{"id":3604,"date":"2011-03-05T08:25:02","date_gmt":"2011-03-05T08:25:02","guid":{"rendered":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=3604"},"modified":"2015-06-04T07:23:00","modified_gmt":"2015-06-04T06:23:00","slug":"lapis-lazuli-the-colour-of-ultramarine","status":"publish","type":"post","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3604","title":{"rendered":"Lapis lazuli: the colour of ultramarine."},"content":{"rendered":"
\n

My colleague Bill Griffith has again<\/a> come up with another colour challenge: that of the ancient semi-precious stone Lapis Lazuli<\/strong><\/em>, mined in the mountains of Afghanistan for more than 6000 years and used by painters in some medieval paintings of the Virgin, the Wilton diptych etc.<\/p>\n

\"\"<\/a>

Lapis Lazuli (photo from Wikipedia).<\/p><\/div>\n

The formula is (approximately): (Na,Ca)8<\/sub>(AlSiO4<\/sub>)6<\/sub>(S,SO4<\/sub>,Cl)1-2<\/sub>, which sounds a bit of a challenge! But, as a very recent article points out[1]<\/a><\/span> the component that imparts the colour is the sulfur, \u00a0more specifically present in the stone as the \u00a0S3<\/sub>–<\/sup> radical anion. No recent calculation of the \u00a0UV\/Vis spectrum of this simple triatomic has been reported, so here goes. A \u03c9B97XD\/aug-cc-pVQZ calculation<\/a>, embedded in a continuum solvent field of water (which serves to compactify the otherwise diffuse anionic aspect) and with TD-DFT applied, shows the following (you will need an SVG enabled Web browser to see the spectrum. I am here promoting the use of this graphical standard, which differs from normal images in scaling as you resize the page size with no loss of resolution).
\n\"\"<\/a><\/p>\n

The \u03bbmax<\/sub> is ~650nm calculated and\u00a0~619nm measured (as a solution in an ionic liquid).\u00a0Not bad agreement! The molecular orbitals involved in the excitation are shown below.<\/p>\n\n\n\n
\n

\"\"

Highest doubly occupied MO. Click for 3D.<\/p><\/div><\/td>\n

\n

\"\"

Lowest singly occupied MO. Click for 3D.<\/p><\/div><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Such a precious colour, and produced using such a cheap material!<\/p>\n

References<\/h2>\n
  1. ?. Boros, M.J. Earle, M.A. G\u00eelea, A. Metlen, A. Mudring, F. Rieger, A.J. Robertson, K.R. Seddon, A.A. Tomaszowska, L. Trusov, and J.S. Vyle, \"On the dissolution of non-metallic solid elements (sulfur, selenium, tellurium and phosphorus) in ionic liquids\", Chem. Commun.<\/i>, vol. 46, pp. 716-718, 2010. https:\/\/doi.org\/10.1039\/b910469k<\/a>\n\n<\/li>\n<\/ol>\n\n<\/div> ","protected":false},"excerpt":{"rendered":"

    My colleague Bill Griffith has again come up with another colour challenge: that of the ancient semi-precious stone Lapis Lazuli, mined in the mountains of Afghanistan for more than 6000 years and used by painters in some medieval paintings of the Virgin, the Wilton diptych etc. The formula is (approximately): (Na,Ca)8(AlSiO4)6(S,SO4,Cl)1-2, which sounds a bit […]<\/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_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":false,"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":[492,491,468,215,469,339],"ppma_author":[2661],"class_list":["post-3604","post","type-post","status-publish","format-standard","hentry","category-interesting-chemistry","tag-afghanistan","tag-bill-griffith","tag-lapis-lazuli","tag-missouri","tag-trisulfide-radical-anion","tag-web-browser"],"yoast_head":"\nLapis lazuli: the colour of ultramarine. - 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=3604\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Lapis lazuli: the colour of ultramarine. - Henry Rzepa's Blog\" \/>\n<meta property=\"og:description\" content=\"My colleague Bill Griffith has again come up with another colour challenge: that of the ancient semi-precious stone Lapis Lazuli, mined in the mountains of Afghanistan for more than 6000 years and used by painters in some medieval paintings of the Virgin, the Wilton diptych etc. The formula is (approximately): (Na,Ca)8(AlSiO4)6(S,SO4,Cl)1-2, which sounds a bit […]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3604\" \/>\n<meta property=\"og:site_name\" content=\"Henry Rzepa's Blog\" \/>\n<meta property=\"article:published_time\" content=\"2011-03-05T08:25:02+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2015-06-04T06:23:00+00:00\" \/>\n<meta property=\"og:image\" content=\"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2011\/03\/337px-Lapis_lazuli_block.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=\"1 minute\" \/>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Lapis lazuli: the colour of ultramarine. - 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I conclude my halide acid series\u00a0by investigating how many water molecules (in gas phase clusters) are required for ionisation\u2026","rel":"","context":"In "General"","block_context":{"text":"General","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=1"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":26199,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=26199","url_meta":{"origin":3604,"position":5},"title":"Blue blood.","author":"Henry Rzepa","date":"August 7, 2023","format":false,"excerpt":"Respiratory pigments are metalloproteins that transport O2, the best known being the bright red\/crimson coloured hemoglobin in human blood. The colour derives from Fe2+ at the core of a tetraporphyrin ring. 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