{"id":698,"date":"2012-06-01T18:43:30","date_gmt":"2012-06-01T18:43:30","guid":{"rendered":"http:\/\/www.chemicool.com\/elements\/?page_id=698"},"modified":"2017-12-07T02:07:55","modified_gmt":"2017-12-07T07:07:55","slug":"gadolinium","status":"publish","type":"page","link":"https:\/\/www.chemicool.com\/elements\/gadolinium.html","title":{"rendered":"Gadolinium Element Facts \/ Chemistry"},"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\">64<\/div>\n<div class=\"clearT\"><\/div>\n<div class=\"elnamT\">Gd<\/div>\n<div class=\"atweiT\"> 157.2<\/div>\n<\/div>\n<p>The chemical element gadolinium is classed as a rare earth metal. It was discovered in 1880 by Jean Charles Galissard de Marignac.<\/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><span class=\"elemglb\">Classification:<\/span><\/td>\n<td>Gadolinium is a rare earth metal<\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Color:<\/td>\n<td>  silvery-white  <\/td>\n<\/tr>\n<tr>\n<td><span class=\"elemglb\">Atomic weight:<\/span><\/td>\n<td> 157.25  g\/mol<\/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> 1314 <sup>o<\/sup>C, 1587 K    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Boiling point:<\/td>\n<td>  3260 <sup>o<\/sup>C, 3533  K     <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Electrons:<\/td>\n<td>64<\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Protons:<\/td>\n<td>64<\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Neutrons in most abundant isotope:<\/td>\n<td>94<\/td>\n<\/tr>\n<tr>\n<td><span class=\"elemglb\">Electron shells:<\/span><\/td>\n<td>  2,8,18,25,9,2 <\/td>\n<\/tr>\n<tr>\n<td><span class=\"elemglb\">Electron configuration:<\/span><\/td>\n<td>[Xe] 4f<sup>7<\/sup> 5d<sup>1<\/sup> 6s<sup>2<\/sup><\/td>\n<\/tr>\n<tr>\n<td><span class=\"elemglb\">Density @ 20 <sup>o<\/sup>C:<\/span><\/td>\n<td>  7.895 g\/cm<sup>3<\/sup><\/td>\n<\/tr>\n<\/table>\n<span class=\"collapseomatic \" id=\"id6a217a10a9798\"  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-id6a217a10a9798\" class=\"collapseomatic_content \">\n<table class=\"datatop\">\n<tr>\n<td><span class=\"elemglb\">Atomic volume:<\/span><\/td>\n<td> 19.9 cm<sup>3<\/sup>\/mol<\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Specific heat capacity<\/td>\n<td>   0.23 J g<sup>-1<\/sup> K<sup>-1<\/sup>  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Heat of fusion<\/td>\n<td>  10.050  kJ mol<sup>-1<\/sup> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Heat of atomization<\/td>\n<td>  389 kJ mol<sup>-1<\/sup> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Heat of vaporization<\/td>\n<td>    311.71  kJ mol<sup>-1<\/sup>   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">1<sup>st<\/sup> ionization energy<\/td>\n<td>  593.40  kJ mol<sup>-1<\/sup>    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">2<sup>nd<\/sup> ionization energy<\/td>\n<td>   1170    kJ mol<sup>-1<\/sup>    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">3<sup>rd<\/sup> ionization energy<\/td>\n<td>   1991  kJ mol<sup>-1<\/sup>   <\/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> 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>   1.20    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Polarizability volume <\/td>\n<td>   23.5   &Aring;<sup>3<\/sup>  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Reaction with air<\/td>\n<td>   mild, &#8658;  Gd<sub>2<\/sub>O<sub>3<\/sub>  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Reaction with 15 M HNO<sub>3<\/sub> <\/td>\n<td>   mild, &#8658; Gd(NO<sub>3<\/sub>)<sub>3<\/sub> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Reaction with 6 M HCl <\/td>\n<td>  mild, &#8658;  H<sub>2<\/sub>, GdCl<sub>3<\/sub> <\/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>  Gd<sub>2<\/sub>O<sub>3<\/sub>  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Hydride(s) <\/td>\n<td>   GdH<sub>2<\/sub>, GdH<sub>3<\/sub>    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Chloride(s) <\/td>\n<td>  GdCl<sub>3<\/sub> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Atomic radius <\/td>\n<td>  180 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>  107.8 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>10.6  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> 1314 <sup>o<\/sup>C, 1587 K    <\/td>\n<\/tr>\n<\/table>\n<\/div>\n<\/div>\n<div class=\"leftimagepadding\">\n<\/div>\n<\/div>\n<p><a id=\"discovery\"><\/a><\/p>\n<h2>Discovery of Gadolinium<\/h2>\n<div class=\"author\">Dr. Doug Stewart<\/div>\n<p>In 1880, Swiss chemist Jean Charles Galissard de Marignac recorded previously unknown spectroscopic lines in an oxide preparation taken from the mineral samarskite. These were caused by the element we now know as gadolinium. <\/p>\n<p>In 1886, French chemist Paul &#201;mile Lecoq de Boisbaudran confirmed Marignac&#8217;s discovery. Boisbaudran suggested the name gadolinium for the new element after the 18th century chemist and mineralogist Johan Gadolin. The name was accepted by Marignac.<\/p>\n<p>Earlier, in 1853, Marignac had discovered <a href=\"https:\/\/www.chemicool.com\/elements\/samarium.html\">samarium<\/a> by a similar method and he also discovered <a href=\"https:\/\/www.chemicool.com\/elements\/ytterbium.html\">ytterbium<\/a> in 1878.<\/p>\n<p>Pure metallic gadolinium (99.3%) was first prepared by French chemist and engineer Felix Trombe in 1935. <sup>(1)<\/sup><\/p>\n<p>A few months later, Georges Urbain, Pierre Weiss and Felix Trombe discovered that gadolinium becomes ferromagnetic at about room temperature, the first pure element to show this property other than the three &#8216;classical&#8217; metals <a href=\"https:\/\/www.chemicool.com\/elements\/iron.html\">iron<\/a>, <a href=\"https:\/\/www.chemicool.com\/elements\/nickel.html\">nickel<\/a>, and <a href=\"https:\/\/www.chemicool.com\/elements\/cobalt.html\">cobalt<\/a>. <\/p>\n<p>They found that gadolinium becomes more ferromagnetic than iron but only at low temperatures. <sup>(1)<\/sup>\t\t\t<\/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:\/\/chemicool.com\/elements\/images\/300-gadolinium-cylinder.jpg\" width=\"300\" height=\"158\" alt=\"A distilled gadolinium cylinder\" class=\"size-full\" \/><p class=\"wp-caption-text\">A distilled gadolinium cylinder.Image Ref.<sup>(4)<\/sup><\/p><\/div>\n<div style=\"width: 310px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.chemicool.com\/elements\/images\/300-gadolinium-153.jpg\" width=\"300\" height=\"260\" alt=\"Gadolinium-153\" class=\"size-full\" \/><p class=\"wp-caption-text\">Gadolinium-153 is used in the calibration of single photon-emission computed tomography (SPECT) systems used for imaging in nuclear medicine. The SPECT images (middle and right) provide functional information about patient health, whereas the MRI image (left) provides only anatomical detail. Gadolinium-153 is produced in a nuclear reactor from <a href=\"https:\/\/www.chemicool.com\/elements\/europium.html\">europium<\/a> or enriched gadolinium targets. Photo: Pacific Northwest National Lab<\/p><\/div>\n<div style=\"width: 310px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.chemicool.com\/elements\/images\/300-dysprosium.jpg\" width=\"300\" height=\"176\" alt=\"Rare earth metals and salts.\" class=\"size-full\" \/><p class=\"wp-caption-text\">The left-most metal disc is cast dysprosium metal, resting on a sheet of sublimated <a href=\"https:\/\/www.chemicool.com\/elements\/images\/dysprosium.html\">dysprosium<\/a>. The other metal disc is <a href=\"https:\/\/www.chemicool.com\/elements\/images\/scandium.html\">scandium<\/a> and the metal cylinder is gadolinium. Photo: <a href=\"https:\/\/www.ameslab.gov\/news\/inquiry\/2010-2-root\">Ames Laboratory <\/a>.<\/p><\/div>\n<div style=\"width: 310px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.chemicool.com\/elements\/images\/300-rare-earth-oxides.jpg\" width=\"300\" height=\"158\" alt=\"Rare earth oxides\" class=\"size-full\" \/><p class=\"wp-caption-text\">Clockwise from top center: Rare earth oxides of praseodymium, cerium, lanthanum, neodymium, samarium and gadolinium. Photo <a href=\"https:\/\/www.llnl.gov\/news\/aroundthelab\/2010\/Nov\/ATL-111910_workshop.html\">LLNL<\/a><\/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>  <strong>Harmful effects:<\/strong> <\/p>\n<p>\t \tGadolinium is considered to be moderately toxic.<\/p>\n<p>\t  <strong>Characteristics:<\/strong><\/p>\n<p>\t\tGadolinium is a bright, soft, silvery-white metal that is both ductile and malleable.<\/p>\n<p>\t\tIt is one of the rare earth metals.<\/p>\n<p>    It does not react in dry air but will tarnish to a flaky white oxide in moist air that does not protect it from further oxidation.<\/p>\n<p>    The metal reacts slowly with water and is soluble in dilute acid. It produces colorless salts. <\/p>\n<p>\t\tWhen present in compounds, gadolinium exists mostly in the trivalent state (Gd<sup>3+<\/sup>).<\/p>\n<p>    At room temperature the metal is paramagnetic, but it becomes ferromagnetic (strongly attracted by a magnet) when cooled. The Curie point of gadolinium is 17 <sup>o<\/sup>C. <sup>(2)<\/sup><\/p>\n<p>    The <sup>157<\/sup>Gd isotope has the highest thermal neutron capture cross-section of any known stable element.<\/p>\n<p><a id=\"uses\"><\/a><\/p>\n<h2>Uses of Gadolinium<\/h2>\n<p>\t\tGadolinium is used in alloys of iron and chromium to improve resistance to high temperatures and oxidation.<\/p>\n<p>    Gadolinium is used to make gadolinium yttrium garnets which have microwave applications.<\/p>\n<p>    Gadolinium compounds are used as green phosphors in color television picture tubes.<\/p>\n<p>    Because of its magnetic properties, gadolinium is also used in intravenous radiocontrast agents in magnetic resonance imaging (MRI).<\/p>\n<p>\t\tArc-melted alloys of gadolinium, <a href=\"https:\/\/www.chemicool.com\/elements\/silicon.html\">silicon<\/a>, and <a href=\"https:\/\/www.chemicool.com\/elements\/germanium.html\">germanium<\/a> demonstrate a strong magnetocaloric effect at room temperatures (where its temperature increases when it enters a magnetic field and decreases when it leaves the magnetic field) making it useful in the field of room temperature magnetic refrigeration. <sup>(3)<\/sup><\/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> 5.2 parts per million by weight, 0.7 parts per million by moles<\/p>\n<p>\t\t<span class=\"elemgl\">Abundance solar system:<\/span>  2 parts per billion by weight,  10 parts per trillion by moles<\/p>\n<p>\t\t\t\t<span class=\"elemgl\">Cost, pure:<\/span>  $450 per 100g<\/p>\n<p>\t\t\t\t<span class=\"elemgl\">Cost, bulk:<\/span> $12  per 100g<\/p>\n<p>\t\t<span class=\"elemgl\">Source:<\/span> Gadolinium is not found free in nature but is found in a number of minerals: mainly monazite and bastnaesite. Commercially, gadolinium is isolated by ion exchange and solvent extraction. The metal can be produced by the reduction of anhydrous gadolinium fluoride with calcium metal.<\/p>\n<p>\t\t<span class=\"elemgl\">Isotopes:<\/span> Gadolinium  has 27 isotopes whose half-lives are known, with mass numbers 137 to 164. Naturally occurring gadolinium is a mixture of seven isotopes and they are found in the percentages shown: <sup>152<\/sup>Gd (0.2%), <sup>154<\/sup>Gd (2.2%), <sup>155<\/sup>Gd (14.8%), <sup>156<\/sup>Gd (20.5%), <sup>157<\/sup>Gd (15.7%), <sup>158<\/sup>Gd (24.8%) and <sup>160<\/sup>Gd (21.9%).  The most abundant isotope is <sup>158<\/sup>Gd at 24.8%.<\/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> T.S.S., <a href=\"http:\/\/www.ias.ac.in\/jarch\/currsci\/4\/114-117.pdf\">The ferromagnetism of gadolinium<\/a>., Current Science., August 1935. pdf<\/li>\n<li> T Lewowski and K Wozniak, <a href=\"http:\/\/www.d.umn.edu\/~jmaps\/phys5061\/projects\/curie\/curie_temp_lewowski.pdf\">Measurement of Curie temperature for gadolinium.<\/a> pdf<\/li>\n<li> West Virginia University, <a href=\"http:\/\/www.che.cemr.wvu.edu\/publications\/projects\/prod_design\/magnetic_refrigerator.pdf\">Magnetic Refrigeration.<\/a> pdf<\/li>\n<li>Image <a href=\"https:\/\/www.ameslab.gov\/rare-earth-metals\">Ames Laboratory.<\/a><\/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\/gadolinium.html\"&gt;Gadolinium&lt;\/a&gt;\r\n<\/pre>\n<p>or<\/p>\n<pre class='code'>\r\n&lt;a href=\"https:\/\/www.chemicool.com\/elements\/gadolinium.html\"&gt;Gadolinium 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\"Gadolinium.\" 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\/gadolinium.html&gt;.<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Data Zone | Discovery | Facts | Appearance &amp; Characteristics | Uses | Abundance &amp; Isotopes | References 64 Gd 157.2 The chemical element gadolinium is classed as a rare earth metal. It was discovered in 1880 by Jean Charles Galissard de Marignac. Data Zone Classification: Gadolinium is a rare earth metal Color: silvery-white Atomic [&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-698","1":"page","2":"type-page","3":"status-publish","5":"entry"},"_links":{"self":[{"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/pages\/698","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=698"}],"version-history":[{"count":28,"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/pages\/698\/revisions"}],"predecessor-version":[{"id":4239,"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/pages\/698\/revisions\/4239"}],"wp:attachment":[{"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/media?parent=698"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}