Flexi Says: Since the alkali metals are very reactive, their main practical and industrial uses are in chemical compounds with other elements. However, pure liquid sodium metal is used as a coolant in some nuclear power plants. Sodium compounds are commonly used for many purposes, including salt (NaCl), baking soda (NaHCO3), and sodium carbonate (Na2CO3). Lithium is an important metal in the kinds of rechargeable batteries used for electronic devices such as phones and computers, and also in larger capacity batteries used for electric cars and household power systems. Potassium is used primarily for fertilizer. Cesium is used in atomic clocks.