Salts of Oxo-Acids

An oxo-acid is one in which the ionisable proton sits on a hydroxyl group that is itself attached to an oxo (=O) group on the same central atom — carbonic acid $H_2CO_3$, written $OC(OH)_2$, and sulphuric acid $H_2SO_4$, written $O_2S(OH)_2$, are two familiar examples. The alkali metals form salts with essentially all oxo-acids, and these salts are, almost without exception, water-soluble and thermally stable. Both the normal carbonates ($M_2CO_3$) and the hydrogencarbonates ($MHCO_3$) of the alkali metals resist decomposition on heating remarkably well, and this thermal stability actually improves down the group as the metal becomes more electropositive. …