How is graphite different from a metal?

Answer 1

Are you talking about the difference from a molecular standpoint, or from a manufacturing one? I'm going to assume here that by "metal" you mean a middle-of-table metal like aluminum or iron, and not an edge-of-table metal like sodium. As far as molecularity goes, graphite is a carbon molecule. (Now, carbon itself is an atom. But in the "graphite" form, it's definitely a molecule--the biggest one you will ever see.) The stuff comes out of the earth as sheets, each sheet consisting of a single molecule. In the molecule, each carbon atom is bonded to three other carbon atoms. There's one more bonding site left, and that's reserved for holding two sheets together face-to-face. Now, it's important not to underestimate the size of a graphite molecule: if you could pull a hunk of graphite five feet square out of the ground and peel off a one-atom-thick layer of it, you would be faced with a single molecule that's bigger than the table in your dining room. These are called "macromolecules" and while most of them are very large, graphite is the only one that makes single molecules you can see with the naked eye. Pencil leads are formed by compacting powdered graphite in a mold until it forms sheets. This doesn't take very long, if you press hard enough. When you write with a pencil, the force of your writing is stronger than the force holding two graphite sheets together, and one is left on the paper. From a manufacturing standpoint, metal is...well, metal. If you want to make a bicycle frame from metal, you braze metal tubing to metal lugs and put a coat of paint on it. The tubing is still in a state recognizable as a metal. Graphite's a different story. What they call "graphite" as a structural element is really "carbon fiber." You take one of a number of fibers and heat it to a very high temperature in a vacuum, and everything except the carbon boils off and the remaining carbon atoms form graphite matrices. (Or at least that's what's supposed to happen--real carbon fibers contain other elements.) Carbon fibers only have strength in one direction--along their length. If you apply force across a fiber, it breaks easily. To solve that problem, carbon fiber is woven into a cloth, which is then formed into a "composite" structure with epoxy resin. It's very much like working with fiberglass. Before anyone changes this, let me tell you about applications for solid graphite. They exist. Its most common application is as carbon brushes in motors.

Answer 2

Graphite is a non-metallic element, while metal is a group of elements characterized by their ability to conduct electricity and heat. Graphite has a layered structure with weak bonds between layers, giving it lubricating properties, while metals have a crystalline structure with closely packed atoms that allow them to be malleable and ductile. Additionally, graphite is a good conductor of electricity in the plane of its layers, whereas metals conduct electricity throughout their entire structure.