22.9+Carbon

First, to introduce this topic, a song: media type="youtube" key="JH96P4Lpobc?rel=0" height="390" width="480"

Now on to the information!

Carbon exists in a variety of inorganic compounds. Its four elemental crystalline forms are graphite, diamond, fullerenes, and carbon nanotubes, while its primary oxides are carbon monoxide (CO) and carbon dioxide (CO 2 ). Carbonates are present in carbonic acid (H 2 CO 3 ) and mineral compounds. Other important inorganic carbon compounds are carbides, hydrogen cyanide (HCN), and carbon disulfide (CS 2 ).

//Graphite// is a soft, black, slippery solid held together by London dispersion forces. It is conductive and has a metallic luster. It exists in two non-crystalline forms as well: //carbon black// and //charcoal//. Heating hydrocarbons in a limited oxygen supply produces carbon black, while heating wood in the absence of air produces charcoal.
 * Elemental Compounds**[[image:Crystallines.png width="267" height="273" align="right" caption="Clockwise from the upper left corner: graphite, diamond, carbon nanotube, and fullerene."]]

//Diamonds// are denser than graphite, and look quite different: they are hard, clear solids.

//Fullerenes// were discovered in the '80s, and exist as a single molecule. For example, C60, also known as the "buckyball," is a fullerene made of sixty carbon atoms.They typically are spherical and hollow, and the carbons are arranged in interlaced hexagons and pentagons. Since fullerenes were so recently discovered, scientists are still researching their properties.

//Carbon nanotubes// are composed of one or more layers of carbon rolled into a cylinder.

This site has 3D pictures of graphite and diamond, while this site has 3D pictures of fullerenes and nanotubes. You can click on them and move them around to examine their structures.

//Carbon monoxide// is produced when carbon or hydrocarbons are burned in a limited oxygen supply. The carbon and oxygen atoms are triple-bonded to one another; therefore, the molecule is very stable. It is a colorless, tasteless, odorless gas that is highly toxic; in fact, it is known as the "silent killer" (its toxicity is explained here). Unfortunately, car engines release carbon monoxide, which is a significant air pollutant. Although it is harmful to humans and the environment, it is useful as a fuel and a reducing agent. It is also used to prepare certain organic compounds.
 * Oxides**[[image:CO_vs._CO2.jpg width="133" height="180" align="left" caption="Space-filling models of carbon monoxide (top) and carbon dioxide (bottom)"]]

//Carbon dioxide// is formed when carbon-containing compounds are burned in an excess of oxygen. It is also produced when several carbonates are heated, and is a byproduct of the creation of ethanol. Synthetically, it is generated by the reaction of acids and carbonates. Like carbon monoxide, it is odorless and colorless; however, it is not nearly as toxic. As a major greenhouse gas, carbon dioxide has a significant impact on the environment. Solid carbon dioxide is commonly known as dry ice, which is used in refrigeration. Carbon dioxide plays a key role in the manufacturing of carbonate beverages, washing soda, and baking soda as well.

//Carbonic acid// is a product of the reaction of aqueous carbon dioxide and water. It is a weak acid; therefore, its conjugate base (HCO 3 - ) is a weak base. Similarly, the carbonate ion (CO 3 2- ) itself is more basic.
 * Carbonates**

//Calcite// (CaCO 3 ) is in essence limestone. It is the primary component of a variety of materials, including marble, pearls, and coral reefs. When a limestone deposit is deep enough, a cave is formed. At high temperatures, calcite decomposes into carbon dioxide and quicklime (CaO), a vital constituent of mortar. This [|page] has a bunch of information about calcite, as well as diagrams of its many forms.

//Carbides// are binary compounds of carbon with metals, metalloids, and nonmetals. Ionic carbides are formed by the more active metals. One of the most important ionic carbides is calcium carbide CaC 2 ) because it produces acetylene, which is useful in welding. Interstitial carbides are created by transition metals, while covalent carbides are formed by silicon and boron. Tungsten carbide (WC) and silicon carbide (SiC) are very hard, and are both used to make cutting tools.
 * Carbides**

//Hydrogen cyanide// is a toxic gas created by the reaction of an acid with a cyanide salt. Cyanides are used to produce various types of plastics.
 * Other Compounds**

//Carbon disulfide// is a poisonous, colorless, volatile, and flammable liquid. It works as a solvent for nonpolar objects, such as waxes, greases, and celluloses.

Overview of Carbon Links to assorted information about carbon and its compounds [|More details about carbon oxides]
 * Other Resources**

Brown, Theodore L., et al. __Chemistry: The Central Science__. 11th ed. Upper Saddle River: Pearson Prentice Hall, 2009. Print.
 * References**

"Carbon Molecule." //EDinformatics.com//. EDinformatics, 1999. Web. 20 Mar. 2011. 

"Carbon Oxides." //Computer Assisted Chemistry Tutorial//. CaCt, n.d. Web. 20 Mar. 2011. 

"Fullerene." //EDinformatics.com//. EDinformatics, n.d. Web. 20 Mar. 2011. 