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Crystal structure of CdSO4(H2O): a redetermination
No full textThe crystal structure of the title compound, cadmium sulfate monohydrate or poly[(μ2-aqua)(μ4-sulfato)cadmium], was redetermined based on modern CMOS (complementary metal oxide silicon) data. In comparison with the previous study [Bregeault & Herpin (1970). Bull. Soc. Fr. Mineral. Cristallogr. 93, 37–42], all non-H atoms were refined with anisotropic displacement parameters and the hydrogen-bonding pattern unambiguously established due to location of the hydrogen atoms. In addition, a significant improvement in terms of precision and accuracy was achieved. In the crystal, the Cd2+ cation is coordinated by four O atoms of four sulfate anions and two O atoms of water molecules, forming a distorted octahedral trans-[CdO6] polyhedron. Each sulfate anion bridges four Cd2+ cations and each water molecule bridges two Cd2+ cations, leading to the formation of a three-dimensional framework, with Cd...Cd separations in the range 4.0757 (2)–6.4462 (3) Å. O—H...O hydrogen-bonding interactions of medium strength between the coordinating water molecules and sulfate anions consolidate the crystal packing
Crystal structure of diaquatris(benzohydrazide-κ2N,O)(isophthalato-κO)samarium(III) nitrate
No full textThe first benzohydrazide complex of a lanthanide is reported. In the title compound, [Sm(C8H4O4)(C7H8N2O)3(H2O)2]NO3, systematic name diaquatris(benzohydrazide-κ2N,O)(isophthalato-κO)samarium(III) nitrate, the SmIII ion is nine-coordinated in a distorted tricapped trigonal–prismatic geometry by three oxygen atoms and three nitrogen atoms from three benzhydrazide (bzz) ligands, one oxygen atom from the isophthalate (itp2−) ligand, and two oxygen atoms from coordinated water molecules. The nitrate group is disordered over two sets of sites with occupancy factors of 0.310 (17) and 0.690 (17). In the crystal, adjacent molecules are linked into chains via pairs of O—H...O and N—H...O hydrogen bonds between the carboxylate acceptor and the coordinated water and amine NH2 donors. Molecules are further stacked by π–π interactions involving the benzene ring of the itp2− ligands, forming double chains that extend in the b-axis direction. These double chains are further linked into a three-dimensional supramolecular network via hydrogen bonds (O—H...O, N—H...O and C—H...O) between the complex molecule and the nitrate groups along with C—H...π and π–π interactions involving the benzene rings of the bzz and itp2− ligands
Tetraaqua(2,2′-bipyridine-κ2N,N′)nickel(II) sulfate
No full textThe asymmetric unit of the title complex, [Ni(C10H8N2)(H2O)4]SO4, consists of a complex [Ni(bipy)(H2O)4]2+ cation (bipy = 2,2′-bipyridine) and a non-coordinating [SO4]2− anion. The NiII atom is six-coordinated in a distorted octahedral geometry defined by the two N atoms of the bipy ligand and four water O atoms. The crystal structure contains extensive classical O—H...O hydrogen bonds, which link the ions into a two-dimensional array in the ab plane. Layers are connected into a three-dimensional supramolecular structure by C—H...O interactions
Synthesis, crystal structure and properties of poly[di-μ3-chlorido-di-μ2-chlorido-bis[4-methyl-N-(pyridin-2-ylmethylidene)aniline]dicadmium(II)]
No full textThe title coordination polymer with the 4-methyl-N-(pyridin-2-ylmethylidene)aniline Schiff base ligand (L, C13H12N2), [Cd2Cl4(C13H12N2)]n (1), exhibits a columnar structure extending parallel to [100]. The columns are aligned in parallel and are decorated with chelating L ligands on both sides. They are elongated into a supramolecular sheet extending parallel to (01\overline{1}) through π–π stacking interactions involving L ligands of neighbouring columns. Adjacent sheets are packed into the tri-periodic supramolecular network through weak C—H...Cl hydrogen-bonding interactions that involve the phenyl CH groups and chlorido ligands. The thermal stability and photoluminescent properties of (1) have also been examined
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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