metal complexes, ml (m=ni, cu, co and zn) of unsymmetrical tetradentate schiff base have been synthesized by the template reaction of the half-units n-(1-hydroxy-2-acetonaphthone)-1-amino-2-phenyleneimine)(hl1) with 2-pyrroleca-rbaldehyde. the complexes have been characterized by elemental analysis, ir, 1h nmr and uv spectroscopy. the crystal structure of the ni(ii) complex has been determine...

A sequence of structural/magnetic transitions on cooling is reported in the literature for hole-doped iron-based superconductor (Ba1 − xKx)Fe2As2 with x = 0.24. By using polarized light microscopy, we directly observe the formation of orthorhombic domains in (Ba1 − xKx)Fe2As2 (x = 0.24) single crystal below a temperature of simultaneous structural/magnetic transition TN ~80 K. The structural do...

has been investigated. The crystal structure of strontium niobate depends on the Sr content of the A site, with cubic symmetry for Sr ≤ 0.92 and orthorhombic symmetric for 0.92 ˂ Sr ≤ 0.97. The change of crystal structure from cubic to orthorhombic symmetry seems to have a negative effect on the photocatalytic activity, as the NbO6 octahedra become distorted and unfavourable for d-orbital overl...

The crystal structure of barbituric acid dihydrate (C4H4N2O3*2H2O) has twice been reported as orthorhombic, space group Pnma, with all atoms (except for CH(2) H atoms) lying on the mirror plane [Al-Karaghouli et al. (1977). Acta Cryst. B33, 1655-1660; Jeffrey et al. (1961). Acta Cryst. 14, 881-887]. The present study has found that at low temperatures, below 200 K, the crystal structure is no l...

The electrical properties, the spontaneous polarization, and the piezoelectric response of ZnO can be tailored by alloying ZnO with BeO for applications such as electrodes in flat panel displays and solar cells, blue and ultraviolet (UV) light emitting devices, and highly sensitive UV detectors. We present here the results of a study that employs density-functional theory to analyze the crystal...

In situ neutron powder diffraction measurements show that the orthorhombic-to-tetragonal phase transition in YBa2Cu307 —,which occurs near 700 C in a pure oxygen atmosphere, is an order-disorder transition in which the disordering of oxygen atoms into a normally vacant site destroys the one-dimensional Cu-0 chains present in the room-temperature orthorhombic structure. For both structures, the ...

TbMnO(3) films have been grown under compressive strain on (001)-oriented SrTiO(3) crystals. They have an orthorhombic structure and display the (001) orientation. With increasing thickness, the structure evolves from a more symmetric (tetragonal) to a less symmetric (bulk-like orthorhombic) structure, while keeping constant the in-plane compression, thereby leaving the out-of-plane lattice spa...

In this paper we present results obtained from first-principles calculations concerning the crystal structure and elastic properties of a three-dimensional-polymerized fullerite. The orthorhombic structure we studied was first proposed on the basis of an x-ray-diffraction analysis of samples quenched from high-pressure and high-temperature conditions. The single-crystal bulk modulus for the opt...