Synthesis and characterization of new hydroxylammonium fluoromanganates and fluoroscandates

New hydroxylammonium fluorometallates of manganese and scandium, with the formulas (NH3OH)2MnF4 and (NH3OH)3ScF6, were prepared by the reactions of hydroxylammonium fluoride with solutions of manganese or scandium in aqueous HF. (NH3OH)2MnF4 crystallizes monoclinic, P21/c, the structure consisting of MnF6 octahedra sharing four of its vertices, resulting in [ Mn F 4 2 − ]n anionic layers perpendicular to a axis. (NH3OH)3ScF6 crystallizes trigonal, R3c, and the structure is made up of isolated ScF6 octahedra, stacked in columns along c axis and surrounded by a cylinder of hydroxylammonium cations. Both title compounds decompose during thermal analysis in several steps, yielding corresponding fluorides (MnF2 and ScF3) at temperatures between 300 and 400 °C and oxides/oxofluorides at higher temperatures.