title: The decomposition of the layered double hydroxides of Co and Al: phase segregation of a new single phase spinel oxide.
abstract: Monophasic Co-Al-CO3-like layered double hydroxides has been prepared by the coprecipitation method. It has been characterised by Rietveld refinement of the X-ray powder diffraction pattern, DTA-TGA, infrared and Raman spectroscopies. Its structure is trigonal, R3̅m with cell parameters a=0.3061(4) nm and c=2.252 (3) nm. The decomposition of this hydrotalcite-like structure on heating up to 800 °C yields to a single phase spinel oxide. Besides, infrared and Raman spectroscopies showed the presence of spinel-like domains. The results of Rietveld refinement have revealed that this compound has the Fd3̅m space group (a=0.8088(4) nm), with crystallographic formula [Co(II)0.75Al0.25](8a)[Co(II)0.252Co(III)0.77Al0.98](16d)O4, which is of the general formula Co1.77Al1.23O4. This structure is also validated by the charge distribution (CD) analysis.
authors: Laboratory of the Physico-Chemistry of Solid States, LR11 ES51, University of Sfax, Road of Soukra km 4, Sfax 3038, Tunisia. Electronic address: salem.babay@yahoo.fr.
authors: Salem
authors: S
authors: Babay
authors: LUMAN Université, Université du Maine, CNRS UMR 6283, Institut des Molécules et Materiaux du Mans (IMMM), Avenue O. Messiaen, 7285 LE MANS Cedex 9, France.
authors: Alain
authors: A
authors: Bulou
authors: LUMAN Université, Université du Maine, CNRS UMR 6283, Institut des Molécules et Materiaux du Mans (IMMM), Avenue O. Messiaen, 7285 LE MANS Cedex 9, France.
authors: Anne Marie
authors: AM
authors: Mercier
authors: Laboratory of the Physico-Chemistry of Solid States, LR11 ES51, University of Sfax, Road of Soukra km 4, Sfax 3038, Tunisia. Electronic address: mohamed.toumi@fss.rnu.tn.
authors: Mouhamed
authors: M
authors: Toumi
mesh_terms: D000535:Aluminum / Q000737:chemistry*; D000537:Aluminum Oxide / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry*; D006878:Hydroxides / Q000737:chemistry*; D008277:Magnesium Oxide / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D055672:Static Electricity; D013696:Temperature; D014732:Vibration; D014961:X-Ray Diffraction
chemical_list: D006878:Hydroxides; D010087:Oxides; C111130:spinell; D008277:Magnesium Oxide; D003035:Cobalt; D000535:Aluminum; D000537:Aluminum Oxide
keywords: Infrared spectroscopy; Inorganic compounds; Raman spectroscopy; Rietveld; X-ray diffraction