What is Cesium: Definition and 15 Discussions

Caesium (IUPAC spelling) (also spelled cesium in American English) is a chemical element with the symbol Cs and atomic number 55. It is a soft, silvery-golden alkali metal with a melting point of 28.5 °C (83.3 °F), which makes it one of only five elemental metals that are liquid at or near room temperature. Caesium has physical and chemical properties similar to those of rubidium and potassium. The most reactive of all metals, it is pyrophoric and reacts with water even at −116 °C (−177 °F). It is the least electronegative element, with a value of 0.79 on the Pauling scale. It has only one stable isotope, caesium-133. Caesium is mined mostly from pollucite, while the radioisotopes, especially caesium-137, a fission product, are extracted from waste produced by nuclear reactors.
The German chemist Robert Bunsen and physicist Gustav Kirchhoff discovered caesium in 1860 by the newly developed method of flame spectroscopy. The first small-scale applications for caesium were as a "getter" in vacuum tubes and in photoelectric cells. In 1967, acting on Einstein's proof that the speed of light is the most constant dimension in the universe, the International System of Units used two specific wave counts from an emission spectrum of caesium-133 to co-define the second and the metre. Since then, caesium has been widely used in highly accurate atomic clocks.
Since the 1990s, the largest application of the element has been as caesium formate for drilling fluids, but it has a range of applications in the production of electricity, in electronics, and in chemistry. The radioactive isotope caesium-137 has a half-life of about 30 years and is used in medical applications, industrial gauges, and hydrology. Nonradioactive caesium compounds are only mildly toxic, but the pure metal's tendency to react explosively with water means that caesium is considered a hazardous material, and the radioisotopes present a significant health and ecological hazard in the environment.

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  1. Mackenzie Cobb

    Chernobyl Cesium 137 Half-Life vs. Chernobyl Contamination

    Let me start out by saying that I have no idea what I'm talking about. I graduated from Indiana University with a Bachelor's in Spanish, and I work as a Loan Review Specialist at a bank, which has NOTHING to do with my degree, and still yet nothing to do with this topic. But lately, I've become...
  2. S

    Why do copper, gold and cesium have special colors?

    Because metals have free electrons, so they have almost continuous energy states going up and down different energy levels and repeating themselves, most metals are silver-white, right?But why do gold, copper, and cesium have special colors? I wanted to know more about this, so I studied the...
  3. T

    B Why does GPS require an accurate clock?

    Why do GPS need a cesium clock accurate to 10ns? Is this strictly for time keeping or is there some synchronization between satellites?
  4. CMATT

    A sample of a compound of cesium (Cs) and iodine (I) contain

    Homework Statement A sample of a compound of cesium (Cs) and iodine (I) contains 51.16g cesium and 48.84 g iodine, how many grams of cesium can be obtained from 85.5g of this compound? The attempt at a solution I don't really know where to begin. What I have tried was the following: 51.16 g +...
  5. Cyril St-Amand

    Dismantlement of Nuclear Power Plant (Canada)

    Hi everyone this is my first time posting here, First of all, excuse my english because here in Mtl we speak French mostly. My team and I are working on an university project in Montreal (Qc) Canada (Polytechnique) regarding the recycling of radioactive material waste. We are working on the...
  6. A

    Einstein notion of time and the oscillation of the cesium atom

    I just read the thread entitled: "How did Einstein Define Time" and I'm very confused. At school, I was taught that time was an abstract representation of movement meaning that the word "time" can only be used to represent movements. For example, when Earth has completed a cycle around the...
  7. J

    How many wavelengths of caesium-133 radiation are used to define the second?

    I am reading a book called advanced physics, which is very good I may add. there is a question in it as follows; The second is defined as 9,192,631,770 periods of radiation from a caesium-133 atom, The metere is defined as the distance traveled by light in 1/299792458 of a second. How many...
  8. T

    Cesium Atom quantum mechanical description

    Hello guys, I need the quantum mechanical description of the Cesium atom/gas with its hyperfine states, and preferably with some density matrix. I don't really know where to start my search. I googled a lot, and looked for articles and books, but failed. Any help is highly appreciated...
  9. T

    How do Cesium gas atoms demagnetise

    Hello guys :), if we magnetise Cs atoms with a magnetic field (or basically any other method like pumping), and got all the spins (moments) aligned in 1 direction, and then turn the cause of the alignment off, how will the decay profile look like? is it going to be a clean exponential decay...
  10. R

    Speed of Light in Cesium Vapors

    I recently read http://www.google.co.in/search?source=ig&hl=en&rlz=&=&q=speed+of+light+in+caesium+vapors&btnG=Google+Search" that speed of light is faster in cesium vapors. It is described as leaving the cesium container even before it has entered it, claims that light travels 310 times faster...
  11. P

    Exploring Cesium Atomic Clock Functionality

    Can anyone recommend me some papers explaing how cesium atomic clock works?
  12. S

    Can Yellow Light Ionize Cesium Atom?

    Cesium is often used in "electric eyes" for self-opening doors in an application of the photoelectric effect. The amount of energy required to ionize (remove an electron from ) a cesium atom is 3.89 electron volts (1 eV = 1.60 x 10-19 J). Show by calculation whether a beam of yellow light with...
  13. C

    Cesium Chloride Crystal Structure

    I am working this problem... http://www.fiu.edu/~saulj/Teaching/Physics2/01-Electric_Force/CrystalStructure.html I got the answer to a as 0, but don't understand b.
  14. marcus

    Teleportation (new Danish experiment with light and cesium atoms)

    http://physicsweb.org/articles/news/10/10/6/1?rss=2.0 ===sample=== 5 October 2006 Danish physicists have managed to light-up a cloud of atoms using light teleported from a source half a metre away. Since Charles Bennett and his team first proposed quantum teleportation in 1993, science...
  15. T

    Exploring the Uses of Cesium and Thallium

    It goes like this, very simple: How and where can cesium and thallium be used?