Sodium is the sixth most common chemical element in the earth's crust and never occurs as a separate element in nature. It combines with many other elements to form compounds. Minerals such as borax and cryolite contain sodium. Plants and animals contain small amounts of sodium. Sodium nitrate is included in fertilizers.
Photographers use sodium thiosulfate to fix photos when printing pictures.
Pure sodium can be used as a catalyst in manufacturing of some types of synthetic rubber. Some nuclear power plants use sodium in liquid form to cool nuclear reactors. Sodium is used to produce such metals as titanium and zirconium. K. It belongs to a group of chemical elements called alkali metals. Like sodium, potassium always occurs combined with other elements.