High pressure synthesis and properties of ternary titanium (III) fluorides in the system KF-TiF{sub 3} containing regular pentagonal bipyramids [TiF{sub 7}]

Journal Article · Fri Jan 15 04:00:00 EST 2010 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2009.11.012· OSTI ID:21372476

Yamanaka, Shoji ^[1]; Yasuda, Akira; Miyata, Hajime ^[1]

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1. Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527 (Japan)

Titanium trifluoride TiF{sub 3} has the distorted ReO{sub 3} structure composed of corner sharing TiF{sub 6} octahedra linked with Ti-F-Ti bridges. Potassium fluoride KF was inserted into the bridges using high-pressure and high-temperature conditions (5 GPa, 1000-1200 deg. C). When the molar ratio KF/TiF{sub 3}>=1, a few low dimensional compounds were obtained forming non-bridged F ions. At the composition KF/TiF{sub 3}=1/2, a new compound KTi{sub 2}F{sub 7} was formed, which crystallizes with the space group Cmmm and the lattice parameters of a=6.371(3), b=10.448(6), c=3.958(2) A, consisting of edge-sharing pentagonal bipyramids [TiF{sub 7}] forming ribbons running along the a axis. The ribbons are linked by corners to construct a three-dimensional framework without forming non-bridged F ions. The compound is antiferromagnetic with the Neel temperature T{sub N}=75 K, and the optical band gap was 6.4 eV. A new fluoride K{sub 2}TiF{sub 5} (KF/TiF{sub 3}=2) with the space group Pbcn and the lattice parameters of a=7.4626(2), b=12.9544(4) and c=20.6906(7) A was also obtained by the high pressure and high temperature treatment (5 GPa at 1000 deg. C) of a molar mixture of 2 KF+TiF{sub 3}. The compound contains one-dimensional chains of corner-sharing TiF{sub 6} octahedra. - Graphical Abstract: A new ternary fluoride KTi{sub 2}F{sub 7} has been developed under high-pressure and high-temperature conditions, which contains pentagonal bipyramid polyhedra [TiF{sub 7}].

• OSTI ID: 21372476
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 1 Vol. 183; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALKALI METAL COMPOUNDS
ANTIFERROMAGNETISM
CHALCOGENIDES
CHARGED PARTICLES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
ENERGY RANGE
EV RANGE
EV RANGE 01-10
FLUORIDES
FLUORINE COMPOUNDS
FLUORINE IONS
HALIDES
HALOGEN COMPOUNDS
IONS
LATTICE PARAMETERS
MAGNETISM
NEEL TEMPERATURE
ORTHORHOMBIC LATTICES
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POTASSIUM COMPOUNDS
POTASSIUM FLUORIDES
PRESSURE RANGE
PRESSURE RANGE GIGA PA
REFRACTORY METAL COMPOUNDS
RHENIUM COMPOUNDS
RHENIUM OXIDES
SPACE GROUPS
SYMMETRY GROUPS
SYNTHESIS
TEMPERATURE RANGE
TEMPERATURE RANGE 1000-4000 K
THERMODYNAMIC PROPERTIES
TITANIUM COMPOUNDS
TITANIUM FLUORIDES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE