Exploiting the Reactivity of Metal Trifluoroacetates to Access Alkali-Niobium(V) Oxyfluorides.

Motivated by the lack of facile routes to alkali-niobium(V) oxyfluorides KNbOF and CsNbOF, we investigated the reactivity of alkali trifluoroacetates KH(tfa) and CsH(tfa) (tfa = CFCOO) toward NbO in the solid state. Tetragonal tungsten bronze KNbOF and pyrochlore CsNbOF were obtained by simply reacting the corresponding trifluoroacetate with NbO at 600 °C under air, without the need for specialized containers or a controlled atmosphere. Thermolysis of KH(tfa) in the presence of NbO yielded single-phase polycrystalline KNbOF.