Sodium chloride is strange stuff because it is made up of two extremely aggressive elements: sodium and chlorine. Sodium and chlorine are the Hell’s Angels of the mineral kingdom. Drop a lump of pure sodium into a bucket of water and it will explode with enough force to kill. Chlorine is even more deadly. It was the active ingredient in the poison gases of the First World War and, as swimmers know, even in very dilute form it makes the eyes sting. Yet put these two aggressive elements together, and what you get is innocuous sodium chloride—common table
