How does the molecular structure of ice differ from that of liquid water?

The molecular structure of ice differs significantly from that of liquid water due to the arrangement of hydrogen bonds and the resulting density of the molecules.21

In the liquid state, water molecules are associated in a polymeric structure consisting of chains connected by weak hydrogen bonds that are in a constant state of breaking and reforming due to thermal agitation. This allows the molecules to be more closely packed together.23

In the solid state (ice), the molecules interact strongly enough to form a highly ordered, rigid crystalline lattice. In this structure, each oxygen atom is tetrahedrally coordinated with four neighboring molecules, creating an open, hexagonal arrangement. This configuration increases the space between molecules, resulting in a lower density compared to liquid water. Because of this open, less dense structure, ice is one of the few substances that floats when in its solid form.23451