{"id":18768,"date":"2017-09-06T19:28:49","date_gmt":"2017-09-06T18:28:49","guid":{"rendered":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=18768"},"modified":"2017-09-22T10:22:57","modified_gmt":"2017-09-22T09:22:57","slug":"two-new-types-in-the-chemical-bonding-zoo-exo-bonds-and-hyper-bonds","status":"publish","type":"post","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=18768","title":{"rendered":"Two new types in the chemical bonding zoo: exo-bonds and hyper-bonds?"},"content":{"rendered":"
\n

The chemical bond zoo is relatively small<\/a> (the bond being a somewhat fuzzy concept, I am not sure there is an actual count of occupants). So when two new candidates come along, it is worth taking notice.\u00a0I have previously noted the Chemical Bonds at the 21st Century-2017: CB2017<\/a>\u00a0Aachen conference, where both were discussed.<\/p>\n

    \n
  1. The first now has a name, the exo-bond<\/strong><\/span><\/em>, one example of which is the C2<\/sub> diatomic. The hint that a quadruple bond could be formulated between the two carbon atoms goes back a little while[1]<\/a><\/span> (see Table 1), but revived interest really took off after ~2010, around the time my blog<\/a> on the topic also appeared. You can see the abundance of post 2010 articles in the bibliography at the Aachen bond-slam<\/a>. At the conference, four speakers all agreed using rather different methods that there was indeed “something” additional to a C\u2261C triple bond and that this “something” might be worth ~15-30 kcal\/mol of stabilization.\u2020<\/sup> The debate centered around whether this term deserved to be called a bond, or whether it should be downgraded to merely that of biradicaloid<\/em> stabilizations.\u2021<\/sup>\u00a0The more conventional population of a \u03c3*<\/sup>-antibond it was argued would not result in such stabilizations. Since many kinds of bonds have stabilization energies of similar magnitude, not least the weaker hydrogen bonds, agostic bonds, halogen bonds etc, let us for the sake of argument call it a bond here. Because four electrons might occupy the same space along the\u00a0\u03c3-symmetric C-C axis, they experience significant so-called static correlation\u221e<\/sup> which results in partition into one electron pair occupying the central region (the endo-bond<\/em>) and the other pair in the outer region (the exo-bond).\u00a0<\/em>\u00a0This separation\u00a0decreases the Pauli electron repulsions along the entire C-C axis region.\u00a0\u00a0An example<\/a> of an exo-bond<\/em> is found in [1.1.1] propellane<\/a>, where the notional central C-C bond is thought to actually occupy the region outside the central C-C bond axis, but largely in this example because of angular strains. In this case however, the propellane bond is not competing with an endo-bond<\/em> along the same axis. We might conclude therefore that the convention of characterising a bond using the separation between the two nuclei (the bond-length<\/em>) is rather stressed when one has two different bonds along the axis of the nuclei, one of which is obviously “longer<\/em>” than the other.\n

    Which brings us to representations; e.g.<\/em> Chemdraw now allows drawing of quadruple bonds and so it can be drawn thus quite simply.
    \n \"\"
    \n The second form breaks the century-old convention that all bonds along a diatomic axis are drawn in the same manner, by isolating the exo-bond<\/em> to make the point clear. Perhaps we should stick to the first, but be prepared to explain the underlying complexity of the quantum mechanical symmetries as we do to students with \u03c3\/\u03c0\/\u03b4\/\u03c6 bonds, which are another mechanism for avoiding having bonds in exactly the same regions. I know the story has not yet ended; but is it time to at least speculate when the text-books will start to reflect\/discuss the exo-bond<\/em>?<\/p>\n<\/li>\n

  2. The second I dub the hyper-bond<\/span><\/strong><\/em>. This goes back to G. N. Lewis and his famous octet rule for main group elements, the expansion of which was subsequently described by the term hypervalent. That term has become rather confused with hypercoordinate, since hypervalent is often used<\/a>\u00a0to describe hypercoordinate species such as\u00a0PCl5<\/sub>, SF6<\/sub> or I.I7<\/sub><\/a>. But this does rather break the original definition, since few if indeed any of these hypercoordinate molecules have a significantly expanded octet shell. At the Aachen meeting, a molecule fitting the original definition was presented<\/a>, appearing first in early form on this blog<\/a>. Put simply, a wavefunction for CH3<\/sub>F2-<\/sup> can be calculated (\u03c9B97XD\/Def2-QZVPPD\/SCRF=water, DOI: cb3n\u00a0<\/a>) for which the two additional electrons populate a molecular orbital with significant contributions from the 3s\/3p valence shell AOs (atomic orbitals) for both carbon and fluorine. The alternative would have been to populate the anti-bonding C-H or C-F orbitals composed of 2s\/2p valence shell AOs. The former results in a total population of these higher valence shells of 1.55e and makes the C-F (Wiberg) bond order >1 (1.14) and the total Wiberg bond indices >4 for carbon (4.162) and >1 for F (1.275). The resulting HOMO (highest occupied molecular orbital) or NBO (they are very similar) looks as below. It takes the approximate form of a torus or cylinder wrapping the inner C-F bond, a second layer to the C-F bond if you wish.\u00a0
    \n\n\n\n
    \n
    \"\"

    Normal valence shell F-C \u03c3-orbital defining the regular C-F bond.<\/p><\/div>\n<\/td>\n

    		\n
    \"\"

    Higher valence shell F-C \u03c3-orbital defining the C-F hyper-bond.<\/p><\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    Rather than the entire molecule being defined as hypervalent, only one (in this case localized) orbital is given the term and the other orbitals are conventional.<\/p>\n<\/li>\n<\/ol>\n

    In both cases the molecules are either very reactive (C2<\/sub>) or with such a low barrier to fragmentation (into CH3<\/sub>–<\/sup> and F–<\/sup> for CH3<\/sub>F2-<\/sup>) that detection of the latter is unlikely. But these are interesting Gedanken experiments<\/i> in quantum mechanics, which in turn catalyse the development of new techniques and in some cases might even lead to the design and isolation of new types of molecules.<\/sup><\/p>\n

    \n

    \u2020<\/sup>The known thermochemistry of the two reactions; HC\u2261CH \u2192 HC\u2261C + H\u2022; HC\u2261C\u2022 \u2192 CC + H\u2022 is ~17 kcal\/mol less endothermic for the second step, suggesting some factor is needed to account for the additional stabilization when CC is formed.<\/p>\n

    \u2021<\/sup>The singlet to triplet excitation energy for C2<\/sub> is ~+30 kcal\/mol, so the biradicaloid<\/em> electrons are certainly spin-coupled.<\/p>\n

    \u221e<\/sup>Other “difficult” correlated molecules include Be2<\/sub> and B2<\/sub>.<\/p>\n

    References<\/h2>\n
    1. R.S. Mulliken, \"Note on Electronic States of Diatomic Carbon, and the Carbon-Carbon Bond\", Physical Review<\/i>, vol. 56, pp. 778-781, 1939. https:\/\/doi.org\/10.1103\/physrev.56.778<\/a>\n\n<\/li>\n<\/ol>\n\n<\/div> ","protected":false},"excerpt":{"rendered":"

      The chemical bond zoo is relatively small (the bond being a somewhat fuzzy concept, I am not sure there is an actual count of occupants). So when two new candidates come along, it is worth taking notice.\u00a0I have previously noted the Chemical Bonds at the 21st Century-2017: CB2017\u00a0Aachen conference, where both were discussed. The first […]<\/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":[2237,4],"tags":[194,1402,2293,2275,2287,2288,2289,2290,2291,2292],"ppma_author":[2661],"class_list":["post-18768","post","type-post","status-publish","format-standard","hentry","category-bond-slam","category-interesting-chemistry","tag-bond","tag-chemical-bond","tag-chemical-bond-zoo","tag-city-aachen","tag-concepts","tag-dialectic","tag-fuzzy-concept","tag-non-classical-logic","tag-psychometrics","tag-triplet-excitation-energy"],"yoast_head":"\nTwo new types in the chemical bonding zoo: exo-bonds and hyper-bonds? - Henry Rzepa'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=18768\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Two new types in the chemical bonding zoo: exo-bonds and hyper-bonds? - Henry Rzepa's Blog\" \/>\n<meta property=\"og:description\" content=\"The chemical bond zoo is relatively small (the bond being a somewhat fuzzy concept, I am not sure there is an actual count of occupants). So when two new candidates come along, it is worth taking notice.\u00a0I have previously noted the Chemical Bonds at the 21st Century-2017: CB2017\u00a0Aachen conference, where both were discussed. The first […]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=18768\" \/>\n<meta property=\"og:site_name\" content=\"Henry Rzepa's Blog\" \/>\n<meta property=\"article:published_time\" content=\"2017-09-06T18:28:49+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2017-09-22T09:22:57+00:00\" \/>\n<meta property=\"og:image\" content=\"http:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/09\/CC-1.jpeg\" \/>\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=\"5 minutes\" \/>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Two new types in the chemical bonding zoo: exo-bonds and hyper-bonds? - Henry Rzepa'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=18768","og_locale":"en_GB","og_type":"article","og_title":"Two new types in the chemical bonding zoo: exo-bonds and hyper-bonds? - Henry Rzepa's Blog","og_description":"The chemical bond zoo is relatively small (the bond being a somewhat fuzzy concept, I am not sure there is an actual count of occupants). So when two new candidates come along, it is worth taking notice.\u00a0I have previously noted the Chemical Bonds at the 21st Century-2017: CB2017\u00a0Aachen conference, where both were discussed. The first […]","og_url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=18768","og_site_name":"Henry Rzepa's Blog","article_published_time":"2017-09-06T18:28:49+00:00","article_modified_time":"2017-09-22T09:22:57+00:00","og_image":[{"url":"http:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/09\/CC-1.jpeg","type":"","width":"","height":""}],"author":"Henry Rzepa","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Henry Rzepa","Estimated reading time":"5 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=18768#article","isPartOf":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=18768"},"author":{"name":"Henry Rzepa","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#\/schema\/person\/2b40f7b9c872a4dc1547e040a11b6281"},"headline":"Two new types in the chemical bonding zoo: exo-bonds and hyper-bonds?","datePublished":"2017-09-06T18:28:49+00:00","dateModified":"2017-09-22T09:22:57+00:00","mainEntityOfPage":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=18768"},"wordCount":957,"commentCount":0,"image":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=18768#primaryimage"},"thumbnailUrl":"http:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/09\/CC-1.jpeg","keywords":["bond","Chemical bond","chemical bond zoo","City: Aachen","Concepts","Dialectic","Fuzzy concept","Non-classical logic","Psychometrics","triplet excitation energy"],"articleSection":["Bond slam","Interesting chemistry"],"inLanguage":"en-GB","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=18768#respond"]}]},{"@type":"WebPage","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=18768","url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=18768","name":"Two new types in the chemical bonding zoo: exo-bonds and hyper-bonds? - Henry Rzepa's Blog","isPartOf":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#website"},"primaryImageOfPage":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=18768#primaryimage"},"image":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=18768#primaryimage"},"thumbnailUrl":"http:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/09\/CC-1.jpeg","datePublished":"2017-09-06T18:28:49+00:00","dateModified":"2017-09-22T09:22:57+00:00","author":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#\/schema\/person\/2b40f7b9c872a4dc1547e040a11b6281"},"breadcrumb":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=18768#breadcrumb"},"inLanguage":"en-GB","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=18768"]}]},{"@type":"ImageObject","inLanguage":"en-GB","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=18768#primaryimage","url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/09\/CC-1.jpeg","contentUrl":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/09\/CC-1.jpeg","width":266,"height":136},{"@type":"BreadcrumbList","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=18768#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog"},{"@type":"ListItem","position":2,"name":"Two new types in the chemical bonding zoo: exo-bonds and hyper-bonds?"}]},{"@type":"WebSite","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#website","url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/","name":"Henry Rzepa's Blog","description":"Chemistry with a twist","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-GB"},{"@type":"Person","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#\/schema\/person\/2b40f7b9c872a4dc1547e040a11b6281","name":"Henry Rzepa","image":{"@type":"ImageObject","inLanguage":"en-GB","@id":"https:\/\/secure.gravatar.com\/avatar\/897b6740f7f599bca7942cdf7d7914af5988937ae0e3869ab09aebb87f26a731?s=96&d=blank&r=g370be3a7397865e4fd161aefeb0a5a85","url":"https:\/\/secure.gravatar.com\/avatar\/897b6740f7f599bca7942cdf7d7914af5988937ae0e3869ab09aebb87f26a731?s=96&d=blank&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/897b6740f7f599bca7942cdf7d7914af5988937ae0e3869ab09aebb87f26a731?s=96&d=blank&r=g","caption":"Henry Rzepa"},"description":"Henry Rzepa is Emeritus Professor of Computational Chemistry at Imperial College London.","sameAs":["https:\/\/orcid.org\/0000-0002-8635-8390"],"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?author=1"}]}},"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/pDef7-4SI","jetpack-related-posts":[{"id":18652,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=18652","url_meta":{"origin":18768,"position":0},"title":"Chemical Bonds at the 21st Century – 2017: the Bond Slam.","author":"Henry Rzepa","date":"August 2, 2017","format":false,"excerpt":"It is always interesting to observe conference experiments taking place. The traditional model involves travelling to a remote venue, staying in a hotel, selecting sessions to attend from a palette of parallel streams and then interweaving chatting to colleagues both old and new over coffee, lunch, dinner or excursions. Sometimes\u2026","rel":"","context":"In "Bond slam"","block_context":{"text":"Bond slam","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=2237"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2017\/08\/BH3F.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":5104,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=5104","url_meta":{"origin":18768,"position":1},"title":"Bonds.","author":"Henry Rzepa","date":"October 13, 2011","format":false,"excerpt":"Bonds are a good example of something all chemists think they can recognise when they see them. But they are also remarkably dependent on context. We are running a molecular modelling course at the moment, and I found myself explaining to someone how very context-sensitive they can be. I thought\u2026","rel":"","context":"In "Chemical IT"","block_context":{"text":"Chemical IT","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=2"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":17115,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=17115","url_meta":{"origin":18768,"position":2},"title":"Long C-C bonds.","author":"Henry Rzepa","date":"November 30, 2016","format":false,"excerpt":"In an earlier post, I searched for small C-C-C angles, finding one example that was also accompanied by an apparently exceptionally long C-C bond (2.18\u00c5). But this arose from highly unusual bonding giving rise not to a single bond order but one closer to one half! How long can a\u2026","rel":"","context":"In "crystal_structure_mining"","block_context":{"text":"crystal_structure_mining","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=1745"},"img":{"alt_text":"long-cc","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2016\/11\/long-cc-1024x757.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":19347,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=19347","url_meta":{"origin":18768,"position":3},"title":"Hypervalent hydrogen?","author":"Henry Rzepa","date":"January 13, 2018","format":false,"excerpt":"I discussed the molecule the molecule CH3F2- a while back. It was a very rare computed example of a system where the added two electrons populate the higher valence shells known as Rydberg orbitals as an alternative to populating the C-F antibonding \u03c3-orbital to produce CH3- and F-. The net\u2026","rel":"","context":"In "Hypervalency"","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":20933,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=20933","url_meta":{"origin":18768,"position":4},"title":"Startling bonds: revisiting C\u2a78N+, via the helium bond in N\u2261C-He+.","author":"Henry Rzepa","date":"May 27, 2019","format":false,"excerpt":"Although the small diatomic molecule known as dicarbon or C2 has been known for a long time, its properties and reactivity have really only been determined\u00a0via its very high temperature generation. My interest started in 2010, when I speculatively proposed here that the related isoelectronic species C\u2a78N+ might sustain a\u2026","rel":"","context":"In "Interesting chemistry"","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":17122,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=17122","url_meta":{"origin":18768,"position":5},"title":"Long C=C bonds.","author":"Henry Rzepa","date":"December 1, 2016","format":false,"excerpt":"Following on from a search for long C-C bonds, here is the same repeated for C=C double bonds. The query restricts the search to each carbon having just two non-metallic substituents. To avoid conjugation with these, they each are 4-coordinated; the carbons themselves are three-coordinated. Further constraints are the usual\u2026","rel":"","context":"In "crystal_structure_mining"","block_context":{"text":"crystal_structure_mining","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=1745"},"img":{"alt_text":"sq","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2016\/12\/sq-1024x415.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\/18768","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=18768"}],"version-history":[{"count":24,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/18768\/revisions"}],"predecessor-version":[{"id":18797,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/18768\/revisions\/18797"}],"wp:attachment":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=18768"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=18768"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=18768"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fppma_author&post=18768"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}