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Author Lee, Jong-Gyu ♦ Hoehn, P. ♦ Greenblatt, M.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword MATERIALS SCIENCE ♦ TANTALUM COMPOUNDS ♦ CRYSTAL STRUCTURE ♦ SILICATES ♦ POTASSIUM COMPOUNDS ♦ TETRAGONAL LATTICES ♦ ACTIVATION ENERGY ♦ ELECTRIC IMPEDANCE ♦ IONIC CONDUCTIVITY
Abstract The crystal structure of a new potassium tantalum(V) cyclotetrasilicate, KTaSi{sub 2}O{sub 2} (K{sub 2}Ta{sub 2}Si{sub 4}O{sub 14}), has been determined by single crystal X-ray diffraction. KTaSi{sub 2}O{sub 7} crystallizes in the tetragonal system, space group P4/mbm with {alpha} = 8.735(2) and c= 7.999(2) {Angstrom}, V= 610.3(2) {Angstrom}{sup 3}, Z = 4, d{sub x} = 4.225 g/cm{sup 3}, {lambda} (MoK{alpha}) = 0.71073 {Angstrom}, {mu} = 190.7 cm{sup {minus}1}, F{sup {prime}} (000) = 704, T = 293 K, R = 0.0421, R{sub w} = 0.0789 for 451 unique reflections (R{sub int} = 0.0227) with F{sub O}{sup 2} > O. The framework structure of KTaSi{sub 2}O{sub 7} is built up from chains of corner-sharing TaO{sub 6} octahedra running parallel to the fourfold axes and linked together by four-membered Si{sub 4}O{sub 12} single units. AC impedance measurements on KTaSi{sub 2}O{sub 7} indicate low ionic conductivities, 5.6 x 10{sup {minus}9} and 3.0 x 10{sup {minus}7} {Omega} {center_dot} cm{sup {minus}1} at 333 and 546{degrees}C, respectively. An activation energy of 0.83 {plus_minus} 0.02 eV is observed.
ISSN 00224596
Educational Use Research
Learning Resource Type Article
Publisher Date 1996-04-01
Publisher Place United States
Journal Journal of Solid State Chemistry
Volume Number 123
Issue Number 1