{"id":755,"date":"2012-06-02T18:05:48","date_gmt":"2012-06-02T18:05:48","guid":{"rendered":"http:\/\/www.chemicool.com\/elements\/?page_id=755"},"modified":"2017-12-07T02:08:24","modified_gmt":"2017-12-07T07:08:24","slug":"neptunium","status":"publish","type":"page","link":"https:\/\/www.chemicool.com\/elements\/neptunium.html","title":{"rendered":"Neptunium 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=\"rareT\">\n<div class=\"atnorT\">93<\/div>\n<div class=\"clearT\"><\/div>\n<div class=\"elnamT\">Np<\/div>\n<div class=\"atweiT\">(237)<\/div>\n<\/div>\n<p>The chemical element neptunium is classed as an actinide metal. It was discovered in 1940 by Edwin McMillan and Philip H. Abelson.<\/p>\n<div style=\"clear:both;\"><\/div>\n<div class=\"adsense300\">\n<div class=\"adsense300spacer\">\n<div style=\"line-height:10px;\">\n<img decoding=\"async\" alt=\"\" src=\"\/\/www.chemicool.com\/ad.png\"\/>\n<\/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=\"3265846807\"><\/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>  Neptunium is an actinide metal   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Color:<\/td>\n<td>  silvery  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Atomic weight:<\/td>\n<td> (237), no stable isotopes <\/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> 640 <sup>o<\/sup>C, 913 K    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Boiling point:<\/td>\n<td>  3900 <sup>o<\/sup>C, 4173 K     <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Electrons:<\/td>\n<td>93<\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Protons:<\/td>\n<td>93<\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Neutrons in most abundant isotope:<\/td>\n<td>144<\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Electron shells:<\/td>\n<td>   2,8,18,32,23,8,2  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Electron configuration:<\/td>\n<td>    [Rn] 5f<sup>4<\/sup> 6d<sup>1<\/sup> 7s<sup>2<\/sup>   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Density @ 20<sup>o<\/sup>C:<\/td>\n<td> 20.45 g\/cm<sup>3<\/sup>   <\/td>\n<\/tr>\n<\/table>\n<span class=\"collapseomatic \" id=\"id6a2bd6046bb17\"  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-id6a2bd6046bb17\" class=\"collapseomatic_content \">\n<table class=\"datatop\">\n<tr>\n<td class=\"elemglb\">Atomic volume:<\/td>\n<td>   11.62 cm<sup>3<\/sup>\/mol  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Structure:<\/td>\n<td>   orthorhombic <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Hardness: <\/td>\n<td>     <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Specific heat capacity<\/td>\n<td>   0.11 J g<sup>-1<\/sup> K<sup>-1<\/sup>  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Heat of fusion<\/td>\n<td>  3.2 kJ mol<sup>-1<\/sup> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Heat of atomization<\/td>\n<td> 337 kJ mol<sup>-1<\/sup> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Heat of vaporization<\/td>\n<td>  &#8211;  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">1<sup>st<\/sup> ionization energy<\/td>\n<td>  597 kJ mol<sup>-1<\/sup>    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">2<sup>nd<\/sup> ionization energy<\/td>\n<td>  &#8211;    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">3<sup>rd<\/sup> ionization energy<\/td>\n<td>   &#8211;   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Electron affinity<\/td>\n<td>  &#8211;  <\/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> 7 <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Max. common oxidation no. <\/td>\n<td>  5  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Electronegativity (Pauling Scale) <\/td>\n<td>  1.3   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Polarizability volume <\/td>\n<td>  24.8  &Aring;<sup>3<\/sup> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Reaction with air<\/td>\n<td> &#8211;  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Reaction with 15 M HNO<sub>3<\/sub> <\/td>\n<td>  &#8211;  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Reaction with 6 M HCl <\/td>\n<td> &#8211; <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Reaction with 6 M NaOH <\/td>\n<td>   &#8211;  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Oxide(s) <\/td>\n<td>  NpO, NpO<sub>2<\/sub>, Np<sub>2<\/sub>O<sub>5<\/sub> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Hydride(s) <\/td>\n<td>    NpH<sub>2<\/sub>, NpH<sub>3<\/sub>   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Chloride(s) <\/td>\n<td>   NpCl<sub>3<\/sub>, NpCl<sub>4<\/sub>  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Atomic radius <\/td>\n<td>   175 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>   124 pm  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Ionic radius (3+ ion) <\/td>\n<td>  115 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\"> Thermal conductivity <\/td>\n<td> 6.3 W m<sup>-1<\/sup> K<sup>-1<\/sup> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Electrical conductivity <\/td>\n<td>  0.8 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> 640 <sup>o<\/sup>C, 913 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:\/\/chemicool.com\/elements\/images\/300-neptunium-metal.jpg\" width=\"300\" height=\"163\" alt=\"Neptunium-237 sphere\" class=\"size-full\" \/><p class=\"wp-caption-text\">Neptunium-237 sphere (6 kg) Photo credit: Los Alamos National Laboratory<\/p><\/div>\n<\/div>\n<\/div>\n<p>\t\t\t<a id=\"discovery\"><\/a>\t<\/p>\n<h2>Discovery of Neptunium<\/h2>\n<div class=\"author\">Dr. Doug Stewart<\/div>\n<p>    Neptunium was the first synthetic transuranium element (elements after uranium) of the actinide series to be discovered.<\/p>\n<p>Neptunium was first produced by Edwin McMillan and Philip H. Abelson in 1940 at Berkeley Radiation Laboratory of the University of California.<\/p>\n<p>McMillan and Abelson bombarded uranium-238 with neutrons and they were able to show chemically that they had produced neptunium-239, which has a half-life of just 2.3 days.<\/p>\n<p>A longer lived isotope neptunium-237 was discovered in 1942. Scientists A. C. Wahl and Glenn T. Seaborg bombarded uranium-238 with fast neutrons in the Berkeley 60-inch cyclotron. They isolated several hundred milligrams of neptunium and made a thorough study of its properties. <sup>(1)<\/sup><\/p>\n<p>The element is named after the planet Neptune, continuing the theme started by Martin Klaproth when he named <a href=\"https:\/\/www.chemicool.com\/elements\/uranium.html\">uranium<\/a> after the planet Uranus. This theme was to continue with <a href=\"https:\/\/www.chemicool.com\/elements\/plutonium.html\">plutonium<\/a>, which follows neptunium in the actinide series.<\/p>\n<p>     <a id=\"appear\"><\/a><\/p>\n<h3>Appearance and Characteristics<\/h3>\n<p>\t\t  <strong>Harmful effects:<\/strong> <\/p>\n<p>\t \tNeptunium is harmful due to its radioactivity. \t<\/p>\n<p>\t  <strong>Characteristics:<\/strong><\/p>\n<p>\t\tNeptunium is a silvery radioactive synthetic metal. (Miniscule quantities of neptunium-237 and neptunium-239 are found in nature as a result of beta decay of uranium.)<\/p>\n<p>Neptunium exists in three allotropes: it has an orthorhombic structure at normal temperatures, a tetragonal structure above 280<sup>o<\/sup>C and a cubic structure above 577<sup>o<\/sup>C. <sup>(2)<\/sup><\/p>\n<p>Neptunium has five oxidation states (+3 to +7) producing different colors in solution: <\/p>\n<p>III: &nbsp; Np<sup>3+<\/sup> (violet)<br \/>\nIV: &nbsp;  Np<sup>4+<\/sup> (yellow green)<br \/>\nV: &nbsp;   NpO<sub>2<\/sub><sup>+<\/sup> in acidic solution (green) and in alkaline solution (yellow)<br \/>\nVI: &nbsp;   NpO<sub>2<\/sub><sup>2+<\/sup> (pink red)<br \/>\nVII:&nbsp;  Np(VII) in alkaline solution (green) or possibly in acidic conditions (brownish-red). <sup>(3)<\/sup> <\/p>\n<p>\t\t<a id=\"uses\"><\/a><\/p>\n<h2>Uses of Neptunium<\/h2>\n<p>\t\tNeptunium is used mainly for research purposes.<\/p>\n<p>\t\t When bombarded with neutrons neptunium-237 is used to produce plutonium-238 which is used for spacecraft generators and terrestrial navigation beacons.<\/p>\n<p>\t\t  Neptunium is also used in neutron detection equipment.<\/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>  0.0005 parts per trillion by weight<\/p>\n<p><span class=\"elemgl\">Abundance earth&#8217;s crust:<\/span>  negligible<\/p>\n<p>\t\t<span class=\"elemgl\">Abundance solar system:<\/span> unknown<\/p>\n<p>\t\t\t\t<span class=\"elemgl\">Cost, pure:<\/span>   per g<\/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> Miniscule concentrations of neptunium-237 and neptunium-239 are found naturally in uranium ores. Neptunium-237 is produced in kilogram quantities from radioactive waste from power reactors. Neptunium-238 is produced from the production of plutonium-238. <sup>(3)<\/sup><\/p>\n<p>\t\t<span class=\"elemgl\">Isotopes:<\/span> Neptunium has 20 isotopes whose half-lives are known, with mass numbers 225 to 244. Neptunium has no stable isotopes. Its longest lived isotopes are <sup>237<\/sup>Np, with a half-life of 2.14 million years, <sup>236<\/sup>Np with a half-life of 154,000 years and <sup>235<\/sup>Np with a half-life of 396.1 days.<\/p>\n<div style=\"clear:both;line-height:2px;\">&nbsp;<\/div>\n<div style=\"max-width:750px;\">\n<div style=\"line-height:10px;\">\n<img decoding=\"async\" alt=\"\" src=\"\/\/www.chemicool.com\/ad.png\"\/>\n<\/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>\n<\/div>\n<p>\t\t<a id=\"refer\"><\/a><\/p>\n<h4>References<\/h4>\n<ol>\n<li>I. Perlman, The Transuranium Elements and Nuclear Chemistry., Journal of Chemical Education., May 1948, p275-276. <\/li>\n<li>David R. Lide, CRC Handbook of Chemistry and Physics., 86th edition., p4-24.<\/li>\n<li>Karen Nilsson and Lars Carlsen, <a href=\"http:\/\/130.226.56.153\/rispubl\/reports_INIS\/RISOM2792.pdf\">The Migration Chemistry of Neptunium<\/a>. (pdf document) <\/li>\n<\/ol>\n<p><a id=\"Cite\"><\/a><\/p>\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\/neptunium.html\"&gt;Neptunium&lt;\/a&gt;\r\n<\/pre>\n<p>or<\/p>\n<pre class='code'>\r\n&lt;a href=\"https:\/\/www.chemicool.com\/elements\/neptunium.html\"&gt;Neptunium 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\"Neptunium.\" Chemicool Periodic Table. Chemicool.com. 07 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\/neptunium.html&gt;.<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Data Zone | Discovery | Facts | Appearance &amp; Characteristics | Uses | Abundance &amp; Isotopes | References 93 Np (237) The chemical element neptunium is classed as an actinide metal. It was discovered in 1940 by Edwin McMillan and Philip H. Abelson. Data Zone Classification: Neptunium is an actinide metal Color: silvery Atomic weight: [&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-755","1":"page","2":"type-page","3":"status-publish","5":"entry"},"_links":{"self":[{"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/pages\/755","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=755"}],"version-history":[{"count":19,"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/pages\/755\/revisions"}],"predecessor-version":[{"id":4271,"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/pages\/755\/revisions\/4271"}],"wp:attachment":[{"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/media?parent=755"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}