{"id":17467,"date":"2017-02-14T09:30:34","date_gmt":"2017-02-14T09:30:34","guid":{"rendered":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=17467"},"modified":"2017-03-10T11:06:25","modified_gmt":"2017-03-10T11:06:25","slug":"vsepr-theory-a-closer-look-at-bromine-trifluoride-brf3","status":"publish","type":"post","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=17467","title":{"rendered":"VSEPR Theory: A closer look at bromine trifluoride, BrF3."},"content":{"rendered":"
\n

I analysed the bonding in chlorine trifluoride<\/a> a few years back in terms of VSEPR theory. I noticed that several searches on this topic which led people to this post also included a query about the differences between it and the bromine analogue. For those who posed this question, here is an equivalent analysis.<\/p>\n

The calculation is done at the same level as before (\u03c9B97XD\/6-311++D(d,p)) for consistency (DOI: 10.14469\/hpc\/2160<\/a>)<\/p>\n

\"\"

Click for 3D<\/p><\/div>\n

    \n
  1. Basins 8 and 9 have electron populations of 2.33e (2.07e for the chlorine analogue) with an angle subtended at Br of 159\u00b0. The greater electron population and hence electron pair repulsion has the effect of increasing the angle compared to Cl (154\u00b0). The coordination is even more square pyramidal than with Cl.<\/li>\n
  2. Basin 7 has a population of 0.73e, this time less than Cl (0.87e). <\/li>\n
  3. Basins 11 and 12 are 0.82e. With Cl, this single basin was replaced by a pair of split basins, each pair summing to 0.91e (the same effect happens with F-F). The angle 4-2-3 is 172\u00b0 (174\u00b0 for Cl) which suggests a slightly increased 2-electron-3-centre interaction between e.g. atoms 1-4 or 1-3 compared to Cl.<\/li>\n
  4. The total basin count surrounding the Br is therefore 7.03e, compared to 6.84e with Cl, which suggests Br is slightly more electronegative in this context than Cl.<\/li>\n<\/ol>\n

    Bromine has a habit of springing surprises<\/a>, but not so much in this example. <\/p>\n\n<\/div> ","protected":false},"excerpt":{"rendered":"

    I analysed the bonding in chlorine trifluoride a few years back in terms of VSEPR theory. I noticed that several searches on this topic which led people to this post also included a query about the differences between it and the bromine analogue. For those who posed this question, here is an equivalent analysis. The calculation […]<\/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":true,"_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":[4],"tags":[1436,2011,1432,1395,2010,1799,2008,2009,1431,1433,1517],"ppma_author":[2661],"class_list":["post-17467","post","type-post","status-publish","format-standard","hentry","category-interesting-chemistry","tag-bromine","tag-bromine-trifluoride","tag-chemical-elements","tag-chemistry","tag-chlorine","tag-fluorides","tag-halogens","tag-interhalogen-compounds","tag-matter","tag-oxidizing-agents","tag-vsepr-theory"],"yoast_head":"\nVSEPR Theory: A closer look at bromine trifluoride, BrF3. - 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=17467\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"VSEPR Theory: A closer look at bromine trifluoride, BrF3. - Henry Rzepa's Blog\" \/>\n<meta property=\"og:description\" content=\"I analysed the bonding in chlorine trifluoride a few years back in terms of VSEPR theory. I noticed that several searches on this topic which led people to this post also included a query about the differences between it and the bromine analogue. For those who posed this question, here is an equivalent analysis. 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I noticed that several searches on this topic which led people to this post also included a query about the differences between it and the bromine analogue. For those who posed this question, here is an equivalent analysis. 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ClF3 is a good illustration of this theory. The standard application of VSEPR theory to this molecule is as follows: Central atom: chlorine\u2026","rel":"","context":"In "Hypervalency"","block_context":{"text":"Hypervalency","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=7"},"img":{"alt_text":"VSEPR","src":"https:\/\/i0.wp.com\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2013\/07\/VSEPR.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":16497,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=16497","url_meta":{"origin":17467,"position":1},"title":"A wider look at chlorine trifluoride: crystal structures and data mining.","author":"Henry Rzepa","date":"June 10, 2016","format":false,"excerpt":"A while ago, I explored how the 3-coordinate halogen compound ClF3\u00a0is conventionally analyzed using\u00a0VSEPR (valence shell electron pair repulsion theory). Here I (belatedly) look at other such tri-coordinate halogen compounds using known structures gleaned from the\u00a0crystal structure database (CSD). The search query specifies\u00a07A as the central atom, defined with just\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":"","width":0,"height":0},"classes":[]},{"id":18993,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=18993","url_meta":{"origin":17467,"position":2},"title":"VSEPR Theory: Octet-busting or not with trimethyl chlorine, ClMe3.","author":"Henry Rzepa","date":"November 12, 2017","format":false,"excerpt":"A few years back, I took a look at the valence-shell electron pair repulsion approach to the geometry of chlorine trifluoride, ClF3 using so-called ELF basins to locate centroids for both the covalent F-Cl bond electrons and the chlorine lone-pair electrons. Whereas the original VSEPR theory talks about five \"electron\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":19433,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=19433","url_meta":{"origin":17467,"position":3},"title":"Is (h\u03bd)3 an allotrope of light?","author":"Henry Rzepa","date":"February 23, 2018","format":false,"excerpt":"A little while ago I pondered allotropic bromine, or Br(Br)3. But this is a far wackier report of a molecule of light. The preparation and detection of dimer and trimer bound photon states is pure physics; probably considered by the physicists themselves as NOT chemistry. It is certainly true, as\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":15552,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=15552","url_meta":{"origin":17467,"position":4},"title":"VSEPR Theory: A closer look at trifluorothionitrile, NSF3.","author":"Henry Rzepa","date":"January 16, 2016","format":false,"excerpt":"The post on applying VSEPR (\"valence shell electron pair repulsion\") theory to the geometry of ClF3\u00a0has proved perennially popular. So here is a follow-up on another little molecue,\u00a0F3SN. As the name implies, it is often represented with an\u00a0S\u2261N bond. Here I take a look at the conventional analysis. This is\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":7580,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7580","url_meta":{"origin":17467,"position":5},"title":"The Sn2 reaction and the anomaly of carbon.","author":"Henry Rzepa","date":"September 6, 2012","format":false,"excerpt":"It was three years ago that I first blogged on the topic of the Sn2 reaction. Matthias Bickelhaupt had suggested that the Sn2 reaction involving displacement at a carbon atom was an anomaly; the true behaviour was in fact exhibited by the next element down in the series, silicon. 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.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2012\/09\/sn2-Na1.gif?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\/17467","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=17467"}],"version-history":[{"count":8,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/17467\/revisions"}],"predecessor-version":[{"id":17477,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/17467\/revisions\/17477"}],"wp:attachment":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=17467"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=17467"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=17467"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fppma_author&post=17467"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}