Ice Ih
Ice Ih (pronounced: ice one h, also known as ice one) is the hexagonal crystal form of ordinary ice, or frozen water. Virtually all ice in the biosphere is ice Ih, with the exception only of a small amount of ice Ic which is occasionally present in the upper atmosphere. Ice Ih exhibits many peculiar properties which are relevant to the existence of life and regulation of global climate.
Ice Ih is stable down to −200 °C (73 K; −328 °F) and can exist at pressures up to 0.2 GPa. The crystal structure is characterized by hexagonal symmetry and near tetrahedral bonding angles.
Read more about Ice Ih: Physical Properties, Crystal Structure, Proton Disorder
Famous quotes containing the word ice:
“When the ice is covered with snow, I do not suspect the wealth under my feet; that there is as good as a mine under me wherever I go. How many pickerel are poised on easy fin fathoms below the loaded wain! The revolution of the seasons must be a curious phenomenon to them. At length the sun and wind brush aside their curtain, and they see the heavens again.”
—Henry David Thoreau (1817–1862)