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Rubidium - Wikipedia, the free encyclopedia /**/ /**/ if (wgNotice != '') document.writeln(wgNotice); Rubidium From Wikipedia, the free encyclopedia Jump to: navigation, search 37krypton ← rubidium → strontiumK↑Rb↓Cs Periodic Table - Extended Periodic TableGeneralName, Symbol, Numberrubidium, Rb, 37Element categoryalkali metalsGroup, Period, Block1, 5, sAppearancegrey white Standard atomic weight85.4678(3) g·mol−1Electron configuration[Kr] 5s1Electrons per shell2, 8, 18, 8, 1Physical propertiesPhasesolidDensity (near r.t.)1.532 g·cm−3Liquid density at m.p.1.46 g·cm−3Melting point312.46 K(39.31 °C, 102.76 °F)Boiling point961 K(688 °C, 1270 °F)Critical point(extrapolated)2093 K, 16 MPaHeat of fusion2.19 kJ·mol−1Heat of vaporization75.77 kJ·mol−1Specific heat capacity(25 °C) 31.060 J·mol−1·K−1Vapor pressureP(Pa)1101001 k10 k100 kat T(K)434486552641769958Atomic propertiesCrystal structurecubic body centeredOxidation states1(strongly basic oxide)Electronegativity0.82 (Pauling scale)Ionization energies(more)1st: 403.0 kJ·mol−12nd: 2633 kJ·mol−13rd: 3860 kJ·mol−1Atomic radius235 pmAtomic radius (calc.)265 pmCovalent radius211 pmVan der Waals radius244 pmMiscellaneousMagnetic orderingno dataElectrical resistivity(20 °C) 128 n Ω·mThermal conductivity(300 K) 58.2 W·m−1·K−1Speed of sound (thin rod)(20 °C) 1300 m/sYoung's modulus2.4 GPaBulk modulus2.5 GPaMohs hardness0.3Brinell hardness0.216 MPaCAS registry number7440-17-7Most-stable isotopesMain article: Isotopes of rubidiumisoNAhalf-lifeDMDE (MeV)DP83Rbsyn86.2 dε-83Krγ0.52, 0.53,0.55-84Rbsyn32.9 dε-84Krβ+1.66, 0.7884Krγ0.881-β-0.89284Sr85Rb72.168%85Rb is stable with 48 neutrons86Rbsyn18.65 dβ-1.77586Srγ1.0767-87Rb27.835%4.88×1010 yβ-0.28387SrReferencesRubidium (pronounced /ruːˈbɪdiəm/, /rəˈbɪdiəm/) is a chemical element with the symbol Rb and atomic number 37. Rb is a soft, silvery-white metallic element of the alkali metal group. Rb-87, a naturally occurring isotope, is slightly radioactive, with a half-life of 4.88×1010 years, which, at 49 billion years, is longer than the estimated age of the universe. Rubidium is very soft and highly reactive, with properties similar to other elements in group 1, like rapid oxidation in air.Contents1 Characteristics2 Uses3 History4 Occurrence5 Isotopes6 Compounds7 Precautions8 Biological effects9 References10 Sources11 External links//[edit] CharacteristicsRubidium is the second most electropositive of the stable alkali elements and liquefies at high ambient temperature (102.7 °F = 39.3 °C). Like other group 1 elements this metal reacts violently in water. In common with potassium and caesium this reaction is usually vigorous enough to ignite the liberated hydrogen. Rubidium has also been reported to ignite spontaneously in air. Also like other alkali metals, it forms amalgams with mercury and it can form alloys with gold, caesium, sodium, and potassium. The element gives a reddish-violet color to a flame, hence its name.[edit] UsesPotential or current uses of rubidium include:A Bose-Einstein condensate.A working fluid in vapor turbines.A getter in vacuum tubes.A photocell component.The resonant element in atomic clocks. This is due to the hyperfine structure of rubidium's energy levels.An ingredient in special types of glass.The production of superoxide by burning in oxygen.The study of potassium ion channels in biology.Rubidium is used to locate brain tumours, due to its slight radioactivity. [1]Rubidium vapor has been used to make atomic magnetometers. 87Rb is currently being used, with other alkali metals, in the development of spin-exchange relaxation-free (SERF) magnetometers.[2]Rubidium is easily ionized, so it has been considered for use in ion engines for space vehicles (but caesium and xenon are more efficient for this purpose).Rubidium compounds are sometimes used in fireworks to give them a purple color.RbAg4I5 has the highest room temperature conductivity of any known ionic crystal. This property could be useful in thin film batteries and in other applications.[3]Rubidium has also been considered for use in a thermoelectric generator using the magnetohydrodynamic principle, where rubidium ions are formed by heat at high temperature and passed through a magnetic field. These conduct electricity and act like an armature of a generator thereby generating an electric current.Rubidium, particularly 87Rb, in the form of vapor, is one of the most commonly used atomic species employed for laser cooling and Bose-Einstein condensation. Its desirable features for this application include the ready availability of inexpensive diode laser light at the relevant wavelength, and the moderate temperatures required to obtain substantial vapor pressures.Rubidium has been used for polarizing 3He (that is, producing volumes of magnetized 3He gas, with the nuclear spins aligned toward a particular direction in space, rather than randomly). Rubidium vapor is optically pumped by a laser and the polarized Rb polarizes 3He by the hyperfine interaction.[4] Spin-polarized 3He cells are becoming popular for neutron polarization measurements and for producing polarized neutron beams for other purposes.[5][edit] HistoryRubidium (L rubidus, deepest red) was discovered in 1861 by Robert Bunsen and Gustav Kirchhoff in the mineral lepidolite through the use of a spectroscope.[6] The extraction of 150 kg of lepidolite yielded only a few grams for analysis. The first rubidium metal was produced by the reaction of rubidium chloride with potassium by Bunsen. However, this element had minimal industrial use until the 1930s. Historically, the most important use for rubidium has been in research and development, primarily in chemical and electronic applications.In 1999 rubidium-87 was used to make a Bose-Einstein condensate[7], for which the discoverers won the 2001 Nobel Prize in Physics[8].[edit] OccurrenceRubidium is about the twenty third [9] most abundant element in the Earth's crust, roughly as abundant as zinc and rather more common than copper. It occurs naturally in the minerals leucite, pollucite, carnallite and zinnwaldite, which contains traces of up to 1% of its oxide. Lepidolite contains 1.5% rubidium and this is the commercial source of the element. Some potassium minerals and potassium chlorides also contain the element in commercially significant amounts. One notable source is also in the extensive deposits of pollucite at Bernic Lake, Manitoba.Rubidium metal can be produced by reducing rubidium chloride with calcium among other methods. In 1997 the cost of this metal in small quantities was about US$25/gram.[edit] IsotopesMain article: Isotopes of rubidiumThere are 26 isotopes of rubidium known with naturally occurring rubidium being composed of just two isotopes; Rb-85 (72.2%) and the radioactive Rb-87 (27.8%). Natural rubidium is radioactive with specific activity of about 670 Bq/g, enough to fog photographic film in approximately 30 to 60 days.Rb-87 has a half-life of 4.88×1010 years. It readily substitutes for potassium in minerals, and is therefore fairly widespread. Rb has been used extensively in dating rocks; Rb-87 decays to stable strontium-87 by emission of a negative beta particle. During fractional crystallization, Sr tends to become concentrated in plagioclase, leaving Rb in the liquid phase. Hence, the Rb/Sr ratio in residual magma may increase over time, resulting in rocks with increasing Rb/Sr ratios with increasing differentiation. Highest ratios (10 or higher) occur in pegmatites. If the initial amount of Sr is known or can be extrapolated, the age can be determined by measurement of the Rb and Sr concentrations and the Sr-87/Sr-86 ratio. The dates indicate the true age of the minerals only if the rocks have not been subsequently altered. See Rubidium-Strontium dating for a more detailed discussion.[edit] CompoundsFor more details on this topic, see Category:Rubidium compounds.Rubidium chloride is probably the most-used rubidium compound; it is used in biochemistry to induce cells to take up DNA, and as a biomarker since it is readily taken up to replace potassium, and does not normally occur in living organisms. Rubidium hydroxide is the starting material for most rubidium-based chemical processes; rubidium carbonate is used in some optical glasses.Rubidium has a number of oxides, including Rb6O and Rb9O2 which appear if rubidium metal is left exposed to air; the final product of reacting with oxygen is the superoxide RbO2. Rubidium forms salts with most anions. Some common rubidium compounds are rubidium chloride (RbCl), rubidium monoxide (Rb2O) and rubidium copper sulfate Rb2SO4·CuSO4·6H20). A compound of rubidium, silver and iodine, RbAg4I5, has interesting electrical characteristics and might be useful in thin film batteries.[citation needed][edit] PrecautionsRubidium reacts violently with water and can cause fires. To ensure both health and safety and purity, this element must be kept under a dry mineral oil, in a vacuum or in an inert atmosphere.[edit] Biological effectsRubidium, like sodium and potassium, is almost always in its +1 oxidation state. The human body tends to treat Rb+ ions as if they were potassium ions, and therefore concentrates rubidium in the body's electrolytic fluid. The ions are not particularly toxic, and are relatively quickly removed in the sweat and urine. However, taken in excess it can be dangerous, as it is slightly radioactive. Rubidium collects in tumours but not in normal tissue so it can thus be used to locate brain tumours.[edit] References^ http://www.rsc.org/chemsoc/visualelements/pages/data/rubidium_data.html^ Li, Zhimin et al. (2006). "Parametric modulation of an atomic magnetometer". Applied Physics Letters 89: 134105. doi:10.1063/1.2357553, http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=APPLAB000089000013134105000001&idtype=cvips&gifs=yes. ^ Bradley, J. N.; Greene, P. D. (1967). "Relationship of structure and ionic mobility in solid MAg4I5". Trans. Faraday Soc. 63: 2516. doi:10.1039/TF9676302516. ^ Gentile, T.R. et al.. "Polarized 3He spin filters for slow neutron physics". Journal of Research of the National Institute of Standards and Technology 100: 299, http://nvl.nist.gov/pub/nistpubs/jres/110/3/j110-3gen.pdf. ^ "Neutron spin filters based on polarized helium-3". NIST Center for Neutron Research 2002 Annual Report.^ G. Kirchhoff, R. Bunsen (1861). "Chemische Analyse durch Spectralbeobachtungen". Annalen der Physik und Chemie 189 (7): 337–381. doi:10.1002/andp.18611890702. ^ "Bose-Einstein Condensation". World of Physics on Bose-Einstein Condensation. BookRags. Retrieved on 2008-01-26.^ Levi, Barbara Goss (2001). "Cornell, Ketterle, and Wieman Share Nobel Prize for Bose-Einstein Condensates". Search & Discovery. Physics Today online. Retrieved on 2008-01-26.^ http://www.rsc.org/chemsoc/visualelements/pages/data/rubidium_data.html[edit] SourcesLos Alamos National Laboratory – RubidiumLouis Meites, Handbook of Analytical Chemistry (New York: McGraw-Hill Book Company, 1963)Daniel A. Steck. "Rubidium-87 D Line Data". Los Alamos National Laboratory (technical report LA-UR-03-8638).[edit] External links Wikimedia Commons has media related to: Rubidium Look up rubidium inWiktionary, the free dictionary.WebElements.com – Rubidiumv • d • eAlkali metals LithiumLiAtomic Number: 3Atomic Weight: 6.941Melting Point: 453.69Boiling Point: 1615Electronegativity: 0.98SodiumNaAtomic Number: 11Atomic Weight: 22.990Melting Point: 370.87Boiling Point: 1156Electronegativity: 0.96PotassiumKAtomic Number: 19Atomic Weight: 39.098Melting Point: 336.58Boiling Point: 1032Electronegativity: 0.82RubidiumRbAtomic Number: 37Atomic Weight: 85.468Melting Point: 312.46Boiling Point: 961Electronegativity: 0.82CaesiumCsAtomic Number: 55Atomic Weight: 132.905Melting Point: 301.59Boiling Point: 944Electronegativity: 0.79FranciumFrAtomic Number: 87Atomic Weight: (223)Melting Point: ?295Boiling Point: ?950Electronegativity: 0.7v • d • ePeriodic tableH HeLiBe BCNOFNeNaMg AlSiPSClArKCa ScTiVCrMnFeCoNiCuZnGaGeAsSeBrKrRbSr YZrNbMoTcRuRhPdAgCdInSnSbTeIXeCsBaLaCePrNdPmSmEuGdTbDyHoErTmYbLuHfTaWReOsIrPtAuHgTlPbBiPoAtRnFrRaAcThPaUNpPuAmCmBkCfEsFmMdNoLrRfDbSgBhHsMtDsRgUubUutUuqUupUuhUusUuoUueUbn Alkali metalsAlkaline earth metalsLanthanoidsActinoidsTransition metalsOther metalsMetalloidsOther nonmetalsHalogensNoble gasesRetrieved from "http://en.wikipedia.org/wiki/Rubidium" Categories: Chemical elements | Alkali metals | RubidiumHidden categories: All articles with unsourced statements | Articles with unsourced statements since December 2007 Views Article Discussion Edit this page History Personal tools Log in / create account if (window.isMSIE55) fixalpha(); Navigation Main page Contents Featured content Current events Random article Search Interaction About Wikipedia Community portal Recent changes Contact Wikipedia Donate to Wikipedia Help Toolbox What links here Related changesUpload fileSpecial pages Printable version Permanent linkCite this page Languages Afrikaans العربية বাংলা Беларуская Bosanski Български Català Česky Corsu Cymraeg Dansk Deutsch Eesti Ελληνικά Español Esperanto Euskara فارسی Français Furlan Gaeilge Gaelg Galego 한국어 Հայերեն हिन्दी Hrvatski Ido Bahasa Indonesia Íslenska Italiano עברית Basa Jawa ಕನ್ನಡ Kiswahili Kurdî / كوردی Latina Latviešu Lëtzebuergesch Lietuvių Lojban Magyar മലയാളം Nederlands 日本語 Norsk (bokmål) Norsk (nynorsk) Occitan O'zbek Polski Português Română Runa Simi Русский Sicilianu Simple English Slovenčina Slovenščina Српски / Srpski Srpskohrvatski / Српскохрватски Suomi Svenska தமிழ் ไทย Tiếng Việt Türkçe Українська Walon 中文   This page was last modified on 18 November 2008, at 00:20. 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