Literature DB >> 21580815

Redetermination of terbium scandate, revealing a defect-type perovskite derivative.

Boža Veličkov, Volker Kahlenberg, Rainer Bertram, Reinhard Uecker.

Abstract

The crystal structure of terbium(III) scandate(III), with ideal formula TbScO(3), has been reported previously on the basis of powder diffraction data [Liferovich & Mitchell (2004 ▶). J. Solid State Chem.177, 2188-2197]. The current data were obtained from single crystals grown by the Czochralski method and show an improvement in the precision of the geometric parameters. Moreover, inductively coupled plasma optical emission spectrometry studies resulted in a nonstoichiometric composition of the title compound. Site-occupancy refinements based on diffraction data support the idea of a Tb deficiency on the A site (inducing O defects on the O2 position). The crystallochemical formula of the investigated sample thus may be written as (A)(□(0.04)Tb(0.96))(B)ScO(2.94). In the title compound, Tb occupies the eightfold-coordinated sites (site symmetry m) and Sc the centres of corner-sharing [ScO(6)] octa-hedra (site symmetry ). The mean bond lengths and site distortions fit well into the data of the remaining lanthanoid scandates in the series from DyScO(3) to NdScO(3). A linear structural evolution with the size of the lanthanoid from DyScO(3) to NdScO(3) can be predicted.

Entities: Chemical Disease Gene

Year: 2008 PMID： 21580815 PMCID： PMC2959553 DOI： 10.1107/S1600536808033394

Source DB: PubMed Journal: Acta Crystallogr Sect E Struct Rep Online ISSN： 1600-5368

Related literature

Rietvelt refinements on powders of LnScO3 with Ln = La3+–Ho3+ were reported by Liferovich & Mitchell (2004 ▶). The crystal structures of the Dy, Gd, Sm and Nd members, refined from single-crystal diffraction data, have been recently provided by Veličkov et al. (2007 ▶). Geometrical parameters have been calculated by means of atomic coordinates following the concept of Zhao et al. (1993 ▶). A more detailed description of the growth procedure of the Ln scandates is given by Uecker et al. (2006 ▶). For the applications of Ln scandates, see: Choi et al. (2004 ▶); Haeni et al. (2004 ▶).

Experimental

Crystal data

Tb0.96ScO2.94 M = 244.56 Orthorhombic, a = 5.7233 (8) Å b = 7.9147 (12) Å c = 5.4543 (7) Å V = 247.07 (6) Å3 Z = 4 Mo Kα radiation μ = 29.58 mm−1 T = 298 (2) K 0.14 × 0.12 × 0.02 mm

Data collection

Stoe IPDS-II diffractometer Absorption correction: analytical (Alcock, 1970 ▶) T min = 0.088, T max = 0.278 2143 measured reflections 353 independent reflections 328 reflections with I > 2σ(I) R int = 0.065

Refinement

R[F 2 > 2σ(F 2)] = 0.024 wR(F 2) = 0.047 S = 1.20 353 reflections 31 parameters 1 restraint Δρmax = 2.15 e Å−3 Δρmin = −1.12 e Å−3 Data collection: X-AREA (Stoe & Cie, 2006 ▶); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2006 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXS97 (Sheldrick, 2008 ▶); molecular graphics: ATOMS (Dowty, 2004 ▶); software used to prepare material for publication: SHELXL97. Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808033394/wm2190sup1.cif Structure factors: contains datablocks I. DOI: 10.1107/S1600536808033394/wm2190Isup2.hkl Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Tb_0.96ScO_2.94	F(000) = 427
M_r = 244.56	D_x = 6.55 Mg m⁻³
Orthorhombic, Pnma	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2n	Cell parameters from 1947 reflections
a = 5.7233 (8) Å	θ = 2.6–29.1°
b = 7.9147 (12) Å	µ = 29.58 mm⁻¹
c = 5.4543 (7) Å	T = 298 K
V = 247.07 (6) Å³	Plate, colourless
Z = 4	0.14 × 0.12 × 0.02 mm

Stoe IPDS-II diffractometer	353 independent reflections
Radiation source: fine-focus sealed tube	328 reflections with I > 2σ(I)
graphite	R_int = 0.065
Detector resolution: 6.67 pixels mm^-1	θ_max = 29.1°, θ_min = 4.5°
ω scans	h = −7→7
Absorption correction: analytical (Alcock, 1970)	k = −9→10
T_min = 0.088, T_max = 0.278	l = −7→7
2143 measured reflections

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.024	w = 1/[σ²(F_o²) + (0.0165P)² + 1.3905P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.047	(Δ/σ)_max = 0.015
S = 1.20	Δρ_max = 2.15 e Å⁻³
353 reflections	Δρ_min = −1.11 e Å⁻³
31 parameters	Extinction correction: SHELXS97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
1 restraint	Extinction coefficient: 0.158 (6)

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

	x	y	z	U_iso*/U_eq	Occ. (<1)
Tb1	0.06029 (6)	0.25	0.01672 (6)	0.0087 (2)	0.9591 (13)
Sc2	0	0	0.5	0.0082 (3)
O1	0.4455 (10)	0.25	0.8761 (9)	0.0114 (10)
O2	0.1946 (7)	0.9357 (5)	0.8100 (6)	0.0108 (8)	0.9693 (10)

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Tb1	0.0074 (3)	0.0106 (3)	0.0080 (2)	0	0.00053 (12)	0
Sc2	0.0085 (6)	0.0085 (7)	0.0075 (5)	−0.0003 (7)	−0.0002 (4)	0.0002 (4)
O1	0.013 (3)	0.010 (2)	0.012 (2)	0	0.0018 (19)	0
O2	0.0078 (19)	0.014 (2)	0.0111 (15)	−0.0024 (14)	−0.0037 (13)	0.0025 (13)

Tb1—O1ⁱ	2.241 (5)	Sc2—O2ⁱⁱ	2.088 (3)
Tb1—O2ⁱⁱ	2.277 (4)	Sc2—O2^xii	2.088 (3)
Tb1—O2ⁱⁱⁱ	2.277 (4)	Sc2—O2^xiii	2.095 (4)
Tb1—O1^iv	2.334 (5)	Sc2—O2^vi	2.095 (4)
Tb1—O2^v	2.586 (4)	Sc2—O1^xiv	2.1141 (19)
Tb1—O2^vi	2.586 (4)	Sc2—O1^x	2.1141 (18)
Tb1—O2^vii	2.837 (4)	Sc2—Tb1^xv	3.2026 (4)
Tb1—O2^viii	2.837 (4)	Sc2—Tb1ⁱ	3.2026 (4)
Tb1—Sc2^ix	3.2026 (4)	Sc2—Tb1^xvi	3.3140 (4)
Tb1—Sc2^x	3.2026 (4)	Sc2—Tb1^xvii	3.4608 (4)
Tb1—Sc2^xi	3.3140 (4)	Sc2—Tb1^xviii	3.4608 (4)
Tb1—Sc2	3.3140 (4)

O1ⁱ—Tb1—O2ⁱⁱ	102.07 (14)	O2^xii—Sc2—O2^xiii	89.16 (7)
O1ⁱ—Tb1—O2ⁱⁱⁱ	102.07 (14)	O2ⁱⁱ—Sc2—O2^vi	89.16 (7)
O2ⁱⁱ—Tb1—O2ⁱⁱⁱ	80.4 (2)	O2^xii—Sc2—O2^vi	90.84 (7)
O1ⁱ—Tb1—O1^iv	87.86 (12)	O2^xiii—Sc2—O2^vi	180
O2ⁱⁱ—Tb1—O1^iv	137.88 (11)	O2ⁱⁱ—Sc2—O1^xiv	87.26 (17)
O2ⁱⁱⁱ—Tb1—O1^iv	137.88 (11)	O2^xii—Sc2—O1^xiv	92.74 (17)
O1ⁱ—Tb1—O2^v	138.63 (11)	O2^xiii—Sc2—O1^xiv	86.91 (18)
O2ⁱⁱ—Tb1—O2^v	117.25 (8)	O2^vi—Sc2—O1^xiv	93.09 (18)
O2ⁱⁱⁱ—Tb1—O2^v	73.97 (9)	O2ⁱⁱ—Sc2—O1^x	92.74 (17)
O1^iv—Tb1—O2^v	72.00 (13)	O2^xii—Sc2—O1^x	87.26 (17)
O1ⁱ—Tb1—O2^vi	138.63 (11)	O2^xiii—Sc2—O1^x	93.09 (18)
O2ⁱⁱ—Tb1—O2^vi	73.97 (9)	O2^vi—Sc2—O1^x	86.91 (18)
O2ⁱⁱⁱ—Tb1—O2^vi	117.25 (8)	O1^xiv—Sc2—O1^x	180
O1^iv—Tb1—O2^vi	72.00 (13)	Sc2^xix—O1—Sc2^xv	138.8 (3)
O2^v—Tb1—O2^vi	69.28 (17)	Sc2^xix—O1—Tb1^xx	105.22 (14)
O1ⁱ—Tb1—O2^vii	72.51 (9)	Sc2^xv—O1—Tb1^xx	105.22 (14)
O2ⁱⁱ—Tb1—O2^vii	76.86 (13)	Sc2^xix—O1—Tb1^xviii	91.96 (15)
O2ⁱⁱⁱ—Tb1—O2^vii	154.79 (10)	Sc2^xv—O1—Tb1^xviii	91.96 (15)
O1^iv—Tb1—O2^vii	67.26 (9)	Tb1^xx—O1—Tb1^xviii	126.2 (2)
O2^v—Tb1—O2^vii	126.67 (6)	Sc2^xxi—O2—Sc2^xxii	141.9 (2)
O2^vi—Tb1—O2^vii	66.45 (5)	Sc2^xxi—O2—Tb1ⁱⁱ	98.72 (15)
O1ⁱ—Tb1—O2^viii	72.51 (9)	Sc2^xxii—O2—Tb1ⁱⁱ	119.09 (16)
O2ⁱⁱ—Tb1—O2^viii	154.79 (10)	Sc2^xxi—O2—Tb1^xxii	85.81 (12)
O2ⁱⁱⁱ—Tb1—O2^viii	76.86 (13)	Sc2^xxii—O2—Tb1^xxii	89.52 (13)
O1^iv—Tb1—O2^viii	67.26 (9)	Tb1ⁱⁱ—O2—Tb1^xxii	103.74 (15)
O2^v—Tb1—O2^viii	66.45 (5)	Sc2^xxi—O2—Tb1^xxiii	87.91 (13)
O2^vi—Tb1—O2^viii	126.67 (6)	Sc2^xxii—O2—Tb1^xxiii	79.43 (12)
O2^vii—Tb1—O2^viii	122.50 (15)	Tb1ⁱⁱ—O2—Tb1^xxiii	103.14 (13)
O2ⁱⁱ—Sc2—O2^xii	180	Tb1^xxii—O2—Tb1^xxiii	153.02 (16)
O2ⁱⁱ—Sc2—O2^xiii	90.84 (7)

Table 1

Selected bond lengths (Å)

Tb1—O1ⁱ	2.241 (5)
Tb1—O2ⁱⁱ	2.277 (4)
Tb1—O1ⁱⁱⁱ	2.334 (5)
Tb1—O2^iv	2.586 (4)
Tb1—O2^v	2.837 (4)
Sc2—O2ⁱⁱ	2.088 (3)
Sc2—O2^vi	2.095 (4)
Sc2—O1^vii	2.1141 (19)

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) ; (v) ; (vi) ; (vii) .

3 in total

1. Room-temperature ferroelectricity in strained SrTiO3.

Authors: J H Haeni; P Irvin; W Chang; R Uecker; P Reiche; Y L Li; S Choudhury; W Tian; M E Hawley; B Craigo; A K Tagantsev; X Q Pan; S K Streiffer; L Q Chen; S W Kirchoefer; J Levy; D G Schlom
Journal: Nature Date: 2004-08-12 Impact factor: 49.962

2. Enhancement of ferroelectricity in strained BaTiO3 thin films.

Authors: K J Choi; M Biegalski; Y L Li; A Sharan; J Schubert; R Uecker; P Reiche; Y B Chen; X Q Pan; V Gopalan; L-Q Chen; D G Schlom; C B Eom
Journal: Science Date: 2004-11-05 Impact factor: 47.728

3. A short history of SHELX.

Authors: George M Sheldrick
Journal: Acta Crystallogr A Date: 2007-12-21 Impact factor: 2.290

3 in total

2 in total

1. Redetermination of EuScO(3).

Authors: Volker Kahlenberg; Dirk Maier; Boža Veličkov
Journal: Acta Crystallogr Sect E Struct Rep Online Date: 2009-01-17

2. Scanning X-ray nanodiffraction from ferroelectric domains in strained K_0.75Na_0.25NbO₃ epitaxial films grown on (110) TbScO₃.

Authors: Martin Schmidbauer; Michael Hanke; Albert Kwasniewski; Dorothee Braun; Leonard von Helden; Christoph Feldt; Steven John Leake; Jutta Schwarzkopf
Journal: J Appl Crystallogr Date: 2017-02-17 Impact factor: 3.304