inorganic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

Redetermination of EuScO3

aUniversity of Innsbruck, Institute for Mineralogy and Petrography, Innrain 52, 6020 Innsbruck, Austria, and bLeibniz-Institute for Crystal Growth, Max-Born-Strasse 2, 12489 Berlin, Germany
*Correspondence e-mail: Velickov@ikz-berlin.de

(Received 19 December 2008; accepted 12 January 2009; online 17 January 2009)

Single crystals of europium(III) scandate(III), with ideal formula EuScO3, were grown from the melt using the micro-pulling-down method. The title compound crystallizes in an ortho­rhom­bic distorted perovskite-type structure, where Eu occupies the eightfold coordinated A sites (site symmetry m) and Sc resides on the centres of corner-sharing [ScO6] octa­hedra (B sites with site symmetry [\overline{1}]). The structure of EuScO3 has been reported previously based on powder diffraction data [Liferovich & Mitchell (2004). J. Solid State Chem. 177, 2188–2197]. The results of the current redetermination based on single-crystal diffraction data shows an improvement in the precision of the structral and geometric parameters and reveals a defect-type structure. Site-occupancy refinements indicate an Eu deficiency on the A site coupled with O defects on one of the two O-atom positions. The crystallochemical formula of the investigated sample may thus be written as A(□0.032Eu0.968)BScO2.952.

Related literature

Details of the synthesis are described by Maier et al. (2007[Maier, D., Rhede, D., Bertram, R., Klimm, D. & Fornari, R. (2007). Opt. Mater. 30, 11-14.]). Rietveld refinements on powders of LnScO3 with Ln = La3+ to Ho3+ are reported by Liferovich & Mitchell (2004[Liferovich, R. P. & Mitchell, R. H. (2004). J. Solid State Chem. 177, 2188-2197.]). 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[Veličkov, B., Kahlenberg, V., Bertram, R. & Bernhagen, M. (2007). Z. Kristallogr. 222, 466-473.]). The crystal structure of the isotypic TbScO3 is described by Veličkov et al. (2008[Veličkov, B., Kahlenberg, V., Bertram, R. & Uecker, R. (2008). Acta Cryst. E64, i79.]). Specific geometrical parameters have been calculated by means of the atomic coordinates following the concept of Zhao et al. (1993[Zhao, Y., Weidner, D. J., Parise, J. B. & Cox, D. E. (1993). Phys. Earth Planet. Inter., 76, 1-16.]).

Experimental

Crystal data
  • Eu0.968ScO2.952

  • Mr = 239.24

  • Orthorhombic, P n m a

  • a = 5.7554 (7) Å

  • b = 7.9487 (10) Å

  • c = 5.5087 (6) Å

  • V = 252.01 (5) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 26.28 mm−1

  • T = 293 (2) K

  • 0.14 × 0.12 × 0.02 mm

Data collection
  • Stoe IPDS-2 diffractometer

  • Absorption correction: analytical (Alcock, 1970[Alcock, N. W. (1970). Crystallographic Computing, edited by F. R. Ahmed, S. R. Hall & C. P. Huber, p. 271. Copenhagen: Munksgaard.]) Tmin = 0.139, Tmax = 0.397

  • 2168 measured reflections

  • 362 independent reflections

  • 345 reflections with I > 2σ(I)

  • Rint = 0.055

Refinement
  • R[F2 > 2σ(F2)] = 0.021

  • wR(F2) = 0.051

  • S = 1.27

  • 362 reflections

  • 31 parameters

  • 1 restraint

  • Δρmax = 1.40 e Å−3

  • Δρmin = −0.84 e Å−3

Table 1
Selected bond lengths (Å)

Eu1—O1i 2.276 (5)
Eu1—O2ii 2.304 (3)
Eu1—O1iii 2.375 (5)
Eu1—O2iv 2.611 (3)
Eu1—O2v 2.845 (3)
Sc2—O2ii 2.094 (3)
Sc2—O2vi 2.107 (3)
Sc2—O1vii 2.1108 (16)
Symmetry codes: (i) [x-{\script{1\over 2}}, y, -z+{\script{1\over 2}}]; (ii) -x, -y+1, -z+1; (iii) x, y, z-1; (iv) [-x+{\script{1\over 2}}, y-{\script{1\over 2}}, z-{\script{1\over 2}}]; (v) x, y-1, z-1; (vi) [-x+{\script{1\over 2}}, -y+1, z-{\script{1\over 2}}]; (vii) [x-{\script{1\over 2}}, y, -z+{\script{3\over 2}}].

Data collection: X-AREA (Stoe & Cie, 2006[Stoe & Cie (2006). X-AREA and X-RED. Stoe & Cie, Darmstadt, Germany.]); cell refinement: X-AREA; data reduction: X-RED (Stoe & Cie, 2006[Stoe & Cie (2006). X-AREA and X-RED. Stoe & Cie, Darmstadt, Germany.]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ATOMS for Windows (Dowty, 2004[Dowty, E. (2004). ATOMS for Windows. Shape Software, Kingsport, Tennessee, USA.]); software used to prepare material for publication: SHELXL97.

Supporting information


Comment top

Liferovich & Mitchell (2004) studied the crystal structure of lanthanoid scandates, including EuScO3, by Rietveld analysis from powder diffraction data. Crystallographic data of DyScO3, GdScO3, SmScO3 and NdScO3 obtained from single crystals were recently reported by Veličkov et al. (2007), and for TbScO3 by Veličkov et al. (2008). Based on these results it was possible to resolve disagreements concerning some structural characteristics and their dependence on the Ln-substitution. Whereas Liferovich & Mitchell (2004) observed no obvious continuous evolution, Veličkov et al. (2007) were able to show that the geometry and the distortion of the sites are linearly coupled with the size of the lanthanoid in the series from DyScO3 to NdScO3. With the structural refinement based on diffraction data collected from single crystalline EuScO3, the present results provide further data for this series.

The orthorhombic distorted perovskite structure for EuScO3 (Fig. 1) is confirmed from our refinements. Whereas the lattice parameters for EuScO3 compare well with the data of Liferovich & Mitchell (2004), the fractional atomic coordinates show deviations of up to 0.006, resulting in slightly different geometrical parameters. The A-site is occupied by Eu in an eightfold coordination and has an average bond length of [8]<A—O> = 2.521 Å with a polyhedral bond length distortion of AΔ8 = 7.98×10-3 (Δn = 1/n Σ{(ri-r)/r2). The B-site shows bond lengths typical for octahedrally coordinated scandium (<B—O> = 2.104 Å) and is rather distorted with BΔ6 = 0.015×10-3 and a bond angle variance of δ = 2.61°. The tilting of the corner sharing octahedra calculated after Zhao et al. (1993) are θ = 19.70° in [110] and Ø = 12.66° in [001] directions. From our data we can establish linear trends for the crystallochemical parameters from DyScO3 to NdScO3 depending on the Ln-substitution.

Related literature top

Details of the synthesis are described by Maier et al. (2007). Rietveld refinements on powders of LnScO3 with Ln = La3+ to Ho3+ are 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). The crystal structure of the isotypic TbScO3 is described by Veličkov et al. (2008). Specific geometrical parameters have been calculated by means of the atomic coordinates following the concept of Zhao et al. (1993).

Experimental top

An EuScO3 fiber was grown using a micro-pulling-down apparatus with induction heating (Maier et al., 2007). The starting material was prepared from 4 N Eu2O3 and Sc2O3 powders by grinding a total weight of 5 g in a plastic mortar and pressing the mixture into pellets. An 5 ml iridium crucible with 500 mg of the starting material was placed on an iridium after-heater and heated by the inductor coil of a 10 kW rf Generator. The crucible after-heater arrangement was surrounded by a zirconia fiber tube and a high-purity alumina tube for thermal insulation. The experiments were carried out in a vacuum-tight steel chamber. It was evacuated before each experiment to 5 x10-3 mbar and filled with 5 N argon gas. Subsequently, a constant flow of about 900 ml/min was kept. During growth the height of the molten zone and consequently the diameter of the fiber (~1 mm) was carefully controlled by manually increasing or decreasing the rf-power. Several starting compositions with different Eu to Sc ratios were tested, resulting in the optimal batch with 47.5 mol% Eu2O3 and 52.5 mol% Sc2O3.

The grown single-crystal was colourless. A part of the single-crystal fiber was crushed and the irregular shaped fragments were screened using a polarizing light microscope to find a sample of good optical quality for the diffraction experiments.

Refinement top

Site occupation refinements indicated deviations from full occupancy on the Eu1 (A-site) and the O2 sites. For the final refinement cycle a constraint ensuring charge neutrality was included. The crystallochemical formula of the investigated sample can thus be written as A(□0.032Eu0.968)BScO2.952. The highest peak and deepest hole of the difference Fourier map are located 0.84 Å and 1.42 Å away from the Eu1 position. In contrast to the previous Rietveld refinement, where the Pbnm setting of space group no. 62 was chosen, the standard setting Pnma was used for the present redetermination.

Computing details top

Data collection: X-AREA (Stoe & Cie, 2006); cell refinement: X-AREA (Stoe & Cie, 2006); data reduction: X-RED (Stoe & Cie, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ATOMS for Windows (Dowty, 2004); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The orthorhombic perovskite structure of EuScO3 is characterized by a tilted corner sharing ScO6 framework incorporating the 8-fold coordinated Eu sites. The ScO6 octahedra are yellow, the Eu atoms are given in grey and the O atoms are presented in red.
[Figure 2] Fig. 2. Projection of the EuScO3 structure along [010], showing the Eu atoms and the Sc coordination with displacement ellipsoids at the 80% probability level.
europium(III) scandate(III) top
Crystal data top
Eu0.968ScO2.952F(000) = 422.4
Mr = 239.24Dx = 6.307 Mg m3
Orthorhombic, PnmaMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2nCell parameters from 2218 reflections
a = 5.7554 (7) Åθ = 2.6–29.2°
b = 7.9487 (10) ŵ = 26.28 mm1
c = 5.5087 (6) ÅT = 293 K
V = 252.01 (5) Å3Platy fragment, colourless
Z = 40.14 × 0.12 × 0.02 mm
Data collection top
Stoe IPDS-2
diffractometer
362 independent reflections
Radiation source: fine-focus sealed tube345 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.055
Detector resolution: 6.67 pixels mm-1θmax = 29.1°, θmin = 4.5°
ω scansh = 77
Absorption correction: analytical
(Alcock, 1970)
k = 109
Tmin = 0.139, Tmax = 0.397l = 77
2168 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.021 w = 1/[σ2(Fo2) + (0.0211P)2 + 0.9412P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.051(Δ/σ)max = 0.011
S = 1.27Δρmax = 1.40 e Å3
362 reflectionsΔρmin = 0.84 e Å3
31 parametersExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
1 restraintExtinction coefficient: 0.113 (5)
Crystal data top
Eu0.968ScO2.952V = 252.01 (5) Å3
Mr = 239.24Z = 4
Orthorhombic, PnmaMo Kα radiation
a = 5.7554 (7) ŵ = 26.28 mm1
b = 7.9487 (10) ÅT = 293 K
c = 5.5087 (6) Å0.14 × 0.12 × 0.02 mm
Data collection top
Stoe IPDS-2
diffractometer
362 independent reflections
Absorption correction: analytical
(Alcock, 1970)
345 reflections with I > 2σ(I)
Tmin = 0.139, Tmax = 0.397Rint = 0.055
2168 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.02131 parameters
wR(F2) = 0.0511 restraint
S = 1.27Δρmax = 1.40 e Å3
362 reflectionsΔρmin = 0.84 e Å3
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Eu10.05854 (5)0.250.01589 (6)0.0090 (2)0.9677 (13)
Sc2000.50.0078 (3)
O10.4506 (8)0.250.8815 (9)0.0111 (9)
O20.1954 (6)0.9378 (4)0.8078 (6)0.0112 (7)0.9758 (10)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Eu10.0070 (3)0.0102 (3)0.0098 (3)00.00051 (11)0
Sc20.0064 (6)0.0079 (6)0.0090 (6)0.0006 (6)0.0000 (3)0.0000 (3)
O10.011 (2)0.008 (2)0.014 (2)00.0025 (17)0
O20.0096 (16)0.0121 (17)0.0119 (14)0.0019 (12)0.0018 (11)0.0005 (12)
Geometric parameters (Å, º) top
Eu1—O1i2.276 (5)Sc2—O2ii2.094 (3)
Eu1—O2ii2.304 (3)Sc2—O2xii2.094 (3)
Eu1—O2iii2.304 (3)Sc2—O2vi2.107 (3)
Eu1—O1iv2.375 (5)Sc2—O2xiii2.107 (3)
Eu1—O2v2.611 (3)Sc2—O1xiv2.1108 (16)
Eu1—O2vi2.611 (3)Sc2—O1x2.1108 (16)
Eu1—O2vii2.845 (3)Sc2—Eu1xv3.2268 (4)
Eu1—O2viii2.845 (3)Sc2—Eu1i3.2268 (4)
Eu1—Sc2ix3.2268 (4)Sc2—Eu1xvi3.3428 (4)
Eu1—Sc2x3.2268 (4)Sc2—Eu1xvii3.4841 (4)
Eu1—Sc2xi3.3428 (4)Sc2—Eu1xviii3.4841 (4)
Eu1—Sc23.3428 (4)
O1i—Eu1—O2ii103.43 (12)O2xii—Sc2—O2vi90.88 (6)
O1i—Eu1—O2iii103.43 (12)O2ii—Sc2—O2xiii90.88 (6)
O2ii—Eu1—O2iii80.77 (17)O2xii—Sc2—O2xiii89.12 (6)
O1i—Eu1—O1iv87.69 (11)O2vi—Sc2—O2xiii180
O2ii—Eu1—O1iv137.24 (9)O2ii—Sc2—O1xiv87.46 (16)
O2iii—Eu1—O1iv137.24 (9)O2xii—Sc2—O1xiv92.54 (16)
O1i—Eu1—O2v137.77 (9)O2vi—Sc2—O1xiv92.67 (15)
O2ii—Eu1—O2v117.06 (6)O2xiii—Sc2—O1xiv87.33 (15)
O2iii—Eu1—O2v73.38 (8)O2ii—Sc2—O1x92.54 (16)
O1iv—Eu1—O2v71.14 (12)O2xii—Sc2—O1x87.46 (16)
O1i—Eu1—O2vi137.77 (9)O2vi—Sc2—O1x87.33 (15)
O2ii—Eu1—O2vi73.38 (8)O2xiii—Sc2—O1x92.67 (15)
O2iii—Eu1—O2vi117.06 (6)O1xiv—Sc2—O1x180
O1iv—Eu1—O2vi71.14 (12)Sc2xix—O1—Sc2xv140.6 (2)
O2v—Eu1—O2vi69.74 (15)Sc2xix—O1—Eu1xx105.10 (13)
O1i—Eu1—O2vii71.82 (8)Sc2xv—O1—Eu1xx105.10 (13)
O2ii—Eu1—O2vii77.31 (12)Sc2xix—O1—Eu1xviii91.82 (14)
O2iii—Eu1—O2vii155.61 (9)Sc2xv—O1—Eu1xviii91.82 (14)
O1iv—Eu1—O2vii67.12 (8)Eu1xx—O1—Eu1xviii124.0 (2)
O2v—Eu1—O2vii126.63 (6)Sc2xxi—O2—Sc2xxii143.00 (18)
O2vi—Eu1—O2vii66.38 (5)Sc2xxi—O2—Eu1ii98.83 (13)
O1i—Eu1—O2viii71.82 (8)Sc2xxii—O2—Eu1ii117.90 (14)
O2ii—Eu1—O2viii155.61 (9)Sc2xxi—O2—Eu1xxii85.85 (11)
O2iii—Eu1—O2viii77.31 (12)Sc2xxii—O2—Eu1xxii89.57 (12)
O1iv—Eu1—O2viii67.12 (8)Eu1ii—O2—Eu1xxii103.48 (13)
O2v—Eu1—O2viii66.38 (5)Sc2xxi—O2—Eu1xxiii88.37 (12)
O2vi—Eu1—O2viii126.63 (6)Sc2xxii—O2—Eu1xxiii79.82 (10)
O2vii—Eu1—O2viii121.45 (13)Eu1ii—O2—Eu1xxiii102.69 (12)
O2ii—Sc2—O2xii180Eu1xxii—O2—Eu1xxiii153.77 (14)
O2ii—Sc2—O2vi89.12 (6)
Symmetry codes: (i) x1/2, y, z+1/2; (ii) x, y+1, z+1; (iii) x, y1/2, z+1; (iv) x, y, z1; (v) x+1/2, y1/2, z1/2; (vi) x+1/2, y+1, z1/2; (vii) x, y1, z1; (viii) x, y+3/2, z1; (ix) x+1/2, y+1/2, z+1/2; (x) x+1/2, y, z1/2; (xi) x, y+1/2, z+1; (xii) x, y1, z; (xiii) x1/2, y1, z+3/2; (xiv) x1/2, y, z+3/2; (xv) x+1/2, y, z+1/2; (xvi) x, y, z+1; (xvii) x, y, z; (xviii) x, y, z+1; (xix) x+1/2, y+1/2, z+3/2; (xx) x+1/2, y, z+1/2; (xxi) x, y+1, z; (xxii) x+1/2, y+1, z+1/2; (xxiii) x, y+1, z+1.

Experimental details

Crystal data
Chemical formulaEu0.968ScO2.952
Mr239.24
Crystal system, space groupOrthorhombic, Pnma
Temperature (K)293
a, b, c (Å)5.7554 (7), 7.9487 (10), 5.5087 (6)
V3)252.01 (5)
Z4
Radiation typeMo Kα
µ (mm1)26.28
Crystal size (mm)0.14 × 0.12 × 0.02
Data collection
DiffractometerStoe IPDS2
diffractometer
Absorption correctionAnalytical
(Alcock, 1970)
Tmin, Tmax0.139, 0.397
No. of measured, independent and
observed [I > 2σ(I)] reflections
2168, 362, 345
Rint0.055
(sin θ/λ)max1)0.685
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.021, 0.051, 1.27
No. of reflections362
No. of parameters31
No. of restraints1
Δρmax, Δρmin (e Å3)1.40, 0.84

Computer programs: X-AREA (Stoe & Cie, 2006), X-RED (Stoe & Cie, 2006), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ATOMS for Windows (Dowty, 2004).

Selected bond lengths (Å) top
Eu1—O1i2.276 (5)Eu1—O2v2.845 (3)
Eu1—O2ii2.304 (3)Sc2—O2ii2.094 (3)
Eu1—O1iii2.375 (5)Sc2—O2vi2.107 (3)
Eu1—O2iv2.611 (3)Sc2—O1vii2.1108 (16)
Symmetry codes: (i) x1/2, y, z+1/2; (ii) x, y+1, z+1; (iii) x, y, z1; (iv) x+1/2, y1/2, z1/2; (v) x, y1, z1; (vi) x+1/2, y+1, z1/2; (vii) x1/2, y, z+3/2.
 

References

First citationAlcock, N. W. (1970). Crystallographic Computing, edited by F. R. Ahmed, S. R. Hall & C. P. Huber, p. 271. Copenhagen: Munksgaard.  Google Scholar
First citationDowty, E. (2004). ATOMS for Windows. Shape Software, Kingsport, Tennessee, USA.  Google Scholar
First citationLiferovich, R. P. & Mitchell, R. H. (2004). J. Solid State Chem. 177, 2188–2197.  Web of Science CrossRef CAS Google Scholar
First citationMaier, D., Rhede, D., Bertram, R., Klimm, D. & Fornari, R. (2007). Opt. Mater. 30, 11–14.  Web of Science CrossRef CAS Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationStoe & Cie (2006). X-AREA and X-RED. Stoe & Cie, Darmstadt, Germany.  Google Scholar
First citationVeličkov, B., Kahlenberg, V., Bertram, R. & Bernhagen, M. (2007). Z. Kristallogr. 222, 466–473.  Google Scholar
First citationVeličkov, B., Kahlenberg, V., Bertram, R. & Uecker, R. (2008). Acta Cryst. E64, i79.  Web of Science CrossRef IUCr Journals Google Scholar
First citationZhao, Y., Weidner, D. J., Parise, J. B. & Cox, D. E. (1993). Phys. Earth Planet. Inter., 76, 1–16.  CrossRef CAS Web of Science Google Scholar

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ISSN: 2056-9890
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