Herschel believed that this occurrence is due to the existence of substances that must be analyzed with a more powerful technique and equipment needed to measure the interactions between light and matter, rather than the usual technique of electrolysis.įast forward to 1989, Robert Bunsen entertained the idea of using filters to block the intense colors emitted by the substances (such as chromium yellow) so that the less intensive colors (potassium’s ultraviolet, for instance) could be more easily detected. This prismatic spectrum of a flame was a point of interest for this English polymath (mathematician, astronomer, chemist, experimental photographer, and inventor of the blueprint). John Herschel heated a compound in one of his chemical attempts, and among the different colors of flame that passed through the prism, Herschel also observed unseen lines of the spectrum. The Revolutionary Invention of the Spectroscopy The most volatile caesium reactions occur in the presence of fluorine, chlorine, bromine, and iodine, while sulfur and phosphorus trigger its incandescence (emission of light) after exposure to high temperatures. In contact with cold water, caesium creates volatile, explosive reactions due to the formation of hydrogen gas and a solution of caesium ions and hydroxide ions:ĢCs (s) + 2H₂O (l) → H₂ (g) + 2Cs⁺ (aq) + 2OH⁻ ( aq) it spontaneously ignites after being exposed to air for only 5 minutes. This alkali metal is pyrophoric by nature, i.e. The crystal structure of caesium is a body-centered cubic, resembling two interpenetrating simple cubic lattices. It’s the most alkaline element of the periodic table.īoth the physical and the chemical properties of caesium resemble those of rubidium and potassium. The atomic radius of caesium according to van der Waals is 0.267 nm. This member of the alkali metals family of elements has an electronegativity of 0.79 according to Pauling which makes it the least electronegative chemical element of the periodic table. It reaches its boiling point at 669 ☌, while the melting point of caesium is achieved at 28.5 ☌ (83.3 ☏). Ĭaesium is a soft and ductile metal in a liquid aggregate state at room temperature. The ground state electronic configuration of neutral caesium is 6s 1. In 1860 by Robert Bunsen, Gustav Kirchhoff, and Carl SetterbergĬaesium has the periodic table symbol Cs, atomic number 55, and an atomic mass of 132.9054 g.mol -1. Latin: coesius (sky blue) for the blue lines of its spectrum. Soft, slightly malleable, silvery-white metal. Since it ionizes readily, it is used as an ion rocket motor propellant. Also used in producing photoelectric devices and atomic clocks. Used as a ‘getter’ to remove air traces in vacuum and cathode-ray tubes. Chemical and Physical Properties of Caesium Property
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