Occurrence of sodium

Sodium is found as a compound in nature due to its high reactivity. It is found in a variety of minerals, but the most common is table salt (NaCl), largely found in seawater and in solid deposits. Other compounds include amphibole, cryolite, soda niter and zeolite. Within the Earth’s crust, sodium is the sixth most abundant element overall and the most abundant alkali metal. It makes up about 2.6% of the Earth’s crust by weight.

Sodium is also abundant in stars, as the D spectral lines of this element are the most prominent in star light. Its presence in the atmosphere of planet Mercury was detected by ground telescopes and confirmed by spacecraft Mariner 10 and MESSENGER because of its high abundance and intense spectral lines.