{"id":236,"date":"2012-05-23T08:16:55","date_gmt":"2012-05-23T08:16:55","guid":{"rendered":"http:\/\/www.chemicool.com\/elements\/?page_id=236"},"modified":"2017-12-07T02:07:25","modified_gmt":"2017-12-07T07:07:25","slug":"calcium","status":"publish","type":"page","link":"https:\/\/www.chemicool.com\/elements\/calcium.html","title":{"rendered":"Calcium 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=\"alkalieT\">\n<div class=\"atnorT\">20<\/div>\n<div class=\"clearT\"><\/div>\n<div class=\"elnamT\">Ca<\/div>\n<div class=\"atweiT\">40.08<\/div>\n<\/div>\n<p>The chemical element calcium is classed as an alkali earth metal. It was discovered in 1808 by Sir Humphry Davy.<\/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>  Calcium is an alkali earth metal   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Color:<\/td>\n<td>  silvery-gray  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Atomic weight:<\/td>\n<td>   40.078 <\/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> 842 <sup>o<\/sup>C, 1115 K    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Boiling point:<\/td>\n<td>  1484 <sup>o<\/sup>C , 1771 K    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Electrons:<\/td>\n<td>20<\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Protons:<\/td>\n<td>20<\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Neutrons in most abundant isotope:<\/td>\n<td>20<\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Electron shells:<\/td>\n<td>  2,8,8,2    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Electron configuration:<\/td>\n<td>   1s<sup>2<\/sup> 2s<sup>2<\/sup> 2p<sup>6<\/sup> 3s<sup>2<\/sup> 3p<sup>6<\/sup> 4s<sup>2<\/sup>   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Density @ 20<sup>o<\/sup>C:<\/td>\n<td>  1.55 g\/cm<sup>3<\/sup>   <\/td>\n<\/tr>\n<\/table>\n<span class=\"collapseomatic \" id=\"id6a34d2e3bee5f\"  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-id6a34d2e3bee5f\" class=\"collapseomatic_content \">\n<table class=\"datatop\">\n<tr>\n<td class=\"elemglb\">Atomic volume:<\/td>\n<td>   29.9 cm<sup>3<\/sup>\/mol  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Structure:<\/td>\n<td>   ccp: cubic close packed <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Hardness: <\/td>\n<td>   1.75 mohs  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Specific heat capacity<\/td>\n<td>  0.63 J g<sup>-1<\/sup> K<sup>-1<\/sup>  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Heat of fusion<\/td>\n<td>8.54 kJ mol<sup>-1<\/sup> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Heat of atomization<\/td>\n<td>  178 kJ mol<sup>-1<\/sup> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Heat of vaporization<\/td>\n<td>  153.6 kJ mol<sup>-1<\/sup> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">1<sup>st<\/sup> ionization energy<\/td>\n<td>  589.8 kJ mol<sup>-1<\/sup>    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">2<sup>nd<\/sup> ionization energy<\/td>\n<td>   1145.4 kJ mol<sup>-1<\/sup>   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">3<sup>rd<\/sup> ionization energy<\/td>\n<td>    4911.8 kJ mol<sup>-1<\/sup>   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\">Electron affinity<\/td>\n<td>    2 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> 2 <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Max. common oxidation no. <\/td>\n<td>  2  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Electronegativity (Pauling Scale) <\/td>\n<td> 1 <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Polarizability volume <\/td>\n<td>   22.8 &Aring;<sup>3<\/sup> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Reaction with air<\/td>\n<td>  vigorous,  &#8658; CaO, Ca<sub>3<\/sub>N<sub>2<\/sub>     <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Reaction with 15 M HNO<sub>3<\/sub> <\/td>\n<td>   vigorous,  &#8658; H<sub>2<\/sub>, Ca(NO<sub>3<\/sub>)<sub>2<\/sub>    <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Reaction with 6 M HCl <\/td>\n<td>  vigorous,  &#8658;  H<sub>2<\/sub>, CaCl<sub>2<\/sub> <\/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>  CaO  <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Hydride(s) <\/td>\n<td>   CaH<sub>2<\/sub>   <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Chloride(s) <\/td>\n<td>  CaCl<sub>2<\/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>    114  pm  <\/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>  201 W m<sup>-1<\/sup> K<sup>-1<\/sup> <\/td>\n<\/tr>\n<tr>\n<td class=\"elemglb\"> Electrical conductivity <\/td>\n<td>   31.3 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> 842 <sup>o<\/sup>C, 1115 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-calcium-metal.jpg\" width=\"300\" height=\"158\" alt=\"Calcium Metal\" class=\"size-full\" \/><p class=\"wp-caption-text\">Calcium metal stored under an argon atmosphere. Image by Matthias Zepper<\/p><\/div>\n<div style=\"width: 310px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.chemicool.com\/elements\/images\/300-colosseum.jpg\" width=\"300\" height=\"195\" alt=\"Roman Colosseum held together with calcium based cement.\" class=\"size-full\" \/><p class=\"wp-caption-text\">Rome&#8217;s Colosseum, resisting the ravages of time (okay, there are one or two missing pieces&#8230;) with the aid of calcium oxide based cement. Photo: <a rel=\"nofollow\" href=\"http:\/\/en.wikipedia.org\/wiki\/User:Diliff\">David Iliff<\/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-calcium-stalactites.jpg\" width=\"300\" height=\"158\" alt=\"Calcium\" class=\"size-full\" \/><p class=\"wp-caption-text\">Stalactites &#8211; Mainly Calcium Carbonate.<\/p><\/div>\n<\/div>\n<\/div>\n<p><a id=\"discovery\"><\/a><\/p>\n<h2>Discovery of Calcium<\/h2>\n<div class=\"author\">Dr. Doug Stewart<\/div>\n<p>People have used calcium&#8217;s compounds for thousands of years &#8211; in cement, for example.<\/p>\n<p>    Limestone [calcium carbonate] was called calx by the Romans. The Romans heated calx, driving off carbon dioxide to leave calcium oxide. To make cement, all you have to do is mix calcium oxide with water. The Romans built vast amphitheaters and aqueducts using calcium oxide cement to bond stones together. <sup>(1)<\/sup><\/p>\n<p>\t\tDespite the long history of calcium&#8217;s compounds, the element itself was not discovered until electricity was available for use in experiments.<\/p>\n<p>\t\tCalcium was first isolated by Sir Humphry Davy in 1808 in London. In a lecture to the Royal Society in June 1808, Davy described his experiments that year, which produced tiny amounts of metal, at best. He could not find any way to produce more calcium metal until a letter from J&#246;ns Berzelius in Stockholm pointed him in the right direction.\t<sup>(3)<\/sup>\t<\/p>\n<p>\t\tDavy learned that Berzelius and Magnus Pontin had used a battery to decompose calcium oxide at a mercury electrode and they had obtained an amalgam of mercury and calcium. (Berzelius, the great Swedish chemist, exchanged a great deal of information with Davy. Berzelius had earlier learned from Davy that potassium could be dissolved in mercury to form an amalgam. Berzelius had extended the method.) <sup>(3),(4)<\/sup>\t<\/p>\n<p>\t\tDavy made a paste of slaked lime [calcium oxide, slightly moistened to form calcium hydroxide] and red oxide of mercury [mercury (II) oxide]. <sup>(3)<\/sup>\t<\/p>\n<p>\t\tHe made a depression in the paste and placed about 3.5 grams of mercury metal there to act as an electrode. Platinum was used as the counter electrode. Davy carried out the experiment under naptha (a liquid hydrocarbon under which he had found he could safely store potassium and sodium).<\/p>\n<p> \t\tWhen electricity was passed through the paste, a calcium-mercury amalgam formed at the mercury electrode. <\/p>\n<p>\t\tDavy removed the mercury by distillation to reveal a new element: calcium.<\/p>\n<p>\t\tDavy used the same procedure to isolate <a href=\"strontium.html\">strontium<\/a>, <a href=\"barium.html\">barium<\/a>, and <a href=\"magnesium.html\">magnesium<\/a>.<\/p>\n<p>\t\tHe named the metal calcium because of its occurrence in calx.<\/p>\n<p><a id=\"facts\"><\/a><\/p>\n<h2>Interesting Facts about Calcium<\/h2>\n<ul>\n<li>Calcium is the most abundant of the metallic elements in the human body. The average adult body contains about 1 kg or 2 lb of calcium, 99% of which is in the bones and teeth. Only oxygen, carbon, hydrogen and nitrogen are more abundant in our bodies than calcium.<\/li>\n<li>Calcium not only builds the structures that support our bodies, many of us also live in homes built using structural concrete or cement made with lime (calcium oxide). Snails and many shellfish use another calcium compound &#8211; calcium carbonate &#8211; to build their own homes too &#8211; their shells.<\/li>\n<li>Modern humans were not the first people to make use of calcium to build things. Egypt&#8217;s pyramids were built using limestone blocks. Limestone is crystalline calcium carbonate. In the later pyramids, the blocks were held together with gypsum or lime based mortar. Gypsum is calcium sulfate dihydrate and lime is calcium oxide.<\/li>\n<li>Have you ever wanted to be &#8216;in the limelight?&#8217; Lime is calcium oxide, which produces a brilliant, intense light when burnt in an oxyhydrogen flame.  It was used to light the stage in theaters during the 1800s until electricity took over &#8211; hence the saying.<\/li>\n<li>Cells in animals and plants must communicate with other cells. This is called signaling. Calcium ions are the most important messengers between cells in living things and are absolutely vital for the existence of multicellular life forms.<\/li>\n<\/ul>\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\"><iframe loading=\"lazy\" width=\"300\" height=\"233\" src=\"https:\/\/www.youtube.com\/embed\/LJz13QW58cY\" allowfullscreen><\/iframe><\/p>\n<div class=\"youtubecaption\">Calcium metal burning in air to form calcium nitride and calcium oxide.<\/div>\n<p><iframe loading=\"lazy\" width=\"300\" height=\"233\" src=\"https:\/\/www.youtube.com\/embed\/yXjVjuFBVrk\" allowfullscreen><\/iframe><\/p>\n<div class=\"youtubecaption\">Calcium metal reacting with water, producing calcium hydroxide and hydrogen gas.<\/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 \tNon-toxic and an <a href=\"https:\/\/www.chemicool.com\/elements\/foods-high-in-calcium.html\">essential metal<\/a> for living organisms. <\/p>\n<p>\t  <strong>Characteristics:<\/strong><\/p>\n<p>\t\tCalcium is reactive and, for a metal, soft. With a bit of effort, it can be cut with a sharp knife.<\/p>\n<p>\t\tIn contact with air, calcium develops a mixed oxide and nitride coating, which protects it from further corrosion.<\/p>\n<p>\t\tCalcium reacts easily with water and acids and the metal burns brightly in air, forming mainly the nitride.  <\/p>\n<p><a id=\"uses\"><\/a><\/p>\n<h2>Uses of Calcium<\/h2>\n<p>\t\tCalcium forms alloys with aluminum, beryllium, copper, lead, and magnesium.<\/p>\n<p>\t\tIt is used in the manufacture of other metals such as uranium and thorium.<\/p>\n<p>\t\tCalcium is used to remove oxygen, sulfur and carbon from alloys.<\/p>\n<p>\t\tCalcium from limestone is a vital component of Portland cement.<\/p>\n<p>\t\tQuicklime (CaO) is used in many applications in the chemical industry, such as treatment of drinking water &#8211; especially for water softening and arsenic removal, animal waste and wastewater.<\/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>  4.2 % by weight, 2.2 % by moles<\/p>\n<p>\t\t<span class=\"elemgl\">Abundance solar system:<\/span> 70 parts per million by weight, 2 parts per million by moles<\/p>\n<p>\t\t\t\t<span class=\"elemgl\">Cost, pure:<\/span>   $20 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> Calcium occurs in nature in various minerals including limestone (calcium carbonate), gypsum (calcium sulfate) and fluorite (calcium fluoride). Commercially it can be made by the electrolysis of molten calcium chloride, CaCl<sub>2<\/sub>. The pure metal can also be produced by replacing the calcium in lime (CaCO<sub>3<\/sub>) with aluminum in hot, low pressure retorts.<\/p>\n<p>\t\t<span class=\"elemgl\">Isotopes:<\/span> Calcium has 19 Isotopes whose half-lives are known, with mass numbers 35 to 53. Naturally occurring calcium is a mixture of six isotopes and they are found in the percentages shown: <sup>40<\/sup>Ca (97%), <sup>42<\/sup>Ca (0.6%), <sup>43<\/sup>Ca (0.1%), <sup>44<\/sup>Ca (2%), <sup>46<\/sup>Ca (0.004%) and <sup>48<\/sup>Ca (0.2%).  <\/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><a href=\"http:\/\/www.romanconcrete.com\/Article1Secrets.pdf\">The Secrets of Roman Concrete<\/a> (pdf download)<\/li>\n<li>John Davy, Memoirs of The Life of Sir Humphry Davy., Vol 1, 1836,  p395, Longman. <\/li>\n<li>John Davy (Editor), The Collected Works of Sir Humphry Davy, Vol V, 1840, p111 Smith, Elder and Co. Cornhill.<\/li>\n<li>Jaime Wisniak, J&#246;ns Jacob Berzelius A Guide to the Perplexed Chemist., Chem. Educator, 2000, 5, p343-350. <\/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\/calcium.html\"&gt;Calcium&lt;\/a&gt;\r\n<\/pre>\n<p>or<\/p>\n<pre class='code'>\r\n&lt;a href=\"https:\/\/www.chemicool.com\/elements\/calcium.html\"&gt;Calcium 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\"Calcium.\" Chemicool Periodic Table. Chemicool.com. 04 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\/calcium.html&gt;.<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Data Zone | Discovery | Facts | Appearance &amp; Characteristics | Uses | Abundance &amp; Isotopes | References 20 Ca 40.08 The chemical element calcium is classed as an alkali earth metal. It was discovered in 1808 by Sir Humphry Davy. Data Zone Classification: Calcium is an alkali earth metal Color: silvery-gray Atomic weight: 40.078 [&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-236","1":"page","2":"type-page","3":"status-publish","5":"entry"},"_links":{"self":[{"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/pages\/236","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=236"}],"version-history":[{"count":28,"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/pages\/236\/revisions"}],"predecessor-version":[{"id":4211,"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/pages\/236\/revisions\/4211"}],"wp:attachment":[{"href":"https:\/\/www.chemicool.com\/elements\/wp-json\/wp\/v2\/media?parent=236"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}