Graphene is a semi-metal or zero-gap semiconductor, allowing it to display high electron mobility at room temperature. Graphene is an exciting new class of material whose unique properties make it the subject of ongoing research in many laboratories. Amorphous carbon refers to carbon that does not have a crystalline structure.
Even though amorphous carbon can be manufactured, there still exist some microscopic crystals of graphite-like or diamond-like carbon. The properties of amorphous carbon depend on the ratio of sp 2 to sp 3 hybridized bonds present in the material. Graphite consists purely of sp 2 hybridized bonds, whereas diamond consists purely of sp 3 hybridized bonds. Materials that are high in sp 3 hybridized bonds are referred to as tetrahedral amorphous carbon owing to the tetrahedral shape formed by sp 3 hybridized bonds , or diamond-like carbon owing to the similarity of many of its physical properties to those of diamond.
Carbon nanomaterials make up another class of carbon allotropes. Fullerenes also called buckyballs are molecules of varying sizes composed entirely of carbon that take on the form of hollow spheres, ellipsoids, or tubes. Buckyballs and buckytubes have been the subject of intense research, both because of their unique chemistry and for their technological applications, especially in materials science, electronics, and nanotechnology.
Carbon nanotubes are cylindrical carbon molecules that exhibit extraordinary strength and unique electrical properties and are efficient conductors of heat. Nanobuds therefore exhibit properties of both nanotubes and fullerenes.
Glassy or vitreous carbon is a class of carbon widely used as an electrode material in electrochemistry as well as in prosthetic devices and high-temperature crucibles. Its most important properties are high temperature resistance, hardness, low density, low electrical resistance, low friction, low thermal resistance, extreme resistance to chemical attack, and impermeability to gases and liquids.
They have a wide range of sizes that depends upon the of C atoms. Notify me of followup comments via e-mail. Skip to content. Coal, graphite, diamond, and other carbon allotropes Home Days of Science Coal, graphite, diamond, and other carbon allotropes. December 25, December 26, Term details.
Chemistry Matter Elements. Apr 16, Because it is a possible structure that carbon can form into. Explanation: An allotrope is a structure that an element can form into. Related questions What periodic table elements are radioactive? How can the periodic table be used to predict the properties of the elements? Miriam Rossi, a professor of chemistry at Vassar College, provides the following explanation:.
Both diamond and graphite are made entirely out of carbon, as is the more recently discovered buckminsterfullerene a discrete soccer-ball-shaped molecule containing carbon 60 atoms.
The way the carbon atoms are arranged in space, however, is different for the three materials, making them allotropes of carbon. The differing properties of carbon and diamond arise from their distinct crystal structures. In a diamond, the carbon atoms are arranged tetrahedrally. Each carbon atom is attached to four other carbon atoms 1. It is a strong, rigid three-dimensional structure that results in an infinite network of atoms.
This accounts for diamond's hardness, extraordinary strength and durability and gives diamond a higher density than graphite 3. Because of its tetrahedral structure, diamond also shows a great resistance to compression. The hardness of a crystal is measured on a scale, devised by Friederich Mohs, which ranks compounds according to their ability to scratch one another. Diamond will scratch all other materials and is the hardest material known designated as 10 on the Mohs scale.
It is the best conductor of heat that we know, conducting up to five times the amount that copper does.
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