Why water make hexagonal structure under low temperature, 1 C? as hydrogen sulfide will do the same thing?

Answer 1

It has to do with the geometry of the H2O molecule. Because of the charges involved, the 2 hydrogen atoms are both on the same side of the oxygen molecule. This imbalance continues up into the visual scale. And since they attract the way they do, those angles join together into a hex structure.

Answer 2

I think that you are mystake, because if water have hexagonal structure it will have density 1.84 g/sm3. But I know that under this temperature one molecule of water surrounds by 4 another molecules of water. But also do you know that there are so many unknown structures of water. About this problem has spoken Bernal, Fauler in 1920 and russian scientist Samoilov. Remember also about sp3-hybridization of molecule and about H-bonds between molecules.
H2S has another structure of molecule and therefore it has another structure when it is liquid (solid)

P.S. If some moments by chemistry seems unintelligible for you I'm glad to answer: [e-mail]

Answer 3

I doubt it. H2S has a different triple point than water and doesn't exhibit the unusual density behavior as the liquid approaches the freezing point. Check the Handbook of Chem & Physics for the crystal structure of solid H2S.