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Bujdosova Z.,arik University | Kuchar J.,arik University | Gyoryova K.,arik University
Acta Crystallographica Section E: Structure Reports Online | Year: 2010

The title mononuclear complex mol-ecule, [Zn(C7H 4BrO3)2(C7H8N 2O)2(H2O)2], has a crystallographically imposed centre of symmetry. The zinc(II) atom is coordinated by two N atoms from two N-methyl-nicotinamide ligands, two O atoms from two 5-bromo-salicylate anions and two aqua O atoms in a slightly distorted octa-hedral geometry. Intra-molecular O - H⋯O hydrogen-bonding inter-actions are present. In the crystal structure, mol-ecules are linked by inter-molecular O - H⋯O and N - H⋯O hydrogen bonds, forming a two-dimensional network perpendicular to [100].


Mihalik Jr. M.,Slovak Academy of Sciences | Mihalik M.,Slovak Academy of Sciences | Fitta M.,Polish Academy of Sciences | Vavra M.,Slovak Academy of Sciences | And 7 more authors.
Journal of Physics: Conference Series | Year: 2014

The effect of substitution of Fe3+ ions by Mn3+ ions on crystal structure, lattice dynamic, heat capacity and magnetic properties in TbMn1-xFexO3 ceramics has been studied. X-ray powder diffraction and Raman spectroscopy revealed that lattice distortion can be mainly attributed to Jahn-Teller distortion and tilting of octahedrons for samples with x < 0.4; for higher Fe concentration, the distortions are dominated by the octahedra tilting with less contribution of the Jahn-Teller effect. The anomalies in heat capacity of parent compounds (TbMnO3 and TbFeO3), which are associated with magnetic transitions, are smeared out by ion substitution. Magnetization measurements indicate that magnetic ordering persists in whole concentration range. The butterfly-type magnetic hysteresis loops suggest that the magnetic ground state of the whole system is complex and thence interesting for next experimental and theoretical studies.


Hanikova J.,arik University | Kuchar J.,arik University | Cernak J.,arik University | Pelosi G.,University of Parma
Acta Crystallographica Section E: Structure Reports Online | Year: 2010

The ionic title complex, [Ni(C2H8N2) 3](SiF6), is built up of [Ni(en)3]2+ complex cations (en = 1,2-diamino-ethane) and hexa-fluoridosilicate anions. Single crystals of the title complex were isolated from an aqueous-ethano-lic Ni2+-en-SiF6 2- system. The Ni(II) and Si atoms are each located on a special position with site symmetry 3.2. The Ni(II) atom coordination sphere is octa-hedrally deformed, being coordinated by three chelating diamine ligands with an Ni - N distance of 2.1233 (18) Å. The crystal packing of the respective ions corresponds to the structure type of the hexa-gonal form of BN. Beside ionic forces, the packing is governed by N - H⋯F hydrogen bonds, which lead to the formation of hydro-phobic channels running along the 63 screw axis. The structure was refined as an inversion twin [0.49 (3): 0.51 (3)].


Pavlova A.,arik University | Cernak J.,arik University | Harms K.,University of Marburg
Acta Crystallographica Section E: Structure Reports Online | Year: 2010

In the crystal structure of the title compound, {[Ni(C4H 2O4)(C10H9N3)(H 2O)2]·4H2O} n , zigzag chains are built up from cis-[Ni(dpya)(H2O)2]2+ cations (dpya is di-2-pyridylamine) linked by bis-monodentate coordinated bridging fumarate ligands. The NiII atom is coordinated by one chelating dpya ligand, two aqua ligands in trans positions and two monodentate fumarate ligands in cis positions in the form of a deformed octahedron. The water molecules, O atoms of the fumarate carboxylate groups and the amine group of the dpya ligand are involved in an extended network of intra- and intermolecular O - H⋯O hydrogen bonds. Moreover, π-π interactions between the pyridine rings of the dpya ligand contribute to the stability of the structure. Two of the five uncoordinated water molecules are half-occupied. © 2010.

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