New synthesis routes for difluorides MF2 (M = Fe, Mn, Zn and Ni)

Fluorine Compounds, Inorganic, Zinc

“…There is xray evidence for dihydrate formation during dehydration of the tetrahydrate (2). Anhydrous zinc fluoride can also be prepared from the reaction of Zn metal powder and pyridinium poly(hydrogen fluoride) at ambient temperature (3); by treating zinc hydroxycarbonate with NH 4 F followed by thermal decomposition (4); by the reaction of NF 3 O (5) or NH 4 F and ZnO (6,7); by the thermal decomposition of (NH 4 ) 2 ZnF 4 (8); by the reaction of SOF 2 and Zn (9); by the reaction of Zn and HF in the presence of acetonitrile (10); by the reaction of SF 6 and Zn (11); by the reaction of PF 3 and ZnO (12); and by the reaction of ZnO and hydrogen fluoride (13). Zinc fluoride of ca 96% purity is commercially produced for use as a flux in metallurgy (qv).…”

Studies on fluorination of Fe3O4 (magnetite) by NH4HF2

“…FeF₃ can also be prepared via thermal process using anhydrous HF or F₂ gas at high temperature in special corrosion-resistant equipment (Johnson., 1981). NH₄F and NH₄HF₂ are recognized as cheaper and versatile fluorinating agent used at low temperatures (<240°C) (Andreev, 2008;Claux et al, 2016;Gordienko et al, 2017;Juneja et al, 1995;Laptash and Maslennikova, 2012;Laptash and Polyshchuk, 1995;Mukherjee et al, 2011;Pourroy and Poix, 1989;Sophronov et al, 2016). However, excess NH₄F should be added in order to produce oxygen-free fluorides due to the highly hygroscopic nature of NH₄F (Mukherjee et al, 2011;Pourroy and Poix, 1989;Sophronov et al, 2016).…”

“…NH₄F and NH₄HF₂ are recognized as cheaper and versatile fluorinating agent used at low temperatures (<240°C) (Andreev, 2008;Claux et al, 2016;Gordienko et al, 2017;Juneja et al, 1995;Laptash and Maslennikova, 2012;Laptash and Polyshchuk, 1995;Mukherjee et al, 2011;Pourroy and Poix, 1989;Sophronov et al, 2016). However, excess NH₄F should be added in order to produce oxygen-free fluorides due to the highly hygroscopic nature of NH₄F (Mukherjee et al, 2011;Pourroy and Poix, 1989;Sophronov et al, 2016). Fluorination of different oxides by NH₄HF₂ therefore appears to be the most convenient method for obtaining oxygen-free fluorides.…”

“…Thus, for Fe₃O₄, the reactions can be written as: [3] On heating, NH₄FeF₃ decomposes to form FeF₂ in ammonium media at 350°C (Andreev., 2008); while (NH₄)₃FeF₆ gradually releases NH₄F to form FeF₃ via two or three steps (Alexeiko et al, 2008;Juneja et al, 1995;Kraidenko, 2008;Laptash and Polyshchuk, 1995;Pourroy and Poix, 1989;Shinn et al, 1966;Sophronov et al, 2016), as listed in Table I. According to Alexeiko et al (2008), Juneja et al1(995), Pourroy andPoix (1989), Shinn, Crocket, andHaendler (1966);and Sophronov et al (2016) the reaction proceeds in two stages:…”

Solvothermal synthesis of MnF2 nanocrystals and the first-principle study of its electronic structure

“…However, the toxicity of fluorine and corrosion of hydrofluoric acid demand corrosionresistant reaction equipments and are harmful for human health and environment during the preparation process, which seriously limits the further study of fluorides. Traditionally, many transition metal fluorides can be prepared by solid-state reaction [17]. Recently, the sol-gel method and microwave-assistant methods were employed in the preparation of various fluorides [2].…”