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DFT calculation applied to K4Nb6O17 allowed to identify and correlate its electronic and vibrational properties with [NbO6] intraoctahedral distortion.

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The polymeric precursor method was used for the synthesis of KNb 3 O 8 and compared to the solid-state method. The materials were characterized by X-ray diffraction (XRD), infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, and determination of surface area and total pore volume by nitrogen isotherms at 77 K. The material prepared by the polymeric precursor method was single-phase while K 2 Nb 4 O 11 was obtained as secondary phase when the solidstate method was used, as evidenced by the XRD patterns and the Raman spectra. The morphology of the materials was significantly altered by the synthesis method, as the KNb 3 O 8 prepared by the polymeric precursor method presented a more porous morphology leading to a higher surface area and pore volume.

KCa 2 Ta 3-x Nb x O 10 samples were synthesized by solid-state reaction and evaluated on the hydroxylation of terephthalic acid under UVC irradiation. Computational simulations via DFT were carried out in order to study their structural and electronic properties. Theoretical results show good agreement with experimental data, regarding lattice parameters and band-gap energy values and indicated that the photocatalytic performance for hydroxyl radicals production is directly related to the degree of octahedral distortions in these materials.