# What is 'autogenous pressure'?

Compound 1 was hydrothermally synthesized under autogenous pressure[1]

I've seen this term used a few times, but with no real explanation of what it means forthcoming. I suspect it refers to the synthesis being performed at equilibrium pressure inside a sealed container (the aforementioned synthesis is performed in an autoclave at 160 C). Is my intuition correct?

[1] Sun, et al., CrystEngComm, (2012), 14, 3982-3988

• Well, my greek/latin intuition is confirmed by Merriam-Webster: merriam-webster.com/dictionary/autogenous But that doesn't mean chemists/engineers use it with the exact same meaning... Interesting. – CHM Aug 27 '12 at 4:08
• @CHM - based off definition 3, I think we can conclude that the autoclave does not require a meal of blood to operate. I hope. – Richard Terrett Aug 27 '12 at 4:58
• Could the term mean that pressure is not controlled? The autoclave is sealed and heated and the pressure comes from the heating??? – tobias47n9e Aug 27 '12 at 7:16
• @RichardTerrett HA! I didn't even read those definitions, went straight for the greek! – CHM Aug 27 '12 at 16:08

Autogenous pressure synthesis is a form of solvothermal synthesis (also known as “hydrothermal synthesis” if the solvent is water). In most publications I could find, the two terms (“autogenous pressure” and “—thermal synthesis”) are used together, making it clear what it is: you seal your solution in a stainless steel autoclave, and heat it up. The pressure thus generated is called autogenous pressure because you don't apply it externally, but it simply derives from the closed nature of the container and the $(\rho,P,T)$ relationship for the fluid (its equation of state).