{"id":19251,"date":"2017-12-23T15:21:31","date_gmt":"2017-12-23T15:21:31","guid":{"rendered":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=19251"},"modified":"2018-02-25T08:46:46","modified_gmt":"2018-02-25T08:46:46","slug":"are-diazomethanes-hypervalent-molecules-probably-but-in-an-unexpected-way","status":"publish","type":"post","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=19251","title":{"rendered":"Are diazomethanes hypervalent molecules? Probably, but in an unexpected way!"},"content":{"rendered":"<div class=\"kcite-section\" kcite-section-id=\"19251\">\n<p>A recently published review on hypervalency<span id=\"cite_ITEM-19251-0\" name=\"citation\"><a href=\"#ITEM-19251-0\">[1]<\/a><\/span> introduced a very simple way of quantifying the effect. One of the molecules which was suggested to be hypervalent using this method was diazomethane. Here I take a closer look.<\/p>\n<p>The new method is called the <strong>valence electron equivalent \u03b3<\/strong>. It is defined as<em>\u00a0&#8220;the formal shared electron count at a given atom, obtained by any combination of valid ionic and covalent resonance forms that reproduces the observed charge distribution&#8221;<\/em>. These atom charge maps can be obtained from various kinds of quantum mechanical calculation; the one adopted in the review was Bader&#8217;s QTAIM analysis.<\/p>\n<p>Three resonance forms used to estimate \u03b3 for the atoms in diazomethane are shown below. According to Durrant<span id=\"cite_ITEM-19251-0\" name=\"citation\"><a href=\"#ITEM-19251-0\">[1]<\/a><\/span>, &#8220;<em>if \u03b3(X) &gt; 8, neither form of the octet rule is obeyed and the atom is hypervalent&#8221;<\/em>. His procedure gives\u00a0\u03b3(N) = <strong>10<\/strong> (table 3 and also structure <strong>27a<\/strong><span id=\"cite_ITEM-19251-0\" name=\"citation\"><a href=\"#ITEM-19251-0\">[1]<\/a><\/span>), suggesting that the third resonance form shown below is the most appropriate.<\/p>\n<p><a href=\"http:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane.svg\"><img decoding=\"async\" class=\"aligncenter size-large wp-image-19253\" src=\"http:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane.svg\" alt=\"\" width=\"450\" \/><\/a><\/p>\n<p>As a result, the nitrogen is to be considered hypervalent, with five formal covalent bonds and hence a ten shared-electron valence shell. If such hypervalence is to be considered as more than just a convenient representation and to have a deeper underlying foundation, similar conclusions should ideally emerge from other ways of analysing the wavefunctions for such species. Here I try the NBO (Natural Bond Orbital) and ELF (Electron localization Function) analyses of two types of wavefunction using both DFT (density functional theory)\u00a0\u03c9B97XD\/Def2-TZVPP and multi-reference CASSCF(12,12)\/Def2-TZVPP Hamiltonians.<sup>\u2021<\/sup><\/p>\n<p>Firstly, the NBO method, which localizes electron pairs. There are four bonding NBOs associated with the <strong>central<\/strong>\u00a0nitrogen and a modest contribution from a fifth, the terminal nitrogen lone pair (bottom).<img decoding=\"async\" class=\"aligncenter size-large wp-image-19271\" src=\"http:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane-NBO-N-886x1024.jpg\" alt=\"\" width=\"400\" srcset=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane-NBO-N-886x1024.jpg 886w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane-NBO-N-260x300.jpg 260w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane-NBO-N-768x888.jpg 768w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane-NBO-N.jpg 1186w\" sizes=\"(max-width: 886px) 100vw, 886px\" \/><\/p>\n<p>The carbon has four NBOs comprising one &#8220;non-bonding lone pair&#8221;, two C-Hs, a C-N and one partial C-N (bottom). This partitioning can be quantified using Wiberg atom <strong>bond<\/strong> indices: C, 3.716; N 3.802; N 2.907 (the C-N and N=N bond orders are 1.425 and 2.368). Note that the &#8220;non-bonding carbon lone pair&#8221; would not contribute to the C <strong>bond<\/strong> index, which is already <strong>3.72<\/strong>. Is numerical evidence perhaps emerging that the carbon may exceed the octet in its valence shell? In contrast, the central nitrogen, with a bond index of 3.802, but not having any associated &#8220;non-bonding lone pair&#8221;, does not look to exceeding the octet. It seems well short of achieving \u03b3(N) = 10, equivalent to a bond index of 5 as shown in the resonance form above.<\/p>\n<p><img decoding=\"async\" class=\"aligncenter size-large wp-image-19269\" src=\"http:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane-NBO-C-833x1024.jpg\" alt=\"\" width=\"400\" srcset=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane-NBO-C-833x1024.jpg 833w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane-NBO-C-244x300.jpg 244w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane-NBO-C-768x944.jpg 768w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane-NBO-C.jpg 1269w\" sizes=\"(max-width: 833px) 100vw, 833px\" \/><\/p>\n<p>Now for ELF, which is derived from the electron density and the basin locations from its kinetic energy density. The values are the integrations for the individual ELF basins, of which 0.498*2 = 0.996 is the monosynaptic basin for the carbon lone pair noted above. The total for this carbon comes to <strong>8.16<\/strong>, the adjacent nitrogen 6.59 and the terminal nitrogen 7.52e.\u00a0<\/p>\n<p><img decoding=\"async\" class=\"aligncenter size-large wp-image-19258\" src=\"http:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane-DFT_ELF-1024x574.jpg\" alt=\"\" width=\"400\" srcset=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane-DFT_ELF-1024x574.jpg 1024w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane-DFT_ELF-300x168.jpg 300w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane-DFT_ELF-768x431.jpg 768w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane-DFT_ELF.jpg 1730w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/> <img decoding=\"async\" class=\"aligncenter size-large wp-image-19257\" src=\"http:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane-CAS_ELF-1024x441.jpg\" alt=\"\" width=\"400\" srcset=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane-CAS_ELF-1024x441.jpg 1024w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane-CAS_ELF-300x129.jpg 300w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane-CAS_ELF-768x331.jpg 768w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane-CAS_ELF.jpg 1947w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/p>\n<p>The CASSCF(12,12) values are respectively are <strong>8.18<\/strong>, 6.50 and 7.50e, which are very similar.\u00a0So these two types of electron partitioning show no evidence that the central nitrogen has \u03b3(N) = 10; it&#8217;s actually ~6.5, which is a long way short of 10! However,\u00a0\u03b3(C) = ~8.2, which <strong>does<\/strong> exceed the octet, if only very modestly. Perhaps this can best be summarised with the following representation based on the bond orders, which indicates three shared covalent bonds to carbon, a partial (dashed) C-N interaction and a lone pair implied by the minus sign, the total of which exceeds\u00a0\u03b3(C) = ~8. It all boils down really to whether that &#8220;lone pair&#8221; of electrons on the carbon is truly a non-bonding electron pair or whether it should be considered a fully covalent pair associated also with the nitrogen. Certainly, there appears to be no evidence from NBO or ELF that this is the case.<a href=\"http:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane1.svg\"><img decoding=\"async\" class=\"aligncenter size-large wp-image-19273\" src=\"http:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane1.svg\" alt=\"\" width=\"150\" \/><\/a><\/p>\n<p>The next logical question to ask is whether the effect can be &#8220;optimised&#8221; such that \u03b3(C)\u00a0&gt; 8 or even &gt;&gt; 8. I will address this in the next post.<\/p>\n<hr \/>\n<p><sup>\u2021<\/sup>FAIR data for all calculations is available at DOI:\u00a0<a href=\"https:\/\/doi.org\/10.14469\/hpc\/3476\">10.14469\/hpc\/3476<\/a><\/p>\n<h2>References<\/h2>\n    <ol class=\"kcite-bibliography csl-bib-body\"><li id=\"ITEM-19251-0\">M.C. Durrant, \"A quantitative definition of hypervalency\", <i>Chemical Science<\/i>, vol. 6, pp. 6614-6623, 2015. <a href=\"https:\/\/doi.org\/10.1039\/c5sc02076j\">https:\/\/doi.org\/10.1039\/c5sc02076j<\/a>\n\n<\/li>\n<\/ol>\n\n<\/div> <!-- kcite-section 19251 -->","protected":false},"excerpt":{"rendered":"<p>A recently published review on hypervalency introduced a very simple way of quantifying the effect. One of the molecules which was suggested to be hypervalent using this method was diazomethane. Here I take a closer look. The new method is called the valence electron equivalent \u03b3. It is defined as\u00a0&#8220;the formal shared electron count at [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"activitypub_content_warning":"","activitypub_content_visibility":"","activitypub_max_image_attachments":5,"activitypub_interaction_policy_quote":"anyone","activitypub_status":"","footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[7,4],"tags":[253],"ppma_author":[2661],"class_list":["post-19251","post","type-post","status-publish","format-standard","hentry","category-hypervalency","category-interesting-chemistry","tag-kinetic-energy-density"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.5 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Are diazomethanes hypervalent molecules? Probably, but in an unexpected way! - Henry Rzepa&#039;s Blog<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=19251\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Are diazomethanes hypervalent molecules? Probably, but in an unexpected way! - Henry Rzepa&#039;s Blog\" \/>\n<meta property=\"og:description\" content=\"A recently published review on hypervalency introduced a very simple way of quantifying the effect. One of the molecules which was suggested to be hypervalent using this method was diazomethane. Here I take a closer look. The new method is called the valence electron equivalent \u03b3. It is defined as\u00a0&#8220;the formal shared electron count at [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=19251\" \/>\n<meta property=\"og:site_name\" content=\"Henry Rzepa&#039;s Blog\" \/>\n<meta property=\"article:published_time\" content=\"2017-12-23T15:21:31+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2018-02-25T08:46:46+00:00\" \/>\n<meta property=\"og:image\" content=\"http:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane.svg\" \/>\n<meta name=\"author\" content=\"Henry Rzepa\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Henry Rzepa\" \/>\n\t<meta name=\"twitter:label2\" content=\"Estimated reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"3 minutes\" \/>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Are diazomethanes hypervalent molecules? Probably, but in an unexpected way! - Henry Rzepa&#039;s Blog","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=19251","og_locale":"en_GB","og_type":"article","og_title":"Are diazomethanes hypervalent molecules? Probably, but in an unexpected way! - Henry Rzepa&#039;s Blog","og_description":"A recently published review on hypervalency introduced a very simple way of quantifying the effect. One of the molecules which was suggested to be hypervalent using this method was diazomethane. Here I take a closer look. The new method is called the valence electron equivalent \u03b3. It is defined as\u00a0&#8220;the formal shared electron count at [&hellip;]","og_url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=19251","og_site_name":"Henry Rzepa&#039;s Blog","article_published_time":"2017-12-23T15:21:31+00:00","article_modified_time":"2018-02-25T08:46:46+00:00","og_image":[{"url":"http:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/diazomethane.svg","type":"","width":"","height":""}],"author":"Henry Rzepa","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Henry Rzepa","Estimated reading time":"3 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=19251#article","isPartOf":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=19251"},"author":{"name":"Henry Rzepa","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#\/schema\/person\/2b40f7b9c872a4dc1547e040a11b6281"},"headline":"Are diazomethanes hypervalent molecules? 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Here I explore the effect of substituting diazomethane\u2026","rel":"","context":"In &quot;Hypervalency&quot;","block_context":{"text":"Hypervalency","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=7"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":19307,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=19307","url_meta":{"origin":19251,"position":1},"title":"Are diazomethanes hypervalent molecules? An attempt into more insight by more &#8220;tuning&#8221; with substituents.","author":"Henry Rzepa","date":"December 26, 2017","format":false,"excerpt":"Recollect the suggestion\u00a0that diazomethane has hypervalent character. When I looked into this, I came to the conclusion that it probably was mildly hypervalent, but on carbon and not nitrogen. Here I try some variations with substituents to see what light if any this casts. I have expanded the resonance forms\u2026","rel":"","context":"In &quot;Hypervalency&quot;","block_context":{"text":"Hypervalency","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=7"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/12\/H2CNCCN_ELF-1024x258.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":18975,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=18975","url_meta":{"origin":19251,"position":2},"title":"Hypervalence revisited. The odd case of hexamethyl selenium.","author":"Henry Rzepa","date":"November 7, 2017","format":false,"excerpt":"One thread that runs through this blog is that of hypervalency. It was therefore nice to come across a recent review of the concept which revisits the topic, and where a helpful summary is given of the evolving meanings over time of the term hypervalent. The key phrase \"it soon\u2026","rel":"","context":"In &quot;Hypervalency&quot;","block_context":{"text":"Hypervalency","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=7"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/11\/165-1024x1008.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":19499,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=19499","url_meta":{"origin":19251,"position":3},"title":"Never mind main group &#8220;hypervalency&#8221;, what about transition metal &#8220;hypervalency&#8221;?","author":"Henry Rzepa","date":"March 18, 2018","format":false,"excerpt":"I have posted often on the chemical phenomenon known as hypervalency, being careful to state that as defined it applies just to \"octet excess\" in main group elements. But what about the next valence shell, occurring in transition metals and known as the \"18-electron rule\"? You rarely hear the term\u2026","rel":"","context":"In &quot;Hypervalency&quot;","block_context":{"text":"Hypervalency","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=7"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2018\/03\/NiPP-987x1024.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":19194,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=19194","url_meta":{"origin":19251,"position":4},"title":"Identification of a simplest hypervalent hydrogen fluoride anion.","author":"Henry Rzepa","date":"December 8, 2017","format":false,"excerpt":"An article with the title shown above in part recently appeared. Given the apparent similarity of HF1- to CH3F1- and CH3F2-, the latter of which I introduced on this blog previously,\u00a0I thought it of interest to apply my analysis to HF1-. The authors conclude that \"the F atom of HF\u2212\u2026","rel":"","context":"In &quot;Hypervalency&quot;","block_context":{"text":"Hypervalency","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=7"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":1103,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=1103","url_meta":{"origin":19251,"position":5},"title":"Hypervalency: a reality check","author":"Henry Rzepa","date":"October 5, 2009","format":false,"excerpt":"We have seen in the series of posts on the topic of hypervalency\u00a0how the first row main group elements such as\u00a0Be, B, C and N can sustain apparent hypercoordination and arguably hypervalency. The latter is defined not so much by expanding the total valence shell of electrons surrounding the hypervalent\u2026","rel":"","context":"In &quot;Hypervalency&quot;","block_context":{"text":"Hypervalency","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=7"},"img":{"alt_text":"YOCVIV: Crystal structure of hexacoordinate boron","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2009\/10\/BBr.jpg?resize=350%2C200","width":350,"height":200},"classes":[]}],"jetpack_likes_enabled":false,"authors":[{"term_id":2661,"user_id":1,"is_guest":0,"slug":"admin","display_name":"Henry Rzepa","avatar_url":"https:\/\/secure.gravatar.com\/avatar\/897b6740f7f599bca7942cdf7d7914af5988937ae0e3869ab09aebb87f26a731?s=96&d=blank&r=g","0":null,"1":"","2":"","3":"","4":"","5":"","6":"","7":"","8":""}],"_links":{"self":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/19251","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=19251"}],"version-history":[{"count":17,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/19251\/revisions"}],"predecessor-version":[{"id":19336,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/19251\/revisions\/19336"}],"wp:attachment":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=19251"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=19251"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=19251"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fppma_author&post=19251"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}