文摘
Iron fluoride trihydrate can be used to prepare iron hydroxyfluoride with the hexagonal鈥搕ungsten鈥揵ronze (HTB) type structure, a potential cathode material for batteries. To understand this phase transformation, a structural description of 尾-FeF3路3H2O is first performed by means of DFT calculations and M枚ssbauer spectroscopy. The structure of this compound consists of infinite chains of [FeF6]n and [FeF2(H2O)4]n. The decomposition of FeF3路3H2O induces a collapse and condensation of these chains, which lead to the stabilization, under specific conditions, of a hydroxyfluoride network FeF3鈥?i>x(OH)x with the HTB structure. The release of H2O and HF was monitored by thermal analysis and physical characterizations during the decomposition of FeF3路3H2O. An average distribution of FeF4(OH)2 distorted octahedra in HTB-FeF3鈥?i>x(OH)x was obtained subsequent to the thermal hydrolysis/olation of equatorial anionic positions involving F鈥?/sup> and H2O. This study provides a clear understanding of the structure and thermal properties of FeF3路3H2O, a material that can potentially bridge the recycling of pickling sludge from the steel industry by preparing battery electrodes.