{"id":455,"date":"2012-05-25T18:06:44","date_gmt":"2012-05-25T18:06:44","guid":{"rendered":"http:\/\/www.chemicool.com\/elements\/?page_id=455"},"modified":"2017-12-07T02:07:55","modified_gmt":"2017-12-07T07:07:55","slug":"hafnium","status":"publish","type":"page","link":"https:\/\/www.chemicool.com\/elements\/hafnium.html","title":{"rendered":"Hafnium 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\">72<\/div>\n<div class=\"clearT\"><\/div>\n<div class=\"elnamT\">Hf<\/div>\n<div class=\"atweiT\"> 178.5<\/div>\n<\/div>\n<p>The chemical element hafnium is classed as a transition metal . It was discovered in 1923 by Georg von Hevesy and Dirk Coster.<\/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>  Hafnium is a transition 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>   178.49 <\/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> 2230 <sup>o<\/sup>C, 2503 K    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Boiling point:<\/td>\n<td>  4600  <sup>o<\/sup>C, 4873 K    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Electrons:<\/td>\n<td>72<\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Protons:<\/td>\n<td>72<\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Neutrons in most abundant isotope:<\/td>\n<td>108<\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Electron shells:<\/td>\n<td>   2,8,18,32,10,2    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Electron configuration:<\/td>\n<td>  [Xe] 4f<sup>14<\/sup> 5d<sup>2<\/sup> 6s<sup>2<\/sup>   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Density @ 20<sup>o<\/sup>C:<\/td>\n<td>  13.2  g\/cm<sup>3<\/sup>   <\/td>\n<\/tr>\n<\/table>\n<span class=\"collapseomatic \" id=\"id69e10c976d911\"  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-id69e10c976d911\" class=\"collapseomatic_content \">\n<table class=\"datatop\">\n<tr>\n<td class=\"elemglb\">Atomic volume:<\/td>\n<td>   13.6 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>    5.5 mohs  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Specific heat capacity<\/td>\n<td> 0.14   J g<sup>-1<\/sup> K<sup>-1<\/sup>  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Heat of fusion<\/td>\n<td>  27.2 kJ mol<sup>-1<\/sup>  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Heat of atomization<\/td>\n<td>  621   kJ mol<sup>-1<\/sup> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Heat of vaporization<\/td>\n<td>   575.0 kJ mol<sup>-1<\/sup>    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">1<sup>st<\/sup> ionization energy<\/td>\n<td>  658.5 kJ mol<sup>-1<\/sup>   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">2<sup>nd<\/sup> ionization energy<\/td>\n<td>   1440  kJ mol<sup>-1<\/sup>    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">3<sup>rd<\/sup> ionization energy<\/td>\n<td>    2250    kJ mol<sup>-1<\/sup>  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Electron affinity<\/td>\n<td>    178  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> 4 <\/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>  1.3   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Polarizability volume <\/td>\n<td>   16.2 &Aring;<sup>3<\/sup>  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Reaction with air<\/td>\n<td>  mild, w\/ht &#8658;  HfO<sub>2<\/sub>  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Reaction with 15 M HNO<sub>3<\/sub> <\/td>\n<td>  passivated  <\/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> HfO<sub>2<\/sub> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Hydride(s) <\/td>\n<td>    HfH<sub>2<\/sub>   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Chloride(s) <\/td>\n<td>    HfCl<sub>4<\/sub> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Atomic radius <\/td>\n<td>  155  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>  23.2  W m<sup>-1<\/sup> K<sup>-1<\/sup> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Electrical conductivity <\/td>\n<td> 3.4 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> 2230 <sup>o<\/sup>C, 2503 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-hafnium.jpg\" width=\"300\" height=\"163\" alt=\"Hafnium metal is a silver color\" class=\"size-full\" \/><p class=\"wp-caption-text\">Hafnium metal is a silver color. It normally appears rather gray because of the oxide layer it forms in air. Hafnium powder, without the oxide layer, can ignite spontaneously in air. Image Ref. (1)<\/p><\/div>\n<\/div>\n<\/div>\n<p><a id=\"discovery\"><\/a><\/p>\n<h2>Discovery of Hafnium<\/h2>\n<p>Hafnium&#8217;s existence was originally predicted by Russian chemist Dmitri Mendeleev.  In his 1869 book &#8220;The Periodic Law of the Chemical Elements&#8221; he predicted the existence of an element with similar properties to, but heavier than <a href=\"https:\/\/www.chemicool.com\/elements\/titanium.html\">titanium<\/a> and <a href=\"https:\/\/www.chemicool.com\/elements\/zirconium.html\">zirconium<\/a>.<\/p>\n<p>In 1911, Georges Urbain, the discoverer of the rare earth <a href=\"https:\/\/www.chemicool.com\/elements\/lutetium.html\">lutetium<\/a>, thought he had discovered element 72 during his spectral analysis of rare earths. He called this new element celtium, but three years later it was shown to be a mixture of already discovered lanthanides. <sup>(2)<\/sup><\/p>\n<p>In 1921, Neils Bohr suggested to Hungarian chemist Georg von Hevesy to look for the missing element in zirconium ores. <sup>(3)<\/sup> According to Bohr&#8217;s quantum theory of atomic structure, these metals would have similar chemical properties, so there was a good chance they would be found in the same ores.<\/p>\n<p>Following Bohr&#8217;s advice, Hevesy and Dutch physicist Dirk Coster discovered hafnium in 1923 using x-ray spectroscopy to analyze zirconium ores. <\/p>\n<p>Anton Eduard van Arkel and Jan Hendrik de Boer discovered a method for producing high purity hafnium in 1925. Hafnium tetraiodide (HfI<sub>4<\/sub>) is decomposed on a white hot tungsten filament creating a crystal bar of pure hafnium. This is known as the crystal bar process.<\/p>\n<p>The element was called Hafnium after the Latin name &#8216;Hafnia,&#8217; meaning Copenhagen, the city where the element was discovered. <\/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-hafnium-carbide.jpg\" width=\"300\" height=\"248\" alt=\"Crystal structure of hafnium carbide\" class=\"size-full\" \/><p class=\"wp-caption-text\">Crystal structure of hafnium carbide (HfC). This is the most refractory (heat resistant) compound known of any two elements in 1:1 ratio.<\/p><\/div>\n<div style=\"width: 310px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.chemicool.com\/elements\/images\/300-nuclear-sub.jpg\" width=\"300\" height=\"240\" alt=\"Hafnium is used in nuclear reactor control rods\" class=\"size-full\" \/><p class=\"wp-caption-text\">Hafnium is used in nuclear reactor control rods in nuclear submarines<\/p><\/div>\n<div style=\"width: 310px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.chemicool.com\/elements\/images\/300-hafnium-iv-oxide.jpg\" width=\"300\" height=\"194\" alt=\"Hafnium oxide\" class=\"size-full\" \/><p class=\"wp-caption-text\">White hafnium (IV) oxide (HfO<sub>2<\/sub>). Hafnium oxide based compounds are being introduced into silicon chips to produce smaller, high performance processors with improved energy efficiency.<\/p><\/div>\n<\/div>\n<\/div>\n<\/div>\n<p><a id=\"appear\"><\/a><\/p>\n<h3>Appearance and Characteristics<\/h3>\n<p>\t  <strong>Harmful effects:<\/strong> <\/p>\n<p>\t \tHafnium is considered to be non-toxic. In powdered form it is pyrophoric (can ignite spontaneously).\t<\/p>\n<p>\t  <strong>Characteristics:<\/strong><\/p>\n<p>\t\t Hafnium is a lustrous, silvery, ductile metal. <\/p>\n<p>\t\tChemically it is similar to zirconium. <\/p>\n<p>When present in compounds, hafnium exists mostly in the oxidation state IV.  <\/p>\n<p>\t\tHafnium resists corrosion due to the formation of an oxide film on exposed surfaces. <\/p>\n<p>\t\tIt is unaffected by all acids (apart from hydrogen fluoride) and all alkalis. <\/p>\n<p>\t\tHafnium reacts with the halogens to form tetrahalides, and at high temperatures it reacts with <a href=\"https:\/\/www.chemicool.com\/elements\/carbon.html\">carbon<\/a>, <a href=\"https:\/\/www.chemicool.com\/elements\/boron.html\">boron<\/a>, <a href=\"https:\/\/www.chemicool.com\/elements\/nitrogen.html\">nitrogen<\/a>, <a href=\"https:\/\/www.chemicool.com\/elements\/oxygen.html\">oxygen<\/a>, <a href=\"https:\/\/www.chemicool.com\/elements\/silicon.html\">silicon<\/a> and <a href=\"https:\/\/www.chemicool.com\/elements\/sulfur.html\">sulfur<\/a>.<\/p>\n<p><a id=\"uses\"><\/a><\/p>\n<h2>Uses of Hafnium<\/h2>\n<p>Hafnium is used for nuclear reactor control rods because of its ability to absorb neutrons and its good mechanical and corrosion resistance qualities. This is in complete contrast to zirconium, which although is chemically is very similar to hafnium, is very poor at absorbing neutrons. Zirconium is therefore used in the cladding (outer layer) of fuel rods through which it is important that neutrons can travel easily. <\/p>\n<p>Hafnium is also used in photographic flash bulbs, light bulb filaments, and in electronic equipment as cathodes and capacitors.<\/p>\n<p>Hafnium alloys with several other metals, such as <a href=\"https:\/\/www.chemicool.com\/elements\/iron.html\">iron<\/a>, <a href=\"https:\/\/www.chemicool.com\/elements\/niobium.html\">niobium<\/a>, <a href=\"https:\/\/www.chemicool.com\/elements\/tantalum.html\">tantalum<\/a> and <a href=\"https:\/\/www.chemicool.com\/elements\/titanium.html\">titanium<\/a>.<\/p>\n<p>\t\tHafnium-niobium alloys, for example, are heat resistant and are used in aerospace applications, such as space rocket engines.<\/p>\n<p>Hafnium carbide is used to line high temperature furnaces \/ kilns due to its refractory properties (it does not melt at high temperatures).<\/p>\n<p>Hafnium-based compounds are used in gate insulators in the 45 nm generation of integrated circuits for computers.<\/p>\n<p>Hafnium oxide-based compounds are being introduced into silicon-based chips to produce smaller, more energy efficient and performance packed processors<sup>(4)<\/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>  3.3 parts per million by weight, 0.4 parts per million by moles<\/p>\n<p>\t\t<span class=\"elemgl\">Abundance solar system:<\/span> 1 part per billion by weight,  0.01 parts per billion by moles<\/p>\n<p>\t\t\t\t<span class=\"elemgl\">Cost, pure:<\/span>   $120 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> Hafnium is not found free in nature but is found in most zirconium minerals at a concentration of between one and five percent. Commercially, hafnium is produced as a by-product of <a href=\"https:\/\/www.chemicool.com\/elements\/zirconium.html\">zirconium<\/a> refining. This is done using the Kroll Process, reducing the tetrachloride with <a href=\"https:\/\/www.chemicool.com\/elements\/magnesium.html\">magnesium<\/a> or with <a href=\"https:\/\/www.chemicool.com\/elements\/sodium.html\">sodium<\/a>.<\/p>\n<p>\t\t<span class=\"elemgl\">Isotopes:<\/span> Hafnium has 32 isotopes whose half-lives are known, with mass numbers 154 to 185. Naturally occurring hafnium is a mixture of six isotopes and they are found in the percentages shown: <sup>174<\/sup>Hf (0.2%), <sup>176<\/sup>Hf (5.3%), <sup>177<\/sup>Hf (18.6%), <sup>178<\/sup>Hf (27.3%), <sup>179<\/sup>Hf (13.6%) and <sup>180<\/sup>Hf (35.1%). The most abundant is <sup>180<\/sup>Hf at 35.1%.  <\/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 by <a rel=\"nofollow\" href=\"http:\/\/en.wikipedia.org\/wiki\/User:Deglr6328\">Deglr6328<\/a><\/li>\n<li>Per Enghag, Encyclopedia of the Elements: Technical Data &#8211; History &#8211; Processing &#8211; Applications, 2008, John Wiley &#38; Sons, p527.<\/li>\n<li>Bob Weintraub, <a rel=\"nofollow\" href=\"http:\/\/www.chemistry.org.il\/booklet\/18\/pdf\/weintraub.pdf\">George De Hevesy (1885 1966)<\/a> (pdf document).<\/li>\n<li>Aile Tamm, Atomic Layer Deposition Of High-Permittivity Insulators From Cyclopentadienyl-Based Precursors, 2010, Tartu University Press, p18.   <\/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\/hafnium.html\"&gt;Hafnium&lt;\/a&gt;\r\n<\/pre>\n<p>or<\/p>\n<pre class='code'>\r\n&lt;a href=\"https:\/\/www.chemicool.com\/elements\/hafnium.html\"&gt;Hafnium 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\"Hafnium.\" 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\/hafnium.html&gt;.<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Data Zone | Discovery | Facts | Appearance &amp; Characteristics | Uses | Abundance &amp; Isotopes | References 72 Hf 178.5 The chemical element hafnium is classed as a transition metal . It was discovered in 1923 by Georg von Hevesy and Dirk Coster. Data Zone Classification: Hafnium is a transition metal Color: silvery 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-455","1":"page","2":"type-page","3":"status-publish","5":"entry"},"_links":{"self":[{"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/pages\/455","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=455"}],"version-history":[{"count":22,"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/pages\/455\/revisions"}],"predecessor-version":[{"id":4244,"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/pages\/455\/revisions\/4244"}],"wp:attachment":[{"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/media?parent=455"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}