# Does graphite burn?

Is it possible to make graphite oxidize in the presence of oxygen?

I know it's possible to make other forms of carbon oxidize and even burn with the production of residual heat in the presence of oxygen.

As far as I know graphite is very resistant to heat, and it isn't possible to make it burn even at high temperatures.

So, my question is: what are the conditions required to make it burn producing carbon dioxide?

• You can burn diamonds if you really want to (even higher heats and needing better than atmospheric oxygen) – Lyndon White Oct 18 '17 at 8:11

## 1 Answer

The autoignition temperature of graphite is $\pu{730^oC}$. This means that pure graphite will ignite at that temperature under standard atmospheric conditions without an external source of ignition. The fraction of carbon that gets oxidized all the way to carbon dioxide at that temperature may not be unity depending on the oxygen concentration, whether the graphite is a fine powder vs. a solid rod, etc. I worked in an analytical laboratory in which we occasionally determined the carbon content of graphitic substances by quantitatively converting the graphite to carbon dioxide at $\pu{950^oC}$ under a pure oxygen atmosphere.

• How does the graphite crucible work? Is it not pure graphite? I have seen some videos of metling precious metals like silver and gold which has higher melting point than 730°C – jnovacho Oct 18 '17 at 7:25
• @jnovacho Bulk graphite won't burn well even at its autoignition temperature (thin sheets might). And graphite crucibles are often used in environments where the hottest parts are not in contact with much oxygen. If the rate of burning is very slow, it may not matter much in a bulk object. – matt_black Oct 3 '19 at 12:00