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The structure of the title centrosymmetric compound, [Zn(C9H6NO)2(H2O)2], has already been solved three times [Merritt, Cady & Mundy (1954). Acta Cryst. 7, 473-476; Palenik (1964). Acta Cryst. 17, 696-700; Chen, Zhang, Shi, Huang, Liang & Zhou (2003). Acta Cryst. E 59, m814-m815]. The authors of the two most recent papers state that they attained lower R1 values than that obtained in the 1954 paper, but they do not mention that Merritt et al. had derived the structural model from a twinned crystal. Also, from a structural point of view, there are strong indications that the most recent report is in fact the isostructural CuII complex already reported by Okabe & Saishu [ Acta Cryst. (2001), E 57, m251-m252] and not the ZnII complex. The structure of the title compound is reported here based on data obtained from a twinned crystal. [ABSTRACT FROM AUTHOR]

All the 139 noncentrosymmetric crystal structures published in Acta Crystallographica Section C between January 2011 and November 2012 inclusive have been used as the basis of a detailed study of the reporting of absolute structure. These structure determinations cover a wide range of space groups, chemical composition and resonant-scattering contribution. Defining A and D as the average and difference of the intensities of Friedel opposites, their level of fit has been examined using 2 AD and selected- D plots. It was found, regardless of the expected resonant-scattering contribution to Friedel opposites, that the Friedel-difference intensities are often dominated by random uncertainty and systematic error. An analysis of data collection strategy is provided. It is found that crystal-structure determinations resulting in a Flack parameter close to 0.5 may not necessarily be from crystals twinned by inversion. Friedifstat is shown to be a robust estimator of the resonant-scattering contribution to Friedel opposites, very little affected by the particular space group of a structure nor by the occupation of special positions. There is considerable confusion in the text of papers presenting achiral noncentrosymmetric crystal structures. Recommendations are provided for the optimal way of treating noncentrosymmetric crystal structures for which the experimenter has no interest in determining the absolute structure. [ABSTRACT FROM AUTHOR]

The article presents a paper about a polymorph of tetrakis(acetonitrile-kN)copper(I) tetrafluoridoborate. It says that for the structure determination, the researchers used a crystal that contained a volume fraction of 0.088 (7) of the Pna21 polymorph. According to the paper, the assymetric unit of (I) contains three independent pairs of cations and anions.

The present paper reports the crystal structures of two short phosphonotripeptides (one in two crystal forms) containing one ΔPhe (dehydrophenylalanine) residue, namely dimethyl (3-{[ tert-butoxycarbonylglycyl-α,β-( Z)-dehydrophenylalanyl]amino}propyl)phosphonate, Boc0-Gly1-Δ( Z)Phe2-α-Abu3PO3Me2, C21H32N3O7P, (I), and diethyl (4-{[ tert-butoxycarbonylglycyl-α,β-( Z)-dehydrophenylalanyl]amino}butyl)phosphonate, Boc0-Gly1-Δ( Z)Phe2-α-Nva3PO3Et2, as the propan-2-ol monosolvate 0.122-hydrate, C24H38N3O7P·C3H8O·0.122H2O, (II), and the ethanol monosolvate 0.076-hydrate, C24H38N3O7P·C2H6O·0.076H2O, (III). The crystals of (II) and (III) are isomorphous but differ in the type of solvent. The phosphono group is linked directly to the last Cα atom in the main chain for all three peptides. All the amino acids are trans linked in the main chains. The crystal structures exhibit no intramolecular hydrogen bonds and are stabilized by intermolecular hydrogen bonds only. [ABSTRACT FROM AUTHOR]

The article presents a paper about quinolin-6-ol at 100 K. It provides background on quinoline derivatives which are said to be known for their antifungal and antibacterial activities. The research focuses on the IR spectra of crystals with open hydrogen-bonded chains in the unit cell that is measured in the frequency range of the proton and deuteron stretching vibrations of the hydrogen bridge.

The article presents a paper which examines the role of isomeric acids in hydrogen-bonding patterns. According to the article, the maleic and fumaric acids in their complex forms exist as semimaleate and semifumarate ions, respectively. It mentions the use of maleic acid as a simple building block in supramolecular architectures in two and three dimensions.

The article presents a paper about bis[2,4-diamino-5-(3,4,5-trimethoxybenzyl)pyrimidin-1-ium] DL-malate. According to the article, a 1:2 salt can be formed from racemic malic acid in which the malate compound is disordered across a centre of inversion. It says that despite of the malic acid being one of the simplest chiral dicarboxylic acids, its role in supramolecular chemistry has not been widely studied.

The article presents a paper about two modes of O-H...O hydrogen bonding used in dimorphs of racemic 6-O-acryloyl-2-O-benzoyl-myo-inositol 1,3,5-orthoformate. It mentions the key role of myo-Inositol 1,3,5-orthoester derivatives in the preparation of biologically relevant myo-inositol phosphates. The study found that orientational changes in a small functional group induce diverse hydrogen-bonding patterns in molecular associations.

The article presents a paper about hydrogen-bonded supramolecular motifs in 2-amino-4,6-dimethoxypyrimidinium picrate and pyrimethaminium picrate dimethyl sulfoxide solvate. It mentions the use of picric acid as an acidic ligand to form salts with polar biomolecules through specific electrostatic or hydrogen-bonding interactions. According to one study, hydrogen bonding plays an important role in molecular recognition and crystal engineering research.

The article presents a paper about tetrameric aggregate of 1,c-3-diphenyltetran-r-1-ol via an R44(8) homodromic ring. According to the authors, the title compound has two chiral centers namely C1 and C3. A view of the tetramer, showing the atom-labelling scheme is provided. One table shows that the four molecules in an asymmetric unit are linked by as many hydrogen bonds in order to constitute a tetramer.

The article presents a paper about a new polymorph of triphenylmethylamine. It looks at hydrogen bond and its importance in a vast number of chemical, biological and materials systems. According to the article, the formation of hydrogen bonds of various types causes a decrease in the total energy of a system and serves as its stabilizing factor.

The article presents a paper about trans-Chlorido(phenyl)bis(triphenyl-phosphine)nickel(II) and its 1:1 cocrystal with chloridobis(triphenyl-phosphine)nickel(I). It mentions the interest attracted by a new class of neutral nickel catalysts based on salicylaldimine or anilinotropone ligands. A view of the crystal packing of cocrystal (3) along c, showing the alternating layers along a is provided.

The article presents a paper about poly[triaqua(µ4-4-carboxybenzenesulfonato-k4O:O':O"':O"')(4-carboxybenzenesulfonato-kO)strontium(II)]. According to the article, the study looks at the coordination modes and two-dimensional network of a novel strontium(II) coordination polymer, [Sr(C7H5O5S)2(H2O)3]n. A view of the coordination unit and the coordination polyhedron of the title compound is provided.

N-Salicylideneaniline (SA), C13H11NO, belongs to the large family of aromatic Schiff bases. It is of particular importance owing to its reversible photoreactivity. SA forms two photochromic polymorphs, both with two non-coplanar benzene rings. In addition, we have recently discovered a planar polymorph, named the β-polymorph, which will be discussed in a subsequent paper. We report here the structure of the α2-polymorph in the orthorhombic crystal system. This compound exhibits a strong intramolecular O—H…N hydrogen bond and the dihedral angle between the two rings varies with temperature. [ABSTRACT FROM AUTHOR]

The article presents a paper about bis[2-(2-hydroxyethyl)pyridinium]µ-decavanadato-bis[pentaaqua-manganate(II)] tetrahydrate. It mentions the role of decavanadate ions as building blocks for supra-molecular assemblies and ligands. A figure showing a view along the a axis of the hydrogen-bonded anionic layers is provided.

The article presents a paper about {[SmCl(en)4][In2Te4]}n, an indium telluride with a one-dimensional sinusoidal chain. It mentions the presence or absence of N-H...Cl hydrogen bonding which affects the conformation of the anion. A figure that presents views of the cation and the anion of (I), showing the atom-numbering schemes, is provided.

The article presents a paper about three-dimensional networks in the 1:2 organic salts 2,2'-biimidazolium bis(3-carboxy-4-hydroxybenzenesulfonate) and 2,2'-bibenzimidazolium bis(3-carboxy-4-hydroxybenzenesulfonate) trihydrate. According to the article, the cation of compound (I) lies on a centre of inversion. It says that the ionic components in the packing structures of the title compounds are linked into three-dimensional networks by a combination of N, H and O hydrogen bonds.

The article presents a paper about gem-dimethylcyclopropanation of dibenzylideneacetone (dba) using triisopropyl sulfoxonium tetrafluoroborate. It mentions the interesting behaviour shown by the packing of the molecules within the crystal structure. A view of an asymmetric unit of compound (IV), showing the atom-numbering scheme is provided.

The title iron(II) complex, [Fe(CN)2(C15H23N3O2)]-H2O, is of interest to the spin-crossover community because of its unusual temperature-dependent magnetic behaviour as well as its relatively high relaxation temperature for the light-induced spin-crossover phenomenon. Structural modifications are strongly suspected to cause the unusual thermal spin-crossover features. Recently, the high-spin crystal structure has been reported but with an inadequate space group. In the present paper, the crystal structure is corrected by a new investigation, and some consequences for the structure-property relationships of this complex are discussed. The FeII ion is seven-coordinate and lies on a twofold axis. [ABSTRACT FROM AUTHOR]

An introduction to the journal is presented in which the guest editor discusses various papers on topics including chemical structure prediction through X-ray analyses and nuclear magnetic resonance (NMR) technology, polymorphism, and stereochemistry.

Focuses on the continued rapid publication of the journal "Acta Crystallographica Section C". Release of high-quality papers related to chemistry, biochemistry, mineralogy, physiclas and materials science; Inclusion of studies involving special techniques and difficult crystalline materials; Issuance of inorganic and metal-organic papers.

This paper reports a new partially oxidized triphylite-type phosphate (lithium iron phosphate), which has been synthesized hydrothermally at 973 K and 0.1 GPa. The structure is similar to that of natural triphylite, LiFe(PO4), and is characterized by two chains of edge-sharing octahedra parallel to the b axis. The weakly distorted M1 octahedra contain Li atoms, whereas the more strongly distorted M2 octahedra contain FeII and FeIII atoms. Refined site occupancies and bond-valence analysis show the presence of FeIII and vacancies on the M2 site, mainly explained by the substitution mechanism 3 FeII = 2 FeIII + vacancies. [ABSTRACT FROM AUTHOR]

The article offers information on the submission of manuscript for the journal, and discusses papers published within the issue.

The permanent address of one of the authors in the paper by Orozco et al. [Acta Cryst. (2009), C65, o549o552] is corrected. [ABSTRACT FROM AUTHOR]

The chemical names of the title compounds in the paper by Sonar et al. [ Acta Cryst. (2007), C63, o743o745] are corrected. [ABSTRACT FROM AUTHOR]

The chemical name of one of the title compounds in the paper by Pourayoubi et al. [ Acta Cryst. (2012), C68, o164o169] is corrected. [ABSTRACT FROM AUTHOR]

The paper by Fang et al. [ ] is retracted. It has subsequently been shown that the crystal studied was borax. [ABSTRACT FROM AUTHOR]

The article presents guidelines for authors on the submission of papers to be published in the journal "Acta Crystallographica Section C: Crystal Structure Communications." Accordingly, the guidelines cites the different aspects and submission requirements needed as well as the warranty and privileges given to authors. It includes, the quality of writing, categories of submission and copyright regulations.

This paper reports the hydrothermal synthesis and crystal structure refinement of diiron(II) phosphate hydroxide, FeII2(PO4)(OH), obtained at 1063 K and 2.5 GPa. This phosphate is the synthetic analogue of the mineral wolfeite, and has a crystal structure topologically identical to those of minerals of the triplite–triploidite group. The complex framework contains edge- and corner-sharing FeO4(OH) and FeO4(OH)2 polyhedra, linked via corner-sharing to the PO4 tetrahedra (average P—O distances are between 1.537 and 1.544 Å). Four five-coordinated Fe sites are at the centers of distorted trigonal bipyramids (average Fe—O distances are between 2.070 and 2.105 Å), whereas the coordination environments of the remaining Fe sites are distorted octahedra (average Fe—O distances are between 2.146 and 2.180 Å). The Fe—O distances are similar to those observed in natural Mg-rich wolfeite, except for two Fe—O bond distances, which are significantly longer in synthetic Fe2+2(PO4)(OH). [ABSTRACT FROM AUTHOR]

Molecules of the title compound, C12H13NO3, are not planar and are stabilized by electrostatic interactions, as the dipole moment of the molecule is 3.76 D. They are also stabilized by intramolecular hydrogen bonds of N...O and C...O types, and by a complicated network of weak intermolecular hydrogen bonds of the C...O type. This paper also reports the theoretical investigation of the hydrogen bonding and electronic structure of the title compound using natural bond orbital (NBO) analysis. [ABSTRACT FROM AUTHOR]

In the crystal structure of the title compound, C23H22BrN3, a strong conjugation of the pyrazoline chromophore with the aromatic rings at positions 1 and 3 is observed, as well as a significant shift in the synclinal→synperiplanar direction. The absolute structure was unequivocally determined. In the absence of clasical hydrogen-bond donors, the structure is stabilized by weak C—H...π interactions. This paper also reports the electronic structure of the title compound using NBO (natural bond order) analysis. The contributions of lone pairs to the relevant bonds were revealed. [ABSTRACT FROM AUTHOR]

Crystal structures are reported for three isomeric compounds, namely 2-(2-hydroxy­phenyl)-2-oxazoline, (I), 2-(3-hydroxy­phenyl)-2-oxazoline, (II), and 2-(4-hydroxy­phenyl)-2-oxazoline, (III), all C9H9NO2 [systematic names: 2-(4,5-dihydro-1,3-oxazol-2-yl)phenol, (I), 3-(4,5-dihydro-1,3-oxazol-2-yl)phenol, (II), and 4-(4,5-dihydro-1,3-oxazol-2-yl)phenol, (III)]. In these compounds, the deviation from coplanarity of the oxazoline and benzene rings is dependent on the position of the hydroxy group on the benzene ring. The coplanar arrangement in (I) is stabilized by a strong intra­molecular O—H⋯N hydrogen bond. Surprisingly, the 2-oxazoline ring in mol­ecule B of (II) adopts a 3 T4 (C2 TC3) conformation, while the 2-oxazoline ring in mol­ecule A, as well as that in (I) and (III), is nearly planar, as expected. Tetra­mers of mol­ecules of (II) are formed and they are bound together via weak C—H⋯N hydrogen bonds. In (III), strong inter­molecular O—H⋯N hydrogen bonds and weak intra­molecular C—H⋯O hydrogen bonds lead to the formation of an infinite chain of mol­ecules perpendicular to the b direction. This paper also reports a theoretical investigation of hydrogen bonds, based on density functional theory (DFT) employing periodic boundary conditions. [ABSTRACT FROM AUTHOR]