Synthesis, crystal structure, and photocatalytical properties of Ba3Ta5O14N.

Light yellow Ba 3 Ta V 5 O 14 N was successfully synthesized as phase-pure material crystallizing isostructurally to well-known mixed-valence Ba 3 Ta V 4 Ta IV O 15 . The electronic structure of Ba 3 Ta 5 O 14 N was studied theoretically with a hybrid Hartree–Fock-DFT method. The most stable structure was obtained when nitrogen atoms were placed at 4 h sites having fourfold coordination. By incorporating nitrogen, the band gap decreases from ∼3.8 eV commonly known for barium tantalum(V) oxides to 2.8 eV for the oxide nitride, giving rise to an absorption band well in the visible-light region. Ba 3 Ta 5 O 14 N was also tested for photocatalytic hydrogen formation. [ABSTRACT FROM AUTHOR]