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Caesium BY RAHMI ANNISA (1310411106)LUTHFI ALFIANDRI (1310412041)History of DiscoveryGustav Kirchhoff (left) and Robert Bunsen (center) discovered caesium spectroscopically

In 1860, Robert Bunsen and Gustav Kirchhoff discovered caesium in the mineral water from Drkheim, Germany.Due to the bright blue lines in its emission spectrum, they chose a name derived from the Latin word caesius, meaning sky-blue.Caesium was the first element to be discovered spectroscopically, only one year after the invention of the spectroscope by Bunsen and Kirchhoff.

History of DiscoveryCaesium salts were isolated by Bunsen by precipitating from the spring water, along with salts of other group 1 elements.Bunsen was able to separate the salts and isolated the chloride and the carbonateThe pure metal was eventually isolated by the German chemist Carl Setterberg while working on his doctorate with Kekul and Bunsen.ble to isolate caesium metal.

History of DiscoveryPyhsical Porperties of Cs

Pyhsical Porperties of Cs

Standard state: solid at 298 K Colour: silvery gold Classification: MetallicCrystal structure : BCC Magnetic ordering : paramagnetic

a.Caesium metal is highly reactive and very pyrophoricb.In addition to igniting spontaneously in air, it reacts explosively with water even at low temperaturesc.The reaction with solid water occurs at temperatures as low as 116C (177F).d.Because of its high reactivity, the metal is classified as a hazardous materialChemical properties

e. It is stored and shipped in dry saturated hydrocarbons, such as mineral oil.f. It must be handled under inert gas, such as argong. A caesium-water explosion is often less powerful than a sodium-water explosion with a similar amount of sodium. Chemical Propertiesh.Caesium can be stored in vacuum-sealed borosilicate glass ampoulesi. Cesium reacts violently with water and ice, forming cesium hydroxide (CsOH)j. Cesium hydroxide is the strongest base known and will attack glassk. It is a mildly toxic elementChemical Properties10HydridesCsH (Caesium Hydride)

FluoridesCsF (Caesium Fluoride)

ChloridesCsCl (Caesium Chloride)

Caesium CompoundIodidesCsI (Caesium Iodide)

Selenides Cs2Se (Dicaesium Selenide)

TelluridesCs2Te (Dicaesium Telluride)

OxidesCs2O (Dicaesium Oxide) CsO2 (Caesium Superoxide)Cs2O2 (Dicaesium Peroxide)SulfideCs2S (Dicaesium Sulfide)Cs2S2 (Dicaesium disulfide)Cs2S3 (Dicaesium Trisulfide)Cs2S6 (Dicaesium Hexasulfide)Cs2S4 (Dicaesium Tetrasulfide)Cs2S5 (Dicaesium Pentasulfide)Cs2S7 (Dicaesium Heptasulfide)

Caesium Compounda. Cesium is naturally present as the isotope 133 in various ores and to a lesser extent in soilb. 3parts per million in the Earth's crust.c.During magma crystallization, caesium is concentrated in the liquid phase and crystallizes last.d.The largest deposits of caesium are zone pegmatite ore bodies formed by this enrichment process.

Natural Source of CaesiumMostly found in few minerals such as Beryl, Avogadrite, Pezzottaite, Londonite, Rhodizite, & Pollucite.

One of the worlds richest sources of cesium is located in Bernic Lake Manitoba

1.Extracted from mineral by three methods: acid digestion, alkaline decomposition, and direct reduction.2. In the acid digestion, the mineral rock is dissolved with strong acids, such as hydrochloric (HCl), hydrobromic (HBr), or hydrofluoric (HF) acids.3. Pure cesium can be produced by thermal decay of cesium azide (CsN3)4. In vacuum applications, caesium dichromate can be reacted with zirconium forming pure caesium metal without other gaseous products.

Cs2Cr2O7 + 2 Zr 2 Cs + 2 ZrO2+ Cr2O3

Synthetic Production5. In the alkaline decomposition, the pure precipitated double salt is decomposed, and pure CsCl is obtained after evaporating the water.6. In the direct reduction, Caesium chloride, and the other caesium halides, as well, can be reduced at 700 to 800C (1,292 to 1,472F) with calcium or barium, followed by distillation of the caesium metal.7. Most of the mined caesium (as salts) is directly converted into caesium formate (HCOOCs+) for applications such as oil drilling.

Synthetic ProductionReaction of caesium with airCs(s) + O2(g) CsO2(s) (caesium superoxide)Cs(s) + O2(g) Cs2O(s) (Dicaesium oxide)Cs(s) + O2(g) Cs2O2(s)(Dicaesium

Reaction of caesium with water2Cs(s) + 2H2O 2CsOH(aq) + H2(g)

Specific ReactionReaction of caesium with the halogens2Cs(s) + F2(g) CsF(s)2Cs(s) + Cl2(g) CsCl(s)2Cs(s) + Br2(g) CsBr(s)2Cs(s) + I2(g) CsI(s)

Reaction of caesium with acids2Cs(s) + H2SO4(aq) 2Cs+(aq) + SO42-(aq) + H2(g)

Specific Reaction

1. The largest current end-use of nonradioactive caesium is in caesium formate-based drilling fluids for the extractive oil industry. 2. Cesium compounds are used in the production of glass and ceramics.3. Doping with caesium compounds is used to enhance the effectiveness of several metal-ion catalysts used in the production of chemicals. Cesium-137 is also used in medical therapy to treat cancer.

The Application of Caesium4. Cesium is also used in atomic clocks, based on the precise movement of its outer electrons. which are accurate to seconds over long periods of time (thousands of years).

The Application of Caesium

Anatomic clockis aclockdevice that uses anelectronic transitionfrequencyin themicrowave,optical, orultravioletregionof the electromagnetic spectrumofatomsas afrequency standardfor its time keeping element. Atomic clocks are the most accuratetime andfrequency standardsknown, and are used asprimary standardsfor internationaltime distribution services, to control the wave frequency of television broadcasts, and inglobal navigation satellite systemssuch asGPS.What is atomic clocks ?The caesium atom defines theSI second. The second is 9.192.631.770 periods of the electromagnetic radiation emitted or absorbed by the ground state hyperfine transition of the caesium atom. This means that a second is the amount of time it takes for the radiation from this transition to complete 9.192.631.770 full waves.

Why do we use caesium?

First, the liquid cesium is put into an oven and heated until it changes into a gas. These cesium atoms escape through a small hole in the oven at very high speeds. After passing through the hole these fast-moving atoms electromagnets force the atoms to split into separate beams according to their energy. The beam of the appropriate energy is sent through a U shaped hole and the atoms are exposed to radiant energy by specific wavelengths of microwaves. The wavelengths used in this procedure are in a very small range that includes 9,192,631,770 Hz. How do Atomic Clocks Work?

These microwaves give the atoms more energy and when they receive the energy at exactly the right frequency, the atom is excited to another energy state. All the atoms are sent through another magnetic field, which filters out those that have been excited to another energy state by the microwaves. A detector at the end of the tube gives an output according to the number of cesium atoms striking it and peaks when the frequency is absolutely correct. This peak is then used to make slight corrections to the crystal oscillator that controls the clocking mechanism, locking in the frequency. This locked frequency is then divided by 9,192,631,770 which results in the familiar one pulse per secondContinue.....The development of atomic clocks has led to many scientific and technological advances such as a worldwide system of precise position measurement (theGlobal Positioning System), and applications in theInternet, which depend critically on frequency and time standards. Atomic clocks are installed at sites oftime signalradio transmitters. They are used at some long wave and medium wave broadcasting stations to deliver a very precise carrier frequency Atomic clocks are used in many scientific disciplines,such as for long baseline interferometryinradioastronomyApplications

5. Electric power and electronicsCesium used in photoelectric cells, devices for changing sunlight into electrical energy.

6. Other uses for cesium and its compounds/isotopes include organic hydrogenation, medical treatment of cancer, organic chemistry, molecular biology, oxidation and pyrotechnics for infrared flares, spectrophotometry, exhaust reduction of military aircraft, industrial applications for gauges and devices, and has also been used in many magnetometers

The Application of CaesiumHousecroft, Catherine. 2008. Inorganic Chemistry. England: Pearson Education Limited.http://en.wikipedia.org/wiki/Caesiumhttp://lenntech.com/periodic/elements/cs.htmlhttp://chemistryexplained.com/elements/A-C/Cesium.htmlhttp://webelements.com/caesium/history.htmlhttp://webelements.com/caesium/compound.htmlhttp://www.redorbit.com/education/reference_library/science_1/elements/2582894/cesium/

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