Structure of Ice Ih and Ice Ic
FIG.1. The structure of (a) ice Ih and (b) ice Ic. Note the
tetrahedral coordination and the openess of the structure. On each
hydrogen bond, shown by a rod joining the oxygen atoms, lies one proton
in an asymmetric position (not shown).Bond lengths, 275 pm, are
indicated. The hexagonal c axis is labeled 732 pm, and one of the
hexagonal a axes is labeled 450 pm. In (b) the cubic unit cell is
outlined with dashed lines; dimensions are in pm at 110 K.