How do oxygen atoms form hexagonal rings in ordinary ice?

At standard atmospheric pressure and temperatures near 0 °C, ordinary ice forms a highly ordered, open structure. In this arrangement, oxygen atoms are joined together in a series of hexagonal rings that form stacked sheets or planes.1

This structure is maintained by intermolecular interactions where each oxygen atom is surrounded by four hydrogen atoms. Two of these hydrogen atoms are connected to the oxygen via covalent bonds, while the other two are linked to the oxygen atom’s unshared electron pairs through hydrogen bonds. This specific configuration creates a "dimpled" laminar structure that is less dense than liquid water, as the molecules are held in a more spacious, open lattice.21