Caesium
SEE-zi-em
Caesium (Cs) is a soft gray coloured metal that has the atomic number 55 in the periodic table. It is an Alkali Metal and is located in Group 1 of the periodic table. it has the symbol Cs.
Caesium was discovered in 1860 by Robert Bunsen and Gustav Kirchhoff whilst analysing the contents of mineral water using spectroscopy. They discovered some lines in one spectrum that did not correspond to any known previously. Like other Alkali metals Caesium has a violent reaction with water and oxygen so must be kept in oil or an inert environment. Caesium’s main use is in atomic clocks for accuracy in timing. It is also used as a catalyst in the hydrogenation of organic compounds. It is a solid metal at room temperature with a melting point of 28.4°c and a boiling point of 670°c. Caesium if found in minerals pollucite and lepidolite in the earth’s crust and is not found naturally.
FAQ's
Gustov Kirchoff, Robert Bunsen
1860
Uses
Used as a 'getter' to remove air traces in vacuum and cathode-ray tubes. Also used in producing photoelectric devices and atomic clocks. Since it ionizes readily, it is used as an ion rocket motor propellant.
Sources
Found in pollucite [(Cs4Al4Si9O26).H2O] and as trace in lepidolite.
About the author
Nathan M
Nathan has a degree in BSc Biomedical Chemistry at Warwick University and a degree in PGCE Science at Wolverhampton University, UK. Nathan's subject matter ranges from general chemistry and organic chemistry. Nathan also created the curriculum on Breaking Atom in the course page.
Citation
Cs
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