Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Hot Ice

  1. Sep 29, 2009 #1
    I'm curious about about an upper limit of temperature at which water can no longer exist in a solid state even as pressure increases. There are "ice" phase states such as VII and X which are apparently solid up to 600K under pressures over 10^9 Pa. Phase X is called a "proton ordered" state. Is there some theoretical temperature where the solid state can no longer be maintained despite increasing pressure short of that of a plasma?

    http://en.wikipedia.org/wiki/Ice See sec 7 phase state chart.
    Last edited: Sep 29, 2009
  2. jcsd
  3. Sep 29, 2009 #2
    These are just some first impression thoughts.
    1.How does one distinguish between the solid state and a super compressed liquid the mobility of the particles being restricted by the pressure and the structure being amorphic?
    Drawing an analogy to gas liquification one clue that liquification occurs is the appearance of a meniscus.
    2.I dont think the graphs showing the phase states are particularly well presented,for example it is not clear that the line rising to the left of the triple point has a negative gradient.
    3.Is there a theoretically maximum pressure?
  4. Sep 29, 2009 #3
    Answer to 3: yes, at most the point at which it gets crushed to be a neutron star
  5. Sep 29, 2009 #4


    User Avatar
    Science Advisor

    There was a http://link.aps.org/doi/10.1103/PhysRevB.79.054107" [Broken] on this just earlier this year.

    Depends all on what you mean by 'solid state'. I think the current theory is that it can go metallic, and then 'superionic'. But at the moment it's all down to theoretical calculations.
    Last edited by a moderator: May 4, 2017
  6. Sep 29, 2009 #5
    Thanks for the link alxm. It surprised me that water forms a "fluid dense plasma" at 20,000K with pressures in Jupiter's core. I thought a plasma state of some kind might exist, but 20,000K seems like a low temperature for a plasma. However I guess that a very dense plasma is a different story then tenuous gas plasmas at several million K.

    When you say "metallic", what happens to the oxygen? I can see solid hydrogen as a metal, but the oxygen would need to be expelled or form some kind hydrogen "rust" (oxide), wouldn't it? In that case, the oxide, but not the metal would be some kind of water ice.

    EDIT: Since the abstract also states that water ice may be superionic in Saturn (and Saturn is not much smaller than Jupiter), it may be that the highest temperature where water ice can exist, before becoming a plasma, is that of the superionic state (under 20000K at 10^11 -10^12 Pa).
    Last edited by a moderator: May 4, 2017
  7. Sep 30, 2009 #6

    It looks like you're right about a metallic state of water (with ammonia).


    EDIT: I guess this state would be some kind of metal-oxide-metal state (where hydrogen is the metal) for water?
    Last edited by a moderator: May 4, 2017
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook