What is the Difference Between Diamond and Graphite?

Diamond and graphite are both composed of carbon, but they have distinct physical properties due to their different crystal structures. The main differences between diamond and graphite are:

1. Crystal Structure: Diamond has a tetrahedral structure, where each carbon atom is bonded to four other carbon atoms. In contrast, graphite has a layered structure, where each carbon atom is bonded to three other carbon atoms, forming sheets of carbon atoms.
2. Hardness: Diamond is the hardest known natural substance, with a hardness of 10 on the Mohs Hardness Scale. Graphite, on the other hand, is very soft and has a hardness of 1 to 2 on the Mohs scale.
3. Transparency: Diamond is transparent and brilliant, while graphite is opaque and metallic- to earthy-looking.
4. Electrical Conductivity: Graphite can conduct electricity due to the planar structure that allows electrons to move easily within the planes. In contrast, diamond does not conduct electricity at all.
5. Lubrication: Graphite can be used as a lubricant or in pencils because the layers can cleave readily, making it soft and slippery. Diamond, due to its strong, rigid structure, cannot be used for these purposes.
6. Density: Graphite has a lower density (2.266 grams per cubic centimeter) than diamond.

These differences in properties arise from the distinct arrangements of carbon atoms in the two structures, leading to the unique characteristics of each material.

Comparative Table: Diamond vs Graphite

Here is a table summarizing the differences between diamond and graphite:

These differences in properties arise from the distinct arrangements of carbon atoms in the two allotropes. In diamond, each carbon atom is covalently bonded to four others, creating a strong, three-dimensional structure. In contrast, graphite has a layered structure with each carbon atom bonded to only three others, allowing the layers to slide past each other and giving graphite its softness and electrical conductivity.