Wieslawa Bronowska
Wrocław University of Technology
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Featured researches published by Wieslawa Bronowska.
Journal of Chemical Physics | 2001
Wieslawa Bronowska
Single crystal and powder diffraction investigations have revealed that the paraelectric phase of cesium dihydrogen phosphate, CsH2PO4 (CDP), from the crystallographic point of view is stable (space group P21/m) up to ca. 231 °C. At this temperature a structural phase transition from the paraelectric phase to the superionic phase (space group Pm–3m) has been observed. The superionic phase of CDP is unstable under normal air condition due to dehydration process. Under H2O-saturated atmosphere the superionic phase transition of CDP takes place without decomposition and is reversible with a temperature hysteresis on cooling.
Polyhedron | 2002
Wieslawa Bronowska; Zbigniew Staszak; Marek Daszkiewicz; Maria Cieślak-Golonka; Agnieszka Wojciechowska
Abstract Nickel(II) dichromate and chromate complexes with 1,10-phenanthroline were isolated from basic (pH 8–9) solutions. [Ni(phen)3]Cr2O7·8H2O (1), NiCrO4 (2), [Ni(phen)3]Cr2O7·3H2O (3) and [Ni(phen)(OCrO3)(H2O)3]·H2O (4) were characterized with spectroscopic (UV–Vis, IR, FIR) methods and one (4), additionally, with X-ray data. In the complex (4) the chromate ion is monodentately coordinated to nickel ion. This complex crystallizes in the triclinic crystal system (space group P 1 ). The single crystal electronic spectrum of complex (4) at 4 K reveals a rare feature when the structured second d–d band (Oh symmetry) is unsplit in spite of lowering symmetry. The filtration process has revealed that this band is vibronically structured in the νs NiOCr quantum. A new broad low intensity band at approximately 14 000 cm−1 was assigned to the forbidden transition in the bridge. An attempt to explain precipitation of dichromates from alkaline solutions has been given.
Journal of Molecular Structure | 2002
Agnieszka Wojciechowska; Wieslawa Bronowska; A. Pietraszko; Zbigniew Staszak; Maria Cieślak-Golonka
Abstract A new Zn(II) complex with 2,2′bipyridine (bpy), chromate and nitrate groups, [Zn(bpy)3](CrO4)0.5NO36.5H2O has been prepared and characterised with crystallographic and spectroscopic methods. The orthorhombic complex crystallises in the space group Ccc2 with the lattice constants a=13.992(3) A , b=24.483(5) A , c=21.556(4) A and Z=8. The coordination environment about Zn(II) ion is nearly octahedral. The CrO42− and NO3− entities exhibit anionic position in the crystal. The electronic spectra enhanced with mathematical methods (filtration and deconvolution) exhibit the presence of vibrational fine structure in the CrO42− entity on the spin-forbidden 3T1 transition.
Ferroelectrics | 1995
Wieslawa Bronowska; Veneta Videnova-Adrabinska; A. Pietraszko
Abstract X-ray structure analysis of the [(NH4)1−xRbx]3H(SO4)2 mixed crystals with x = 0.57 was performed at 180 K in order to study the hydrogen bond character. The measurements were performed with the KUMA-4 single crystal diffractometer. The crystal structure was refined by using SHELXL93 program. At the room temperature and at 180 K the crystals are isostructural and belong to monoclinic system C2/c. The hydrogen bond distance R(O…O) at 180 K is 2.558(5)A. The electron density of split hydrogen atoms in R(O…O) bonds has been observed on a differential Fourier map.
Ferroelectrics | 1988
Wieslawa Bronowska; J. Dziedzic
Abstract Temperature dependence of the thermal expansion coefficients of CsLASO4 crystals have been measured in the temperature range from that of liquid nitrogen to 300 K on cooling and heating by an air-capacitor dilatometer. Anomalies cf the linear expansion coefficients connected with the phase transition at T = 203 K have been observed. Changes of the thermal dilatation on cooling and heating have been discussed.
Ferroelectrics Letters Section | 1988
Marek Wlodarz; Wieslawa Bronowska; J. Dziedzic
Abstract Temperature dependence of the thermal expansion coefficients of Rochelle salt (RS) crystals for the basic crystallographic directions have been measured in the temperature range from 100 K to 308 K by an air-capacitor dilatometer. Anomalies of thermal expansion coefficients at about 210 K and 153 K have been observed, besides these corresponding to known ferroelectric phase transitions at the temperatures of 255 and 297 K.
Polyhedron | 2001
Agnieszka Wojciechowska; Zbigniew Staszak; Wieslawa Bronowska; A. Pietraszko; Maria Cieślak-Golonka
Journal of Molecular Structure | 2005
Marek Daszkiewicz; Wieslawa Bronowska; A. Pietraszko; Zbigniew Staszak; Maria Cieślak-Golonka
Structural Chemistry | 2006
Marek Daszkiewicz; Zbigniew Staszak; A. Pietraszko; Wieslawa Bronowska; Maria Cieślak-Golonka
Journal of Molecular Structure | 2003
Agnieszka Wojciechowska; Zbigniew Staszak; Wieslawa Bronowska; A. Pietraszko; Maria Cieślak-Golonka