As far as I know, water is unique. However, there may be more exotic liquids that exhibit similar properties. I doubt that you would find any of them outside of a lab. Edward Gordon University of Illinois Medical School Water is the only liquid which expands when it freezes. Generally, all substances shrink as they cool.
Water is no exception, for the most part.
There is a sharp expansion as the water freezes. You know this is true, that ice is lighter than water, because you can see ice cubes floating in a glass of water. The reason it expands is that the molecules of water re-arrange at the time of freezing to form the crystal structure of ice. This expansion takes place with tremendous force, as anyone knows who has left a full container of water with a tight lid in the freezer. The force is enough to burst the strongest water pipes if the water in them freezes, which is why people in cold climates sometimes leave a little water trickling through the pipes on freezing nights.