Appearance of carbon

Answer 1

Carbon is an element that has 'allotropes' - different crystalline forms that look different from each other and have different physical properties, and yet are made from the same kinds of atoms - carbon atoms. Carbon produces four true allotropes: Charcoal is a black powder that is not truly crystalline. Soot and amorphous carbon are all variations of this allotrope and all look the same - a black powder. Graphite is the substance used in pencils (it isn't 'lead' and never has been!) and in its pure state is a grey, greasy looking shiny solid which, if stroked is very slimy to the touch. Carbon fibre is a refined form of graphite. The carbon atoms in graphite are in sheets that can slide over each other - creating its slippery properties. Diamond is a clear colourless crystalline solid that, in its pure state forms crystals that resemble 2 Egyptian pyramids placed base to base. (Diamonds in jewellery have been cut into different shapes to reflect light in a pleasing way). Diamond is the hardest naturallly occurring material in the world. In diamoond the atoms are bonded together strongly in a large 3-dimensional lattice giving the diamond its great hardness. Finally, there is the allotrope Buckminsterfullerene discovered in 1985 by Harold W. Kroto, Robert F. Curl and Richard E. Smalley who won the Nobel prize in 1996 for their discovery. Buckminsterfullerene has the appearance of a shiny black powder, but differs in its structure from the other allotropes in that the carbon atoms in it form hollow balls of 60 carbon atoms in each. Research is now being undertaken to extend these balls into hollow tubes so that long carbon 'nanotubes' can be made. If these are eventually made on a large scale, they will be immenselly strong being able to make fibres that are stronger than any other at the moment. As an example, it is believed that such a fibre could suspend a car (automobile) without breaking and still be the less than the thickness of a human hair.