{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,8]],"date-time":"2026-10-08T00:27:02Z","timestamp":1791419222005,"version":"4.3.3"},"reference-count":0,"publisher":"International Union of Crystallography (IUCr)","issue":"5","license":[{"start":{"date-parts":[[2008,9,16]],"date-time":"2008-09-16T00:00:00Z","timestamp":1221523200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/journals.iucr.org\/services\/copyrightpolicy.html"},{"start":{"date-parts":[[2008,9,16]],"date-time":"2008-09-16T00:00:00Z","timestamp":1221523200000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/journals.iucr.org\/services\/copyrightpolicy.html#TDM"}],"content-domain":{"domain":["iucr.org","wiley.com","iucrj.org"],"crossmark-restriction":true},"short-container-title":["Acta Crystallogr B Struct Sci","Acta Cryst B","Acta Cryst Sect B","Acta Crystallogr B","Acta Crystallogr Sect B","Acta Crystallogr Sect B Struct Sci"],"accepted":{"date-parts":[[2008,8,18]]},"published-print":{"date-parts":[[2008,10,1]]},"abstract":"<jats:p>The crystal structures of three polymorphs found for the addition complex of urea and barbituric acid are described and compared. Two polymorphs are monoclinic, space groups <jats:italic>P<\/jats:italic>2<jats:sub>1<\/jats:sub>\/<jats:italic>c<\/jats:italic> and <jats:italic>Cc<\/jats:italic>, whereas the third is triclinic, P\\bar 1. The displacement of electron density towards the mesomeric forms, corresponding to the tautomeric forms of higher stability, of the barbituric acid molecule seem to influence the type of hydrogen bonds formed, which in turn determines the different packing topology in the polymorphs. While the polymorphic forms can be easily differentiated at the first-level graph-set analysis of their hydrogen-bonding patterns, a higher-level analysis enables important features of the mutual spatial arrangement of the structural components to be revealed.<\/jats:p>","DOI":"10.1107\/s0108768108026645","type":"journal-article","created":{"date-parts":[[2008,9,16]],"date-time":"2008-09-16T16:09:14Z","timestamp":1221581354000},"page":"623-632","update-policy":"https:\/\/doi.org\/10.1107\/cm_01","source":"Crossref","is-referenced-by-count":50,"title":["Polymorphism of urea\u2013barbituric acid co-crystals"],"prefix":"10.1107","volume":"64","author":[{"given":"Marlena","family":"Gryl","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anna","family":"Krawczuk","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Katarzyna","family":"Stadnicka","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"329","published-online":{"date-parts":[[2008,9,16]]},"container-title":["Acta Crystallographica Section B Structural Science"],"original-title":[],"link":[{"URL":"http:\/\/journals.iucr.org\/b\/issues\/2008\/05\/00\/bs5065\/bs5065.pdf","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"http:\/\/journals.iucr.org\/b\/issues\/2008\/05\/00\/bs5065\/bs5065.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,1,11]],"date-time":"2025-01-11T15:08:19Z","timestamp":1736608099000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.iucr.org\/paper?S0108768108026645"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2008,9,16]]},"references-count":0,"journal-issue":{"issue":"5","published-print":{"date-parts":[[2008,10]]}},"alternative-id":["S0108768108026645"],"URL":"https:\/\/doi.org\/10.1107\/s0108768108026645","relation":{"is-supplemented-by":[{"id-type":"doi","id":"10.1107\/S0108768108026645\/bs5065sup1.cif","asserted-by":"subject"},{"id-type":"doi","id":"10.1107\/S0108768108026645\/bs5065Isup2.fcf","asserted-by":"subject"},{"id-type":"doi","id":"10.1107\/S0108768108026645\/bs5065IIsup3.fcf","asserted-by":"subject"},{"id-type":"doi","id":"10.1107\/S0108768108026645\/bs5065IIIsup4.fcf","asserted-by":"subject"}]},"ISSN":["0108-7681"],"issn-type":[{"value":"0108-7681","type":"print"}],"subject":[],"published":{"date-parts":[[2008,9,16]]},"assertion":[{"value":"Acta Crystallographica Section B: Structural Science","order":0,"name":"journal","label":"Publication","explanation":{"URL":"http:\/\/journals.iucr.org\/b"},"group":{"name":"general","label":"General"}},{"value":"research papers","order":1,"name":"content_type","label":"Content type","explanation":{"URL":"https:\/\/journals.iucr.org\/b\/services\/notesforauthors.html"},"group":{"name":"general","label":"General"}},{"value":"Available","URL":"http:\/\/scripts.iucr.org\/cgi-bin\/citedin?bs5065","order":2,"name":"article_metrics","label":"Article metrics","group":{"name":"general","label":"General"}},{"value":"Yes","order":0,"name":"peer_reviewed","label":"Peer reviewed","group":{"name":"peer_review","label":"Peer review"}},{"value":"Single blind","order":1,"name":"review_process","label":"Review process","group":{"name":"peer_review","label":"Peer review"}},{"value":"23 May 2008","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication history"}},{"value":"18 August 2008","order":1,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication history"}},{"value":"16 September 2008","order":2,"name":"published_online","label":"Published online","group":{"name":"publication_history","label":"Publication history"}},{"value":"This article has supporting information","name":"supplementary_materials","label":"Supplementary materials","explanation":{"URL":"http:\/\/scripts.iucr.org\/cgi-bin\/sendsup?bs5065"}},{"value":"\u00a9 2008 International Union of Crystallography","order":0,"name":"copyright","label":"Copyright","explanation":{"URL":"http:\/\/journals.iucr.org\/services\/copyrightpolicy.html"},"group":{"name":"copyright_and_licensing","label":"Copyright and licencing"}}]}}