# Can the pyrophoric tendencies of a pyrophoric substance be suppressed in a pressurized environment?

It's common knowledge that the pressure of an environment influences many properties of a substance, like the melting point, boiling point, or triple point. Pyrophoric substances ignite spontaneously at temperatures below $\pu{55^\circ C}$, like caesium for example.

I wish to ask if the tendency for pyrophoric substances to ignite is influenced at all by pressure? Obviously, these substances would not spontaneously ignite in a vacuum, but would their ignition temperature change and/or be dependent on the pressure of their environment? Is there a pressure apart from a vacuum that could cause the substance to lost its pyrophoric properties?

• How do you imagine changing triple point? Are you only asking about elements and phase changes or pressure induced reactions? Mar 7 '18 at 17:16