cesium

CESIUM


 * Atomic Number:** 55
 * Atomic __Weight__:** 132.9054519
 * Melting Point:** 301.59 K (28.44°C or 83.19°F)
 * Boiling Point:** 944 K (671°C or 1240°F)
 * Density:** 1.93 grams per cubic centimeter
 * Phase at Room Temperature:** liquid
 * Element Classification:** Metal
 * Period Number:** 6 **Group Number:** 1 **Group Name:** Alkali Meta


 * Number of Energy Levels:** 6
 * First Energy Level:**2
 * Second Energy Level:**8
 * Third Energy Level:**18
 * Fourth Energy Level:**18
 * Fifth Energy Level:**8
 * Sixth Energy Level:**1

Isotopes

 * ** Isotope ** || ** Half __Life__ ** ||
 * Cs-126 || 1.6 minutes ||
 * Cs-129 || 1.3 days ||
 * Cs-131 || 9.7 days ||
 * Cs-132 || 6.4 days ||
 * Cs-133 || Stable ||
 * Cs-134 || 2.1 years ||
 * Cs-134m || 2.9 hours ||
 * Cs-135 || 2300000.0 years ||
 * Cs-136 || 13.2 days ||
 * Cs-137 || 30.2 years ||
 * Cs-138 || 32.2 minutes ||
 * Cs-139 || 9.3 minutes ||

__Facts__

 * Date of Discovery:** 1860
 * Discoverer:** Fustov Kirchoff
 * Name Origin:** From the Latin word //caesius// (sky blue)
 * Uses:** removes air traces in vacuum tubes
 * Obtained From:** pollucite, lepidolite

__**History of Cesium**__ It was discovered in 1860 by Kirchoff and Bunsen while examining the residues that were obtained by evaporation of mineral waters. The new bright lines in the blue region were attributed to a new element - given the name cesium for the Latin caesius - sky blue. Extraction of cesium compounds by Bunsen involved concentration of the cesium and other impurities by evaporation of large volumes of mineral water. Bunsen prepared chlorides, carbonates and other salts of cesium. He studied the properties of these salts and attempted to prepare cesium metal but was unsuccessful. The metal was first obtained by Setterburg in 1882 by electrolysis of a cesium cyanide-barium cyanide melt. Cesium had no significant industrial application until 1926 when the metal was used as a getter and an effective means for reducing the electron work function on coated tingsten filaments in radio tubes.

This silvery metal with a golden cast is the most reactive and one of the softest of all metals. It melts at 28.4 °C (83.1 °F), just above room temperature. It is about half as abundant as lead and 70 times as abundant as silver. Cesium occurs in minute quantities (7 parts per million) in Earth's crust in the minerals pollucite, rhodizite, and lepidolite. Pollucite (Cs 4 Al 4 Si 9 O 26 ∙H 2 O) is a cesium-rich mineral resembling quartz. It contains 40.1 percent cesium on a pure basis, and impure samples are ordinarily separated by hand-sorting methods to greater than 25 percent cesium. Large pollucite deposits have been found in Zimbabwe and in the lithium-bearing pegmatites at Bernic Lake, Manitoba, Can. Rhodizite is a rare mineral found in low concentrations in lepidolite and in salt brine and saline deposits. Cesium is a soft, ductile, silvery-white alkali metal, a hazardous metal. it has a melting pint of 82 degrees F and is a liquid at room temperature. Since the 1900s, Cesium's main use has been caesium formate for drilling fluids. It has been used in the production of electricity for electronics and chemistry. It is widely used in atomic clocks. It has a half life of about 30 years. When Cesium reacts with oxygen, it develops a silvery-gold hue. It also forms alloys with other alkali metals as well as with gold, amalgams, and mercury. This substance is only mildly hazardous but does pose a health risk of radiation leaks. Cesium is highly reactive and will ignite spontaneously in air (pyrophoric). It reacts explosively with water even at low temperatures.

Cesium metal is highly reactive and very pyrophoric. In addition to igniting spontaneously in air, it reacts explosively with water even at low temperatures, more so than other members of the first group of the periodic table. The reaction with solid water occurs at temperatures as low as −116 °C (−177 °F). Because of its high reactivity, the metal is classified as a hazardous material. It is stored and shipped in dry saturated hydrocarbons such as mineral oil. Similarly, it must be handled under inert atmosphere such as argon. It can be stored in vacuum-sealed borosilicate glass ampoules. In quantities of more than about 100 grams (3.5 oz), cesium is shipped in hermetically sealed __stainless steel containers__. The chemistry of cesium is similar to that of other alkali metals, but is more closely similar to that of rubidium, the element above cesium in the periodic table. Some small differences arise from the fact that it has a higher atomic mass and is more electropositive than other (non-radioactive) alkali metals. Cesium is the most electropositive stable chemical element. The caesium ion is also larger and less "hard" than those of the lighter alkali metals.
 * Chemical Characteristics**

Cesium is a relatively rare element as it is estimated to average approximately 3 parts per million in the Earth's crust. This makes it the 45th most abundant of all elements and the 36th of all the metals. Nevertheless, it is more abundant than such elements as antimony, cadmium, tin and tungsten, and two orders of magnitude more abundant than mercury or silver, but 30 times less abundant than rubidium—with which it is so closely chemically associated.
 * Natural Occurrence**



Cesium is a rare element and there is an average of 3 ppm in the Earth's crust. It is considered an incompatible element to do its large ionic radius. It can be used to conduct electricity by thermionic generators that convert heat energy to electricity. Also, its vapor is used magnetometers; it has a great affinity for oxygen.

=Health Hazards= Most cesium compounds are mildly toxic because of chemical similarity of cesium to potassium. Exposure to large amounts of cesium compounds can cause hyperirritability and spasms, but as such amounts would not ordinarily be encountered in natural sources, cesium is not Major chemical environmental pollutant. Cesium metal is one of the most reactive elements and is highly explosive when it comes in contact with water. The hydrogen gas produced by the reaction is heated by the thermal energy released at the same time, causing ignition and a violent explosion Cesium is so potent that this explosive reaction can even be triggered by cold water The metal is highly pyrophoric, and ignites spontaneously in air to form cesium hydroxide and various oxides. Cesium hydroxide is a very strong base, and can rapidly corrode glass
 * Name:** Cesium **Symbol:** Cs **Atomic Number:** 55 **Atomic Mass:** 132.90546 amu **Melting Point:** 28.5 °C (301.65 K, 83.3 °F) **Boiling Point:** 678.4 °C (951.55005 K, 1253.12 °F) **Number of Protons/Electrons:** 55 **Number of Neutrons:** 78 **Classification:** Alkali Metal **Crystal Structure:** Cubic **Density @ 293 K:** 1.873 g/cm3 **Color:** silver **British Spelling:** Caesium **IUPAC Spelling:** Caesium

Atomic Structure

 * [[image:http://www.chemicalelements.com/bohr/b0055.gif width="355" height="353"]] ||  || **Number of Energy Levels:** 6
 * First Energy Level:** **Second Energy Level:** **Third Energy Level:** **Fourth Energy Level:** **Fifth Energy Level:** **Sixth Energy Level:** ||

Isotopes

 * ** Isotope ** || ** Half Life ** ||
 * Cs-126 || 1.6 minutes ||
 * Cs-129 || 1.3 days ||
 * Cs-131 || 9.7 days ||
 * Cs-132 || 6.4 days ||
 * Cs-133 || Stable ||
 * Cs-134 || 2.1 years ||
 * Cs-134m || 2.9 hours ||
 * Cs-135 || 2300000.0 years ||
 * Cs-136 || 13.2 days ||
 * Cs-137 || 30.2 years ||
 * Cs-138 || 32.2 minutes ||
 * Cs-139 || 9.3 minutes ||

Facts

 * Date of Discovery:** 1860 **Discoverer:** Fustov Kirchoff **Name Origin:** From the __Latin__ word //caesius// (sky blue) **Uses:** removes air traces in vacuum tubes **Obtained From:** pollucite, lepidolite