In liquid water each
molecule is hydrogen bonded to approximately 3.4 other water molecules. In ice
each each molecule is hydrogen bonded to 4 other molecules.
the two structures below. Notice the empty spaces within the ice structure. Click
In ice Ih, each water forms four hydrogen bonds
with O---O distances of 2.76 Angstroms to the nearest oxygen neighbor. The O-O-O
angles are 109 degrees, typical of a tetrahedrally coordinated lattice structure.
The density of ice Ih is 0.931 gm/cubic cm. This compares with
a density of 1.00 gm/cubic cm. for water.