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Name Cesium
Atomic Number 55
Atomic Weight 132.90546 amu
Symbol Cs
Melting Point ( °C ) 28.5 °C
Boiling Point ( °C ) 678.4 °C
Density (g/cm3) 293 K: 1.873 g/cm3
Earth crust (%) 0.00019%
Discovery (Year) 1860
Group Alkali metal
Electron configuration [Xe] 6s1
Ionization energy (eV) 3,8939

Description The element’s name is Cesium, its chemical symbol is Cs. Cesium’s atomic number is 55, its atomic mass is 132.90546 amu, its melting point is 28.5 °C (301.65 K, 83.3 °F), its boiling point is 678.4 °C (951.55005 K, 1253.12 °F), and it has 55 protons/electrons and 78 neutrons. It’s classified as an alkali metal, which means it’s soft, malleable, ductile, and it’s a good conductor of heat and electricity. Its crystal structure is cubic, it has a density of 293 K: 1.873 g/cm3, and a silver color.

Discovery Cesium was discovered by Robert Bunsen and Gustav Kirchhoff in 1860 in Heidelberg, Germany, when they analyzed the spectrum of mineral water. It was the first element discovered using a spectroscope, which was developed a year earlier by Bunsen and Kirchhoff; it was based on a prism which separated light from a flame into a rainbow of colors. In every spectrum they observed, Bunsen and Kirchhoff found colored lines. They realized that these colored lines were unique to the substance being burnt. When studying the spectrum of spa mineral water residue, they found a series of colored emission spectra lines that did not correspond to any known element, and named the element cesium, from the Latin word ‘caesius’ meaning sky blue, since the lines seen in the spectrum for this element were blue.

Uses 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 strengthen 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 chloride is also an unproven treatment for cancer; it is not currently endorsed by the medical "establishment". There are some intriguing case studies, but the documented scientific evidence is pretty murky at this point.

Cesium Market The cesium market is very small. As a result, there is no active trading of the metal and, therefore, no official market price. However, several companies publish prices for cesium and cesium compounds. These prices are relatively stable for several years. The per-unit price for the metal or compounds purchased from these companies varies inversely with the quantity of material purchased. For example, in 1996, one company offered 1-gram ampoules of 99.98% grade cesium metal at $40.80. The price for 100 grams of the same material from this company was $535.00 or $5.35 per gram. At another company, the price for a 1-gram ampoule of 99.95% pure cesium was $38.64.

Abundance of Cesium Cesium is not a very common element, it’s about the 45th most abundant in the Earth's crust. It occurs in pollucite, which is found in North America, Italy, Kazakhstan, and Sweden. Caesium is also found in rhodizite, a borate mineral containing aluminium, caesium, beryllium, and sodium. This is found in the Urals and in Madagascar. Caesium is also contained in some potassium ores. In the universe, cesium’s abundance is 8.×10-8%

Resources www.findfast.org, / www.webelements.com / periodictable.com / minerals.usgs.gov