Synthesis of nanocrystalline mixed metal fluorides in nonaqueous medium

Bulletin of materials science

Nikesh Gupta¹  Neetu Tyagi¹  N P Lalla²  Epsita Ghanti¹  Rajamani Nagarajan¹ 

[1] Department of Chemistry, University of Delhi, Delhi 110 007, India$$Department of Chemistry, University of Delhi, Delhi 110 007, IndiaDepartment of Chemistry, University of Delhi, Delhi 110 007, India$$;Inter University Consortium for DAE Facilities, University Campus, Indore 452 017, India$$Inter University Consortium for DAE Facilities, University Campus, Indore 452 017, IndiaInter University Consortium for DAE Facilities, University Campus, Indore 452 017, India$$

关键词: Fluorides;    perovskites;    nanomaterials;    soft synthesis;    X-ray diffraction;    non-stoichiometry.;   

DOI  :  

学科分类：材料工程

来源: Indian Academy of Sciences

【 摘 要 】

Synthesis of mixed metal fluorides of the general formula, KMF₃ (M = Mg, Mn, Co, Ni, Cu and Zn), possessing perovskite structure was investigated in non-aqueous medium. The fluorides were characterized by powder X-ray diffraction, FTâ€�?�IR spectroscopy, thermal analysis, SEM and TEM. Monophasic cubic phases were obtained for the central metal ions such as Mg, Mn, Co, Ni, and Zn and a tetragonally distorted phase was observed for Cu. The usage of non-aqueous medium is advantageous for the bulk synthesis of these fluorides, since it eliminated the generation and handling of the hazardous HF that has usually been encountered during aqueous preparations. The average crystallite size of the fluorides obtained by this approach was estimated to be in the range of 9â€�??30 nm. SEM micrographs of KZnF₃ showed cubic morphology of perovskite phases. TEM studies on KCuF₃ confirmed the presence of tetragonal distortion. The fluoride content was determined by titrimetry and found to be nearly stoichiometric. Some of these fluorides were found to be thermally stable up to 225°C in air. These fluorides were employed as fluorinating agents in organic fluorination reactions, thereby suggesting their possible utilization for selective fluorination of aliphatic and aromatic hydrofluorocarbons (HFCs) that are industrially relevant.

【 授权许可】

Unknown