Editing Graphite (section)

===Thermodynamics===
[[File:Carbon basic phase diagram.png|thumb|upright=1.15|Theoretically predicted [[phase diagram]] of carbon]]
The equilibrium pressure and temperature conditions for a transition between graphite and diamond is well established theoretically and experimentally. The pressure changes linearly between {{val|1.7|ul=GPa}} at {{val|0|u=K}} and {{val|12|u=GPa}} at {{val|5000|u=K}} (the diamond/graphite/liquid [[triple point]]).<ref name=Bundy>{{cite journal |last1=Bundy |first1=P. |last2=Bassett |first2=W. A. |last3=Weathers |first3=M. S. |last4=Hemley |first4=R. J. |last5=Mao |first5=H. K. |last6=Goncharov |first6=A. F. |title=The pressure-temperature phase and transformation diagram for carbon; updated through 1994 |journal=Carbon |date=1996 |volume=34 |issue=2 |pages=141–153 |doi=10.1016/0008-6223(96)00170-4|bibcode=1996Carbo..34..141B }}</ref><ref>{{cite book |first1=C. X. |last1=Wang |first2=G. W. |last2=Yang |chapter=Thermodynamic and kinetic approaches of diamond and related nanomaterials formed by laser ablation in liquid |editor-last1=Yang |editor-first1=Guowei |title=Laser ablation in liquids : principles and applications in the preparation of nanomaterials |date=2012 |publisher=Pan Stanford Pub |isbn=9789814241526 |pages=164–165}}</ref>
However, the phases have a wide region about this line where they can coexist. At [[Standard temperature and pressure|normal temperature and pressure]], {{convert|20|C|K}} and {{convert|1|atm|MPa}}, the stable phase of carbon is graphite, but diamond is [[metastable]] and its rate of conversion to graphite is negligible.<ref name=ChemThermo>{{cite book |last1=Rock |first1=Peter A. |title=Chemical Thermodynamics |date=1983 |publisher=University Science Books |isbn=9781891389320 |pages=257–260}}</ref> However, at temperatures above about {{val|4500|u=K}}, diamond rapidly converts to graphite. Rapid conversion of graphite to diamond requires pressures well above the equilibrium line: at {{val|2000|u=K}}, a pressure of {{val|35|u=GPa}} is needed.<ref name=Bundy/>