Neutron diffraction study of the thermal and oxygen position parameters in rutile

Gonschorek, W.; Feld, R.

doi:10.1524/zkri.1982.161.1-2.1

Cited by 17 publications

(18 citation statements)

References 2 publications

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“…The present powder results agree well with those obtained by Gonschorek & Feld (1982) from their single-crystal measurements, the maximum discrepancy being 1.2 combined e.s.d.'s. This is taken as further evidence that neutron powder diffraction, analysed by the Rietveld method, gives reliable results.…”

Section: Comparison With Previous Experimental Resultssupporting

confidence: 91%

“…These additional investigations have been motivated by interests in the electronic properties, the nature of the bonding, and the general relationship between electronic properties and crystal structure in these materials. The further work includes an X-ray powder diffraction study of anatase and rutile (Cromer & Herrington, 1955), single-crystal X-ray diffraction investigations of anatase (Horn, Schwerdtfeger & Meagher, 1972) and of rutile (Abrahams & Bernstein, 1971;Shintani, Sato & Saito, 1975;Gonschorek, 1982), and neutron diffraction investigations of rutile using both singlecrystal (Gonschorek & Feld, 1982) and powder (Sabine & Howard, 1982) techniques. For rutile, which has received rather more attention than the other polymorphs, neutron scattering methods have been employed to determine the phonon dispersion curves, and a shell model which includes first-and second-neighbour forces has been developed to fit the results (Traylor, Smith, Nicklow & Wilkinson, 1971).…”

Section: Introductionmentioning

confidence: 99%

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Structural and thermal parameters for rutile and anatase

Howard¹,

Sabine²,

Dickson³

1991

Acta Crystallogr B Struct Sci

732

349

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Neutron powder diffraction patterns from rutile (TiO2, P42/mnm, a = 4.594, c = 2.959/k) and anatase (TiO2, I41/amd, a= 3-785, c=9-514/k) have been analysed by the Rietveld method. The positional parameters were determined to be xo=Yo= 0.30478 (6) in rutile and Zo = 0.20806 (5) in anatase. The anisotropic thermal parameters were also determined. The results from this constant-wavelength neutron diffraction study are in remarkably good agreement with the results from a recently published analysis of time-of-flight neutron data from the same phases. A comparison is made with results from earlier X-ray single-crystal investigations of these polymorphs of titania, and again the agreement is good. In particular, there is no evidence for any significant difference between X-ray and neutron determinations of the oxygen position such as might have resulted from polarization effects. The thermal vibrations show marked anisotropy, which appears to be determined by the stereochemistry of the crystal structure. The Debye temperatures esti-* Present address: Bristows Cooke and Carpmael, 10 Lincoln's Inn Fields, London WC2A 3BP, England.0108-7681/91/040462-07503.00 mated from the diffraction data are 600 (10)K for rutile and 520(10)K for anatase at room temperature.

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Section: Comparison With Previous Experimental Resultssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Structural and thermal parameters for rutile and anatase

Howard¹,

Sabine²,

Dickson³

1991

Acta Crystallogr B Struct Sci

732

349

View full text Add to dashboard Cite

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“…Gonschorek [87,88] concluded from his room-temperature study using four crystals and Pd-filtered Ag Ka radiation that the TiÀ ÀO bonds are highly covalent. However, the difference Fourier and deformation maps appear to show important differences between the inequivalent TiÀ ÀO bonds: the main density maxima are near the short equatorial ones and the axial bond does not show a density maximum.…”

Section: D-metal Oxidesmentioning

confidence: 99%

Iono‐Covalent Character of the Metal–Oxygen Bonds in Oxides: A Comparison of Experimental and Theoretical Data

Lenglet

2003

Active and Passive Electronic Components

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The aim of this paper is to review the actual data on the chemical bond in binary and mixed oxides. The electronegativity (w M ) and the acidity Pa scales are the most significant semi-empirical concepts for predicting the trend of bonding character in iono-covalent oxides. A satisfactory correlation between the data issued from the acidity scale and the calculated ionic charges has been established.The most recent studies show that the hybrid methods such as the B3LYP method lead to more reliable results for the description of structural, energetic and electronic properties of binary oxides than those from standard methods.

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“…Nous avons alors cherch6 ta confirmer ce comportement du titane en effectuant les repr6sentations ORTEP (Johnson, 1965) sur quelques titanates. II est av6r6 que l'61ongation de Ti se manifeste dans d'autres compos6s ayant des cha~nes d'octa~dres TiO6 parall61es ou entrecrois6es comme CaSn0,95Ti0,05OSiO4 (Higgins & Ribbe, 1977), Ca(Tio,90Alo,09Feo,01 )O0,98SiO3,96(OHo,08Fo,02) (Hollabaugh & Foit, 1984), Na4TiP209 (Maximov, Bolotina, Simonov et al, 1994;Maximov, Bolotina & Tamazyan, 1994), NaScTiO4 (Reid et al, 1968), A12Ti70~5 (Remy et al, 1988), BaTiO3 (Buttner & Maslen, 1992, SrTiO3 (Abramov et al, 1995) et TiO2 la forme rutile (Gonschorek, 1982;Gonschorek & Feld, 1982;Seki et al, 1984;Sugiyama & Takeuchi, 1991;Howard et al, 1991;Swope et al, 1995). …”

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“…Les processus d'acc~s h ces archives sont donn6s au dos de la couverture. Gonschorek, W. (1982). Z. Kristallogr.…”

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Na₄TiAs₂O₉

Yaakoubi¹,

T.²

1998

Acta Crystallogr C

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The three-dimensional framework of tetrasodium titanium nonaoxodiarsenate, Na4TiAs209, consists of infinite [TiO(AsOn)2]n chains linked together by Na ÷ cations. The structure is compared with those of Na3SbO(PO4)2 (P212121) and NaaTiP209 (P2/c, Ibam and Bmcm). msO4 (Fig. 1). Chaque chalne [TiO(AsO4)2]n est li6e quatreoVOisines situ6es ?~ des distances Ti--Ti de 7,72 et 7,94 A, au moyen de liaisons Na---O (Fig. 2). Commentaire Les 6tudes 6ffectu6es dans les syst~mes ternaires A20-TiO2-As205 ont permis d'isoler la s6rie de formulation ATi2(AsO4)3 (A = Li, Na, K et Ag) (Yaakoubi et al., 1991) de type Nasicon caract6ris6 par une conductivit6 ionique 61ev6e (Hagman & Kierkegaard, 1968) et les compos6s ATiOAsO4 (A = alcalin). Ces derniers adoptent trois types de structures: LiTiOAsO4 (Robertson et al., 1994) a une charpente tridimensionnelle analogue h celle de fl-LiVOPO4 (Lii et al., 1991), le titanyl-ars6niate de sodium et de potassium Nao,87Ko,13TiOAsO4 (Phillips et al., 1992) isotype de CaTiOSiO4 (Donnay & Ondik, 1973) et de NaVOAsO4 (Haddad et at., 1992, et enfin les compos6s KTiOAsO4 (El Brahimi & Durand, 1986), CsTiOmsO4 (Protas et al., 1989), RbTiOAsO4 (Thomas et at., 1992) et Ag0,98Ko,02TiOAsO4 (Phillips et at., 1992 isostructuraux de KTiOPO4 (Tordjman et al., 1974) connu pour ses propri6t6s optiques de doubleur de fr6quence (Zumesteg et al., 1976). Le pr6sent travail est consacr6 la pr6paration et ~ l'6tude structurale de Na4TiO(AsO4)2. (Fig. 2). Cette structure est 6troitement reli6e h celles de Na3SbO(PO4)2 (NSP) (Guyomard et al., 1991) et Na4TiP209 (NTP) Tamazyan et al., 1994;Bolotina et al., 1993Bolotina et al., , 1995Maximov, Bolotina & Tamazyan, 1994;Maximov, Bolotina, Simonov et al., 1994;Maksimov et al., 1990) Tamazyan et al., 1994;Bolotina et al., 1993;Maximov, Bolotina & Tamazyan, 1994;Maksimov et al., 1990), les octa~dres TiO6 d'une m~me cha3ne ont une configuration 6clips6e par contre ceux de NTP basse temp6rature (Bolotina et al., 1995;Maximov, Bolotina, Simonov et al., 1994) ainsi que les octa~dres SbO6 de NSP (Guyomard et al., 1991) (AsO4)2]n. Ce fait est h prendre en consid6ration car il r6v~le la tendance du titane h se d4placer du centre de l'octa~dre de mani~re h former des liaisons titanyles. Si un tel d6placement se faisait de faqon ordonn6e il n'y aurait pas de sym6trie donn6e par le miroir. Mais le d6placement du titane est probablement dynamique ou si faible que l'affinement dans C2 n'est pas possible. Nous avons alors cherch6 ta confirmer ce comportement du titane en effectuant les repr6sentations ORTEP (Johnson, 1965) sur quelques titanates. II est av6r6 que l'61ongation de Ti se manifeste dans d'autres compos6s ayant des cha~nes d'octa~dres TiO6 parall61es ou entrecrois6es comme CaSn0,95Ti0,05OSiO4 (Higgins & Ribbe, 1977), Ca(Tio,90Alo,09Feo,01 )O0,98SiO3,96(OHo,08Fo,02) (Hollabaugh & Foit, 1984), Na4TiP209 (Maximov, Bolotina, Simonov et al., 1994;Maximov, Bolotina & Tamazyan, 1994), NaScTiO4 (Reid et al., 1968), A12Ti70~5 (Remy et al., 1988), BaTiO3 (Buttner & ...

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Neutron diffraction study of the thermal and oxygen position parameters in rutile

Cited by 17 publications

References 2 publications

Structural and thermal parameters for rutile and anatase

Structural and thermal parameters for rutile and anatase

Iono‐Covalent Character of the Metal–Oxygen Bonds in Oxides: A Comparison of Experimental and Theoretical Data

Na₄TiAs₂O₉

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Neutron diffraction study of the thermal and oxygen position parameters in rutile

Cited by 17 publications

References 2 publications

Structural and thermal parameters for rutile and anatase

Structural and thermal parameters for rutile and anatase

Iono‐Covalent Character of the Metal–Oxygen Bonds in Oxides: A Comparison of Experimental and Theoretical Data

Na4TiAs2O9

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Na₄TiAs₂O₉