Editing Urea (section)

====Thermolysis====
Molten urea decomposes into [[ammonium cyanate]] at about 152&nbsp;°C, and into [[ammonia]] and [[isocyanic acid]] above 160&nbsp;°C:<ref name="Schaber 2004">{{cite journal | last1=Schaber | first1=Peter M. | last2=Colson | first2=James | last3=Higgins | first3=Steven | last4=Thielen | first4=Daniel | last5=Anspach | first5=Bill | last6=Brauer | first6=Jonathan | title=Thermal decomposition (pyrolysis) of urea in an open reaction vessel | journal=Thermochimica Acta | volume=424 | year=2004 | issue=1–2 | issn=0040-6031 | doi=10.1016/j.tca.2004.05.018 | pages=131–142| bibcode=2004TcAc..424..131S }}</ref>
{{block indent |left=1.5 |text={{chem2|CO(NH2)2 → [NH4]+[OCN]- → NH3 + HNCO}}}}

Heating above 160&nbsp;°C yields [[biuret]] {{chem2|NH2CONHCONH2}} and [[triuret]] {{chem2|NH2CONHCONHCONH2}} via reaction with isocyanic acid:<ref name="Meessen 2012">{{Ullmann |last=Meessen |first=Jozef H. |title=Urea |year=2012 |doi=10.1002/14356007.a27_333.pub2}}</ref><ref name="Schaber 2004"/>
{{block indent |left=1.5 |text={{chem2|CO(NH2)2 + HNCO → NH2CONHCONH2}}}}
{{block indent |left=1.5 |text={{chem2|NH2CONHCONH2 + HNCO → NH2CONHCONHCONH2}}}}

At higher temperatures it converts to a range of [[condensation reaction|condensation product]]s, including [[cyanuric acid]] {{chem2|(CNOH)3}}, [[guanidine]] {{chem2|HNC(NH2)2}}, and [[melamine]].<ref name="Meessen 2012" /><ref name="Schaber 2004"/>