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Ice phases

link Phase diagram

 

Water has many solid phases (ices), There are sixteen or so crystalline phases and three amorphous (non-crystalline) phases All the crystalline phases of ice involve the water molecules being hydrogen bonded to four neighboring water molecules (see [1300] for a recent review). In most cases the two hydrogen atoms are equivalent, with the water molecules retaining their symmetry, and they all obey the 'ice' rules: two hydrogen atoms near each oxygen, one hydrogen atom on each O····O bond.j The H-O-H angle in the ice phases is expected to be a little less than the tetrahedral angle (109.47°), at about 107°. The Clapeyron equationo for many ice phase changes has to be adapted due to water's negative expansion coefficient and anomalous change in entropy with volume [1147c].

 

Structural data on the ice polymorphs

Ice polymorph

Density,
g cm-3 a

Protonsf Crystalh Symmetry Dielectric constant, εSi Notes
Hexagonal ice, Ih

0.92

disordered Hexagonal one C6 97.5  
Cubic ice, Ic

0.92

disordered Cubic four C3    
LDA, Ia b

0.94

disordered Non-crystalline     As prepared, may be mixtures of several types
HDA c

1.17

disordered Non-crystalline     As prepared, may be mixtures of several types
VHDA d

1.25

disordered Non-crystalline      
II, Ice-two

1.17

ordered Rhombohedral one C3 3.66  
III, Ice-three

1.14

disordered Tetragonal one C4 117 protons may be partially ordered
IV, Ice-four

1.27

disordered Rhombohedral one C3   metastable in ice V phase space
V, Ice-five

1.23

disordered Monoclinic one C2 144 protons may be partially ordered
VI, Ice-six

1.31

disordered Tetragonale one C4 193 protons can be partly ordered
VII, Ice-seven

1.50

disordered Cubice four C3 150 two interpenetrating ice Ic frameworks
VIII, Ice-eight

1.46

ordered Tetragonale one C4 4 low temperature form of ice VII
IX, Ice-nine

1.16

ordered Tetragonal one C4 3.74 low temperature form of ice III, metastable in ice II space
X, Ice-ten

2.51

symmetric Cubice four C3   symmetric proton form of ice VII
XI, Ice-eleven

0.92

ordered Orthorhombic three C2   low temperature form of ice Ih
XI, Ice-elevenk

>2.51

symmetric Hexagonal close packed e distorted   Found in simulations only
XII, Ice-twelve

1.29

disordered Tetragonal one C4   metastable in ice V phase space
XIII, Ice-thirteen

1.23

ordered Monoclinic one C2   ordered form of ice V phase
XIV, Ice-fourteen

1.29

mostly ordered Orthorhombic one C4   ordered form of ice XII phase
XV, Ice-fifteen n

1.31 (?)

ordered ? ?   ordered form of ice VI phase

 

Two different forms of ice-eleven have been described by different research groups: the high-pressure form (also known as ice-thirteen) involves hydrogen atoms equally-spaced between the oxygen atoms [84] (like ice-ten) whereas the lower pressure, low temperature, form uses the incorporation of hydroxide defect doping (and interstitial K+ ions) to order the hydrogen bonding of ice Ih [207], that otherwise occurs too slowly. Another ice-ten has been described, being the proton ordered form of ice-six (VI) occurring below about 110 K. Only hexagonal ice-one (Ih), ice-three (III), ice-five (V), ice-six (VI), ice-seven (VII) and, perhaps, ice-ten (X) can be in equilibrium with liquid water (ice-ten with supercritical water), whereas all the others ices, including ice-two (II, [273]), are not stable in its presence under any conditions of temperature and pressure. The low-temperature ices, ice-two, ice-eight (VIII), ice-nine (IX), ice-eleven (low pressure form), ice-thirteen (XIII) [1002] and ice-fourteen (XIV) [1002] all possess (ice-nine and ice-fourteen incompletely) low entropy ordered hydrogen-bonding whereas in the other ices (except ice-ten [80] and ice-eleven where the hydrogen atoms are symmetrically placed) the hydrogen-bonding is disordered even down to 0 K, where reachable. Ice-four (IV) and ice-twelve (XII) [82] are both metastable within the ice-five phase space. Cubic ice (Ic) is metastable with respect to hexagonal ice (Ih). It is worth emphasizing that liquid water is stable throughout its phase space above. However, ice-seven (VII) undergoes X-ray-induced (~9.7 keV) dissociation to an O2 - H2 alloyg at high pressure (>2.5 GPa) but reverts to ice-seven near its melting point at 700 K and 15 GPa [1383]. A new ice phase has been reported to lie on what had been thought to be the liquid (supercritica)l side of ice-seven at high pressures, with approximate triple points of about 700 K, 20 MPa with liquid and ice-seven and about 1500 K, 40 MPa with liquid and ice-ten [1521].

 

Kurt Vonnegut's highly entertaining story concerning an (imaginary) ice-nine, which was capable of crystallizing all the water in the world [83], fortunately has no scientific basis (see also IE) as ice-nine, in reality, is a proton ordered form of ice-three, only exists at very low temperatures and high pressures and cannot exist alongside liquid water under any conditions. Ice Ih may be metastable with respect to empty clathrate structures of lower density under negative pressure conditions (that is, stretched) at very low temperatures [520].


More structural data on the ice polymorphs

Ice polymorph

Molecular environments
Small ring size(s)
Helix
Approximate O-O-O angles, °
Ring penetration hole size
Hexagonal ice, Ih
1
6
None
All 109.47±0.16
None
Cubic ice, Ic
1
6
None
109.47
None
LDA, Iab
3+
5, 6
None
mainly 108, 109 and 111
None
HDA c
6+
5, 6
None
broad range
None
VHDA d
6+
5, 6
None
broad range
None [747]
II, Ice-two
2 (1:1)
6
None
80,100,107,118,124,128;
86,87,114,116,128,130
None
III, Ice-three
2 (1:2)
5, 7
4—fold
(1) 91,95,112,112,125,125
(2) 98,98,102,106,114,135
None
IV, Ice-four
2 (1:3)
6
None
(1) 92,92,92,124,124,124
(3) 88,90,113,119,123,128
some 6
V, Ice-five
4 (1:2:2:2)
4, 5, 6, 8
None
(1) 82,82,102,131,131,131
(2) 88,91,109,114,118,128
(3) 85,91,101,103,130,135
(4) 84,93,95,123,125,126
8 (1 bond)
VI, Ice-six
2 (1:4)
4, 8
None
(1) 77,77,128,128,128,128
(2) 78,89,89,128,128,128
8 (2 bond)
VII, Ice-seven
1
6
None
109.47
every 6
VIII, Ice-eight
1
6
None
109.47
every 6
IX, Ice-nine
2 (1:2)
5, 7
4—fold
(1) 91,95,112,112,125,125
(2) 98,98,102,106,114,135
None
X, Ice-ten
1
6
None
109.47
every 6
XI, Ice-eleven
1
6
None
109.47
None
XI, Ice-elevenk
undetermined
6
None
undetermined
every 6
XII, Ice-twelve
2 (1:2)
7, 8
5—fold
(1) 107,107,107,107,115,115
(2) 67,83,93,106,117,132
None
XIII, Ice-thirteen
7 (all equal)
4, 5, 6, 8
None
(1) 82,82,102,131,131,131
(2) 88,91,109,114,118,128
(3) 85,91,101,103,130,135
(4) 84,93,95,123,125,126
8 (1 bond)
XIV, Ice-fourteen
2 (1:2)
7, 8
5—fold
(1) 107,107,107,107,115,115
(2) 67,83,93,106,117,132
None
XIV, Ice-fifteen n
2 (1:4)
4, 8
None
(1) 77,77,128,128,128,128
(2) 78,89,89,128,128,128
8 (2 bond)

The thermal conductivities properties of crystalline and amorphous ices have been reviewed [1202]. Other stable or metastable phases of ice have been proposed (for example, Ice XIII and ice XIV [958]) and may exist but their structures have not been established. Such new phases are thought particularly likely to be found within the phase space of ice II and ice V. Several new phases (for example ice i) have only been found (so far) in modeling studies, but other ices have been found at confined surfaces. 'Metallic' water, where electrons are freed to move extensively throughout the material and the atoms of water exist as ions, probably exists as an antifluorite type structurem above 1.76 TPa [1138]. It is not thought that any other phases are stable at higher pressures than this.

 

The proposed topology of the transformations between ice XI --> ice II--> ice IX and ice VIII --> ice X has been described [1237]. [Back to Top to top of page]

 


Footnotes

a density at atmospheric pressure. [Back]

 

b Low-density amorphous ice (LDA). The structural data in the Table is given assuming LDA has the structure of ES. [Back]

 

c High-density amorphous ice (HDA). The structural data in the Table is given assuming HDA has the structure of crushed CS. [Back]

 

d Very high-density amorphous ice (VHDA). The structural data in the Table assumes no hydrogen bond rearrangements from LDA or HDA. As VHDA is likely to be a a relaxed form of HDA, this assumption seems unlikely [935]. [Back]

 

e Structure consists of two interpenetrating frameworks. [Back]

 

f Although primarily ordered or disordered, ordered arrangements of hydrogen bonding may not be perfect and disordered arrangements of hydrogen bonding are not totally random as there are correlated and non-bonded preferential effects. [Back]

 

g This ice is reported to be more likely a trigonal structure made up of 2H3Oδ++ O2δ- + H2 rather than a 2H2 + O2 alloy [1419]. [Back]

 

h Crystal cell parameters have been collated [711]. [Back]

 

i Dielectric constants fall into two categories dependent on whether the hydrogen bonds are ordered (low values) or disordered (high values). [Back]

 

j Weaknesses (Bjerrum defects) in the ice crystal are apparent where the ice rules are disobeyed. Both O····O contacts, without an intervening proton (L defect) and O-H····H-O contacts (D defect) may occur due to molecular rotations where neighboring water molecules fail to adjust their hydrogen bonding. Other defects may be caused by the presence of H3O+ and OH- ions. [Back]

 

k Also known as ice XIII. [Back]

 

m The antifluorite structure consists of an face centered cubic (FCC) unit cell with oxygen anions occupying the FCC lattice points (corners and faces) and hydrogen cations occupy the eight tetrahedral sites within the FCC lattice. [Back]

 

n This ice has not yet been prepared. [Back]

 

o The Clapeyron equation is normally stated as dT/dP=TΔV/ΔH=ΔV/ΔS where P, T, H, V and S are the pressure, temperature, enthalpy, volume and entropy. This may be extended to be dT/dP=T(sign α2V2 - sign α1V1)ΔV/ΔH ,where α represents the thermal expansion coefficients, for use with phases with negative expansion coefficients including the ice phase changes LDA-->Ic, HDA-->LDA, LDA-->HDA, III-->V, V-->VI, VI-->VII and VI-->VIII [1147b]. [Back]

 

 

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This page was last updated by Martin Chaplin on 29 October, 2008