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A question about terminology of phase state & criticality

  1. Jul 8, 2012 #1
    I'm looking at the diagram (Figure 1) at


    I get that the region in which both the temperature & pressure are higher than the critical point is called a supercritical fluid, which really means it is both a gas & a liquid, thermodynamically speaking.

    And as I understand it, the term subcritical gas or liquid is for the region in which the temperature & pressure are both less than the critical point - with the subcritical gas also termed a vapor here.

    But what about a gas that is a higher temperature but lower pressure, or a liquid at a higher pressure, but lower temperature, than the critical point. It seems that there should be some term for this that is something like a "saddle" state. I don't think the term supercritical should be used, but something with critical should be.

    Any idea what the terminology of this is?
  2. jcsd
  3. Jul 10, 2012 #2


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    Isn't it just normal gas? How does it differ?

    Isn't it just a normal liquid? Ditto?
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