1. The crystallographic and magnetic characteristics of Sr2CrO4 (K2NiF4-type) and Sr10(CrO4)6F2 (apatite-type)
- Author
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Madhavi Srinivasan, Tom Baikie, Timothy J. White, Stevin S. Pramana, Zahara Ahmad, Antoine Maignan, Division of Materials Science, Nanyang Technological University, Nanyang Technological University [Singapour], Laboratoire de cristallographie et sciences des matériaux (CRISMAT), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), and Normandie Université (NU)-Institut de Chimie du CNRS (INC)
- Subjects
Diffraction ,Neutron diffraction ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Inorganic Chemistry ,Tetragonal crystal system ,Electron diffraction ,X-ray photoelectron spectroscopy ,Materials Chemistry ,XPS ,Ruddlesden–Popper ,[CHIM]Chemical Sciences ,Powder X-ray/neutron diffraction ,Physical and Theoretical Chemistry ,Apatite ,Valence (chemistry) ,Chemistry ,Space group ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Chromate ,Crystallography ,X-ray crystallography ,Ceramics and Composites ,0210 nano-technology - Abstract
Solid-state reaction between SrCO{sub 3}, Cr{sub 2}O{sub 3} and SrF{sub 2} has produced the apatite phase Sr{sub 10}(CrO{sub 4}){sub 6}F{sub 2} and Sr{sub 2}CrO{sub 4} which adopts the K{sub 2}NiF{sub 4}-type structure. The reaction outcome was very sensitive to the heating rate with rapid rise times favouring the formation of Sr{sub 2}CrO{sub 4}, which has been synthesised at ambient pressure for the first time. Powder X-ray diffraction and electron diffraction confirmed that Sr{sub 2}CrO{sub 4} adopts a body centred tetragonal cell (space group I4/mmm) with lattice parameters a=3.8357(1) A and c=12.7169(1) A, while a combination of neutron and X-ray diffraction verified Sr{sub 10}(CrO{sub 4}){sub 6}F{sub 2} is hexagonal (space group P6{sub 3}/m) with lattice parameters a=9.9570(1) A and c=7.4292(1) A. X-ray photoelectron spectroscopy and magnetic measurements were used to characterise the oxidation states of chromium contained within these phases. - Graphical abstract: A solid-state reaction between SrCO{sub 3}, Cr{sub 2}O{sub 3} and SrF{sub 2} produced Sr{sub 10}(CrO{sub 4}){sub 6}F{sub 2} apatite and Sr{sub 2}CrO{sub 4} which adopts the K{sub 2}NiF{sub 4}-type structure. Powder X-ray and electron diffraction confirmed that Sr{sub 2}CrO{sub 4} is body-centred tetragonal, while a combination of neutron and X-ray diffraction verified Sr{sub 10}(CrO{sub 4}){sub 6}F{sub 2} ismore » hexagonal. X-ray photoelectron spectroscopy and magnetic measurements identified the oxidation states of chromium in these phases.« less
- Published
- 2007