Boron nitride and graphite are important crystalline materials. They have different atomic compositions, which results in different chemical and physical properties.
What is Boron Nitride?
Boron nitride is a diatomic compound having the chemical formula BN. It is a thermally and chemically resistant, refractory material. There are several different structures of boron nitride that are isoelectronic to carbon lattice. Among them, the most common and stable form is the hexagonal form that corresponds to the graphite structure. And, this form is very useful in manufacturing lubricants and cosmetic products.
The softest polymorph of boron nitride is the hexagonal form. The cubic form resembles the structure of diamonds, but it is softer than diamonds. However, the stability of this form is superior to that of the diamond. Due to the excellent thermal and chemical stability of all boron nitride structures, this material is used mainly as ceramics in high-temperature equipment. Boron nitride usually appears as colourless crystals, and this material is insoluble in water. It can undergo sublimation upon heating.
What is Graphite?
Graphite is an allotrope of carbon that has a stable, crystalline structure. It is a form of coal. Moreover, it is a native mineral (native minerals are substances containing one chemical element that occurs in nature without combining with any other element). Furthermore, graphite is the most stable form of carbon that occurs at standard temperature and pressure. The repeating unit of the graphite allotrope is a carbon (C). When considering the crystal structure of graphite, it has a hexagonal crystal system. The appearance of this material can be defined as iron-black to steel-grey colour, and it has a metallic lustre as well. The streak colour of graphite is black (the colour of the finely powdered mineral).
Graphite has a honeycomb lattice. There are graphene sheets separated at a 0.335 nm distance. In the lattice structure of graphite, the distance between carbon atoms is 0.142 nm distance. These carbon atoms bind with each other via covalent bonds, one carbon atom having three covalent bonds around it. The valency of a carbon atom is 4; thus, there is a fourth unoccupied electron in each and every carbon atom of this structure. Therefore, this electron is free to migrate, making graphite electrically conductive. Natural graphite is useful in refractories, batteries, steelmaking, expanded graphite, brake linings, foundry facings and lubricants.
What is the Difference Between Boron Nitride and Graphite?
The key difference between boron nitride and graphite is that boron nitride is composed of boron and nitrogen atoms, whereas graphite contains carbon atoms. Moreover, boron nitride is an excellent thermal and chemical resistant refractory material while graphite has excellent electrical conductivity.
The following table summarizes the difference between boron nitride and graphite.
Summary – Boron Nitride vs Graphite
Boron nitride and graphite are important crystalline materials. They have different atomic compositions, thus, different chemical and physical properties. The key difference between boron nitride and graphite is that boron nitride is composed of boron and nitrogen atoms, whereas graphite contains carbon atoms.
1. “Boron nitride” By Akeramop – Own work using ACD/ChemSketch; transferred from el.wikipedia; transferred to Commons by User:MARKELLOS using CommonsHelper (Public Domain) via Commons Wikimedia
2. “Graphite” By James St. John (CC BY 2.0) via Flickr