{"id":21846,"date":"2020-01-02T10:05:36","date_gmt":"2020-01-02T10:05:36","guid":{"rendered":"https:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=21846"},"modified":"2020-01-03T08:41:56","modified_gmt":"2020-01-03T08:41:56","slug":"comment-on-resolving-the-quadruple-bonding-conundrum-in-c2-using-insights-derived-from-excited-state-potential-energy-surfaces-the-7%cf%83-heptet-excited-states-for-related-molecules","status":"publish","type":"post","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=21846","title":{"rendered":"Comment on “Resolving the Quadruple Bonding Conundrum in C2 Using Insights Derived from Excited State Potential Energy Surfaces”: The 7\u03a3 heptet excited states for related molecules."},"content":{"rendered":"
\n

I noted in an earlier blog<\/a>, a potential (if difficult) experimental test of the properties of the singlet state of dicarbon, C2<\/sub>. Now, just a few days ago, a ChemRxiv article has been published suggesting another (probably much more realistic) test.[1]<\/a><\/span>\u00a0This looks at the so-called 7<\/sup>\u03a3 open shell state of the molecule where three electrons from one \u03c3 and two \u03c0 orbitals are excited into the corresponding \u03c3*<\/sup> and \u03c0*<\/sup> unoccupied orbitals.\u00a0The argument is presented that these states are not dissociative, showing a deep minimum and hence a latent quadruple bonding nature<\/i><\/span>. They also note that the isoelectronic BN molecule IS dissociative.\u2020<\/sup> Thus to quote: “Hence, the proof of existence of a minimum in the 7<\/sup>\u03a3u+<\/sub> for C2<\/sub> and the absence of such a minimum in the equivalent case for BN is likely to corroborate our findings on quadruple bonding in these two cases.<\/span>“<\/i><\/p>\n

Although a PES (potential energy surface) is shown for 7<\/sup>\u03a3 C2<\/sub>, no vibrational wavenumber is reported. So in the spirit of a commentary on this pre-print, I have calculated these values (CCSD(T)\/Def2-TZVPP) for the molecules noted in the article and a few other isoelectronic species. The results are collected at\u00a0DOI: 10.14469\/hpc\/6599<\/a><\/p>\n\n\n\n\n\n
Property<\/th>\nBeC2-<\/sup><\/th>\nBB2-<\/sup><\/th>\nBC1-<\/sup><\/th>\nBN<\/th>\nCC<\/th>\nCN1+<\/sup><\/th>\nNN2+<\/sup><\/th>\nBeO<\/th>\nBO1+<\/sup><\/th>\nLiF<\/th>\n<\/tr>\n
Bond length,
\n\u00c5<\/td>\n		2.281<\/td>\n1.858<\/td>\n1.768<\/td>\n3.216<\/td>\n1.585<\/td>\n1.638<\/td>\n1.523<\/td>\n2.602<\/td>\n200.7<\/td>\n2.179<\/td>\n<\/tr>\n
Bond stretch,
\ncm-1<\/sup><\/td>\n		182<\/td>\n638<\/td>\n699<\/td>\n48<\/td>\n1055<\/td>\n759<\/td>\n934<\/td>\n363<\/td>\n0.4<\/td>\n626\u2021<\/sup><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

The two singly occupied \u03c3-orbitals are shown below and are in part responsible for the non-dissociative behaviour. \"\"<\/a> \"\"<\/a><\/p>\n

The results using this method (the article reports many more methods), reveal that C2<\/sub> does indeed exist in a minimum for the heptet state, whilst the isoelectronic BN is only very weakly bound, in effect dissociative. Another dissociative isoelectronic is BO1+<\/sup>, whilst N2<\/sub>2+<\/sup> despite the coulombic repulsions of a double positive charge, still manages to be bound with a relatively short bond length. A further neutral diatomic BeO is also clearly non-dissociative.<\/p>\n

Lets hope a spectroscopist somewhere tries to take a look at these heptet excited states of such molecules so that further experimental insight can be cast on this fascinating problem.<\/p>\n

\n

\u2021<\/sup>The orbital occupancy of this species is different from the others. \u2020<\/sup>As are the neutral ten valence electron N\u2261N (confirmed here<\/a>) and HC\u2261CH.<\/p>\n

References<\/h2>\n
  1. I. Bhattacharjee, D. Ghosh, and A. Paul, \"Resolving the Quadruple Bonding Conundrum in C2 Using Insights Derived from Excited State Potential Energy Surfaces: A Molecular Orbital Perspective\", 2019. https:\/\/doi.org\/10.26434\/chemrxiv.11446224.v1<\/a>\n\n<\/li>\n<\/ol>\n\n<\/div> ","protected":false},"excerpt":{"rendered":"

    I noted in an earlier blog, a potential (if difficult) experimental test of the properties of the singlet state of dicarbon, C2. Now, just a few days ago, a ChemRxiv article has been published suggesting another (probably much more realistic) test.\u00a0This looks at the so-called 7\u03a3 open shell state of the molecule where three electrons […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_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},"jetpack_post_was_ever_published":false},"categories":[4],"tags":[],"ppma_author":[2661],"class_list":["post-21846","post","type-post","status-publish","format-standard","hentry","category-interesting-chemistry"],"yoast_head":"\nComment on "Resolving the Quadruple Bonding Conundrum in C2 Using Insights Derived from Excited State Potential Energy Surfaces": The 7\u03a3 heptet excited states for related molecules. - 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=21846\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Comment on "Resolving the Quadruple Bonding Conundrum in C2 Using Insights Derived from Excited State Potential Energy Surfaces": The 7\u03a3 heptet excited states for related molecules. - Henry Rzepa's Blog\" \/>\n<meta property=\"og:description\" content=\"I noted in an earlier blog, a potential (if difficult) experimental test of the properties of the singlet state of dicarbon, C2. Now, just a few days ago, a ChemRxiv article has been published suggesting another (probably much more realistic) test.\u00a0This looks at the so-called 7\u03a3 open shell state of the molecule where three electrons […]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=21846\" \/>\n<meta property=\"og:site_name\" content=\"Henry Rzepa's Blog\" \/>\n<meta property=\"article:published_time\" content=\"2020-01-02T10:05:36+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2020-01-03T08:41:56+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2020\/01\/checkpoint_10062095-300x169.jpg\" \/>\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=\"2 minutes\" \/>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Comment on \"Resolving the Quadruple Bonding Conundrum in C2 Using Insights Derived from Excited State Potential Energy Surfaces\": The 7\u03a3 heptet excited states for related molecules. - 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=21846","og_locale":"en_GB","og_type":"article","og_title":"Comment on \"Resolving the Quadruple Bonding Conundrum in C2 Using Insights Derived from Excited State Potential Energy Surfaces\": The 7\u03a3 heptet excited states for related molecules. - Henry Rzepa's Blog","og_description":"I noted in an earlier blog, a potential (if difficult) experimental test of the properties of the singlet state of dicarbon, C2. Now, just a few days ago, a ChemRxiv article has been published suggesting another (probably much more realistic) test.\u00a0This looks at the so-called 7\u03a3 open shell state of the molecule where three electrons […]","og_url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=21846","og_site_name":"Henry Rzepa's Blog","article_published_time":"2020-01-02T10:05:36+00:00","article_modified_time":"2020-01-03T08:41:56+00:00","og_image":[{"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2020\/01\/checkpoint_10062095-300x169.jpg","type":"","width":"","height":""}],"author":"Henry Rzepa","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Henry Rzepa","Estimated reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=21846#article","isPartOf":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=21846"},"author":{"name":"Henry Rzepa","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#\/schema\/person\/2b40f7b9c872a4dc1547e040a11b6281"},"headline":"Comment on “Resolving the Quadruple Bonding Conundrum in C2 Using Insights Derived from Excited State Potential Energy Surfaces”: The 7\u03a3 heptet excited states for related molecules.","datePublished":"2020-01-02T10:05:36+00:00","dateModified":"2020-01-03T08:41:56+00:00","mainEntityOfPage":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=21846"},"wordCount":387,"commentCount":0,"image":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=21846#primaryimage"},"thumbnailUrl":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2020\/01\/checkpoint_10062095-300x169.jpg","articleSection":["Interesting chemistry"],"inLanguage":"en-GB","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=21846#respond"]}]},{"@type":"WebPage","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=21846","url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=21846","name":"Comment on \"Resolving the Quadruple Bonding Conundrum in C2 Using Insights Derived from Excited State Potential Energy Surfaces\": The 7\u03a3 heptet excited states for related molecules. - 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=21846#primaryimage"},"image":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=21846#primaryimage"},"thumbnailUrl":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2020\/01\/checkpoint_10062095-300x169.jpg","datePublished":"2020-01-02T10:05:36+00:00","dateModified":"2020-01-03T08:41:56+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=21846#breadcrumb"},"inLanguage":"en-GB","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=21846"]}]},{"@type":"ImageObject","inLanguage":"en-GB","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=21846#primaryimage","url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2020\/01\/checkpoint_10062095.jpg","contentUrl":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2020\/01\/checkpoint_10062095.jpg","width":708,"height":398},{"@type":"BreadcrumbList","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=21846#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog"},{"@type":"ListItem","position":2,"name":"Comment on “Resolving the Quadruple Bonding Conundrum in C2 Using Insights Derived from Excited State Potential Energy Surfaces”: The 7\u03a3 heptet excited states for related molecules."}]},{"@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\/pDef7-5Gm","jetpack-related-posts":[{"id":22971,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=22971","url_meta":{"origin":21846,"position":0},"title":"A new example of a quadruple bond from carbon – to Fe.","author":"Henry Rzepa","date":"November 7, 2020","format":false,"excerpt":"Way back in 2010, I was writing about an experience I had just had during an organic chemistry tutorial, which morphed into speculation as to whether a carbon atom might sustain a quadruple bond to nitrogen. A decade on, and possibly approaching 100 articles by many authors on the topic,\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":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2020\/11\/NMn_33a-1024x839.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":3462,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3462","url_meta":{"origin":21846,"position":1},"title":"Shorter is higher: the strange case of diberyllium.","author":"Henry Rzepa","date":"January 21, 2011","format":false,"excerpt":"Much of chemistry is about bonds, but sometimes it can also be about anti-bonds. It is also true that the simplest of molecules can have quite subtle properties. Thus most undergraduate courses in chemistry deal with how to describe the bonding in the diatomics of the first row of the\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":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2011\/01\/Be2a.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":23777,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=23777","url_meta":{"origin":21846,"position":2},"title":"A suggestion for a molecule with a M\u2a78C quadruple bond with trigonal metal coordination.","author":"Henry Rzepa","date":"May 13, 2021","format":false,"excerpt":"The proposed identification of molecules with potential metal to carbon quadruple bonds, in which the metal exhibits trigonal bipyramidal coordination rather than the tetrahedral modes which have been proposed in the literature,, leads on to asking whether simple trigonal coordination at the metal can also sustain this theme? The rational\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":23686,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=23686","url_meta":{"origin":21846,"position":3},"title":"A reality-based suggestion for a molecule with a metal M\u2a78N quadruple bond.","author":"Henry Rzepa","date":"May 13, 2021","format":false,"excerpt":"I noted in an earlier post the hypothesized example of (CO)3Fe\u2a78C as exhibiting a carbon to iron quadruple bond and which might have precedent in known five-coordinate metal complexes where one of the ligands is a \"carbide\" or C ligand. I had previously mooted that the Fe\u2a78C combination might be\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":"","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/05\/Screenshot-703-1024x818.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":23588,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=23588","url_meta":{"origin":21846,"position":4},"title":"Two new reality-based suggestions for molecules with a metal M\u2a78C quadruple bond.","author":"Henry Rzepa","date":"May 8, 2021","format":false,"excerpt":"Following from much discussion over the last decade about the nature of C2, a diatomic molecule which some have suggested sustains a quadruple bond between the two carbon atoms, new ideas are now appearing for molecules in which such a bond may also exist between carbon and a transition metal\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":"","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/05\/Screenshot-702-300x63.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":23855,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=23855","url_meta":{"origin":21846,"position":5},"title":"A closer look at that fourth bond in C2.","author":"Henry Rzepa","date":"June 2, 2021","format":false,"excerpt":"From the last few posts here, you might have noticed much discussion about how the element carbon might sustain a quadruple bond. The original post on this topic from some years ago showed the molecular orbitals of the species CN+, which included two bonding \u03c0-types and a low lying nodeless\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":[]}],"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","author_category":"1","first_name":"Henry","last_name":"Rzepa","user_url":"https:\/\/orcid.org\/0000-0002-8635-8390","job_title":"","description":"Henry Rzepa is Emeritus Professor of Computational Chemistry at Imperial College London."}],"_links":{"self":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/21846","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=21846"}],"version-history":[{"count":34,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/21846\/revisions"}],"predecessor-version":[{"id":21882,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/21846\/revisions\/21882"}],"wp:attachment":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=21846"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=21846"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=21846"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fppma_author&post=21846"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}