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Acta Crystallogr Sect E Struct Rep Online. 2009 September 1; 65(Pt 9): i68.
Published online 2009 August 15. doi:  10.1107/S1600536809031559
PMCID: PMC2969891

Titanium germanium anti­monide, TiGeSb

Abstract

TiGeSb adopts the PbFCl- or ZrSiS-type structure, with Ti atoms (4mm symmetry) centred within monocapped square anti­prisms generated by the stacking of denser square nets of Ge atoms (An external file that holds a picture, illustration, etc.
Object name is e-65-00i68-efi1.jpg m2 symmetry) alternating with less dense square nets of Sb atoms (4mm symmetry).

Related literature

For PbFCl- or ZrSiS-type structures, see: Tremel & Hoffmann (1987 [triangle]). For a previous report on TiGeSb, see: Dashjav & Kleinke (2002 [triangle]). The Ti—Ge—Sb phase diagram at 670 K was reported by Kozlov & Pavlyuk (2004 [triangle]). For the related ZrGeSb, see: Lam & Mar (1997 [triangle]). For background to solid solutions in this class of compounds, see: Soheilnia et al. (2003 [triangle]); Kozlov & Pavlyuk (2004 [triangle]). Metallic radii were taken from Pauling (1960 [triangle]).

Experimental

Crystal data

  • TiGeSb
  • M r = 242.24
  • Tetragonal, An external file that holds a picture, illustration, etc.
Object name is e-65-00i68-efi2.jpg
  • a = 3.7022 (5) Å
  • c = 8.2137 (12) Å
  • V = 112.58 (3) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 28.18 mm−1
  • T = 295 K
  • 0.12 × 0.11 × 0.01 mm

Data collection

  • Enraf–Nonius CAD-4 diffractometer
  • Absorption correction: numerical (SHELXTL; Sheldrick, 2008 [triangle]) T min = 0.117, T max = 0.718
  • 1906 measured reflections
  • 181 independent reflections
  • 178 reflections with I > 2σ(I)
  • R int = 0.125
  • 3 standard reflections frequency: 120 min intensity decay: none

Refinement

  • R[F 2 > 2σ(F 2)] = 0.032
  • wR(F 2) = 0.081
  • S = 1.17
  • 181 reflections
  • 10 parameters
  • Δρmax = 1.95 e Å−3
  • Δρmin = −2.53 e Å−3

Data collection: CAD-4-PC (Enraf–Nonius, 1993 [triangle]); cell refinement: CAD-4-PC; data reduction: XCAD4 (Harms & Wocadlo, 1995 [triangle]); program(s) used to solve structure: SHELXTL (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXTL; molecular graphics: ATOMS (Dowty, 1999 [triangle]); software used to prepare material for publication: SHELXTL.

Table 1
Selected bond lengths (Å)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809031559/wm2247sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809031559/wm2247Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

The Natural Sciences and Engineering Research Council of Canada supported this work.

supplementary crystallographic information

Comment

After a report of the ternary antimonide ZrGeSb (Lam & Mar, 1997), the corresponding Ti and Hf analogues were later described in a conference proceeding, but full crystallographic details have not been forthcoming (Dashjav & Kleinke, 2002). The complete structure of TiGeSb, which is absent in the Ti—Ge—Sb phase diagram at 670 K (Kozlov & Pavlyuk, 2004) but was prepared here at 1273 K, is presented. Common to many equiatomic compounds of the formulation MAB (M = large transition-metal atom; A, B = main group atoms), TiGeSb adopts the PbFCl- or ZrSiS-type structure, among other names (Tremel & Hoffmann, 1987). Square nets of each type of atom, with the Ge net being twice as dense as the other two, are stacked along the c axis (Fig. 1). The Zr atoms are nine-coordinate, centred within monocapped square antiprisms. The Ge–Ge distances are 0.13 Å longer than the sum of the Pauling metallic radii (2.48 Å; Pauling, 1960), indicative of weak polyanionic bonding. The solid solutions ZrGexSb1-x and HfGexSb1-x (up to x = 0.2) form related orthorhombic PbCl2-type structures (Soheilnia et al., 2003), whereas TiGexSb1-x adopts a NiAs-type structure (Kozlov & Pavlyuk, 2004).

Experimental

A 0.25 g mixture of Ti (99.98%, Cerac), Ge (99.999%, Cerac), and Sb (99.995%, Aldrich) powders in a 1:1:3 molar ratio was placed in an evacuated fused-silica tube. The tube was heated at 873 K for 2 d and 1273 K for 2 d. Silver plate-shaped crystals were obtained, which were found by semiquantitative energy-dispersive X-ray (EDX) analysis to have a composition (at%) of 32 (2)% Ti, 35 (2)% Ge, and 33 (2)% Sb, in good agreement with the formula TiGeSb.

Refinement

Analysis of Weissenberg photographs on a plate-shaped crystal, subsequently transferred to the four-circle diffractometer, established Laue symmetry 4/mmm and provided approximate cell parameters of a = 3.71 Å and c = 8.22 Å. In the final Fourier map based on origin choice 2 of space group P4/nmm the maximum peak and deepest hole are located 0.67 Å and 0.02 Å, respectively, from the Sb atom.

Figures

Fig. 1.
Projection of the TiGeSb structure approximately along the a axis. Displacement ellipsoids are drawn at the 90% probability level.

Crystal data

TiGeSbDx = 7.146 Mg m3
Mr = 242.24Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P4/nmmCell parameters from 24 reflections
Hall symbol: -P 4a 2aθ = 11.0–23.3°
a = 3.7022 (5) ŵ = 28.18 mm1
c = 8.2137 (12) ÅT = 295 K
V = 112.58 (3) Å3Plate, silver
Z = 20.12 × 0.11 × 0.01 mm
F(000) = 210

Data collection

Enraf–Nonius CAD-4 diffractometer178 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.125
graphiteθmax = 34.8°, θmin = 2.5°
θ/2θ scansh = −5→5
Absorption correction: numerical (SHELXTL; Sheldrick, 2008)k = −5→5
Tmin = 0.117, Tmax = 0.718l = −13→13
1906 measured reflections3 standard reflections every 120 min
181 independent reflections intensity decay: none

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.032w = 1/[σ2(Fo2) + (0.044P)2 + 0.3679P] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.081(Δ/σ)max < 0.001
S = 1.17Δρmax = 1.95 e Å3
181 reflectionsΔρmin = −2.53 e Å3
10 parametersExtinction correction: SHELXTL (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraintsExtinction coefficient: 0.038 (9)

Special details

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)

xyzUiso*/Ueq
Ti0.25000.25000.24875 (16)0.0054 (3)
Ge0.75000.25000.00000.0063 (3)
Sb0.25000.25000.61556 (6)0.0063 (3)

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Ti0.0060 (4)0.0060 (4)0.0043 (6)0.0000.0000.000
Ge0.0065 (4)0.0065 (4)0.0059 (4)0.0000.0000.000
Sb0.0056 (3)0.0056 (3)0.0076 (4)0.0000.0000.000

Geometric parameters (Å, °)

Ti—Gei2.7570 (10)Ge—Geix2.6179 (3)
Ti—Geii2.7570 (10)Ge—Tii2.7570 (10)
Ti—Geiii2.7570 (10)Ge—Tix2.7570 (10)
Ti—Ge2.7570 (10)Ge—Tiiii2.7570 (10)
Ti—Sbiv2.8452 (7)Sb—Tiiv2.8452 (7)
Ti—Sbv2.8452 (7)Sb—Tiv2.8452 (7)
Ti—Sbvi2.8452 (7)Sb—Tivi2.8452 (7)
Ti—Sbvii2.8452 (7)Sb—Tivii2.8452 (7)
Ti—Sb3.0129 (14)Sb—Sbv3.2337 (7)
Ge—Geviii2.6179 (4)Sb—Sbiv3.2337 (7)
Ge—Gei2.6179 (4)Sb—Sbvii3.2337 (7)
Ge—Geiii2.6179 (4)Sb—Sbvi3.2337 (7)
Gei—Ti—Geii56.69 (2)Tii—Ge—Tix123.31 (2)
Gei—Ti—Geiii84.35 (4)Geviii—Ge—Ti118.344 (11)
Geii—Ti—Geiii56.69 (2)Gei—Ge—Ti61.656 (11)
Gei—Ti—Ge56.69 (2)Geiii—Ge—Ti61.656 (11)
Geii—Ti—Ge84.35 (4)Geix—Ge—Ti118.344 (11)
Geiii—Ti—Ge56.69 (2)Tii—Ge—Ti123.31 (2)
Gei—Ti—Sbiv136.65 (2)Tix—Ge—Ti84.35 (4)
Geii—Ti—Sbiv136.65 (2)Geviii—Ge—Tiiii61.656 (11)
Geiii—Ti—Sbiv81.574 (14)Gei—Ge—Tiiii118.344 (11)
Ge—Ti—Sbiv81.574 (14)Geiii—Ge—Tiiii61.656 (11)
Gei—Ti—Sbv81.574 (14)Geix—Ge—Tiiii118.344 (11)
Geii—Ti—Sbv81.574 (14)Tii—Ge—Tiiii84.35 (4)
Geiii—Ti—Sbv136.65 (2)Tix—Ge—Tiiii123.31 (2)
Ge—Ti—Sbv136.65 (2)Ti—Ge—Tiiii123.31 (2)
Sbiv—Ti—Sbv133.88 (5)Tiiv—Sb—Tiv133.88 (5)
Gei—Ti—Sbvi136.65 (2)Tiiv—Sb—Tivi81.17 (2)
Geii—Ti—Sbvi81.574 (14)Tiv—Sb—Tivi81.17 (2)
Geiii—Ti—Sbvi81.574 (14)Tiiv—Sb—Tivii81.17 (2)
Ge—Ti—Sbvi136.65 (2)Tiv—Sb—Tivii81.17 (2)
Sbiv—Ti—Sbvi81.17 (2)Tivi—Sb—Tivii133.88 (5)
Sbv—Ti—Sbvi81.17 (2)Tiiv—Sb—Ti113.06 (3)
Gei—Ti—Sbvii81.574 (14)Tiv—Sb—Ti113.06 (3)
Geii—Ti—Sbvii136.65 (2)Tivi—Sb—Ti113.06 (3)
Geiii—Ti—Sbvii136.65 (2)Tivii—Sb—Ti113.06 (3)
Ge—Ti—Sbvii81.574 (14)Tiiv—Sb—Sbv167.11 (4)
Sbiv—Ti—Sbvii81.17 (2)Tiv—Sb—Sbv59.01 (3)
Sbv—Ti—Sbvii81.17 (2)Tivi—Sb—Sbv103.295 (14)
Sbvi—Ti—Sbvii133.88 (5)Tivii—Sb—Sbv103.295 (14)
Gei—Ti—Sb137.823 (19)Ti—Sb—Sbv54.051 (16)
Geii—Ti—Sb137.823 (19)Tiiv—Sb—Sbiv59.01 (3)
Geiii—Ti—Sb137.823 (19)Tiv—Sb—Sbiv167.11 (4)
Ge—Ti—Sb137.823 (19)Tivi—Sb—Sbiv103.295 (14)
Sbiv—Ti—Sb66.94 (3)Tivii—Sb—Sbiv103.295 (14)
Sbv—Ti—Sb66.94 (3)Ti—Sb—Sbiv54.051 (16)
Sbvi—Ti—Sb66.94 (3)Sbv—Sb—Sbiv108.10 (3)
Sbvii—Ti—Sb66.94 (3)Tiiv—Sb—Sbvii103.295 (14)
Geviii—Ge—Gei180.0Tiv—Sb—Sbvii103.295 (14)
Geviii—Ge—Geiii90.0Tivi—Sb—Sbvii167.11 (4)
Gei—Ge—Geiii90.0Tivii—Sb—Sbvii59.01 (3)
Geviii—Ge—Geix90.0Ti—Sb—Sbvii54.051 (16)
Gei—Ge—Geix90.0Sbv—Sb—Sbvii69.840 (16)
Geiii—Ge—Geix180.0Sbiv—Sb—Sbvii69.840 (16)
Geviii—Ge—Tii118.344 (11)Tiiv—Sb—Sbvi103.295 (14)
Gei—Ge—Tii61.656 (11)Tiv—Sb—Sbvi103.295 (14)
Geiii—Ge—Tii118.344 (11)Tivi—Sb—Sbvi59.01 (3)
Geix—Ge—Tii61.656 (11)Tivii—Sb—Sbvi167.11 (4)
Geviii—Ge—Tix61.656 (11)Ti—Sb—Sbvi54.051 (16)
Gei—Ge—Tix118.344 (11)Sbv—Sb—Sbvi69.840 (16)
Geiii—Ge—Tix118.344 (11)Sbiv—Sb—Sbvi69.840 (16)
Geix—Ge—Tix61.656 (11)Sbvii—Sb—Sbvi108.10 (3)

Symmetry codes: (i) −x+1, −y, −z; (ii) x−1, y, z; (iii) −x+1, −y+1, −z; (iv) −x+1, −y+1, −z+1; (v) −x, −y, −z+1; (vi) −x, −y+1, −z+1; (vii) −x+1, −y, −z+1; (viii) −x+2, −y+1, −z; (ix) −x+2, −y, −z; (x) x+1, y, z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: WM2247).

References

  • Dashjav, E. & Kleinke, H. (2002). Z. Anorg. Allg. Chem.628, 2176.
  • Dowty, E. (1999). ATOMS Shape Software, Kingsport, Tennessee, USA.
  • Enraf–Nonius (1993). CAD-4-PC Enraf–Nonius, Delft, The Netherlands.
  • Harms, K. & Wocadlo, S. (1995). XCAD4 University of Marburg, Germany.
  • Kozlov, A. Yu. & Pavlyuk, V. V. (2004). J. Alloys Compd, 367, 76–79.
  • Lam, R. & Mar, A. (1997). J. Solid State Chem.134, 388–394.
  • Pauling, L. (1960). The Nature of the Chemical Bond, 3rd ed. Ithaca, NY: Cornell University Press.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Soheilnia, N., Assoud, A. & Kleinke, H. (2003). Inorg. Chem.42, 7319–7325. [PubMed]
  • Tremel, W. & Hoffmann, M. (1987). J. Am. Chem. Soc.109, 124–140.

Articles from Acta Crystallographica Section E: Structure Reports Online are provided here courtesy of International Union of Crystallography