{"id":431,"date":"2012-05-25T15:05:21","date_gmt":"2012-05-25T15:05:21","guid":{"rendered":"http:\/\/www.chemicool.com\/elements\/?page_id=431"},"modified":"2017-12-07T02:07:39","modified_gmt":"2017-12-07T07:07:39","slug":"cesium","status":"publish","type":"page","link":"https:\/\/www.chemicool.com\/elements\/cesium.html","title":{"rendered":"Cesium Element Facts"},"content":{"rendered":"<div class=\"insidepagelinks\">\n<a href=\"#data\">Data Zone<\/a> |  <a href=\"#discovery\">Discovery<\/a> |  <a href=\"#facts\">Facts<\/a> | <a href=\"#appear\">Appearance &amp; Characteristics<\/a> | <a href=\"#uses\">Uses<\/a> | <a href=\"#abund\">Abundance &amp; Isotopes<\/a>  | <a href=\"#refer\">References<\/a>\n<\/div>\n<div class=\"alkaliT\">\n<div class=\"atnorT\">55<\/div>\n<div class=\"clearT\"><\/div>\n<div class=\"elnamT\">Cs<\/div>\n<div class=\"atweiT\"> 132.9<\/div>\n<\/div>\n<p>The chemical element cesium is classed as an alkali metal. It was discovered in 1860 by Robert Bunsen and Gustav Kirchhoff.<\/p>\n<div style=\"clear:both;\"><\/div>\n<div class=\"adsense300\">\n<div class=\"adsense300spacer\">\n<div style=\"line-height:10px;\"><img decoding=\"async\" src=\"\/\/www.chemicool.com\/ad.png\" alt=\"\" \/><\/div>\n<p><script async src=\"\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js\"><\/script><ins class=\"adsbygoogle\" style=\"display: block;\" data-ad-client=\"ca-pub-9461632227417539\" data-ad-slot=\"8753977201\" data-ad-format=\"auto\"><\/ins><script>(adsbygoogle = window.adsbygoogle || []).push({});<\/script><\/p>\n<p><a id=\"data\"><\/a><\/p>\n<h2>Data Zone<\/h2>\n<table class=\"datatop\">\n<tr>\n<td class=\"elemglb\">Classification:<\/td>\n<td>  Cesium is an alkali metal   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Color:<\/td>\n<td>  yellow\/silvery  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Atomic weight:<\/td>\n<td>  132.9055 <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">State:<\/td>\n<td>  solid  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Melting point:<\/td>\n<td> 28.4 <sup>o<\/sup>C , 301.6 K  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Boiling point:<\/td>\n<td>   670  <sup>o<\/sup>C, 943.2  K     <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Electrons:<\/td>\n<td>55<\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Protons:<\/td>\n<td>55<\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Neutrons in most abundant isotope:<\/td>\n<td>78<\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Electron shells:<\/td>\n<td>    2,8,18,18,8,1    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Electron configuration:<\/td>\n<td>   [Xe] 6s<sup>1<\/sup>     <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Density @ 20<sup>o<\/sup>C:<\/td>\n<td>  1.873 g\/cm<sup>3<\/sup>   <\/td>\n<\/tr>\n<\/table>\n<span class=\"collapseomatic \" id=\"id6a23ae8d17834\"  tabindex=\"0\" title=\"Show more, including: Heats, Energies, Oxidation, Reactions,&lt;br \/&gt; Compounds, Radii, Conductivities\"    >Show more, including: Heats, Energies, Oxidation, Reactions,<br \/> Compounds, Radii, Conductivities<\/span><div id=\"target-id6a23ae8d17834\" class=\"collapseomatic_content \">\n<table class=\"datatop\">\n<tr>\n<td class=\"elemglb\">Atomic volume:<\/td>\n<td>   71.07 cm<sup>3<\/sup>\/mol   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Structure:<\/td>\n<td>    bcc: body-centered cubic  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Hardness: <\/td>\n<td>   0.2 mohs  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Specific heat capacity<\/td>\n<td>   0.24 J g<sup>-1<\/sup> K<sup>-1<\/sup>  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Heat of fusion<\/td>\n<td>  2.092  kJ mol<sup>-1<\/sup> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Heat of atomization<\/td>\n<td>   76 kJ mol<sup>-1<\/sup> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Heat of vaporization<\/td>\n<td>   67.740  kJ mol<sup>-1<\/sup>  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">1<sup>st<\/sup> ionization energy<\/td>\n<td>   375.7 kJ mol<sup>-1<\/sup>    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">2<sup>nd<\/sup> ionization energy<\/td>\n<td>  2234.3   kJ mol<sup>-1<\/sup>  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">3<sup>rd<\/sup> ionization energy<\/td>\n<td>    3400   kJ mol<sup>-1<\/sup>   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Electron affinity<\/td>\n<td>    45.506 kJ mol<sup>-1<\/sup>  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Minimum oxidation number<\/td>\n<td>  0    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Min. common oxidation no.<\/td>\n<td>  0   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Maximum oxidation number <\/td>\n<td> 3 <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Max. common oxidation no. <\/td>\n<td>  3  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Electronegativity (Pauling Scale) <\/td>\n<td>  0.79  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Polarizability volume <\/td>\n<td>   59.6  &Aring;<sup>3<\/sup>  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Reaction with air<\/td>\n<td> vigorous, &#8658;  Cs<sub>2<\/sub>O  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Reaction with 15 M HNO<sub>3<\/sub> <\/td>\n<td> vigorous, &#8658;  CsNO<sub>3<\/sub> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Reaction with 6 M HCl <\/td>\n<td>  vigorous, &#8658;  H<sub>2<\/sub>, CsCl   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Reaction with 6 M NaOH <\/td>\n<td>  vigorous, &#8658;  H<sub>2<\/sub>, CsOH <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Oxide(s) <\/td>\n<td>  Cs<sub>2<\/sub>O, CsO<sub>2<\/sub>, Cs<sub>2<\/sub>O<sub>2<\/sub> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Hydride(s) <\/td>\n<td>   CsH   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Chloride(s) <\/td>\n<td>  CsCl <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Atomic radius <\/td>\n<td>  260 pm <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Ionic radius (1+ ion) <\/td>\n<td>  181  pm <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Ionic radius (2+ ion) <\/td>\n<td>   &#8211;  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Ionic radius (3+ ion) <\/td>\n<td> &#8211; <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Ionic radius (1- ion) <\/td>\n<td>   &#8211;  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Ionic radius (2- ion) <\/td>\n<td> &#8211; <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Ionic radius (3- ion) <\/td>\n<td>   &#8211;  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Thermal conductivity <\/td>\n<td> 35.9 W m<sup>-1<\/sup> K<sup>-1<\/sup> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Electrical conductivity <\/td>\n<td>   5.3 x 10<sup>6<\/sup> S m<sup>-1<\/sup> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Freezing\/Melting point:<\/td>\n<td> 28.4 <sup>o<\/sup>C , 301.6 K  <\/td>\n<\/tr>\n<\/table>\n<\/div>\n<\/div>\n<div class=\"leftimagepadding\">\n<div style=\"width: 310px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.chemicool.com\/elements\/images\/300-cesium.jpg\" width=\"300\" height=\"158\" alt=\"Cesium\" class=\"size-full\" \/><p class=\"wp-caption-text\">High purity cesium crystals under argon. Photo by Dennis S.K.<\/p><\/div>\n<div style=\"width: 310px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.chemicool.com\/elements\/images\/300-flame-emission-spectra-k-cs.gif\" width=\"300\" height=\"143\" alt=\"Flame emission spectra potassium and cesium.\" class=\"size-full\" \/><p class=\"wp-caption-text\">Basic flame emission spectra similar to those that Bunsen and Kirchoff saw. The top spectrum is potassium, with the distinctive violet line. For cesium, the twin sky blue lines showed a new element was present.<\/p><\/div>\n<\/div>\n<\/div>\n<p><a id=\"discovery\"><\/a><\/p>\n<h2>Discovery of Cesium<\/h2>\n<div class=\"author\">Dr. Doug Stewart<\/div>\n<p>Cesium was the first element discovered using a spectroscope.<\/p>\n<p>It was discovered by Robert Bunsen and Gustav Kirchhoff in 1860 in Heidelberg, Germany, when they analyzed the spectrum of mineral water. <\/p>\n<p>A year earlier, Bunsen and Kirchhoff had developed the spectroscope. The device was based on a prism which separated light from a flame into a rainbow of colors. <\/p>\n<p>In every spectrum they looked at, Bunsen and Kirchhoff found colored lines. They realized that these lines were unique to the substance being burnt.<\/p>\n<p>When studying the spectrum of spa mineral water residue, they found a series of colored emission spectra lines that did not correspond to any known element.<\/p>\n<p>Bunsen and Kirchhoff named the element cesium, from the Latin word &#8216;caesius&#8217; meaning sky blue, after the blue lines they saw in the spectrum.<\/p>\n<p>The Latin spelling is still reflected in British English where cesium is spelt &#8216;caesium.&#8217;<\/p>\n<p>In 1861 Bunsen and Kirchhoff also discovered <a href=\"rubidium.html\">rubidium<\/a> by the same method.<\/p>\n<div style=\"clear: both; line-height: 20px;\"><\/div>\n<div class=\"adsense300\">\n<div class=\"adsense300spacer\">\n<div style=\"line-height: 10px;\"><img decoding=\"async\" src=\"\/\/www.chemicool.com\/ad.png\" alt=\"\" \/><\/div>\n<p><script async src=\"\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js\"><\/script><ins class=\"adsbygoogle\" style=\"display: inline-block; width: 336px; height: 280px;\" data-ad-client=\"ca-pub-9461632227417539\" data-ad-slot=\"2986645201\"><\/ins><script>(adsbygoogle = window.adsbygoogle || []).push({});<\/script><\/p>\n<div class=\"leftimagepadding\">\n<iframe loading=\"lazy\" width=\"300\" height=\"225\" src=\"https:\/\/www.youtube.com\/embed\/sNdijknRxfU?rel=0\" allowfullscreen><\/iframe><\/p>\n<div class=\"youtubecaption\">Cesium (preceded by rubidium) reacting with water.<\/div>\n<div style=\"width: 310px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/chemicool.com\/images\/nist-2.jpg\" width=\"300\" height=\"214\" alt=\"Cesium atomic clock\" class=\"size-full\" \/><p class=\"wp-caption-text\">Cesium atomic clock. Accurate to 1 second in 300 million years.<\/p><\/div>\n<\/div>\n<\/div>\n<\/div>\n<p><a id=\"appear\"><\/a><\/p>\n<h3>Appearance and Characteristics<\/h3>\n<p>  <strong>Harmful effects:<\/strong> <\/p>\n<p>\t \tCesium must be kept under an inert liquid\/gas or in a vacuum to protect it from air and water. Cesium compounds are considered to be mildly toxic.<\/p>\n<p> <strong>Characteristics:<\/strong><\/p>\n<p>\t\t Cesium is silvery-gold, soft, ductile alkali metal. It is liquid in a warm room, melting at 28.4 <sup>o<\/sup>C (83.1 <sup>o<\/sup>F).<\/p>\n<p>\t\tCesium is one of the few metals that is liquid near room temperature. The others are <a href=\"https:\/\/www.chemicool.com\/elements\/gallium.html\">gallium<\/a>, <a href=\"https:\/\/www.chemicool.com\/elements\/francium.html\">francium<\/a> and <a href=\"https:\/\/www.chemicool.com\/elements\/mercury.html\">mercury<\/a>.<\/p>\n<p>\t\tCesium is an extremely reactive metal and the most alkaline of the elements. It reacts explosively upon contact with water producing cesium hydroxide (CsOH), an extremely strong base that can rapidly corrode glass.<\/p>\n<p><a id=\"uses\"><\/a><\/p>\n<h2>Uses of Cesium<\/h2>\n<p>\t\tCesium is used in atomic clocks, which are incredibly accurate. NIST-F2, America&#8217;s primary time and frequency standard, is a cesium fountain atomic clock developed at the NIST laboratories in Boulder, Colorado. NIST-F2 contributes to the international group of atomic clocks that define Coordinated Universal Time (UTC), the official world time. As scientists continue to improve its technology, uncertainty in NIST-F1&#8217;s measurement of time is continually improving. Currently it neither gains nor loses as much a second in more than 300 million years. See also <a href=\"https:\/\/www.chemicool.com\/elements\/strontium.html\">strontium<\/a>.<\/p>\n<p>\t\tCesium is also used in photoelectric cells and as a catalyst in the hydrogenation of organic compounds. The metal is used as a &#8216;getter&#8217; in vacuum tubes.<\/p>\n<p>\t\tCesium hydroxide is used to etch silicon.<\/p>\n<p><a id=\"abund\"><\/a><\/p>\n<h2>Abundance and Isotopes<\/h2>\n<p><span class=\"elemgl\">Abundance earth&#8217;s crust:<\/span>  3 parts per million by weight, 0.5 parts per million by moles<\/p>\n<p>\t\t<span class=\"elemgl\">Abundance solar system:<\/span> 8 parts per billion by weight, 70 parts per trillion by moles<\/p>\n<p>\t\t\t\t<span class=\"elemgl\">Cost, pure:<\/span>   $1100 per 100g<\/p>\n<p>\t\t\t\t<span class=\"elemgl\">Cost, bulk:<\/span>  $ per 100g<\/p>\n<p>\t\t<span class=\"elemgl\">Source:<\/span> Cesium is found in the minerals pollucite and lepidolite. Commercially, most cesium is produced as a byproduct of the production of lithium metal. More than two-thirds of the world&#8217;s reserves of Cesium &#8211; 110,000 tonnes &#8211; are found at <a href=\"\/\/www.canadafacts.org\/canada-worlds-largest-source-of-cesium\/\">Bernic Lake, Manitoba, Canada<\/a>. <\/p>\n<p>\t\t<span class=\"elemgl\">Isotopes:<\/span> Cesium has 36 isotopes whose half-lives are known, with mass numbers 112 to 148. Naturally occurring cesium consists of its one stable isotope, <sup>133<\/sup>Cs.<\/p>\n<div style=\"max-width: 750px;\">\n<div style=\"line-height: 10px;\"><img decoding=\"async\" src=\"\/\/www.chemicool.com\/ad.png\" alt=\"\" \/><\/div>\n<p><script async src=\"\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js\"><\/script><ins class=\"adsbygoogle\" style=\"display: block;\" data-ad-client=\"ca-pub-9461632227417539\" data-ad-slot=\"8753977201\" data-ad-format=\"auto\"><\/ins><script>(adsbygoogle = window.adsbygoogle || []).push({});<\/script><\/p>\n<\/div>\n<p><a id=\"refer\"><\/a><\/p>\n<h4>References<\/h4>\n<ol>\n<\/ol>\n<h4>Cite this Page<\/h4>\n<p>For online linking, please copy and paste one of the following:<\/p>\n<pre class='code'>\r\n&lt;a href=\"https:\/\/www.chemicool.com\/elements\/cesium.html\"&gt;Cesium&lt;\/a&gt;\r\n<\/pre>\n<p>or<\/p>\n<pre class='code'>\r\n&lt;a href=\"https:\/\/www.chemicool.com\/elements\/cesium.html\"&gt;Cesium Element Facts&lt;\/a&gt;\r\n<\/pre>\n<p>To cite this page in an academic document, please use the following MLA compliant citation:<\/p>\n<pre class='code'>\r\n\"Cesium.\" Chemicool Periodic Table. Chemicool.com. 10 Nov. 2014. Web. <script type=\"text\/javascript\">\r\n<!--\r\nvar currentTime = new Date()\r\nvar month = currentTime.getMonth() + 1\r\nvar day = currentTime.getDate()\r\nvar year = currentTime.getFullYear()\r\ndocument.write(month + \"\/\" + day + \"\/\" + year)\r\n\/\/-->\r\n<\/script> \r\n&lt;https:\/\/www.chemicool.com\/elements\/cesium.html&gt;.<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Data Zone | Discovery | Facts | Appearance &amp; Characteristics | Uses | Abundance &amp; Isotopes | References 55 Cs 132.9 The chemical element cesium is classed as an alkali metal. It was discovered in 1860 by Robert Bunsen and Gustav Kirchhoff. Data Zone Classification: Cesium is an alkali metal Color: yellow\/silvery Atomic weight: 132.9055 [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_genesis_hide_title":false,"_genesis_hide_breadcrumbs":false,"_genesis_hide_singular_image":false,"_genesis_hide_footer_widgets":false,"_genesis_custom_body_class":"","_genesis_custom_post_class":"","_genesis_layout":"","footnotes":""},"class_list":{"0":"post-431","1":"page","2":"type-page","3":"status-publish","5":"entry"},"_links":{"self":[{"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/pages\/431","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/comments?post=431"}],"version-history":[{"count":32,"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/pages\/431\/revisions"}],"predecessor-version":[{"id":4216,"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/pages\/431\/revisions\/4216"}],"wp:attachment":[{"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/media?parent=431"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}