Moctezumite, [PbUO2](TeO3)2, is monoclinic, P2(1)/c, with a = 7.813(5), b = 7.061(2), c = 13.775(4) angstrom, beta = 93.71(2)-degrees, and Z = 4. Its structure has been refined to an unweighted residual of 0.041 using 1440 reflections. Moctezumite possesses a layer structure parallel to (001). In each layer, U-coordination pentagonal bipyramids form zigzag chains parallel to b by sharing edges. The U chains alternate with chains of Pb edge-sharing monocapped trigonal-prism coordination polyhedra. The U-Pb layers stacked along c* are connected by Te2O6 units. Each Te2O6 unit is composed of TeO3psi and TeO4psi (psi = lone pair), which share an 0 atom. The structure of moctezumite consists of slightly modified schmitterite-like (UTeO5) winged U polyhedral chains separated by Pb polyhedral chains.

ChemInformVolume 20, Issue 37 Heterocyclic Compounds ChemInform Abstract: Dimethyl 4-Oxobenzo(b)cyclooct-5-ene(1,6-e)-1,4-thiazine-1,2-dicarboxylates. X-Ray Crystal Structure of the 2,2-Dimethyl Homologue G. M. ISKANDER, G. M. ISKANDER Dep. Chem., Fac. Sci., Univ. Khartoum, Khartoum, SudanSearch for more papers by this authorL. E. S. EL KHAWAD, L. E. S. EL KHAWAD Dep. Chem., Fac. Sci., Univ. Khartoum, Khartoum, SudanSearch for more papers by this authorGH. YOUSIF, GH. YOUSIF Dep. Chem., Fac. Sci., Univ. Khartoum, Khartoum, SudanSearch for more papers by this authorK. O. FAIR, K. O. FAIR Dep. Chem., Fac. Sci., Univ. Khartoum, Khartoum, SudanSearch for more papers by this authorE. O. SCHLEMPER, E. O. SCHLEMPER Dep. Chem., Fac. Sci., Univ. Khartoum, Khartoum, SudanSearch for more papers by this author G. M. ISKANDER, G. M. ISKANDER Dep. Chem., Fac. Sci., Univ. Khartoum, Khartoum, SudanSearch for more papers by this authorL. E. S. EL KHAWAD, L. E. S. EL KHAWAD Dep. Chem., Fac. Sci., Univ. Khartoum, Khartoum, SudanSearch for more papers by this authorGH. YOUSIF, GH. YOUSIF Dep. Chem., Fac. Sci., Univ. Khartoum, Khartoum, SudanSearch for more papers by this authorK. O. FAIR, K. O. FAIR Dep. Chem., Fac. Sci., Univ. Khartoum, Khartoum, SudanSearch for more papers by this authorE. O. SCHLEMPER, E. O. SCHLEMPER Dep. Chem., Fac. Sci., Univ. Khartoum, Khartoum, SudanSearch for more papers by this author First published: September 12, 1989 https://doi.org/10.1002/chin.198937256Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume20, Issue37September 12, 1989 RelatedInformation

AbstractThe reaction between Fe(II) salts and 18‐crown‐6 gives no stable products, whereas Fe(III) halides and crown ethers form the complexes (I)‐(IV) depending on the reaction conditions.

AbstractSeveral original allene syntheses are reviewed. Two novel organometallic approaches are discussed in some detail. Recent observations made in the case of the one‐step synthesis of allenes by homologation of alkynes are described. The reaction mechanism which is proposed is supported by X‐ray crystallographic data on a CuBr complex which appears to be a reaction intermediate.