this is explained a lot better at http://www.mpg.de/6362003/water-ice-crystal http://www.mpg.de/6362003/water-ice-crystal : In ice crystals, the water molecule

this is explained a lot better at http://www.mpg.de/6362003/water-ice-crystal http://www.mpg.de/6362003/water-ice-crystal : In ice crystals, the water molecules arrange themselves in a six-sided, or hexagonal, to use the scientific term, spatial lattice. Each water molecule forms chemical bonds, so-called hydrogen bonds, to four adjacent molecules. This honeycomb crystal lattice of water ice requires more space than liquid water, which is unusual. As long as the water clusters have not reached the minimum size for a crystal, the Göttingen experiment presents them with a dilemma. The experiments take place at around minus 180 to minus 150 degrees Celsius - the molecules are therefore much too cold for a liquid. For a crystal, however, they are still too few in number. The tiny clusters escape this quandary by forming a type of liquid that has clotted in the cold: they form a rather disordered, “amorphous” spatial lattice. If the cluster now grows, the water molecules at its core can change at some stage from the disordered chemical game into the crystalline structure by each of them taking four neighbours by the chemical hand. 275 water molecules thus create the initial beginnings of a real ice crystal with hexagonal structure in the interior of the cluster. To begin with, this structure is still slightly deformed; however, as the cluster grows in size, this interior grows to become a nicely ordered ice crystal, while the outer layers remain amorphous. “When there are 475 molecules, the very core is already perfect,” says Buck. also, http://physicsworld.com/cws/article/news/2012/sep/21/how-many-water-molecules-does-it-take-to-make-ice http://physicsworld.com/cws/article/news/2012/sep/21/how-man...