Graphite and Its Chemical Formula
Graphite, like diamond and carbon nanotubes, is an allotrope of carbon. The chemical formula of graphite is C. C is in group 14 of the periodic table. It comprises carbon atoms layered structure with a hexagonal planar network structure and is a non-metallic mineral. These layers can easily slide over one another, making the graphite highly lubricated.
Graphite has two packing forms: one is a hexagonal crystal system, and the other is an orthorhombic crystal system. The orthorhombic crystal system accounts for 20%-30% of natural graphite, and it will become a hexagonal crystal system after being treated at a high temperature of 3000 degrees Celsius. Scientists believe no such thing as substantially graphitic crystals with the ideal structure exists.
Physical Properties of Graphite
The color of graphite is dark gray, and the material is fine, soft, and greasy. The hardness is 1-2, and the specific gravity is 1.9-2.3. Under isolating oxygen, its melting point is above 3000 degrees Celsius, one of the most temperature-resistant minerals.
Furthermore, its layered structure leads to unique physical properties. Weak van der Waals forces hold the carbon layers together, allowing them to slide over each other easily. This characteristic makes graphite an effective lubricant. Moreover, it is also known for its high melting point and good thermal stability, attributable to the strong covalent bonds within the carbon layers.
Electrical and Thermal Conductivity
Graphite’s electrical conductivity is derived from its unique crystal structure. Composed of hexagonal layers, each carbon atom within graphite is covalently linked to three others. The fourth outer-shell electron of each carbon atom is free to move along the layers, forming a “sea” of delocalized electrons. These electrons are integral to its high electrical conductivity, enabling an effective electricity transmission upon applying voltage.
Similarly, its unique structure is responsible for its notable thermal conductivity. The systematic and hexagonal layering of carbon atoms facilitates an effective transfer of heat energy through the vibrations of these atoms. This phenomenon, phonon conduction, is responsible for its excellent heat conduction properties.
Notably, the thermal conductivity of graphite is anisotropic, which means it varies with the direction of heat flow. It exhibits high thermal conductivity parallel to the layers, owing to the tightly packed carbon atoms and efficient phonon conduction. Conversely, thermal conductivity is relatively low perpendicular to the layers due to the wider spacing between these layers and lesser atomic interactions.
Uses of Graphite
From Pencils to Batteries
The vast array of graphite’s applications can be traced back to its chemical structure. Its ability to act as a lubricant is why it’s used in pencils – the layers of carbon slide over the paper, leaving a trail of carbon (the pencil mark). In electronics, its conductivity leads to its use in batteries and as electrodes.
High-End Industrial and Technological Uses
Graphite’s high-temperature stability and corrosion resistance have given it special use in industrial applications, such as manufacturing steel and other metals or alloys. In technology, it is used in heat sinks to dissipate heat from electronic components. Even in the field of nuclear energy, it is used as a neutron moderator in some types of nuclear reactors.
Graphite is a unique form of carbon, Its chemical formula, C, signifies its composition, with each carbon atom bonded to three others in a hexagonal lattice structure. This arrangement grants graphite exceptional properties, such as its lubricity, electrical conductivity, and thermal stability. Knowing the chemical formula of graphite helps to understand its molecular structure and highlights its importance in metallurgy, the chemical industry, electronics, energy storage， and other industrial fields. By delving into the chemical composition of graphite, we gain a deeper appreciation for this remarkable substance and its diverse range of uses.