For road de-icing or in sports drinks: calcium chloride helps
Calcium chloride (chemical formula CaCl2) crystals attract and absorb water easily: they are hygroscopic. That’s why they are typically kept in tightly sealed containers. This white salt performs very well at preventing ice formation and at de-icing roads. At lower temperatures it is much more effective than sodium chloride and it is relatively harmless to the soil and to plants.
In swimming pools, adding some calcium chloride reduces corrosion, especially of concrete structures. In marine aquariums it constitutes a calcium source for the calcium carbonate shelled animals such as molluscs.
The substance is also used as a food additive, e.g. in canned vegetables, and for flavouring pickled food without increasing the sodium level. In sports drinks, calcium chloride is an electrolyte that replaces the calcium ions that you lose when you perspire. In some cheeses, like Brie and Stilton, adding some calcium chloride helps restoring the natural calcium balance.
And last but certainly not least, calcium chloride can play a life-saving role in the prevention of potential heart attacks caused by the side-effects of certain medicines.