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Synthetic, Structural, and Spectroscopic Investigations of K 3 Nb 8 O 21 ‐type Complex Oxides K 3 M Ta 7 O 21 ( M = Ti, Zr)
Author(s) -
Odynets Ievgen V.,
Babaryk Artem A.,
Baumer Vyacheslav N.,
Slobodyanik Nikolay S.,
Shiskin Oleg V.
Publication year - 2011
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201100185
Subject(s) - tantalate , crystallography , tantalum , molybdate , space group , potassium , bond length , materials science , boron , crystal structure , chemistry , x ray crystallography , inorganic chemistry , diffraction , physics , optoelectronics , organic chemistry , dielectric , optics , metallurgy , ferroelectricity
Potassium‐containing zirconium(IV)/titanium(IV) tantalum(V) oxides, K 3 TiTa 7 O 21 ( 1 ) and K 3 ZrTa 7 O 21 ( 2 ), of K 3 Nb 8 O 21 ‐type of compounds are afforded from potassium‐molybdate flux. Both compounds crystallize in the hexagonal space group P 6 3 / mcm (no. 193) with a = 908.69(2), c = 1202.83(7) pm and c / a = 1.324 ( Z = 2) for 1 and a = 913.30(3), c = 1219.21(6) pm and c / a = 1.335 ( Z = 2) for 2 , respectively. The Structural motif of [ M Ta 7 O 21 ] 3– ( M = Ti 4+ or Zr 4+ ) consists of edge‐shared ( M ,Ta) 6 O 24 ‐units that are similar to corner‐sharing Ta 6 O 27 units of synthetic soro ‐silicate K 3 Ta 3 Si 2 O 13 and double borate K 3 Ta 3 B 2 O 12 . The solid state bandgap measurements revealed that calculated values (3.26 eV for K 3 TiTa 7 O 21 and 3.14 eV for K 3 ZrTa 7 O 21 ) are dependent on aperture of Ta–O–Ta bond angle as it was previously shown for perovskite‐type tantalate photocatalysts.