Cesium is an alkali metal, like sodium; hence, it forms a salt, cesium chloride ([math]CsCl[/math]) similar to table salt, sodium chloride. read more
It's worth noting that the formation of salts is highly exothermic, that is, if you were to get cesium metal and gaseous chlorine to combine to form this salt, the reaction would produce a lot of heat along the way! read more