How are carbon isotopes used in carbon dating
Although crystalline nanotubes have been observed, they are generally amorphous.
Carbon has the highest melting/sublimation point of all the elements and, in the form of diamond, has the highest thermal conductivity of any element.
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.
Graphite is used for pencil tips, high temperature crucibles, dry cells, electrodes and as a lubricant.
Diamonds are used in jewelry and – because they are so hard – in industry for cutting, drilling, grinding, and polishing.