%0 Journal Article %T Scaling relation for the bond length, mass density, and packing order of water ice %A Chang Q Sun %J Physics %D 2013 %I arXiv %X The packing order of molecules and the distance between adjacent oxygen atoms (dOO) in water and ice are most basic yet puzzling. Here we present a scaling solution for this purpose based only on the mass density (gcm-3), (Equation) where dL is the length ({\AA}) of the O:H van der Waals bond and dH the H-O polar-covalent bond projecting on the O---O line. Validated by the measured proton symmetrization of compressed ice, dOO of water and ice, and dOO expansion at water surface, this solution confirms that the fluctuated, tetrahedrally-coordinated structure is unique for water ice. %U http://arxiv.org/abs/1305.4246v1