Stable Isotopes of Cesium
|Isotope||Z(p)||N(n)||Atomic Mass||Natural Abundance||Nuclear Spin|
Cesium, also spelled caesium, was discovered in 1860 by Robert Bunsen and Gustav Kirchhoff. Its name derives from the Latin word caesius, meaning "sky blue" or "heavenly blue."
Cesium is a golden yellow, soft, ductile metal with a body-centered cubic structure. It is liquid at slightly above room temperature and a soft solid below its melting point. It is highly reactive and decomposes in water, evolving hydrogen, which ignites instantly. It also reacts violently with oxygen, the halogens, sulfur and phosphorus, with spontaneous ignition and/or explosion. Cesium has the highest position in the electromotive series, the lowest melting point of any alkali metal, and the lowest ionization potential of any element. It is soluble in acids and alcohol, reacts explosively with water, and dissolves in liquid ammonia, forming a blue solution. It combines with most nonmetals, forming one or more binary compounds. Combustion with oxygen (or air) first forms the oxide Cs2O, which converts to the peroxide Cs2O2, and then the superoxide CsO2.
Applications of cesium include the following: usefulness as a "getter" in electron tubes, in photoelectric cells, in ion propulsion systems, as heat transfer fluid in power generators, and in atomic clocks. Radioactive Cesium-137 has prospective applications in the sterilization of wheat, flour and potatoes.
Cesium presents a dangerous fire and explosion risk. It ignites spontaneously in moist air, may explode in contact with sulfur or phosphorus, and reacts violently with oxidizing materials. It causes burns on contact with skin.
Properties of Cesium
|Standard state||Solid at 298 ºK (but melts only slightly above this temperature)|
|CAS Registry ID||7440-46-2|
|Group in periodic table||1|
|Group name||Alkali metal|
|Period in periodic table||6|
|Block in periodic table||s-block|
|Melting point||28.44 °C|
|Boiling point||669.3 °C|
|Thermal conductivity||35.9 W/(m·K) at 298.2 °K|
|Electrical resistivity||20 µΩ·cm at 20 °C|
|Specific heat||242 J/kg K|
|Heat of vaporization||65 kJ·mol-1|
|Heat of fusion||2.09 kJ·mol-1|
|Density of liquid||1.843 g/cm3|
|Density of solid||1.93 g/cm3|
|Mohs hardness scale||0.2|
|Atomic radius||2.65 Å|
|Ionic radius||Cs+: 1.84 Å|
|Ionization potential||3.89 eV|
- Spallation reaction study for fission products in nuclear waste: Cross section measurements for 137Cs and 90Sr on proton and deuteron
- Characterising legacy spent nuclear fuel pond materials using microfocus X-ray absorption spectroscopy
- Comparison of radiocesium and stable isotope ratios of carbon and nitrogen among three stocks of Pacific cod (Gadus macrocephalus) around Hokkaido, Japan
- Current radiological situation in areas of Ukraine contaminated by the Chernobyl accident: Part 1. Human dietary exposure to Caesium-137 and possible mitigation measures
- Discovery of fissionogenic Cs and Ba capture five years after Oklo reactor shutdown
- Background gamma radiation and soil activity measurements in the northern Marshall Islands