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

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ISSN: 2056-9890

C-type Nd2Se3

aInstitut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
*Correspondence e-mail: schleid@iac.uni-stuttgart.de

(Received 26 January 2009; accepted 16 February 2009; online 21 February 2009)

The title compound, neodymium sesquiselenide, is isotypic with the other known rare-earth metal(III) selenides M2Se3 (M = La–Pr and Sm–Lu) with the cubic C-type structure. It adopts a cation-defective Th3P4-type arrangement with close to 8/9 of the unique neodymium-cation site occupied, leading to the composition Nd2.667Se4 (Z = 4) or Nd2Se3 (Z = 5.333), respectively. The Nd3+ cations are thus surrounded by eight selenide anions, forming trigonal [NdSe8]13− dodeca­hedra, whereas the Se2− anions exhibit a sixfold coordination, but due to the under-occupation of neodymium, each one is statistically surrounded by only 5.333 cations. The crystal studied was a merohedral twin with a 0.31 (6):0.69 (6) domain ratio.

Related literature

For the structural family with the cation-defective Th3P4-type arrangement, see: Pardo et al. (1963[Pardo, M. P., Flahaut, J. & Domange, L. (1963). C. R. Acad. Sci., 256, 1793-1796.]); Flahaut et al. (1965[Flahaut, J., Guittard, M., Patrie, M., Pardo, M. P., Golabi, S. M. & Domange, L. (1965). Acta Cryst. 19, 14-19.]); Lashkarev & Paderno (1965[Lashkarev, G. V. & Paderno, Y. B. (1965). Inorg. Mater. (USSR), 1, 1620-1623.]). For the rare-earth sesquiselen­ides M2Se3 with M = La–Pr and Sm–Lu, see: Grundmeier & Urland (1995[Grundmeier, T. & Urland, W. (1995). Z. Anorg. Allg. Chem. 621, 1977-1979.]); Folchnandt (1997[Folchnandt, M. (1997). Dissertation, University of Stuttgart, Germany.]); Folchnandt & Schleid (2001[Folchnandt, M. & Schleid, Th. (2001). Z. Anorg. Allg. Chem. 627, 1411-1413.]); Folchnandt et al. (2004[Folchnandt, M., Schneck, C. & Schleid, Th. (2004). Z. Anorg. Allg. Chem. 630, 149-155.]).

Experimental

Crystal data
  • Nd2.667Se4

  • Mr = 700.48

  • Cubic, [I \overline 43d ]

  • a = 8.8632 (6) Å

  • V = 696.26 (8) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 40.39 mm−1

  • T = 293 K

  • 0.03 × 0.03 × 0.02 mm

Data collection
  • Stoe IPDS-I diffractometer

  • Absorption correction: numerical (X-SHAPE; Stoe & Cie, 1999[Stoe & Cie (1999). X-SHAPE. Stoe & Cie, Darmstadt, Germany.]) Tmin = 0.305, Tmax = 0.401

  • 8964 measured reflections

  • 220 independent reflections

  • 214 reflections with I > 2σ(I)

  • Rint = 0.065

Refinement
  • R[F2 > 2σ(F2)] = 0.026

  • wR(F2) = 0.060

  • S = 1.22

  • 220 reflections

  • 7 parameters

  • Δρmax = 1.01 e Å−3

  • Δρmin = −2.11 e Å−3

  • Absolute structure: Flack (1983[Flack, H. D. (1983). Acta Cryst. A39, 876-881.]), 92 Friedel pairs

  • Flack parameter: 0.31 (6)

Table 1
Selected bond lengths (Å)

Nd—Sei (4×) 2.9675 (5)
Nd—Se (4×) 3.1732 (6)
Symmetry codes: (i) [-x+{\script{1\over 2}}, -y, z+{\script{1\over 2}}].

Data collection: DIF4 (Stoe & Cie, 1992[Stoe & Cie (1992). DIF4 and REDU4. Stoe & Cie, Darmstadt, Germany.]); cell refinement: DIF4; data reduction: REDU4 (Stoe & Cie, 1992[Stoe & Cie (1992). DIF4 and REDU4. 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: DIAMOND (Brandenburg, 2006[Brandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany.]); software used to prepare material for publication: SHELXL97.

Supporting information


Comment top

C-type Nd2Se3 (Fig. 1) belongs to a structural family with the cation-defect Th3P4-type arrangement (Pardo et al., 1963; Flahaut et al., 1965; Lashkarev & Paderno, 1965) adopted by rare-earth sesquiselenides M2Se3 with M = La – Pr and Sm – Lu (Grundmeier & Urland, 1995; Folchnandt, 1997; Folchnandt & Schleid, 2001; Folchnandt et al., 2004) following the general formula M2.6670.333Se4. The Nd3+ cations occupy the 12a position, whereas selenium resides at the 16c position. Despite the fact that out of the 12 possible cationic sites (per 16 Se2- and unit cell), only 10.667 are allowed to be occupied to realise the composition Nd2Se3 (with Z = 5.333, i.e. M2.6670.333Se4 with Z = 4); these exhibit the coordination number 8 with respect to the selenide anions. The [NdSe8]13- coordination polyhedra can be described as trigonal dodecahedra with 4-symmetry (Fig. 2). On average, the Se2- anions are surrounded by 5.333 Nd3+ cations in a trigonal hemiprism of symmetry .3. with faces rotated 38.2° with respect to each other (Fig. 3).

Related literature top

For the structural family with the cation-defective Th3P4-type arrangement, see: Pardo et al. (1963); Flahaut et al. (1965); Lashkarev & Paderno (1965). For the rare-earth sesquiselenides M2Se3 with M = La–Pr and Sm–Lu, see: Grundmeier & Urland (1995); Folchnandt (1997); Folchnandt & Schleid (2001); Folchnandt et al. (2004).

Experimental top

Ruby-red, multifaceted, transparent crystals of Nd2Se3 were obtained from stoichiometric reaction of the elements in the presence of CsCl as a flux, placed within a torch-sealed evacuated fused-silica vessel. The mixture was heated at 1123 K for seven days, followed by cooling to ambient temperature with 10 K/h.

Computing details top

Data collection: DIF4 (Stoe & Cie, 1992); cell refinement: DIF4 (Stoe & Cie, 1992); data reduction: REDU4 (Stoe & Cie, 1992); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2006); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. Crystal structure of C-Type Nd2Se3.
[Figure 2] Fig. 2. Coordination sphere of the Nd3+ cation in the shape of a trigonal dodecahedron. Displacement ellipsoids are drawn at 95% probability level. [Symmetry codes: (i) -x + 1/2, -y, z + 1/2; (ii) y + 1/4, x + 1/4, z + 1/4; (iii) y + 1/4, -x - 1/4, -z + 1/4; (iv) -x + 1/2, y, -z; (v) -y + 3/4, -x + 1/4, z + 1/4; (vi) -y + 3/4, x - 1/4, -z + 1/4; (vii) x, -y, -z + 1/2.]
[Figure 3] Fig. 3. Coordination sphere of the Se2- anion. Due to the under-occupation of the neodymium site, each selenium is surrounded by 5.333 Nd3+ cations. Displacement ellipsoids are drawn at 95% probability level. [Symmetry codes: (viii) y, -z, -x + 1/2; (ix) -x + 1/2, -y, z - 1/2; (x) -y - 1/4, x - 1/4, -z + 1/4; (xi) y, z, x; (xii) y + 1/4, -x + 3/4, -z + 1/4.]
dineodymium(III) triselenide top
Crystal data top
Nd2.667Se4Dx = 6.682 Mg m3
Mr = 700.48Mo Kα radiation, λ = 0.71069 Å
Cubic, I43dCell parameters from 5000 reflections
Hall symbol: I -4bd 2c 3θ = 1.0–32.7°
a = 8.8632 (6) ŵ = 40.39 mm1
V = 696.26 (8) Å3T = 293 K
Z = 4Block, red
F(000) = 11840.03 × 0.03 × 0.03 mm
Data collection top
Stoe IPDS-I
diffractometer
220 independent reflections
Radiation source: fine-focus sealed tube214 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.065
imaging plate detector system scansθmax = 32.7°, θmin = 5.6°
Absorption correction: numerical
(X-SHAPE; Stoe & Cie, 1999)
h = 1313
Tmin = 0.305, Tmax = 0.401k = 1313
8964 measured reflectionsl = 1313
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: full w = 1/[σ2(Fo2) + (0.0359P)2]
where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.026(Δ/σ)max = 0.007
wR(F2) = 0.060Δρmax = 1.01 e Å3
S = 1.22Δρmin = 2.11 e Å3
220 reflectionsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
7 parametersExtinction coefficient: 0.0086 (7)
0 restraintsAbsolute structure: Flack (1983), 92 Friedel pairs
Primary atom site location: structure-invariant direct methodsAbsolute structure parameter: 0.31 (6)
Crystal data top
Nd2.667Se4Z = 4
Mr = 700.48Mo Kα radiation
Cubic, I43dµ = 40.39 mm1
a = 8.8632 (6) ÅT = 293 K
V = 696.26 (8) Å30.03 × 0.03 × 0.03 mm
Data collection top
Stoe IPDS-I
diffractometer
220 independent reflections
Absorption correction: numerical
(X-SHAPE; Stoe & Cie, 1999)
214 reflections with I > 2σ(I)
Tmin = 0.305, Tmax = 0.401Rint = 0.065
8964 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0260 restraints
wR(F2) = 0.060Δρmax = 1.01 e Å3
S = 1.22Δρmin = 2.11 e Å3
220 reflectionsAbsolute structure: Flack (1983), 92 Friedel pairs
7 parametersAbsolute structure parameter: 0.31 (6)
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)
Nd0.37500.00000.25000.0053 (2)0.89
Se0.07261 (5)0.07261 (5)0.07261 (5)0.0028 (3)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Nd0.0066 (3)0.0046 (3)0.0046 (3)0.0000.0000.000
Se0.0028 (3)0.0028 (3)0.0028 (3)0.00063 (16)0.00063 (16)0.00063 (16)
Geometric parameters (Å, º) top
Nd—Sei2.9675 (5)Nd—Se3.1732 (6)
Nd—Seii2.9675 (5)Se—Ndviii2.9675 (5)
Nd—Seiii2.9675 (5)Se—Ndix2.9675 (5)
Nd—Seiv2.9675 (5)Se—Ndx2.9675 (5)
Nd—Sev3.1732 (6)Se—Ndxi3.1732 (6)
Nd—Sevi3.1732 (6)Se—Ndxii3.1732 (6)
Nd—Sevii3.1732 (6)
Sei—Nd—Seii91.403 (3)Seii—Nd—Se77.283 (2)
Sei—Nd—Seiii91.403 (3)Seiii—Nd—Se87.467 (16)
Seii—Nd—Seiii162.00 (2)Seiv—Nd—Se67.092 (10)
Sei—Nd—Seiv162.00 (2)Sev—Nd—Se135.510 (1)
Seii—Nd—Seiv91.403 (3)Sevi—Nd—Se135.510 (1)
Seiii—Nd—Seiv91.403 (3)Sevii—Nd—Se64.738 (1)
Sei—Nd—Sev77.284 (2)Ndviii—Se—Ndix88.609 (17)
Seii—Nd—Sev67.092 (10)Ndviii—Se—Ndx88.609 (17)
Seiii—Nd—Sev130.811 (11)Ndix—Se—Ndx88.609 (17)
Seiv—Nd—Sev87.468 (16)Ndviii—Se—Ndxi107.535 (2)
Sei—Nd—Sevi87.468 (16)Ndix—Se—Ndxi162.372 (6)
Seii—Nd—Sevi130.811 (11)Ndx—Se—Ndxi84.849 (2)
Seiii—Nd—Sevi67.092 (10)Ndviii—Se—Ndxii162.372 (6)
Seiv—Nd—Sevi77.283 (2)Ndix—Se—Ndxii84.849 (2)
Sev—Nd—Sevi64.739 (1)Ndx—Se—Ndxii107.534 (2)
Sei—Nd—Sevii67.092 (10)Ndxi—Se—Ndxii81.565 (16)
Seii—Nd—Sevii87.468 (16)Ndviii—Se—Nd84.849 (2)
Seiii—Nd—Sevii77.283 (2)Ndix—Se—Nd107.535 (2)
Seiv—Nd—Sevii130.810 (11)Ndx—Se—Nd162.372 (6)
Sev—Nd—Sevii135.510 (1)Ndxi—Se—Nd81.565 (16)
Sevi—Nd—Sevii135.510 (1)Ndxii—Se—Nd81.565 (16)
Sei—Nd—Se130.811 (11)
Symmetry codes: (i) x+1/2, y, z+1/2; (ii) y+1/4, x+1/4, z+1/4; (iii) y+1/4, x1/4, z+1/4; (iv) x+1/2, y, z; (v) y+3/4, x+1/4, z+1/4; (vi) y+3/4, x1/4, z+1/4; (vii) x, y, z+1/2; (viii) y, z, x+1/2; (ix) x+1/2, y, z1/2; (x) y1/4, x1/4, z+1/4; (xi) y, z, x; (xii) y+1/4, x+3/4, z+1/4.

Experimental details

Crystal data
Chemical formulaNd2.667Se4
Mr700.48
Crystal system, space groupCubic, I43d
Temperature (K)293
a (Å)8.8632 (6)
V3)696.26 (8)
Z4
Radiation typeMo Kα
µ (mm1)40.39
Crystal size (mm)0.03 × 0.03 × 0.03
Data collection
DiffractometerStoe IPDS-I
diffractometer
Absorption correctionNumerical
(X-SHAPE; Stoe & Cie, 1999)
Tmin, Tmax0.305, 0.401
No. of measured, independent and
observed [I > 2σ(I)] reflections
8964, 220, 214
Rint0.065
(sin θ/λ)max1)0.761
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.026, 0.060, 1.22
No. of reflections220
No. of parameters7
Δρmax, Δρmin (e Å3)1.01, 2.11
Absolute structureFlack (1983), 92 Friedel pairs
Absolute structure parameter0.31 (6)

Computer programs: DIF4 (Stoe & Cie, 1992), REDU4 (Stoe & Cie, 1992), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2006).

Selected bond lengths (Å) top
Nd—Sei2.9675 (5)Nd—Sev3.1732 (6)
Nd—Seii2.9675 (5)Nd—Sevi3.1732 (6)
Nd—Seiii2.9675 (5)Nd—Sevii3.1732 (6)
Nd—Seiv2.9675 (5)Nd—Se3.1732 (6)
Symmetry codes: (i) x+1/2, y, z+1/2; (ii) y+1/4, x+1/4, z+1/4; (iii) y+1/4, x1/4, z+1/4; (iv) x+1/2, y, z; (v) y+3/4, x+1/4, z+1/4; (vi) y+3/4, x1/4, z+1/4; (vii) x, y, z+1/2.
 

Acknowledgements

Financial support by the state of Baden–Württemberg (Stuttgart) and the Deutsche Forschungsgemeinschaft (DFG; Frankfurt/Main) is gratefully acknowledged. Furthermore we thank Dr Falk Lissner for the data collection.

References

First citationBrandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany.  Google Scholar
First citationFlack, H. D. (1983). Acta Cryst. A39, 876–881.  CrossRef CAS Web of Science IUCr Journals Google Scholar
First citationFlahaut, J., Guittard, M., Patrie, M., Pardo, M. P., Golabi, S. M. & Domange, L. (1965). Acta Cryst. 19, 14–19.  CrossRef CAS IUCr Journals Web of Science Google Scholar
First citationFolchnandt, M. (1997). Dissertation, University of Stuttgart, Germany.  Google Scholar
First citationFolchnandt, M. & Schleid, Th. (2001). Z. Anorg. Allg. Chem. 627, 1411–1413.  Web of Science CrossRef CAS Google Scholar
First citationFolchnandt, M., Schneck, C. & Schleid, Th. (2004). Z. Anorg. Allg. Chem. 630, 149–155.  Web of Science CrossRef Google Scholar
First citationGrundmeier, T. & Urland, W. (1995). Z. Anorg. Allg. Chem. 621, 1977–1979.  CrossRef CAS Web of Science Google Scholar
First citationLashkarev, G. V. & Paderno, Y. B. (1965). Inorg. Mater. (USSR), 1, 1620–1623.  Google Scholar
First citationPardo, M. P., Flahaut, J. & Domange, L. (1963). C. R. Acad. Sci., 256, 1793–1796.  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 (1992). DIF4 and REDU4. Stoe & Cie, Darmstadt, Germany.  Google Scholar
First citationStoe & Cie (1999). X-SHAPE. Stoe & Cie, Darmstadt, Germany.  Google Scholar

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ISSN: 2056-9890
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