Synthesis of nanocrystalline mixed metal fluorides in nonaqueous medium

Abstract

Synthesis of mixed metal fluorides of the general formula, KMF 3 (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, FT-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 9-30 nm. SEM micrographs of KZnF 3 showed cubic morphology of perovskite phases. TEM studies on KCuF 3 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.

Optical and Photocatalytic Properties of Heavily F–-Doped SnO2 Nanocrystals by a Novel Single-Source Precursor Approach

“…Monoclinic KSnF 3 was synthesized by a simple and green precipitation reaction of SnCl 2 ·2H 2 O and KF in methanol as reported for other KMF 3 fluoride complexes . The powder X-ray diffraction pattern of KSnF 3 is presented in Figure a, which matched well with JCPDS file no.…”

“…Our research group has reported green synthetic approaches for various mixed metal fluoride complexes . KSnF 3 was synthesized from SnCl 2 ·2H 2 O (99.9%, Aldrich) and KF (99%, AR grade, CDH) in a 1:3 molar ratio.…”

Investigations on the electron paramagnetic resonance parameters for Mn2+ in the ABF3 fluoroperovskites

“…The molecular orbital coefficients N x and x are acquired for the anti-bonding and bonding orbitals from Eqs. (5)- (7). Applying Eqs.…”

“…Fluoroperovskites ABF 3 (A = K, Cs and B = Zn, Mg, Cd, Ca) doped with Mn 2+ show unique photo and thermostimulated luminescence [1], mechanoluminescent [2], dielectric [3], optical [4] and structure properties [5][6][7]. Usually, the doped Mn 2+ impurities may play an important role in the above properties.…”