Occurrence, extraction and uses Occurrence of Group 1

Sodium and potassium are abundant in the Earth’s biosphere (2.6% and 2.4% respectively) but do not occur naturally in the elemental state. The main sources of Na and K are rock salt (almost pure NaCl), natural brines and seawater, sylvite (KCl), sylvinite (KCl/NaCl) and carnallite (KCl. MgCl₂.6H₂O). Other Na- and K-containing minerals such as borax (Na2[B₄O₅)OH(₄].8H₂O) and Chile saltpetre (NaNO₃) are commercially important sources of other elements (e.g. B and N respectively). Unlike many inorganic chemicals, NaCl need not be manufactured since large natural deposits are available. Evaporation of seawater yields a mixture of salts, but since NaCl represents the major component of the mixture, its production in this manner is a viable operation.

  In contrast to Na and K, natural abundances of Li, Rb and Cs are small (% abundance Rb > Li > Cs); these metals occur as various silicate minerals, e.g. spodumene (LiAlSi₂O₆).