Computer-generated model of a 60-carbon molecule enclosing a potassium ion. The 60-carbon molecule, called a buckminster-fullerene, was discovered by organic chemists in 1985. (Reproduced by permission of Photo Researchers, Inc.) Carbon Chemistry http://www.hk-phy.org/articles/laser/c-atom_e.gif http://upload.wikimedia.org/wikipedia/commons/thumb/5/53/Types_of_Carbon_Nanotubes.png/350px-Types_of_Carbon_Nanotubes.png http://images.google.com/imgres?imgurl=http://www.scienceclarified.com/images/uesc_03_img0127.jpg&imgrefurl=http://www.scienceclarified.com/Ca-Ch/Chemistry.html&h=327&w=327&sz=17&hl=en&start=56&usg=__g0D84hp4DSxdLCxrUKCjoBjcWiY=&tbnid=Cm2b0-JV5xqV8M:&tbnh=118&tbnw=118&prev=/images%3Fq%3DCarbon%2Bchemistry%26start%3D40%26gbv%3D2%26ndsp%3D20%26hl%3Den%26safe%3Dactive%26sa%3DN

Carbon (C) appears in the second row of the periodic table and has four bonding electrons in its valence shell. Similar to other non-metals, carbon needs eight electrons to satisfy its valence shell. http://www.visionlearning.com/library/module_viewer.php?mid=60 http://www.historyforkids.org/scienceforkids/chemistry/atoms/pictures/carbon.jpg

Carbon therefore forms four bonds with other atoms (each bond consisting of one of carbon's electrons and one of the bonding atom's electrons). Every valence electron participates in bonding, thus a carbon atom's bonds will be distributed evenly over the atom's surface. http://www.chemistryland.com/ElementarySchool/BuildingBlocks/CarbonTetrFluoride.jpg http://www.physorg.com/newman/gfx/news/moresolidtha.jpg

These bonds form a tetrahedron (a pyramid with a spike at the top), as illustrated below: Carbon forms 4 bonds http://www.visionlearning.com/library/module_viewer.php?mid=60

The simplest organic chemicals, called hydrocarbons Contain only carbon and hydrogen atoms The simplest hydrocarbon (called methane) contains a single carbon atom bonded to four hydrogen atoms: http://www.visionlearning.com/library/module_viewer.php?mid=60 http://itech.dickinson.edu/chemistry/wp-content/uploads/2008/04/methanejoke.jpg Methane - a carbon atom bonded to 4 hydrogen atoms 

But carbon can bond to other carbon atoms in addition to hydrogen, as illustrated in the molecule ethane below: http://www.visionlearning.com/library/module_viewer.php?mid=60 Ethane - a carbon-carbon bond

Hexane - a 6-carbon chain The uniqueness of carbon comes from the fact that it can bond to itself in many different ways. Carbon atoms can form long chains: http://www.visionlearning.com/library/module_viewer.php?mid=60 Hexane - a 6-carbon chain

Branched Chains: FATTY ACIDS: BRANCHED-CHAIN http://www.visionlearning.com/library/module_viewer.php?mid=60 http://www.lipidlibrary.co.uk/Lipids/fa_branc/image004.gif Isohexane - a branched-carbon chain

Rings: Cyclohexane - a ringed hydrocarbon http://www.visionlearning.com/library/module_viewer.php?mid=60 http://www.mississauga.rasc.ca/Spitzer_Smith_Fingers_low_res.jpg http://www.nano-ou.net/Images/benzeneGIF2.gif http://www.nano-ou.net/Images/benzeneGIF2.gif This is an image of the massive star formation region in Carina, from Spitzer, showing the 8micron emission from PAHs (small carbon rings)

There appears to be almost no limit to the number of different structures that carbon can form. To add to the complexity of organic chemistry, neighboring carbon atoms can form double and triple bonds in addition to single carbon-carbon bonds: Single bonding Double bonding Triple bonding http://www.visionlearning.com/library/module_viewer.php?mid=60 As the number of bonds between any two carbon atoms increases, the number of hydrogen atoms in the molecule decreases (as can be seen in the figures above).

Alkanes are the first class of simple hydrocarbons and contain only carbon-carbon single bonds. The alkanes are named by combining a prefix that describes the number of carbon atoms in the molecule with the root ending "ane". The chemical formula for any alkane is given by the expression CnH2n+2 http://www.visionlearning.com/library/module_viewer.php?mid=60

Carbon Prefix Alkane Chemical Structural Atoms Name Formula Formula 1 Meth Methane CH 4 CH4 2 Eth Ethane C2H6 CH3CH3 3 Prop Propane C3H8 CH3CH2CH3 4 But Butane C4H10 CH3CH2CH2CH3 5 PENT Pentane C5H12 CH3CH2CH2CH2CH3 6 Hex Hexane C6H14 7 Hep Heptane C7H16 8 Oct Octane C8H18 9 Non Nonane C9H20 10 Dec Decane C10H22 http://www.visionlearning.com/library/module_viewer.php?mid=60

Alkenes The second class of simple hydrocarbons, the alkenes, consists of molecules that contain at least one double-bonded carbon pair. Alkenes follow the same naming convention used for alkanes. A prefix (to describe the number of carbon atoms) is combined with the ending "ene" to denote an alkene. http://www.visionlearning.com/library/module_viewer.php?mid=60

The chemical formula for the simple alkenes follows the expression CnH2n. Because one of the carbon pairs is double bonded, simple alkenes have two fewer hydrogen atoms than alkanes. http://www.visionlearning.com/library/module_viewer.php?mid=60 Ethene Ethene, for example is the two- carbon molecule that contains one double bond.

Alkynes - are the third class of simple hydrocarbons and are molecules that contain at least one triple-bonded carbon pair. Like the alkanes and alkenes, alkynes are named by combining a prefix with the ending "yne" to denote the triple bond. The chemical formula for the simple alkynes follows the expression CnH2n-2. http://www.visionlearning.com/library/module_viewer.php?mid=60 Ethyne

Isomers
 Because carbon can bond in so many different ways, a single molecule can have different bonding configurations. Consider the two molecules illustrated here: C6H14 CH3CH2CH2CH2CH2CH3 http://www.visionlearning.com/library/module_viewer.php?mid=60 C6H14 CH3 | CH3CH2CHCH2CH3

Isomers - are molecules that have the same chemical formula but different structural formulas http://www.visionlearning.com/library/module_viewer.php?mid=60 http://www.elmhurst.edu/~chm/vchembook/images/549comparerecsite.gif

http://content. answers http://content.answers.com/main/content/wp/en/thumb/d/db/333px-Eight_Allotropes_of_Carbon.png Eight allotropes of carbon: Diamond, graphite, lonsdaleite, C60, C540, C70, amorphous carbon and a carbon nanotube.

Diamond: Hardest known natural mineral Diamond: Hardest known natural mineral. Structure: each atom is bonded tetrahedrally to four others, making a 3-dimensional network of puckered six-membered rings of atoms. Graphite: One of the softest substances. Structure: each atom is bonded trigonally to three other atoms, making a 2-dimensional network of flat six-membered rings; the flat sheets are loosely bonded Lonsdaleite: A corruption of diamond. Structure: similar to diamond, but forming a hexagonal crystal lattice. Carbon nanotubes: Nanotubes are cylindrical fullerenes. Tiny tubes. Structure: each atom is bonded trigonally in a curved sheet that forms a hollow cylinder. http://www.answers.com/topic/carbon

Buckminsterfullerene (IUPAC name (C60-Ih)[5,6]fullerene) is the smallest fullerene molecule in which no two pentagons share an edge (which can be destabilizing; see pentalene). It is also the most common in terms of natural occurrence, as it can often be found in soot. Another fairly common buckminsterfullerene is C70, but fullerenes with 72, 76, 84 and even up to 100 carbon atoms are commonly obtained http://www.answers.com/topic/carbon

This Power Point presentation was constructed and is copyrighted by Roger Price 10/08