2. • Because of its unique ability to
combine in many ways with
itself and other elements.
– Four valence electrons
– Makes it possible to arrange the
same number of atoms many
different ways
• Why does carbon
play a central
role in the
chemistry of
living organisms?
3. Carbon Atoms and Bonding
• Because of its unique ability to combine in
many ways with itself and other elements,
carbon has a central role in the chemistry of
living organisms.
– All living things contain carbon is some form
– Forms proteins, lipids, nucleic acids and
carbohydrates
– Four valence electrons
4. Forms of Pure Carbon
• Diamonds
• Graphite
• Fullerenes
• Nanotubes
5. Diamonds
• A crystalline form of carbon in which each
carbon atoms is bonded strongly to four other
carbon atoms. Hard and nonreactive (3,500o C)
6. Graphite
• Each carbon atom is bonded tightly to three
other carbon atoms in flat layers.
– Slippery used as a lubricant
8. Nanotubes
• Carbon atoms are arranged in the shape of
long, hollow cylinder, something like a sheet
of graphite rolled into a tube.
– Only a few nanometers wide
– Nanotubes are members of the fullerene
structural family. Their name is derived from their
long, hollow structure with the walls formed by
one-atom-thick sheets of carbon, called graphene.
9. • Diamond: crystalline form of carbon
in which each C atom is bonded to 4
other C atoms.
• Graphite: each C atom is bonded
tightly to 3 other C in flat layers. Bond
between layers is weak.
• Fullerenes: C atom arranged in the
shape of a geodesic dome
• Nanotube: C atoms are arranged in
the shape of a long, hollow cylinder
• What are four
forms of pure
carbon?
Notes de l'éditeur
Macromolecule: a very large molecule, especially used in reference to large biological polymers (ex. Nucleic acids and proteins.
Carbon Cycle: the physical cycle of carbon through the earth’s biosphere, geosphere, hydrosphere, and atmosphere, includes such processes as photosynthesis, decomposition, respiration and carbonification
In some cases, the carbon seems to have originated within the mantle of the Earth, so carbon that was already in the Earth. In other cases, there's evidence very curiously to suggest that the carbon may have originated near the surface of the Earth. The thinking there is that this carbon could have literally been carbon that was part of carbonate sediments or animals, plants, shells, whatever, that was carried down into the upper mantle of the Earth by the plate tectonics mechanism called subduction.Read more: http://www.smithsonianmag.com/science-nature/diamonds-unearthed-141629226/#YBFhHjhur4wEf0kY.99Give the gift of Smithsonian magazine for only $12! http://bit.ly/1cGUiGvFollow us: @SmithsonianMag on Twitter
Truncated icosahedron: technical term for a soccer ball in the United States, a football everywhere else. The scientists who vaporized the graphite to produce C60 named the new carbon allotrope buckminsterfullerene (shortened to fullerenes or buckyballs) because the geodesic domes designed by inventor and architect Buckminster Fuller provided a clue to the molecule’s structure.
The 1996 Nobel Prize for Chemistry has been won by Harold W. Kroto, Robert F. Curl and Richard E. Smalley for their discovery in 1985 of a new allotrope of carbon, in which the atoms are arranged in closed shells. The new form was found to have the structure of a truncated icosahedron, and was named Buckminsterfullerene, after the architect Buckminster Fuller who designed geodesic domes in the 1960's.