Graphite

Graphite is one of the very common allotropes of carbon. It is also the most stable allotrope of carbon and thus used in electrochemistry as the standard state for defining the heat of formation of carbon compounds.  Graphite is a good conductor of heat and electricity with a density of 2.09–2.23 g/cm³. Graphite was accidentally synthesized by Edward G. Acheson for the first time when he was working on a high-temperature experiment on carborundum. He found that at around 4150⁰C, the silicon in the carborundum gets vaporized, whereas leaving behind the carbon in the graphitic form. He was granted the patent for the graphite manufacture in 1896, and then the commercial production of the graphite started in 1897. Graphite is not an element or a compound, it's an allotrope of carbon. It doesn’t have any chemical formula of its own. 

Structure of Graphite

Graphite is a big covalent structure with each carbon atom joined with three other carbon atoms with covalent bonds. Each carbon atom is sp² hybridized. These carbon atoms form a layer like structure with a hexagonal arrangement of carbon atoms. These layers have weak forces between them. Due to these weak forces, the layers can slip over each very easily. Each carbon atom has one non bonded electron, which becomes delocalized.

Properties of Graphite

1. Physical Properties of Graphite

• Graphite is a good conductor of electricity due to its free delocalized electron which is free to move throughout the sheets. 

• Graphite is insoluble in organic solvents and water, this is because the attraction between solvent molecules and carbon atoms is not strong enough to overcome the covalent bonds between the carbon atoms in the graphite.  

• Graphite has a high melting point of 3650⁰C near the melting point of Diamond. 

• Due to its layer-like structure, it is soft and slippery in nature.

• Graphite has the ability to absorb high-speed neutrons.

Important Chemical Reactions

Reaction with Air - Carbon in the form of Graphite, burns in the air to form Carbon Monoxide and carbon Dioxide depending upon the availability of air or oxygen.

\[C(s) + O_{2} \rightarrow CO_{2}(g)\]

\[2C(s) + O_{2}(g) \rightarrow 2CO(g)\]

Reaction with Water - Carbon in the form of Graphite doesn’t react with water in normal conditions.  Under certain circumstances, the given reaction becomes possible and forms water gas which is a mixture of carbon monoxide and hydrogen gas. 

\[C + H_{2}O \rightarrow CO + H_{2}\]

Types of Graphite

1. Natural Graphite

Natural Graphite, an excellent conductor of heat and electricity, is a mineral composed of graphitic carbon. It is stable over a range of temperatures, with the melting point of around 3650°C. There are three types of natural graphite.

• High crystalline

• Amorphous

• Flake

2. Synthetic Graphite

Synthetic graphite is produced from coke and pith. It is less crystalline in nature than the natural one. There are basically two types of synthetic graphites. The first one is electro graphite, pure carbon produced from coal tar pitch, and calcined petroleum coke in an electric furnace. The second one is synthetic graphite produced by heating calcined petroleum pitch to 2800⁰C.

Uses of Graphite

• Graphite is used in making pencil lead.

• Graphite is used in the nuclear reactor to control the nuclear fission reaction because of the ability of graphite to absorb fast-moving neutrons. 

• Due to the slippery nature of Graphite, it is used as a lubricant in the machine parts.

• Graphite is used as a conductor of heat and electricity in several processes due to its free electrons. 

• Graphite is used in high-temperature applications like in the production of phosphorus and calcium carbide.

• Graphite is used as an anode in aqueous electrolytic processes such as in the production of halogens.

• Graphite is used as an electrical material in the electric motor as a carbon brush.

• Due to its resistant nature towards chemicals and high melting temperatures, it is used to make crucibles.

• Graphite materials are used as the anode material for lithium-ion batteries.

Important Facts About Graphite

• Graphite word comes from the word “Graphene” which means to write or draw in ancient greek. 

• Graphite is the only non-metal that conducts electricity. This is due to the delocalized electron.  

• Graphite is really tough to melt. It does not have a melting point at atmospheric pressure.

• Most of the graphite used today is manufactured from coal in the electric furnace and not mined. 

• Pencil manufacturing is one of the important uses of graphite. In 2011, around 7 % of the total graphite was used to make pencils.

What is the Process of Making Graphite in a Lab?

Graphite is a composite of black metal that is used in many different industrial inductor processes and your pencil case. When we make graphite in the lab, we require some elements and fluids:

• Sucrose for about 10- 15 grams,

• Sulfuric acid of about 10 MLS of 18 molars,

• Sodium Bicarbonate for about 10- 20 grams, 

• 250 mil beaker, 

• stirring bowl rod, 

• 10 ml graduated cylinder and plastic zipper lock. 

Now first place 10 ml of 18 molars sulfuric acid in a 10-millilitre cylinder. Put 15 grams of sucrose in a 50 ml bucket. Now pour 10 MLS of punch chisel, Cassatt, into sucrose. It aroused vigorously. You will notice the reaction as things get darker and eventually darker. After some time the reaction subsides and the result is graphite.

What Do You Mean by Graphene?

Allotrope carbon, a single layer of graphite discovered in 2003. The structure of graphene includes something similar to a honeycomb. Graphene is not only one of the softest materials but also the strongest. The heat is conducted well in graphene which is better than any other material. It is a great electric conductor, it is optically transparent. The versatility of these amazing structures makes graphene perfect for a wide range of applications from electron ice to optics sensors and biodevices.

Applications of Graphite

• Chemical Industry - In the chemical field, graphite is used in many hot climates, such as in the production of phosphorus and calcium carbide in arc furnaces. Graphite is used as an anode in certain electrolytic processes in liquids such as halogen production (chlorine and fluorine).

• Nuclear Industry - Large quantities of high-purity electro graphite are used to produce presidential sticks and display components in nuclear reactors. The lowest absorption of neutrons leads to the building of suitability of electro graphite and high thermal conductivity, with high strength and high temperatures.

• Electricity Applications - The manufacture of carbon brushes in electric motors have incorporated a huge amount of graphite which is used as an electric material. Here, the service life of a component and performance depends largely on the distance and structure.

• Mechanical Applications - Graphite is widely used as an engineering material in all applications such as piston rings, thrust bearings, journal bearings, and vanes. Carbon-based seals are used in petrol pumps and on the engine walls of several aircraft engines.

Some General Facts About Graphite

• Allotropy or allotropes is the property of certain chemical elements that will be present in 2 or more different types, known as allotropes of these elements. Allotropes are various versions of the structure of the element. Carbon allotropes are graphite, diamond, and Florence.

• Carbon is a natural gas that holds heat but since the industrial revolution, there has been a lot of carbon dioxide in the atmosphere. People now have an unnatural influence on climate control. We burn too much fuel and use it for transportation. Deforestation is another human-caused phenomenon.

• The bond formed by the electron sharing between the elements is a joint bond.