Synthesis and structural, spectroscopic and magnetic studies of two new polymorphs of Mn(SeO3)·H2O
| Autor: | Teófilo Rojo, José L. Pizarro, José L. Mesa, María I. Arriortua, A. Peña, Aitor Larrañaga, R. Olazcuaga |
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| Přispěvatelé: | Departamento de Mineralogía-Petrología, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU), Departamento de Química Inorgánica, Facultad de Ciencia y Tecnologia, Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB) |
| Rok vydání: | 2005 |
| Předmět: |
Single-crystal and powder
Infrared spectroscopy Visible–UV 02 engineering and technology Crystal structure 010402 general chemistry 01 natural sciences Magnetic susceptibility Inorganic Chemistry Materials Chemistry Physical and Theoretical Chemistry Spectroscopy Luminiscence ESR Chemistry Space group [CHIM.MATE]Chemical Sciences/Material chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics X-ray diffraction 0104 chemical sciences Electronic Optical and Magnetic Materials Crystallography Octahedron X-ray crystallography IR Ceramics and Composites 0210 nano-technology Powder diffraction |
| Zdroj: | Journal of Solid State Chemistry Journal of Solid State Chemistry, Elsevier, 2005, vo. 178, n° 12, p. 3686-3697. ⟨10.1016/j.jssc.2005.09.034⟩ |
| ISSN: | 0022-4596 1095-726X |
| DOI: | 10.1016/j.jssc.2005.09.034 |
| Popis: | Two new manganese(II) selenite polymorphs with formula Mn(SeO3)·H2O have been synthesized by slow evaporation from an aqueous solution. The crystal structure of both compounds (1) and (2) have been solved from X-ray diffraction data. The structure of (1) was determined from single-crystal X-ray diffraction techniques. The compound crystallizes in the Ama2 space group, with a = 5.817 ( 1 ) , b = 13.449 ( 3 ) , c = 4.8765 ( 9 ) A and Z = 4 . The structure of (2) has been solved from X-ray powder diffraction data. This phase crystallizes in the P21/n space group with unit-cell parameters of a = 4.921 ( 3 ) , b = 13.121 ( 7 ) , c = 5.816 ( 1 ) A , β = 90.03 ( 2 ) ° and Z = 4 . Both polymorphs exhibit a layered structure formed by isolated sheets of MnO6 octahedra and (SeO3)2− trigonal pyramids in the (010) plane. These layers, which contain one manganese and selenium atom crystallographically independent, are formed by octahedra linked between them through the selenite oxoanions. The difference of both compounds consists in the stacking of the layers along the b-axis. The IR spectra show the characteristic bands of the selenite anion. Studies of luminescence performed at 6 K and diffuse reflectance spectroscopy have been carried out for both phases. The Dq and Racah (B and C) parameters, from luminescence and diffuse reflectance spectroscopy, are Dq = 705 , B = 750 , C = 3325 cm - 1 for (1) and Dq = 720 , B = 745 , C = 3350 cm - 1 for (2). The ESR spectra of both compounds are isotropic with g-values of 1.99(1). Magnetic measurements indicate the presence of antiferromagnetic couplings in both phases. The J-exchange parameters have been estimated by fitting the experimental magnetic data to a model for square-planar lattice. The values obtained are J / k = - 0.83 , −0.91 K and J ′ / k = - 0.97 , −1.20 K, for polymorphs (1) and (2), respectively. |
| Databáze: | OpenAIRE |
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