Liquid water: The helical perspective of structure

•Ice Ih structure converts into the helices retaining the four-fold connectivity.•Liquid water appears a racemic mixture of two types of helical clusters.•Cooperative hydrogen bonds control the helical specimens without strain.•Well-structured helical clusters determine unusual properties of water.

The structure of water, especially the bulk liquid, is a fundamental question. We show that the infinite network of perfectly tetragonal oxygen atoms in ice Ih can be converted into the helical geometry, retaining the four-fold connectivity but being non-tetrahedral with respect to neighboring oxygen atoms. Thus, liquid water appears as a racemic mixture of two types of discrete, helical clusters of water molecules joined tightly together by two types of hydrogen bonds, which are very similar in all cluster entities.

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