Although crystalline nanotubes have been observed, they are generally amorphous.The structures of eight allotropes are shown at the bottom of this page.Lavoisier noted the overall weight of the jar was unchanged and that when it burned, the diamond had combined with oxygen to form carbon dioxide.

A large family of fullerenes exists, starting at C20 and reaching up to C540.

The most recently discovered allotrope of carbon is graphene, which consists of a single layer of carbon atoms arranged in hexagons.

Your brain interprets this rapid transfer of heat energy away from your skin as meaning you are touching something very cold – so diamonds at room temperature can feel like ice.

Carbon (in the form of coal, which is mainly carbon) is used as a fuel.

Note: At normal atmospheric pressure, carbon does not melt when heated, it sublimes. it undergoes a phase change directly from solid to gas.

If the pressure is increased to 10 atmospheres carbon (graphite) is observed to melt at 3550 °C.Diamond’s high thermal conductivity is the origin of the slang term ‘ice.’ At typical room temperatures your body temperature is higher than the room’s – including any large diamonds you may just happen to have lying around.If you touch any of these diamonds, their high thermal conductivity carries heat away from your skin faster than any other material.The buckyballs arrived in comets or asteroids and have been discovered in rocks associated with the Permian-Triassic mass extinction 250 million years ago. A wonderful image released by Michael Ströck under the GNU Free Documentation License: The structures of eight allotropes of carbon: a) Diamond b) Graphite c) Lonsdaleite d) C60 (Buckminsterfullerene) e) C540 Fullerene f) C70 Fullerene g) Amorphous carbon h) Single-walled carbon nanotube. Harmful effects: Pure carbon has very low toxicity.Inhalation of large quantities of carbon black dust (soot/coal dust) can cause irritation and damage to the lungs.Graphene has a 2D crystal structure.(Fullerenes can sometimes exist in amorphous form.) Carbon can also exist in an amorphous state.