High density amorphous ice - Definition and Overview

When water is cooled below its normal freezing point, it normally freezes to form hexagonal ice, or Ice I. If it is very pure and cooled carefully, it may be supercooled to about -42°C. If water is cooled very rapidly then it forms an amorphoric glass.

HDA, High-Density Amorphous Ice, may be prepared by submitting Ice I (normal ice), cubic ice, or Low density amorphous ice, to high pressure at very low temperatures, like cooled in liquid nitrogen. HDA's is that the thermal conductivity is less than that of Ice Ih's, Ice Ic's, or LDA's during their pressurized densification; usually the thermal conductivity of materials increases with pressure.

See also

• low density amorphous ice
• very high density amorphous ice
• amorphous solid water
• hyperquenched glassy water
• vitrification