Mechanochemical synthesis of MgF2 – MF2 composite systems (M = Ca, Sr, Ba)

摘要: Abstract The capability of mechanochemical synthesis for the formation MgF2–MF2 (M: Ca, Sr, Ba) composites, solid solutions or well-defined compounds was tested applying a fluorination different fluorine-free metal sources with NH4F directly at milling. No evidence found substitution Mg2+ Ca2+ (Sr2+, Ba2+) ions, vice versa, in rutile fluorite structure. However, an equimolar ratio to second cation allows tetrafluoromagnesates, MMgF4, which is more and hampered smaller radius M2+ is. BaMgF4 formed even phase pure from acetates, SrMgF4 can only be observed mixture accompanied by binary fluorides. In addition, 19F MAS NMR spectra along calculations isotropic chemical shift values according superposition model point metastable CaMgF4, disappears thermal treatment decomposes into fluorides CaF2 MgF2.