarily within each sheet. | High parallel to the sheets and much lower perpendicular to the sheets | High parallel to the sheets and lower perpendicular to the sheets |  Which of the following statements best accounts for the conductivity data?"
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url: "https://nerd-notes.com/ubq/120035/"
date_modified: "2026-08-21T08:40:44+00:00"
---

# A student compares the structures and conductivities of three carbon allotropes. In a solid, electrical current requires mobile charged particles, whereas thermal energy can be transferred by mobile electrons or by vibrations transmitted through a bonded lattice.

| Allotrope | Simplified bonding model | Electrical conductivity | Thermal conductivity |
|—|—|—|—|
| Diamond | Each \(\text{C}\) atom forms \(4\) localized \(\sigma\) bonds in a continuous network. | Very low | High throughout the crystal |
| Graphene | Each \(\text{C}\) atom forms \(3\) localized \(\sigma\) bonds in a planar sheet, and the remaining valence electrons form a delocalized \(\pi\) system within the sheet. | High along the sheet | High along the sheet |
| Graphite | Graphene-like sheets are stacked with weak attractions between sheets; the \(\pi\) electrons are delocalized primarily within each sheet. | High parallel to the sheets and much lower perpendicular to the sheets | High parallel to the sheets and lower perpendicular to the sheets |

Which of the following statements best accounts for the conductivity data?

A student compares the structures and conductivities of three carbon allotropes. In a solid, electrical current requires mobile charged particles, whereas thermal energy can be transferred by mobile electrons or by vibrations transmitted through a bonded lattice.

| Allotrope | Simplified bonding model | Electrical conductivity | Thermal conductivity |
|---|---|---|---|
| Diamond | Each \(\text{C}\) atom forms \(4\) localized \(\sigma\) bonds in a continuous network. | Very low | High throughout the crystal |
| Graphene | Each \(\text{C}\) atom forms \(3\) localized \(\sigma\) bonds in a planar sheet, and the remaining valence electrons form a delocalized \(\pi\) system within the sheet. | High along the sheet | High along the sheet |
| Graphite | Graphene-like sheets are stacked with weak attractions between sheets; the \(\pi\) electrons are delocalized primarily within each sheet. | High parallel to the sheets and much lower perpendicular to the sheets | High parallel to the sheets and lower perpendicular to the sheets |

Which of the following statements best accounts for the conductivity data?

- **A.** Diamond should conduct electrical current nearly as well as it conducts heat, because its continuous network of strong \(\text{C}-\text{C}\) bonds provides paths for both delocalized electrons and lattice vibrations to travel through the crystal.
- **B.** Graphite should conduct electrical current nearly equally parallel and perpendicular to its sheets, because stacking the sheets creates a delocalized \(\pi\) system that extends throughout the entire graphite crystal.
- **C.** Graphene and graphite conduct electrical current more readily than diamond, and diamond conducts heat well because electrons hop among its localized \(\sigma\) bonds; therefore, mobile electrons are the principal carriers of both electrical and thermal energy in each allotrope.
- **D.** Graphene and graphite conduct electrical current readily within their sheets because delocalized \(\pi\) electrons act as mobile charge carriers, whereas diamond's electrons remain localized. Diamond can still conduct heat effectively because lattice vibrations pass through its strong bonded network, and weak coupling between graphite's sheets limits transfer perpendicular to them.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/120035/*