Ice VI is a form of
ice
Ice is water frozen into a solid state, typically forming at or below temperatures of 0 degrees Celsius or Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opaq ...
that exists at
high pressure
In science and engineering the study of high pressure examines its effects on materials and the design and construction of devices, such as a diamond anvil cell, which can create high pressure. By ''high pressure'' is usually meant pressures of th ...
at the order of about 1
GPa
Grading in education is the process of applying standardized measurements for varying levels of achievements in a course. Grades can be assigned as letters (usually A through F), as a range (for example, 1 to 6), as a percentage, or as a numbe ...
(= 10 000
bar
Bar or BAR may refer to:
Food and drink
* Bar (establishment), selling alcoholic beverages
* Candy bar
* Chocolate bar
Science and technology
* Bar (river morphology), a deposit of sediment
* Bar (tropical cyclone), a layer of cloud
* Bar (u ...
) and temperatures ranging from 130 up to 355 Kelvin (−143 °C up to 82 °C); see also the phase diagram of water. Its discovery and the discovery of other high-pressure forms of water were published by
P.W. Bridgman in January 1912.
It is part of one of the inner layers of
Titan.
Properties
Ice VI has a
density
Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematical ...
of 1.31 g/cm
3 and a
tetragonal crystal system
In crystallography, the tetragonal crystal system is one of the 7 crystal systems. Tetragonal crystal lattices result from stretching a cubic lattice along one of its lattice vectors, so that the cube becomes a rectangular prism with a square ...
with the
space group P42/nmc; its
unit cell
In geometry, biology, mineralogy and solid state physics, a unit cell is a repeating unit formed by the vectors spanning the points of a lattice. Despite its suggestive name, the unit cell (unlike a unit vector, for example) does not necessaril ...
contains 10 water molecules and has the dimensions a=6.27
Å and c=5.79 Å.
The
triple point
In thermodynamics, the triple point of a substance is the temperature and pressure at which the three phases (gas, liquid, and solid) of that substance coexist in thermodynamic equilibrium.. It is that temperature and pressure at which the subli ...
of ''ice VI'' with
ice VII
Ice VII is a cubic crystalline form of ice. It can be formed from liquid water above 3 GPa (30,000 atmospheres) by lowering its temperature to room temperature, or by decompressing heavy water (D2O) ice VI below 95 K. (Different types of ice, fr ...
and liquid water is at about 82 °C and 2.22 GPa and its triple point with
ice V
Ice V, pronounced "ice five", is a monoclinic crystalline phase of water, formed by cooling water to 253 K at 500 MPa. It has a density
Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The s ...
and liquid water is at 0.16 °C and 0.6324 GPa = 6324 bar.
Water Phase Diagram
www1.lsbu.ac.uk, version of 9 September 2019, retrieved 3 October 2019
Ice VI undergoes phase transitions into ices XV and XIX upon cooling depending on pressure as hydrochloric acid
Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid
Acid strength is the tendency of an acid, symbol ...
is doped.
See also
* Ice phases (overview)
External links
Physik des Eises
(PDF in German, iktp.tu-dresden.de)
Ice phases
(www.idc-online.com)
References
Water ice
{{physical-chemistry-stub