Proton state in hydrated fluoro-substituted brownmillerites Ba2In2O5-0.5y F y a™nDe2D

Solid solutions Ba2In2O5-0.5y F (y) with the structure of brownmillerite are studied by IR and (1)De MAS NMR spectroscopy. During the fluorine doping, the nearest oxygen environment of indium atoms is distorted and a part of In-O bonds is shortened. It is shown that partial fluoride ion substitution for oxygen atoms results in an increase in the proton mobility in hydrated Ba2In2O5-0.5y F (y) a (TM) nDe(2)D phases.