structure of solid water, or ice, is shown on the right. Each oxygen
atom is surrounded tetrahedrally by oxygens of neighboring molecules.
An oxygen atom has two O-H bonds extended toward two of these neighbors,
and is hydrogen bonded to them. In turn, this oxygen atom receives
two hydrogen bonds from two other neighbors. In one form of ice the
oxygen atoms are arranged like the carbon atoms in diamond. The more
common ice structure shown here represents another way of connecting
atoms by tetrahedral bonds. If the ice structure is thought of as
stacked layers of tetrahedra connected by hydrogen bonds, then the
structure shown on the right and the diamond like structure merely
represent different ways of stacking the layers.