Alkali Metals 5 : Lithium, sodium, potassium, rubidium, cesium, and francium. Alkali metals decompose in water on contact, giving off hydrogen which may be ignited by the exothermic reaction
Ralph W. Burklin & Robert G. Purington, Fire Terms: A Guide to Their Meaning and Use, National Protection Association, Boston, MA 1980 USA. (Guide: Meaning and Use, Nat Prot Association Fr Srvc - Amer) {457}