In this table values are given in units of ppb (parts per billion; 1 billion = 109), both in terms of weight and in terms of numbers of atoms. Values for abundances are difficult to determine with much certainty, so all values should be treated with some caution, especially so for the less common elements. Local concentrations of any element can vary from those given here by orders of magnitude.
|View graphs||Abundance||ppb by weight||ppb by atoms|
|Universe|| 20000 || 1000 |
|Sun|| 40000 || 2000 |
|Meteorite (carbonaceous)|| 5600000 || 4800000 |
|Crustal rocks|| 23000000 || 21000000 |
|Sea water|| 11050000 || 2970000 |
|Stream|| 8000 || 350 |
|Human|| 1400000 || 380000 |
Sodium is never found as the free element ("native") in nature as it is so reactive. Sodium is the sixth most abundant element in the earth"s crust at about 2.6 - 3.0%. The most common mineral is rock salt (sodium chloride, NaCl, or halite), but it occurs in many other minerals including sodium borate (borax), sodium carbonate (soda), sodium nitrate (Chile saltpetre). and sodium sulphate (thenardite). In those species, however, it is the anions that are the reason for mining.
Sodium is present in some abundance in the sun and other stars andclearly identifiable by the sodium D lines which are very prominent in the solar spectrum and those of other stars.