Science / Periodic Table of Elements / Cesium (Cs): Atomic number: 55, Atomic mass: 132.9054 g.mol -1, Electronegativity: 0.7, Density: 1.9 g.cm-3 at 20°C, Melting point: 28.4 °C, Boiling point: 669 °C, Vanderwaals radius: 0.267 nm, Ionic radius: 0.167, Isotopes: 12, Electronic shell: [ Xe ] 6s1, Energy of first ionisation: 375.6 kJ.mol -1, Discovered by: Fustov Kirchhoff in 1860. The metal is characterised by a spectrum containing two bright lines in the blue (accounting for its name). It is silvery gold, soft, and ductile. It is the most electropositive and most alkaline element. Cesium, gallium, and mercury are the only three metals that are liquid at or around room temperature. Cesium reacts explosively with cold water, and reacts with ice at temperatures above -116°C. Cesium hydroxide is a strong base and attacks glass. Cesium reacts with the halogens to form a fluoride, chloride, bromide, and iodide. Cesium metal oxidized rapidly when exposed to the air and can form the dangerous superoxide on its surface. Applications: Cesium is used in industry as a catalyst promoter, boosting the performance of other metal oxides in the capacity and for the hydrogenation of organic compounds. Cesium nitrate is used to make optical glasses. Cesium is sometimes used to remove traces of oxygen from the vacuum tubes and from light bulbs. Cesium salts are used to strenght various types of glass. The chloride is used in photoelectric cells, in optical instruments, and in increasing the sensitivity of electron tubes. Cesium is used in atomic clocks and more recently in ion propulsion systems. Cesium in the environment: Although cesium is much less abundant than the other alkali metals, it is still more common than elements like arsenic, iodine and uranium. Few cesium mineral are know, pollucite is the main: they are silicate magmas cooled from granites. World production of cesium compounds is just 20 tonnes per year, coming mainly from the Bernic lake (Canada) with a little from Zimbabwe and South-West Africa.
Science / Periodic Table of Elements / Cesium (Cs): Atomic number: 55, Atomic mass: 132.9054 g.mol -1, Electronegativity: 0.7, Density: 1.9 g.cm-3 at 20°C, Melting point: 28.4 °C, Boiling point: 669 °C, Vanderwaals radius: 0.267 nm, Ionic radius: 0. MORE