Homeopathy

You don't present any evidence that they have been.

There's no scientific basis for the idea that water's molecular structure can "retain" information about solutes that it once contained. And if it could, surely all water would have the "memory" of countless substances that once had been dissolved within it, so we should be poisoning ourselves with every glass.Yet we're not. There's simply no scientific basis for homeopathy, and there's absolutely no evidence that a dilution of solution so weak that none of the solute molecules are retained can be distinguished from pure water.

Pure liquid water doesn't form structures, by definition. It's a liquid.Ice forms structures because it's a solid. Water doesn't form crystals at room temperature (at standard pressure), the kinetic energy of its molecules are too great to stay in one place for long.