Scaling of H2O-Sciencnet.pdf

The packing order of molecules and the distancebetween adjacent oxygen atoms (d_OO) in water and ice are most basic yetpuzzling. Here we present a scaling solution for this purpose based only on themass density r(gcm^-3),

where d_Lis the length (Å) of the O:H van der Waals bond and d_H the H-Opolar-covalent bo​nd projecting on the O---O line. Validated by the measured proton symmetrization of compressed ice, d_OO of water and ice, and d_OOexpansion at water surface, this solution confirms that: i) the fluctuated,tetrahedrally-coordinated  structure is unique for water ice; ii) Inter-electron-pair repulsion mediate the relxation of the hydrogen bond; and iii) supersolidity of water molecules with fewer than four neighbors .