{"id":471,"date":"2012-05-26T07:45:07","date_gmt":"2012-05-26T07:45:07","guid":{"rendered":"http:\/\/www.chemicool.com\/elements\/?page_id=471"},"modified":"2017-12-07T02:08:24","modified_gmt":"2017-12-07T07:08:24","slug":"osmium","status":"publish","type":"page","link":"https:\/\/www.chemicool.com\/elements\/osmium.html","title":{"rendered":"Osmium 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=\"tmetalsT\">\n<div class=\"atnorT\">76<\/div>\n<div class=\"clearT\"><\/div>\n<div class=\"elnamT\">Os<\/div>\n<div class=\"atweiT\"> 190.2<\/div>\n<\/div>\n<p>The chemical element osmium is classed as a transition metal. It was discovered in 1803 by Smithson Tennant.<\/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>  Osmium is a transition metal   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Color:<\/td>\n<td>  bluish-white <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Atomic weight:<\/td>\n<td>   190.2 <\/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> 3030 <sup>o<\/sup>C, 3303  K    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Boiling point:<\/td>\n<td>  5012 <sup>o<\/sup>C, 5285  K     <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Electrons:<\/td>\n<td>76<\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Protons:<\/td>\n<td>76<\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Neutrons in most abundant isotope:<\/td>\n<td>116<\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Electron shells:<\/td>\n<td>  2,8,18,32,14,2    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Electron configuration:<\/td>\n<td>  [Xe] 4f<sup>14<\/sup> 5d<sup>6<\/sup> 6s<sup>2<\/sup>     <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Density @ 20<sup>o<\/sup>C:<\/td>\n<td>  22.61  g\/cm<sup>3<\/sup>   <\/td>\n<\/tr>\n<\/table>\n<span class=\"collapseomatic \" id=\"id6a57261e33412\"  tabindex=\"0\" title=\"Show more, including: Heats, Energies, Oxidation,&lt;br \/&gt; Reactions, Compounds, Radii, Conductivities\"    >Show more, including: Heats, Energies, Oxidation,<br \/> Reactions, Compounds, Radii, Conductivities<\/span><div id=\"target-id6a57261e33412\" class=\"collapseomatic_content \">\n<table class=\"datatop\">\n<tr>\n<td class=\"elemglb\">Atomic volume:<\/td>\n<td>   8.49 cm<sup>3<\/sup>\/mol   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Structure:<\/td>\n<td>   hcp: hexagonal close pkd   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Hardness: <\/td>\n<td>   7.0  mohs  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Specific heat capacity<\/td>\n<td>   0.13   J g<sup>-1<\/sup> K<sup>-1<\/sup>  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Heat of fusion<\/td>\n<td>  31.80 kJ mol<sup>-1<\/sup>  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Heat of atomization<\/td>\n<td>  789    kJ mol<sup>-1<\/sup> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Heat of vaporization<\/td>\n<td>  627.6  kJ mol<sup>-1<\/sup>   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">1<sup>st<\/sup> ionization energy<\/td>\n<td>  840  kJ mol<sup>-1<\/sup>   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">2<sup>nd<\/sup> ionization energy<\/td>\n<td>   1600  kJ mol<sup>-1<\/sup>   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">3<sup>rd<\/sup> ionization energy<\/td>\n<td>    kJ mol<sup>-1<\/sup>  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Electron affinity<\/td>\n<td>    104  kJ mol<sup>-1<\/sup>  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Minimum oxidation number<\/td>\n<td>  -2    <\/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> 8 <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Max. common oxidation no. <\/td>\n<td>  4  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Electronegativity (Pauling Scale) <\/td>\n<td> 2.2  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Polarizability volume <\/td>\n<td>   8.5 &Aring;<sup>3<\/sup> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Reaction with air<\/td>\n<td>  mild, &#8658; OsO<sub>4<\/sub>  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Reaction with 15 M HNO<sub>3<\/sub> <\/td>\n<td>   mild, &#8658; OsO<sub>2<\/sub> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Reaction with 6 M HCl <\/td>\n<td> none <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Reaction with 6 M NaOH <\/td>\n<td>   none  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Oxide(s) <\/td>\n<td> OsO<sub>2<\/sub>, OsO<sub>4<\/sub> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Hydride(s) <\/td>\n<td>   none  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Chloride(s) <\/td>\n<td>  OsCl<sub>3<\/sub>, OsCl<sub>4<\/sub>, OsCl<sub>5<\/sub> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Atomic radius <\/td>\n<td>   135 pm  <\/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\"> 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>  87.6  W m<sup>-1<\/sup> K<sup>-1<\/sup> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Electrical conductivity <\/td>\n<td> 12.3 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> 3030 <sup>o<\/sup>C, 3303  K    <\/td>\n<\/tr>\n<\/table>\n<\/div>\n<\/div>\n<div class=\"leftimagepadding\">\n<p><strong>The Six Platinum Group Metals<\/strong><\/p>\n<table class=\"navbar\">\n<tr>\n<td><a class=\"tmetals\" href=\"https:\/\/www.chemicool.com\/elements\/ruthenium.html\" title=\"ruthenium \"><sup>44<\/sup><br \/>Ru<\/a> <\/td>\n<td><a class=\"tmetals\" href=\"https:\/\/www.chemicool.com\/elements\/rhodium.html\" title=\"rhodium \"><sup>45<\/sup><br \/>Rh<\/a> <\/td>\n<td><a class=\"tmetals\" href=\"https:\/\/www.chemicool.com\/elements\/palladium.html\" title=\"palladium \"><sup>46<\/sup><br \/>Pd<\/a> <\/td>\n<\/tr>\n<tr>\n<td><a class=\"tmetals\" href=\"https:\/\/www.chemicool.com\/elements\/osmium.html\" title=\"osmium \"><sup>76<\/sup><br \/>Os<\/a> <\/td>\n<td><a class=\"tmetals\" href=\"https:\/\/www.chemicool.com\/elements\/iridium.html\" title=\"iridium \"><sup>77<\/sup><br \/>Ir<\/a> <\/td>\n<td><a class=\"tmetals\" href=\"https:\/\/www.chemicool.com\/elements\/platinum.html\" title=\"platinum \"><sup>78<\/sup><br \/>Pt<\/a> <\/td>\n<\/tr>\n<\/table>\n<div style=\"width:290px;text-align:center;\">\nOsmium is one of the platinum group metals. These metals have similar properties and are often present in the same mineral ores &#8211; osmium and iridium were found by Smithson Tennant in a sample of crude platinum.<\/div>\n<\/div>\n<\/div>\n<p><a id=\"discovery\"><\/a><\/p>\n<h2>Discovery of Osmium<\/h2>\n<p>Osmium was discovered in 1803, in London, by English chemist Smithson Tennant. He also discovered <a href=\"https:\/\/www.chemicool.com\/elements\/iridium.html\">iridium<\/a> in the same year.<sup> (3)<\/sup> Earlier in his career, Smithson Tennant had established that diamond is pure <a href=\"https:\/\/www.chemicool.com\/elements\/carbon.html\">carbon<\/a>.<\/p>\n<p>Tennant&#8217;s discovery of osmium began when he dissolved a sample of crude <a href=\"https:\/\/www.chemicool.com\/elements\/platinum.html\">platinum<\/a> in aqua regia, a mixture of hydrochloric acid and nitric acid, resulting in a metallic, black powder. <\/p>\n<p>Previous chemists had believed this powder was graphite, but Tennant &#8211; who had previous experience of working with carbon&#8217;s allotropes &#8211; thought differently.<sup> (3)<\/sup><\/p>\n<p>Tennant treated the powder with sodium hydroxide and heated to the solution. He removed an alkali from the residue by adding water. He added hydrochloric acid to the remaining residue to form an acidic solution. The alkaline solution was found to contain osmium, while the acidic contained iridium.<sup> (4)<\/sup><\/p>\n<p>The highly toxic osmium tetroxide, OsO<sub>4<\/sub>, has a characteristic unpleasant odor, so Tennant named the element after the Greek word for smell, &#8216;osme&#8217;.<\/p>\n<p>In the image below, on the left is an electron microscopy image of osmium catalyst clusters containing nominally 5 atoms of osmium each, dispersed on a magnesium oxide support material. Image by ORNL <sup>(1)<\/sup>. On the right, an osmium bead. Image by Tomihadnorf <sup>(2)<\/sup><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/chemicool.com\/elements\/images\/osmium.jpg\" width=\"300\" height=\"158\" alt=\"Osmium\" class=\"aligncenter size-full\" \/><\/p>\n<div style=\"clear:both;line-height:20px;\">&nbsp;<\/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<div style=\"width: 310px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.chemicool.com\/elements\/images\/300-osmium-pacemaker.jpg\" width=\"300\" height=\"299\" alt=\"Pacemaker\" class=\"size-full\" \/><p class=\"wp-caption-text\">Alloys of platinum and osmium are used in the construction of pacemaker electrodes  because they are highly resistant to corrosion. Photo by Sunzi99.<\/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 \tPowdered osmium in air forms the pungent, highly toxic osmium tetroxide (OsO<sub>4<\/sub>) which can cause lung, skin and eye damage.  <\/p>\n<p>\t  <strong>Characteristics:<\/strong><\/p>\n<p>\t\tOsmium is a rare, lustrous, very hard, brittle, bluish-white metal.<\/p>\n<p>\t\tIt is the densest of all the elements. (Although osmium&#8217;s density is very similar to iridium&#8217;s, osmium&#8217;s is slightly higher &#8211; both measured and calculated.<\/p>\n<p>\t\tCalculated: Osmium 22.587 &#038;#177 0.009 g\/cm<sup>3<\/sup> &nbsp; &amp; &nbsp; Iridium: 22.562 &#038;#177 0.009 g\/cm<sup>3<\/sup> at 20 <sup>O<\/sup>C. <a href=\"http:\/\/www.platinummetalsreview.com\/pdf\/pmr-v39-i4-164-164.pdf\">See data source<\/a>.)<\/p>\n<p>\t\tOsmium has the highest melting point and the lowest vapor pressure of the platinum group (<a href=\"https:\/\/www.chemicool.com\/elements\/ruthenium.html\">ruthenium<\/a>, <a href=\"https:\/\/www.chemicool.com\/elements\/rhodium.html\">rhodium<\/a>, <a href=\"https:\/\/www.chemicool.com\/elements\/palladium.html\">palladium<\/a>, <a href=\"https:\/\/www.chemicool.com\/elements\/iridium.html\">iridium<\/a>, and <a href=\"https:\/\/www.chemicool.com\/elements\/platinum.html\">platinum<\/a>).<\/p>\n<p><a id=\"uses\"><\/a><\/p>\n<h2>Uses of  Osmium<\/h2>\n<p>\tOsmium is principally used alloyed with other metals in the platinum group to produce very hard alloys.<\/p>\n<p>\t\tAn alloy of 90% platinum and 10% osmium is used in surgical implants such as pacemakers and replacement heart valves.<\/p>\n<p>\t\tOsmium tetroxide is used in microscopy as a stain for fatty tissue and in fingerprint detection.\t<\/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>  1.5  parts per billion by weight, 0.2  parts per billion by moles<\/p>\n<p>\t\t<span class=\"elemgl\">Abundance solar system:<\/span> 2 parts per billion by weight, 20 parts per trillion by moles<\/p>\n<p>\t\t\t\t<span class=\"elemgl\">Cost, pure:<\/span>   $7700 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> \tOsmium is found in platinum ores and in the mineral osmiridium (an alloy of osmium and <a href=\"https:\/\/www.chemicool.com\/elements\/iridium.html\">iridium<\/a>). Commercially, osmium is recovered as a by-product of <a href=\"https:\/\/www.chemicool.com\/elements\/nickel.html\">nickel<\/a> refining.<\/p>\n<p>\t\t<span class=\"elemgl\">Isotopes:<\/span> Osmium has 34 isotopes whose half-lives are known, with mass numbers from 162 to 196. Naturally occurring osmium is a mixture of seven isotopes and they are found in the percentages shown: <sup>184<\/sup>Os (0.02%), <sup>186<\/sup>Os (1.6%), <sup>187<\/sup>Os (2.0%), <sup>188<\/sup>Os (13.2%), <sup>189<\/sup>Os (16.1%), <sup>190<\/sup>Os (26.3%)  and <sup>192<\/sup>Os (40.8%). Naturally the most common isotope is <sup>192<\/sup>Os, with an abundance of 40.8%.  <\/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<li>Photo: <a href=\"http:\/\/www.ornl.gov\/info\/ornlreview\/v35_3_02\/microscope_lab.shtml\">ORNL<\/a><\/li>\n<li>Photo: <a rel=\"nofollow\" href=\"http:\/\/commons.wikimedia.org\/wiki\/File:Osmium_1.jpg\">Tomihahndorf<\/a> <\/li>\n<li> T. Tegg, First Lines of Science, 1827, James Mitchell, p205<\/li>\n<li>Jacob Green, Edward Turner, A Text Book of Chemical Philosophy, 1829, R.H. Small, p325<\/li>\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\/osmium.html\"&gt;Osmium&lt;\/a&gt;\r\n<\/pre>\n<p>or<\/p>\n<pre class='code'>\r\n&lt;a href=\"https:\/\/www.chemicool.com\/elements\/osmium.html\"&gt;Osmium 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\"Osmium.\" Chemicool Periodic Table. Chemicool.com. 17 Oct. 2012. 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\/osmium.html&gt;.<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Data Zone | Discovery | Facts | Appearance &amp; Characteristics | Uses | Abundance &amp; Isotopes | References 76 Os 190.2 The chemical element osmium is classed as a transition metal. It was discovered in 1803 by Smithson Tennant. Data Zone Classification: Osmium is a transition metal Color: bluish-white Atomic weight: 190.2 State: solid Melting [&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-471","1":"page","2":"type-page","3":"status-publish","5":"entry"},"_links":{"self":[{"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/pages\/471","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=471"}],"version-history":[{"count":22,"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/pages\/471\/revisions"}],"predecessor-version":[{"id":4278,"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/pages\/471\/revisions\/4278"}],"wp:attachment":[{"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/media?parent=471"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}