55 xenon ← caesium → barium Rb ↑ Cs ↓ Fr Periodic Table - Extended Periodic Table
General
Name, Symbol, Number	caesium, Cs, 55
Chemical series	alkali metals
Group, Period, Block	1, 6, s
Appearance	silvery gold
Standard atomic weight	132.9054519(2)  g·mol−1
Electron configuration	[Xe] 6s1
Electrons per shell	2, 8, 18, 18, 8, 1
Physical properties
Phase	solid
Density (near r.t.)	1. Xenon (ˈzɛnɒn or) is a Chemical element represented by the symbol Xe. Barium (ˈbɛəriəm is a Chemical element. It has the symbol Ba, and Atomic number 56 Rubidium (ruːˈbɪdiəm /rəˈbɪdiəm/ is a Chemical element with the symbol Rb and Atomic number 37 Francium (ˈfrænsiəm formerly known as eka-caesium and actinium K, is a Chemical element that has the symbol Fr and This is a typical display of the periodic table of the elements and contains the symbol and Atomic number of each element Wikipedia talkFeatured lists for an explanation of this and other inclusion tags below -->This is a list of Chemical elements, sorted by name Wikipedia talkFeatured lists for an explanation of this and other inclusion tags below -->This is a list of chemical elements by symbol, including the A table of Chemical elements ordered by Atomic number and color coded according to type of element In Chemistry a group, also known as a family, is a vertical column in the Periodic table of the Chemical elements There are 18 groups in Trends The alkali metals show a number of trends when moving down the group - for instance decreasing electronegativity increasing reactivity and decreasing melting and boiling In Chemistry a group, also known as a family, is a vertical column in the Periodic table of the Chemical elements There are 18 groups in In the Periodic table of the elements, a period is a horizontal row of the table A block of the Periodic table of elements is a set of adjacent groups The respective highest-energy electrons in each element in a block belong to the same Atomic Trends The alkali metals show a number of trends when moving down the group - for instance decreasing electronegativity increasing reactivity and decreasing melting and boiling A period 6 element is one of the Chemical elements in the sixth row (or period) of the periodic table of the elements, including the Lanthanides See also Electron configuration The atomic mass (ma is the Mass of an atom most often expressed in unified atomic mass units The atomic mass may be considered to be the total mass To help compare different orders of magnitude, the following list describes various Mass levels between 10&minus36&thinsp kg and 1053&thinspkg In Atomic physics and Quantum chemistry, electron configuration is the arrangement of Electrons in an Atom, Molecule, or other Xenon (ˈzɛnɒn or) is a Chemical element represented by the symbol Xe. The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J An electron shell may be crudely thought of as an Orbit followed by Electrons around an Atom nucleus. In the Physical sciences a phase is a Set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties A solid' object is in the States of matter characterized by resistance to Deformation and changes of Volume. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different Room temperature (also referred to as ambient temperature) is a common term to denote a certain Temperature within enclosed space at which humans are accustomed 93  g·cm−3
Liquid density at m.p.	1. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different The melting point of a solid is the temperature range at which it changes state from solid to Liquid. 843  g·cm−3
Melting point	301. The melting point of a solid is the temperature range at which it changes state from solid to Liquid. 59 K (28. The kelvin (symbol K) is a unit increment of Temperature and is one of the seven SI base units The Kelvin scale is a thermodynamic 44 °C, 83. The Celsius Temperature scale was previously known as the centigrade scale. 19 °F)
Boiling point	944 K (671 °C, 1240 °F)
Critical point	1938 K, 9. Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit (1686–1736 a German Physicist who proposed it in 1724 The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid The kelvin (symbol K) is a unit increment of Temperature and is one of the seven SI base units The Kelvin scale is a thermodynamic The Celsius Temperature scale was previously known as the centigrade scale. Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit (1686–1736 a German Physicist who proposed it in 1724 In Physical chemistry, Thermodynamics, Chemistry and Condensed matter physics, a critical point, also called a critical state The kelvin (symbol K) is a unit increment of Temperature and is one of the seven SI base units The Kelvin scale is a thermodynamic 4 MPa
Heat of fusion	2. The standard Enthalpy of fusion (symbol \Delta{}H_{fus} also known as the heat of fusion or specific melting heat, is the amount of 09  kJ·mol−1
Heat of vaporization	63. The joule per mole (symbol J·mol-1 is an SI derived unit of energy per amount of material The enthalpy of vaporization, (symbol \Delta{}_{v}H also known as the heat of vaporization or heat of evaporation, is the Energy required 9  kJ·mol−1
Specific heat capacity	(25 °C) 32. The joule per mole (symbol J·mol-1 is an SI derived unit of energy per amount of material Specific heat capacity, also known simply as specific heat, is the measure of the heat energy required to increase the Temperature of a unit quantity 210  J·mol−1·K−1
Vapor pressure P(Pa) 1 10 100 1 k 10 k 100 k at T(K) 418 469 534 623 750 940
Atomic properties
Crystal structure	body centered cubic
Oxidation states	1 (strongly basic oxide)
Electronegativity	0. Vapor pressure (also known as equilibrium vapor pressure or saturation vapor pressure) is the Pressure of a Vapor in equilibrium In Mineralogy and Crystallography, a crystal structure is a unique arrangement of Atoms in a Crystal. In Chemistry, the oxidation state is an indicator of the degree of Oxidation of an Atom in a Chemical compound. In Chemistry, a base is most commonly thought of as an aqueous substance that can accept Protons This refers to the Brønsted-Lowry theory of acids and " Electronegativity " is the opposite of " Electropositivity," which describes an element's ability to donate electrons 79 (Pauling scale)
Ionization energies	1st: 375. The ionization potential, ionization energy or EI of an Atom or Molecule is the Energy required to remove an Electron 7 kJ/mol
	2nd: 2234. The joule per mole (symbol J·mol-1 is an SI derived unit of energy per amount of material 3 kJ/mol
	3rd: 3400 kJ/mol
Atomic radius	260  pm
Atomic radius (calc. Atomic radius, and more generally the size of an atom, is not a precisely defined Physical quantity, nor is it constant in all circumstances A picometre ( American spelling: picometer, symbol pm) is a unit of Length in the Metric system, equal to one trillionth )	298  pm
Covalent radius	225  pm
Miscellaneous
Magnetic ordering	no data
Electrical resistivity	(20 °C) 205 n Ω·m
Thermal conductivity	(300 K) 35. The covalent radius, r cov is a measure of the size of Atom which forms part of a Covalent bond. In Physics, magnetism is one of the Phenomena by which Materials exert attractive or repulsive Forces on other Materials. Electrical resistivity (also known as specific electrical resistance) is a measure of how strongly a material opposes the flow of Electric current. In Physics, thermal conductivity, k is the property of a material that indicates its ability to conduct Heat. 9  W·m−1·K−1
Thermal expansion	(25 °C) 97  µm·m−1·K−1
Young's modulus	1. When the Temperature of a substance changes the energy that is stored in the Intermolecular bonds between atoms changes In Solid mechanics, Young's modulus (E is a measure of the Stiffness of an isotropic elastic material 7  GPa
Bulk modulus	1. 6  GPa
Mohs hardness	0. The Mohs scale of mineral hardness characterizes the scratch resistance of various Minerals through the ability of a harder material to scratch a softer material 2
Brinell hardness	0. The Brinell scale characterizes the indentation Hardness of materials through the scale of penetration of an indenter loaded on a material test-piece 14  MPa
CAS registry number	7440-46-2
Selected isotopes
Main article: Isotopes of caesium iso NA half-life DM DE (MeV) DP 133Cs 100% 133Cs is stable with 78 neutrons 134Cs syn 65. CAS registry numbers are unique numerical identifiers for Chemical compounds Polymers biological sequences mixtures and Alloys They are also referred to Caesium ( Cs) has at least 39 known isotopes which is more than any other element except Francium. Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides In Chemistry, natural abundance (NA refers to the abundance Isotopes of a Chemical element as naturally found on a planet Half-Life (computer-game page here It's already listed in the disambiguation page Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. The decay energy is the Energy released by a Nuclear decay. The energy difference of the Reactants is often written as Q: where Q In Nuclear physics, a decay product, also known as a daughter product, daughter isotope or daughter nuclide, is a Nuclide Stable isotopes are chemical isotopes that are not Radioactive (to current knowledge This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. A synthetic radioisotope is a Radionuclide that is not found in nature no natural process or mechanism exists which produces it or it is so unstable that it decays away in 159 Ms (2. The second ( SI symbol s) sometimes abbreviated sec, is the name of a unit of Time, and is the International System of Units 0648y) ε 1. A year (from Old English gēr) is the time between two recurrences of an event related to the Orbit of the Earth around the Sun Electron capture (sometimes called inverse beta decay) is a Decay mode for Isotopes that will occur when there are too many Protons in the 229 134Xe β- 2. Xenon (ˈzɛnɒn or) is a Chemical element represented by the symbol Xe. In Nuclear physics, beta decay is a type of Radioactive decay in which a Beta particle (an Electron or a Positron) is emitted 059 134Ba 135Cs trace 73 Ts (2,300,000y) β- 0. Barium (ˈbɛəriəm is a Chemical element. It has the symbol Ba, and Atomic number 56 A trace radioisotope is a Radioisotope that occurs naturally in trace amounts (i The second ( SI symbol s) sometimes abbreviated sec, is the name of a unit of Time, and is the International System of Units In Nuclear physics, beta decay is a type of Radioactive decay in which a Beta particle (an Electron or a Positron) is emitted 269 135Ba 137Cs syn 948. Barium (ˈbɛəriəm is a Chemical element. It has the symbol Ba, and Atomic number 56 A synthetic radioisotope is a Radionuclide that is not found in nature no natural process or mechanism exists which produces it or it is so unstable that it decays away in 9 Ms (30. 07y) β- 1. In Nuclear physics, beta decay is a type of Radioactive decay in which a Beta particle (an Electron or a Positron) is emitted 176 137Ba
References

Caesium or cesium (pronounced /ˈsiːziəm/) is the chemical element with the symbol Cs and atomic number 55. Barium (ˈbɛəriəm is a Chemical element. It has the symbol Ba, and Atomic number 56 Recommended values for many properties of the elements together with various references are collected on these data pages A chemical element is a type of Atom that is distinguished by its Atomic number; that is by the number of Protons in its nucleus. See also List of elements by atomic number In Chemistry and Physics, the atomic number (also known as the proton It is a soft, silvery-gold alkali metal with a melting point of 28 °C (83 °F), which makes it one of only five metals that are liquid at or near room temperature. Trends The alkali metals show a number of trends when moving down the group - for instance decreasing electronegativity increasing reactivity and decreasing melting and boiling Room temperature (also referred to as ambient temperature) is a common term to denote a certain Temperature within enclosed space at which humans are accustomed ^[1] Caesium is most notably used in atomic clocks. An atomic clock is a type of Clock that uses an Atomic resonance Frequency standard as its timekeeping element

The more common spelling cesium is used especially in North American English, but caesium is the international spelling standardized by the IUPAC. North American English is a collective term used for the varieties of the English language that are spoken in North America, namely in the United States The International Union of Pure and Applied Chemistry ( IUPAC) (aɪjuːpæk or ay-yoo-pec) is an international Non-governmental organization

Notable characteristics

The emission spectrum of caesium has two bright lines in the blue part of the spectrum along with several other lines in the red, yellow, and green. An element's 'emission spectrum' is the relative intensity of Electromagnetic radiation of each Frequency it emits when it is Heated (or more generally when This metal is silvery gold in color and is both soft and ductile. Caesium is the second most electropositive and alkaline of the chemical elements and has the second lowest ionization potential (after francium). Electropositivity is a measure of an element's ability to donate Electrons, and therefore form positive Ions. In Chemistry, an alkali (from Arabic: Al-Qaly القلي القالي) is a basic, ionic salt of an Alkali metal A chemical element is a type of Atom that is distinguished by its Atomic number; that is by the number of Protons in its nucleus. The ionization potential, ionization energy or EI of an Atom or Molecule is the Energy required to remove an Electron Francium (ˈfrænsiəm formerly known as eka-caesium and actinium K, is a Chemical element that has the symbol Fr and Caesium is the least abundant of the five non-radioactive alkali metals. (Francium is the least common alkali metal, but since it is highly radioactive with an estimated 30 grams in the entire Earth's crust at one time,^[2] its abundance can be considered zero in practical terms. Francium (ˈfrænsiəm formerly known as eka-caesium and actinium K, is a Chemical element that has the symbol Fr and In Geology, a crust is the outermost solid shell of a planet or moon )

Along with gallium, francium, rubidium, and mercury, caesium is among the only metals that are liquid at or near room temperature. Gallium (ˈgæliəm is a Chemical element that has the symbol Ga and Atomic number 31 Francium (ˈfrænsiəm formerly known as eka-caesium and actinium K, is a Chemical element that has the symbol Fr and Rubidium (ruːˈbɪdiəm /rəˈbɪdiəm/ is a Chemical element with the symbol Rb and Atomic number 37 Mercury (ˈmɜrkjʊri also called quicksilver or hydrargyrum, is a Chemical element with the symbol Hg ( Latinized hydrargyrum Caesium reacts explosively in cold water and also reacts with ice at temperatures above −116 °C (−177 °F, 157 K). Water ( H2[[oxygen O]] H OH) is the most abundant Molecule on Earth 's surface composing of about 70% of the Earth's surface as

Caesium hydroxide (CsOH) is a very strong base and will rapidly etch the surface of glass. Caesium hydroxide (CsOH is a Chemical compound consisting of an atom of Caesium and a Hydroxide group (also known as Hydroxyl) In Chemistry, a base is most commonly thought of as an aqueous substance that can accept Protons This refers to the Brønsted-Lowry theory of acids and Glass in the common sense refers to a Hard, Brittle, transparent Solid, such as that used for Windows many CsOH is often stated to be the "strongest base", but in fact many compounds such as n-butyllithium and sodium amide are stronger. n -Butyllithium (abbreviated BuLi is the most prominent Organolithium reagent. Sodium amide, commonly called sodamide is the Chemical compound with the formula NaNH2

Applications

Probably the most widespread use of caesium today is in caesium formate-based drilling fluids for the oil industry. Drilling a very deep hole is a very costly business The hole size is kept very small as the drilled depth increases because it is to cased and cemented after wards The high density of the caesium formate brine (up to 2. 3 sg), coupled with the relatively benign nature of ¹³³Cs , reduces the requirement for toxic high-density suspended solids in the drilling fluid, which is a significant technological, engineering and environmental advantage. Specific gravity is defined as the ratio of the Density of a given solid or liquid substance to the density of water at a specific temperature and pressure typically ^[3][4]

Caesium is also used in atomic clocks, which are accurate to seconds in many thousands of years. An atomic clock is a type of Clock that uses an Atomic resonance Frequency standard as its timekeeping element Since 1967, the International System of Measurements has based its unit of time, the second, on the properties of caesium. For other uses see Time (disambiguation Time is a component of a measuring system used to sequence events to compare the durations of The second ( SI symbol s) sometimes abbreviated sec, is the name of a unit of Time, and is the International System of Units SI defines the second as 9,192,631,770 cycles of the radiation which corresponds to the transition between two hyperfine energy levels of the ground state of the ¹³³Cs atom. The second ( SI symbol s) sometimes abbreviated sec, is the name of a unit of Time, and is the International System of Units Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. In Atomic physics, hyperfine coupling is the weak magnetic interaction between Electrons and nuclei. A quantum mechanical system or particle that is bound, confined spacially can only take on certain discrete values of energy as opposed to classical particles which In Quantum mechanics, a stationary state is an Eigenstate of a Hamiltonian, or in other words a state of definite energy History See also Atomic theory, Atomism The concept that matter is composed of discrete units and cannot be divided into arbitrarily tiny

• ¹³⁴Cs has been used in hydrology as a measure of caesium output by the nuclear power industry. Hydrology (from Greek Yδωρ hudōr, "water" and λόγος logos, "study" is the study of the movement distribution and quality of Nuclear power is any Nuclear technology designed to extract usable Energy from atomic nuclei via controlled Nuclear reactions This isotope is used because, while it is less prevalent than either ¹³³Cs or ¹³⁷Cs, ¹³⁴Cs can be produced solely by nuclear reactions. Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides Caesium-137 (also spelled cesium is a radioactive Isotope of Caesium which is formed mainly by Nuclear fission. ¹³⁵Cs has also been used in this function.
• Like other elements of group 1, caesium has a great affinity for oxygen and is used as a "getter" in vacuum tubes. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Getters are reactive materials used for removing traces of gas from vacuum systems This article is about the electronic device not an evacuated pipe used for experiments in Free-fall.
• This metal is also used in photoelectric cells due to its ready emission of electrons. A solar cell or photovoltaic cell is a device that converts Solar energy into Electricity by the photovoltaic effect. The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J
• Caesium was used as a propellant in early ion engines. An ion thruster is a form of Electric propulsion used for Spacecraft propulsion that creates thrust by accelerating Ions Ion thrusters are characterized It used a method of ionization to strip the outer electron from the propellant by simple contact with tungsten. Caesium use as a propellant was discontinued when Hughes Research Laboratory conducted a study finding xenon gas as a suitable replacement. HRL redirects here For the US airport see Valley International Airport. Xenon (ˈzɛnɒn or) is a Chemical element represented by the symbol Xe.
• Caesium is used as a catalyst in the hydrogenation of certain organic compounds. Catalysis is the process in which the rate of a Chemical reaction is increased by means of a Chemical substance known as a catalyst Hydrogenation is the Chemical reaction that results in addition of Hydrogen (H2 An organic compound is any member of a large class of Chemical compounds whose Molecules contain Carbon.
• Radioactive isotopes of caesium are used in the medical field to treat certain types of cancer. Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. Cancer (medical term Malignant Neoplasm) is a class of Diseases in which a group of cells display uncontrolled
• Caesium fluoride is widely used in organic chemistry as a base and as a source of anhydrous fluoride ion. Caesium fluoride ( cesium fluoride in North America is an ionic compound usually found as a hygroscopic white solid Organic chemistry is a discipline within Chemistry which involves the scientific study of the structure properties composition reactions, and preparation In Chemistry, a base is most commonly thought of as an aqueous substance that can accept Protons This refers to the Brønsted-Lowry theory of acids and As a general term a substance is said to be anhydrous if it contains no Water. Fluoride is the reduced form of Fluorine. Both organic and Inorganic compounds containing the element fluorine are considered fluorides
• Caesium vapor is used in many common magnetometers. A magnetometer is a scientific instrument used to measure the strength and/or direction of the Magnetic field in the vicinity of the instrument
• Because of their high density, caesium chloride solutions are commonly used in molecular biology for density gradient ultracentrifugation, primarily for the isolation of viral particles, subcellular organelles and fractions, and nucleic acids from biological samples. Cesium chloride is the Chemical compound with the formula Cs[[Chlorine Cl]]
• Caesium nitrate is used as an oxidizer to burn silicon in infrared flares^[5] like the LUU-19 flare,^[6] because it emits much of its light in the near infrared spectrum. An oxidizing agent or oxidising agent (also called an oxidant, oxidizer or oxidiser) can be defined as either a Chemical compound Silicon (ˈsɪlɪkən or /ˈsɪlɪkɒn/ silicium is the Chemical element that has the symbol Si and Atomic number 14 Infrared ( IR) radiation is Electromagnetic radiation whose Wavelength is longer than that of Visible light, but shorter than that of A flare, also sometimes called a fusee, is a type of Pyrotechnic that produces a brilliant light or intense heat without an Explosion. Infrared ( IR) radiation is Electromagnetic radiation whose Wavelength is longer than that of Visible light, but shorter than that of
• Caesium-137 is an extremely common radioisotope used as a gamma-emitter in industrial applications such as:
  • moisture density gauges
  • leveling gauges
  • thickness gauges
  • well-logging devices which are used to measure the electron density, which is analagous to the bulk density, of the rock formations.
• Caesium is also used as an internal standard in spectrophotometry. In Physics, spectrophotometry is the quantitative study of electromagnetic spectra.
• Caesium has been used to reduce the radar signature of exhaust plumes in military aircraft.

History

Caesium (Latin caesius meaning "blueish grey")^[7][8] was spectroscopically discovered by Robert Bunsen and Gustav Kirchhoff in 1860 in mineral water from Dürkheim, Germany. Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. Spectroscopy was originally the study of the interaction between Radiation and Matter as a function of Wavelength (λ Robert Wilhelm Eberhard Bunsen (31 March 1811 &ndash 16 August 1899 was a German Chemist. Gustav Robert Kirchhoff ( March 12, 1824 &ndash October 17, 1887) was a German Physicist who contributed to the fundamental In many places mineral water is often colloquially used to mean Carbonated water (which is usually carbonated mineral water as opposed to tap water Bad Dürkheim is a town on the German Wine Route in Rhineland-Palatinate, Germany, capital of the eponymous district. Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. The residues of 44000 liters of mineral water yielded several grams of caesium salt for further analysis. Its identification was based upon the bright blue lines in its spectrum and it was the first element discovered by spectrum analysis. Spectrum analysis also known as Emission Spectrochemical Analysis is the original scientific method of charting and analyzing the chemical properties of matter and gases by looking ^[9] The first caesium metal was produced in 1882 by electrolysis of caesium chloride by Carl Setterberg. Setterberg received his PhD from Kekule and Bunsen for this work. Friedrich August Kekule von Stradonitz (also August Kekulé) (7 September 1829 &ndash 13 July 1896 was a German organic chemist. Historically, the most important use for caesium has been in research and development, primarily in chemical and electrical applications.

Occurrence

Pollucite, a caesium mineral

An alkali metal, caesium occurs in lepidolite, pollucite (hydrated silicate of aluminium and caesium) and within other sources. Lepidolite (KLi2Al(AlSi3O10(FOH2 is a lilac or rose-violet colored phyllosilicate Mineral of the Mica group Pollucite is a Zeolite mineral with the formula ( Cs, Na)2 Al 2 Si 4 O 12·2 H2O Hydrate is a term used in Inorganic chemistry and Organic chemistry to indicate that a substance contains Water. For the Artificial intelligence Androids of the 1990s Science fiction series Space Above and Beyond, see Silicate (AI WikipediaNaming One of the world's most significant and rich sources of this metal is at Bernic Lake in Manitoba. Manitoba (English ˌmænɨˈtoʊbə French /manitoba/ is a province of Canada, spanning 647797 square kilometres (250116  sq mi of North America The deposits there are estimated to contain 300,000 metric tons of pollucite at an average of 20% caesium. This article is about the tonne or metric ton For other tons see Ton.

It can be isolated by electrolysis of fused caesium cyanide and in a number of other ways. In chemistry and manufacturing electrolysis is a method of separating chemically bonded elements and compounds by passing an Electric current A cyanide is any Chemical compound that contains the cyano group (C≡N which consists of a Carbon Atom triple-bonded to a Exceptionally pure and gas-free caesium can be made by the thermal decomposition of caesium azide. Azide is the anion with the formula N3− It is the Conjugate base of Hydrazoic acid. The primary compounds of caesium are caesium chloride and its nitrate. Cesium chloride is the Chemical compound with the formula Cs[[Chlorine Cl]] In Inorganic chemistry, a nitrate is a salt of Nitric acid with an Ion composed of one Nitrogen and three Oxygen atoms The price of caesium metal in 1997 was about US$30 per gram, but its compounds are much cheaper.

See also Caesium minerals.

Isotopes

Main article: isotopes of caesium

Caesium has at least 39 known isotopes, which is more than any other element except francium. Caesium ( Cs) has at least 39 known isotopes which is more than any other element except Francium. Francium (ˈfrænsiəm formerly known as eka-caesium and actinium K, is a Chemical element that has the symbol Fr and The atomic masses of these isotopes range from 112 to 151. The atomic mass (ma is the Mass of an atom most often expressed in unified atomic mass units The atomic mass may be considered to be the total mass Even though this element has a large number of isotopes, it has only one naturally occurring stable isotope, ¹³³Cs. Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides Most of the other isotopes have half-lives from a few days to fractions of a second. Half-Life (computer-game page here It's already listed in the disambiguation page The radiogenic isotope ¹³⁷Cs has been used in hydrologic studies, analogous to the use of ³H. A radiogenic Nuclide is one that is produced by a process of Radioactive decay. Caesium-137 (also spelled cesium is a radioactive Isotope of Caesium which is formed mainly by Nuclear fission. Tritium (ˈtɹɪtiəm symbol or, also known as Hydrogen-3) is a radioactive Isotope of Hydrogen. ¹³⁷Cs is produced from the detonation of nuclear weapons and is produced in nuclear power plants, and was released to the atmosphere most notably from the 1986 Chernobyl meltdown. A nuclear weapon is an explosive device that derives its destructive force from Nuclear reactions either fission or a combination of fission and fusion. Nuclear power is any Nuclear technology designed to extract usable Energy from atomic nuclei via controlled Nuclear reactions The Chernobyl disaster was a nuclear reactor accident in the Chernobyl Nuclear Power Plant in the Soviet Union. This isotope (¹³⁷Cs) is one of the numerous products of fission, directly issued from the fission of uranium.

High purity caesium-133 (preserved under argon)

Beginning in 1945 with the commencement of nuclear testing, ¹³⁷Cs was released into the atmosphere where it is not absorbed readily into solution and is returned to the surface of the earth as a component of radioactive fallout. Nuclear weapons tests are experiments carried out to determine the effectiveness yield and explosive capability of Nuclear weapons Throughout the twentieth century most nations Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five Fallout is the residual radiation hazard from a Nuclear explosion, so named because it "falls out" of the atmosphere into which it is spread during the explosion Once ¹³⁷Cs enters the ground water, it is deposited on soil surfaces and removed from the landscape primarily by particle transport. As a result, the input function of these isotopes can't be estimated as a function of time. Caesium-137 has a half-life of 30. 17 years. It decomposes to barium-137m (a short-lived product of decay) then to a form of nonradioactive barium.

Precautions

All alkali metals are highly reactive. Caesium, being one of the heavier alkali metals, is also one of the most reactive and is highly explosive when it comes in contact with water. Trends The alkali metals show a number of trends when moving down the group - for instance decreasing electronegativity increasing reactivity and decreasing melting and boiling An explosive material is a material that either is chemically or otherwise Energetically unstable or produces a sudden expansion of the material usually accompanied Water is a common Chemical substance that is essential for the survival of all known forms of Life. The hydrogen gas produced by the reaction is heated by the thermal energy released at the same time, causing ignition and a violent explosion (the same as all alkali metals) - but caesium is so reactive that this explosive reaction can even be triggered by cold water or ice. Caesium hydroxide is an extremely strong base, and can etch glass. Caesium hydroxide (CsOH is a Chemical compound consisting of an atom of Caesium and a Hydroxide group (also known as Hydroxyl) In Chemistry, a base is most commonly thought of as an aqueous substance that can accept Protons This refers to the Brønsted-Lowry theory of acids and Glass in the common sense refers to a Hard, Brittle, transparent Solid, such as that used for Windows many

Caesium compounds are encountered rarely by most persons. All caesium compounds should be regarded as mildly toxic because of its chemical similarity to potassium. Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 Large amounts cause hyperirritability and spasms, but such amounts would not ordinarily be encountered in natural sources, so Cs is not a major chemical environmental pollutant. Irritability is an excessive response to stimuli. Irritability takes many forms from the Contraction of a Unicellular organism when touched to complex A spasm is a sudden involuntary contraction of a Muscle, a group of muscles or a hollow organ, or a similarly sudden Contraction of an Orifice Rats fed caesium in place of potassium in their diet die, so this element cannot replace potassium in function.

The isotopes ¹³⁴Cs and ¹³⁷Cs (present in the biosphere in small amounts as a result of radiation leaks) represent a radioactivity burden which varies depending on location. Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides The biosphere is the broadest level of ecological study the global sum of all Ecosystems. Radiocaesium does not accumulate in the body as effectively as many other fission products (such as radioiodine and radiostrontium), which are actively accumulated by the body.

See also

• Cs-137
• Goiânia accident, a major radioactive contamination incident involving a small rod of caesium chloride. Caesium-137 (also spelled cesium is a radioactive Isotope of Caesium which is formed mainly by Nuclear fission. The Goiânia accident was an incident of Radioactive contamination in central Brazil that killed several people and injured many others
• Caesium compounds
• Dirty bomb

References

• Los Alamos National Laboratory - Cesium
• Daniel A. Steck. Cesium D Line Data. Los Alamos National Laboratory (technical report LA-UR-03-7943).

External links

• WebElements.com – Caesium
• Humor site dedicated to caesium