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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}
}
  • Series of compositions Bi{sub 2}(M'{sub x}M{sub 1-x}){sub 4}O{sub 9} with x=0.0, 0.1,..., 1.0 and M'/M=Ga/Al, Fe/Al and Fe/Ga were synthesized by dissolving appropriate amounts of corresponding metal nitrate hydrates in glycerine, followed by gelation, calcination and final heating at 800 {sup o}C for 24 h. The new compositions with M'/M=Ga/Al form solid-solution series, which are isotypes to the two other series M'/M=Fe/Al and Fe/Ga. The XRD data analysis yielded in all cases a linear dependence of the lattice parameters related on x. Rietveld structure refinements of the XRD patterns of the new compounds, Bi{sub 2}(Ga{sub x}Al{sub 1-x}){sub 4}O{sub 9} revealmore » a preferential occupation of Ga in tetrahedral site (4 h). The IR absorption spectra measured between 50 and 4000 cm{sup -1} of all systems show systematic shifts in peak positions related to the degree of substitution. Samples treated in {sup 18}O{sub 2} atmosphere (16 h at 800 {sup o}C, 200 mbar, 95% {sup 18}O{sub 2}) for {sup 18}O/{sup 16}O isotope exchange experiments show a well-separated IR absorption peak related to the M-{sup 18}O{sub c}-M vibration, where O{sub c} denotes the common oxygen of two tetrahedral type MO{sub 4} units. The intensity ratio of M-{sup 18}O{sub c}/M-{sup 16}O{sub c} IR absorption peaks and the average crystal sizes were used to estimate the tracer diffusion coefficients of polycrystalline Bi{sub 2}Al{sub 4}O{sub 9} (D=2x10{sup -22} m{sup 2}s{sup -1}), Bi{sub 2}Fe{sub 4}O{sub 9} (D=5x10{sup -21} m{sup 2}s{sup -1}), Bi{sub 2}(Ga/Al){sub 4}O{sub 9} (D=2x10{sup -21} m{sup 2}s{sup -1}) and Bi{sub 2}Ga{sub 4}O{sub 9} (D=2x10{sup -20} m{sup 2}s{sup -1}). - Graphical abstract: Fig. Perspective view of the mullite-type Bi{sub 2}(M'{sub x}M{sub 1-x}){sub 4}O{sub 9} unit cell (M', M=Al, Ga, Fe). Display Omitted« less
  • Single crystals of a new sodium manganese oxide, NaMn{sub 2}O{sub 4}, were synthesized for the first time using a high-temperature and high-pressure technique. The NaMn{sub 2}O{sub 4} single crystal is black, has a needle shape, and crystallizes in the orthorhombic calcium ferrite-type structure, space group Pnam with a=8.9055(18)A, b=11.0825(22)A, c=2.8524(5)A, V=281.52(9)A{sup 3}, and Z=4. The structure was determined from a single-crystal X-ray study and refined to the conventional values R=0.041 and wR=0.034 for 1190 observed reflections. The framework structure is built up from edge-sharing chains of MnO{sub 6} octahedra that condense to form one-dimensional tunnels in which the sodium atomsmore » are located. The Mn-O bond distance and bond valence analyses revealed the manganese valence Mn{sup 3+}/Mn{sup 4+} ordering in the two 'double rutile' chains of NaMn{sub 2}O{sub 4}.« less
  • The first microporous solids incorporating two octahedrally coordinated transition elements, the phosphates (TMA)[sub 2](NH[sub 4])[sub 2][Fe[sub 2]Mo[sub 12]O[sub 30](H[sub 2]PO[sub 4])[sub 6](HOP[sub 4])[sub 2]][center dot]11H[sub 2]O (1) and (TMA)[sub 2]Na[sub 4][Fe[sub 3]Mo[sub 12]O[sub 30](H[sub x]PO[sub 4])[sub 8]][center dot]16H[sub 2]O (2) (TMA = (CH[sub 3])[sub 4]N[sup +]), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction and water absorption isotherms. Phosphate 1 is prepared in 94% yield from Na[sub 2]MoO[sub 4], Mo, FeCl[sub 3], (NH[sub 4])[sub 2]HPO[sub 4], (TMA)OH, H[sub 3]PO[sub 4], and H[sub 2]O in a mole ratio of 5:1:1:2:7:16:150 at 200[degrees]C for 64 h, while 2 is synthesizedmore » in 62% yield by the reaction of Na[sub 2]MoO[sub 4], Mo, FeCl[sub 3], (TMA)OH, H[sub 3]PO[sub 4] and H[sub 2]O in a mole ratio of 5:1:1:8:18:250 at 200[degrees]C for 3 days. Orange crystals of 1 are rhombohedral. Both structures are based on Fe[Mo[sub 6]O[sub 15](H[sub x]PO[sub 4])[sub 2]] units which are connected via their phosphate groups to additional Fe[sup 3+] ions to give three-dimensional frameworks. Both compounds display structures that can be rationalized on the basis of regions of hydrophobic and hydrophilic interactions. The interconnected voids and channels in the ferric molybdenum phosphate frameworks are filled with a mixture of charged-compensating cations and water of solvation. Reversible water absorption isotherms indicate that both compounds are microporous with internal void volumes of about 15 and 25 vol % for 1 and 2, respectively. 23 refs., 10 figs., 3 tabs.« less
  • The syntheses, structures, and physical properties of several members of a new family of noncentrosymmetric, open-framework, ion-exchangeable phases which have a substantial nonlinear optical response (Nd:YAG 1064 nm) are described. Single-crystal (to 2 mm) hydrothermal synthesis of Na[sub 1/2](H[sub 3]O)[sub 1/2]Nb[sub 2]PO[sub 8] was carried out at 30,000-40,000 psi and 650-700[degrees]C. The structure of Na[sub 1/2](H[sub 3]O)[sub 1/2]Nb[sub 2]PO[sub 8], as determined from single-crystal X-ray data consists of an octahedral (NbO[sub 6])/tetrahedral (PO[sub 4]) framework, connected via Nb-O-P and Nb-O-Nb bonds, with cavities and channels occupied by the Na[sup +] and H[sub 3]O[sup +] cations. Members of the solid solutionmore » K[sub 2/3]Li[sub 1/3]Nb[sub 2[minus]x]Ta[sub x]PO[sub 8] (0 < x < 2) have been synthesized as powders by solid-state methods and are all isomorphous with Na[sub 1/2](H[sub 3]O)[sub 1/2]Nb[sub 2]PO[sub 8]. Various ion-exchange reactions with NH[sub 4][sup +], Rb[sup +], and Ag[sup +] are possible. These materials have been characterized by X-ray powder diffraction, TGA, [sup 31]P MAS NMR spectroscopy, second-harmonic generation measurements, and UV/visible spectroscopy. Crystal data: Na[sub 1/2](H[sub 3]O)[sub 1/2]Nb[sub 2]PO[sub 8], M[sub r] = 364.94, rhombohedral, R32 (No. 155), a = 8.4962 [angstrom], [alpha] = 104.775[degrees], V = 538.77 [angstrom][sup 3], Z = 3, R = 2.88%, R[sub w] = 3.56% for 66 parameters and 743 observations [I > 3[sigma](I)]. 23 refs., 10 figs., 5 tabs.« less
  • A new caesium uranyl molybdate belonging to the M{sub 6}U{sub 2}Mo{sub 4}O{sub 21} family has been synthesized by solid-state reaction and its structure determined from single-crystal X-ray diffraction data. Contrary to the other alkali uranyl molybdates of this family (A=Na, K, Rb) where molybdenum atoms adopt only tetrahedral coordination and which can be formulated A{sub 6}[(UO{sub 2}){sub 2}O(MoO{sub 4}){sub 4}], the caesium compound Cs{sub 6}U{sub 2}Mo{sub 4}O{sub 21} should be written Cs{sub 6}[(UO{sub 2}){sub 2}(MoO{sub 4}){sub 3}(MoO{sub 5})] with molybdenum atoms in tetrahedral and square pyramidal environments. Cs{sub 6}[(UO{sub 2}){sub 2}(MoO{sub 4}){sub 3}(MoO{sub 5})] crystallizes in the triclinic symmetry withmore » space group P1-bar and a=10.4275(14) A, b=15.075(2) A, c=17.806(2) A, {alpha}=70.72(1){sup o}, {beta}=80.38(1){sup o} and {gamma}=86.39(1){sup o}, V=2604.7(6) A{sup 3}, Z=4, {rho}{sub mes}=5.02(2) g/cm{sup 3} and {rho}{sub cal}=5.08(3) g/cm{sup 3}. A full-matrix least-squares refinement on the basis of F{sup 2} yielded R{sub 1}=0.0464 and wR{sub 2}=0.0950 for 596 parameters with 6964 independent reflections with I{>=}2{sigma}(I) collected on a BRUKER AXS diffractometer with Mo(K{alpha}) radiation and a CCD detector. The crystal structure of Cs compound is characterized by {sub {infinity}}{sup 1}[(UO{sub 2}){sub 2}(MoO{sub 4}){sub 3}(MoO{sub 5})]{sup 6-} parallels chains built from U{sub 2}O{sub 13} dimeric units, MoO{sub 4} tetrahedra and MoO{sub 5} square pyramids, whereas, Na, K and Rb compounds are characterized by {sub {infinity}}{sup 1}[(UO{sub 2}){sub 2}O(MoO{sub 4}){sub 4}]{sup 6-} parallel chains formulated simply of U{sub 2}O{sub 13} units and MoO{sub 4} tetrahedra. Infrared spectroscopy measurements using powdered samples synthesized by solid-state reaction, confirm the structural results. The thermal stability and the electrical conductivity are also studied. The four compounds decompose at low temperature (between 540 and 610 {sup o}C). -- Graphical abstract: The staking of {sub {infinity}}{sup 1}[(UO{sub 2}){sub 2}(MoO{sub 4}){sub 3}(MoO{sub 5})]{sup 6-} infinite uranyl molybdate ribbons in the Cs{sub 6}[(UO{sub 2}){sub 2}(MoO{sub 4}){sub 3}(MoO{sub 5})] structure. Display Omitted Highlights: {yields} Cs{sub 6}U{sub 2}Mo{sub 4}O{sub 2} a new compound with bidimensional crystal structure, characterized by infinite uranyl molybdate chains. {yields} Crystal structure similar to these of the compounds containing Na, K, Rb. {yields} Molybdenum atoms surrounded by five oxygen atoms to form an original and strongly distorted MoO{sub 5} environment. {yields} The chains arrangement illustrates the key role of the alkaline ionic radius, in the crystal structure distortion for Cs compound.« less