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Title: Single-crystal synthesis, structure analysis, and physical properties of the calcium ferrite-type Na {sub x} Ti{sub 2}O{sub 4} with 0.558<x<1

Abstract

Single crystals of calcium ferrite CaFe{sub 2}O{sub 4}-type NaTi{sub 2}O{sub 4} having millimeter-sized needle shapes were synthesized by a reaction of Na metal and TiO{sub 2} in a sealed iron vessel at 1473 K. Sodium-deficient Na {sub x} Ti{sub 2}O{sub 4} single crystals with 0.558<x<1 were successfully synthesized by a topotactic oxidation reaction using NaTi{sub 2}O{sub 4} single crystals as parent materials. The crystal structures of Na {sub x} Ti{sub 2}O{sub 4} with x=0.970, 0.912, 0.799, 0.751, 0.717, 0.686, 0.611, and 0.558 were determined by the single-crystal X-ray diffraction method. The basic framework constructed by the Ti1O{sub 6} and Ti2O{sub 6} double rutile chains was maintained in these Na {sub x} Ti{sub 2}O{sub 4} compounds. Based on the results of bond valence analysis, we speculated that the Ti1 sites are preferentially occupied by Ti{sup 3+} cations over the compositional range of 0.8<x<1, while both the Ti1 and Ti2 sites are randomly occupied by Ti{sup 3+} and Ti{sup 4+} cations at x=0.558. Magnetic susceptibility data indicated that the broad maximum around 40 K observed in as-grown NaTi{sub 2}O{sub 4} is suppressed by an Na deficiency and vanishes in Na{sub 0.717}Ti{sub 2}O{sub 4}. The electrical resistivity increased with the Na deficiency; however,more » it was still semiconductive in Na{sub 0.799}Ti{sub 2}O{sub 4}. - Graphical abstract: Magnetic susceptibility of three Na {sub x} Ti{sub 2}O{sub 4} samples below 300 K. The broad maximum around 40 K observed in as-grown NaTi{sub 2}O{sub 4} is suppressed by an Na deficiency and vanishes in Na{sub 0.717}Ti{sub 2}O{sub 4}.« less

Authors:
 [1];  [1];  [2];  [3];  [1];  [1];  [1];  [4]
  1. National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8565 (Japan)
  2. (Japan)
  3. Institute of Materials Science, University of Tsukuba, Tsukuba 305-8573 (Japan)
  4. National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8565 (Japan), E-mail: j.akimoto@aist.go.jp
Publication Date:
OSTI Identifier:
21015742
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 180; Journal Issue: 3; Other Information: DOI: 10.1016/j.jssc.2006.12.023; PII: S0022-4596(07)00012-6; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CRYSTAL GROWTH; CRYSTAL STRUCTURE; ELECTRIC CONDUCTIVITY; MAGNETIC SUSCEPTIBILITY; MONOCRYSTALS; OXIDATION; OXIDES; SODIUM COMPOUNDS; SYNTHESIS; TEMPERATURE RANGE 1000-4000 K; TITANIUM COMPOUNDS; TITANIUM IONS; TITANIUM OXIDES; X-RAY DIFFRACTION

Citation Formats

Takahashi, Yasuhiko, Kataoka, Kunimitsu, Institute of Materials Science, University of Tsukuba, Tsukuba 305-8573, Ohshima, Ken-ichi, Kijima, Norihito, Awaka, Junji, Kawaguchi, Kenji, and Akimoto, Junji. Single-crystal synthesis, structure analysis, and physical properties of the calcium ferrite-type Na {sub x} Ti{sub 2}O{sub 4} with 0.558<x<1. United States: N. p., 2007. Web. doi:10.1016/j.jssc.2006.12.023.
Takahashi, Yasuhiko, Kataoka, Kunimitsu, Institute of Materials Science, University of Tsukuba, Tsukuba 305-8573, Ohshima, Ken-ichi, Kijima, Norihito, Awaka, Junji, Kawaguchi, Kenji, & Akimoto, Junji. Single-crystal synthesis, structure analysis, and physical properties of the calcium ferrite-type Na {sub x} Ti{sub 2}O{sub 4} with 0.558<x<1. United States. doi:10.1016/j.jssc.2006.12.023.
Takahashi, Yasuhiko, Kataoka, Kunimitsu, Institute of Materials Science, University of Tsukuba, Tsukuba 305-8573, Ohshima, Ken-ichi, Kijima, Norihito, Awaka, Junji, Kawaguchi, Kenji, and Akimoto, Junji. Thu . "Single-crystal synthesis, structure analysis, and physical properties of the calcium ferrite-type Na {sub x} Ti{sub 2}O{sub 4} with 0.558<x<1". United States. doi:10.1016/j.jssc.2006.12.023.
@article{osti_21015742,
title = {Single-crystal synthesis, structure analysis, and physical properties of the calcium ferrite-type Na {sub x} Ti{sub 2}O{sub 4} with 0.558<x<1},
author = {Takahashi, Yasuhiko and Kataoka, Kunimitsu and Institute of Materials Science, University of Tsukuba, Tsukuba 305-8573 and Ohshima, Ken-ichi and Kijima, Norihito and Awaka, Junji and Kawaguchi, Kenji and Akimoto, Junji},
abstractNote = {Single crystals of calcium ferrite CaFe{sub 2}O{sub 4}-type NaTi{sub 2}O{sub 4} having millimeter-sized needle shapes were synthesized by a reaction of Na metal and TiO{sub 2} in a sealed iron vessel at 1473 K. Sodium-deficient Na {sub x} Ti{sub 2}O{sub 4} single crystals with 0.558<x<1 were successfully synthesized by a topotactic oxidation reaction using NaTi{sub 2}O{sub 4} single crystals as parent materials. The crystal structures of Na {sub x} Ti{sub 2}O{sub 4} with x=0.970, 0.912, 0.799, 0.751, 0.717, 0.686, 0.611, and 0.558 were determined by the single-crystal X-ray diffraction method. The basic framework constructed by the Ti1O{sub 6} and Ti2O{sub 6} double rutile chains was maintained in these Na {sub x} Ti{sub 2}O{sub 4} compounds. Based on the results of bond valence analysis, we speculated that the Ti1 sites are preferentially occupied by Ti{sup 3+} cations over the compositional range of 0.8<x<1, while both the Ti1 and Ti2 sites are randomly occupied by Ti{sup 3+} and Ti{sup 4+} cations at x=0.558. Magnetic susceptibility data indicated that the broad maximum around 40 K observed in as-grown NaTi{sub 2}O{sub 4} is suppressed by an Na deficiency and vanishes in Na{sub 0.717}Ti{sub 2}O{sub 4}. The electrical resistivity increased with the Na deficiency; however, it was still semiconductive in Na{sub 0.799}Ti{sub 2}O{sub 4}. - Graphical abstract: Magnetic susceptibility of three Na {sub x} Ti{sub 2}O{sub 4} samples below 300 K. The broad maximum around 40 K observed in as-grown NaTi{sub 2}O{sub 4} is suppressed by an Na deficiency and vanishes in Na{sub 0.717}Ti{sub 2}O{sub 4}.},
doi = {10.1016/j.jssc.2006.12.023},
journal = {Journal of Solid State Chemistry},
number = 3,
volume = 180,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}