Talk:Ice VII

Triple point

The triple point for ice VII with liquid water and ice VI is 2.2 GPa at 81.6 C. It forms ice VI if below this temperature and pressure. Martin Chaplin (talk) 11:36, 19 February 2008 (UTC)

At room temperature the transition from ice VI occurs at 2.1 GPa (2.0 in D2o)Yadevol (talk) 12:17, 22 February 2008 (UTC)

I believe we are both after accuracy here. 2.1 GPa is still below the liquid water triple point and the page seems to indicate that ice VII is forme from the liquid phase. I used 3 GPa as this is the actual pressure originally used. How about the number 2.2 GPa? Martin Chaplin (talk) 12:38, 22 February 2008 (UTC)

The Johari reference does not refer to the liquid ice VII phase line; is it required? Martin Chaplin (talk) 13:18, 22 February 2008 (UTC)

I was using the pressure of the ice VI to VII transition at RT which is how most experiments access the phase and for which the Johari reference is a good one. I am not sure why you want to focus on the formation from liquid but what you have written OK although I think the precision to which the pressure is given is rather optimistic. In my experience I wouldn't believe a pressure in this range to better than +/- 0.02 GPa .129.215.196.17 (talk) 10:34, 28 February 2008 (UTC)

I feel that the whole thing about proton order and disorder in ice needs explanation. Any objections me writing something about this.Yadevol (talk) 10:39, 28 February 2008 (UTC)

I agree. The articles i read were unclear, which is what led me to write that ice X is the "ordered" form of VII. If someone could provide some information explaining why one ice would be considered the proton-ordered form that would be great. Quickmythril (talk) 11:33, 28 February 2008 (UTC)

Kelvin scale to Celsius temps

I was surprised that no one has commented on the obvious error in equating 473 deg K with 100 deg C.

is the correct temp 473 K (200 C) or 373 K (100 C)?

ck DocKrin (talk) 13:27, 14 November 2008 (UTC)

The source says 355 K, so I assume that whoever added that was just impressed at the existence of solid H₂O at above the STP boiling temperature. I added a little more information and precision from IAPWS, and removed the erroneous statement that all liquid water freezes to Ice VII under pressure, as between about 300 and 355 K it freezes to VI instead (though as of 15 years ago the tentative VI/VII transformation line slopes, so isothermal compression can give water → VI → VII). - Eldereft (cont.) 21:56, 14 November 2008 (UTC)

Looking at my CRC Handbook of Chemistry and Physics, 87th ed. Sect 12, pg 179, figure 3 and table 1:

there is a discrepancy between the figure (labeled in GPa) and the table (labeled in MPa)

the phase line between VI and VII is essentially vertical (at or about 2200 GPa), and the line between VII and VIII is horizontal (at or about +10 C). Given adequate pressure, VII exists to the limits of the chart (200C/473K and 4000 GPa)

the triple point for liquid/VI/VII reads out at or about 110 C/383 K and 2200 GPa (listed as 82 C/ 355K and 2216 MPa in the table)

Similarly, the phase line between V and VI is also vertical, with the triple point (liquid/V/VI) listed as 0.16 C/273.3K and 632.4 MPa

I think that the reference to should be changed to 373K...since our figures (except the error in listing pressures in the GPa range on figure 3) seem to agree well.

ck DocKrin (talk) 01:31, 15 November 2008 (UTC)

Picture unclear

The image shows each water molecule as if it had 1 oxygen and 4 hydrogens (H
₄O). I suppose that those are actually "half-hydrogens" each of them occupied by an H or vacant with probability 1/2. Whatever the correct interpretation, it should be better explained in the article, in tems that a non-specialist can understand. All the best, --Jorge Stolfi (talk) 18:56, 21 December 2009 (UTC)

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Readability

There should be a "conclusion" or "consequences" for this article. It is completely unfathomable for the layman. The article is useless to check if news like this https://www.livescience.com/63986-ice-vii-forms-fast-in-diamonds.html?utm_source=quora&utm_medium=referral are to be taken serioulsy. — Preceding unsigned comment added by 201.2.27.232 (talk) 22:53, 18 November 2018 (UTC)