supplementary materials
Stoichiometric ZrGeTe4
Zirconium germanium tetratelluride, ZrGeTe4, is isostructural with Hf0.85GeTe4 [Mar & Ibers (1993). J. Am Chem. Soc. 115, 3227-3238], but the Zr site in ZrGeTe4 is fully occupied and the compound is stoichiometric. ZrGeTe4 adopts a layered structural type. Each layer is composed of two unique one-dimensional chains of face-sharing Zr-centered bicapped trigonal prisms and corner-sharing Ge-centered tetrahedra.
ZrGeTe4 was obtained from a reaction of Zr(CERAC, 99.7%), Ge(CERAC, 99.999%) and Te(CERAC, 99.95%) in an elemental ratio of 1:1:4 in the presence of KCl as flux. The mass ratio of reactants and flux was 1:2. The starting materials were placed in a fused-silica tube. The tube was evacuated to 10−3 torr, sealed, and heated to 973 K at a rate of 15 K/hr, where it was kept for 72 hrs. The tube was cooled at a rate of 8 K/hr to 373 K and the furnace was shut off. Air- and water-stable metallic shiny needle-shaped crystals were isolated after the flux was removed with water. Qualitative analysis of the crystals with a WDX-equipped scanning electron microscope indicated the presence of Zr, Ge, and Te. No other element was detected.
Although the anisotropic displacement parameters (ADPs) of the Zr atom were comparable to those of the other atoms, the nonstoichiometry of Zr in ZrGeTe4 was checked by refining the occupancy and ADPs of Zr while those of the other atoms were fixed. With the nonstoichiometric model, both parameter were not changed significantly and the residuals (wR2, R1 indices) were remained the same. The highest peak/deepest hole in the Fourier map are found 1.74Å from Te2 and 0.73Å from Te3.
Data collection: RAPID-AUTO (Rigaku, 2006); cell refinement: RAPID-AUTO (Rigaku, 2006); data reduction: RAPID-AUTO (Rigaku, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: locally modified version of ORTEP (Johnson, 1965); software used to prepare material for publication: WinGX (Farrugia, 1999).
Zirconium germanium tetratelluride
top
Crystal data top
| ZrGeTe4 | F(000) = 1120 |
| Mr = 674.24 | Dx = 6.425 Mg m−3 |
| Orthorhombic, Cmc21 | Mo Kα radiation, λ = 0.71073 Å |
| Hall symbol: C 2c -2 | Cell parameters from 3442 reflections |
| a = 3.9794 (2) Å | θ = 3.2–27.5° |
| b = 15.9296 (10) Å | µ = 22.09 mm−1 |
| c = 10.9957 (6) Å | T = 150 K |
| V = 697.02 (7) Å3 | Needle, metallic silver |
| Z = 4 | 0.50 × 0.03 × 0.02 mm |
Data collection top
Rigaku R-AXIS RAPID
diffractometer | 899 reflections with I > 2σ(I) |
| ω scans | Rint = 0.081 |
Absorption correction: numerical
(NUMABS; Higashi, 2000) | θmax = 27.5°, θmin = 3.2° |
| Tmin = 0.482, Tmax = 0.625 | h = −5→4 |
| 3351 measured reflections | k = −20→20 |
| 904 independent reflections | l = −13→14 |
Refinement top
| Refinement on F2 | w = 1/[σ2(Fo2) + (0.0268P)2 + 0.122P]
where P = (Fo2 + 2Fc2)/3 |
| Least-squares matrix: full | (Δ/σ)max < 0.001 |
| R[F2 > 2σ(F2)] = 0.036 | Δρmax = 1.40 e Å−3 |
| wR(F2) = 0.080 | Δρmin = −2.31 e Å−3 |
| S = 1.07 | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
| 904 reflections | Extinction coefficient: 0.0134 (6) |
| 38 parameters | Absolute structure: Flack (1983), 420 Friedel pairs |
| 1 restraint | Flack parameter: −0.01 (3) |
Crystal data top
| ZrGeTe4 | V = 697.02 (7) Å3 |
| Mr = 674.24 | Z = 4 |
| Orthorhombic, Cmc21 | Mo Kα radiation |
| a = 3.9794 (2) Å | µ = 22.09 mm−1 |
| b = 15.9296 (10) Å | T = 150 K |
| c = 10.9957 (6) Å | 0.50 × 0.03 × 0.02 mm |
Data collection top
Rigaku R-AXIS RAPID
diffractometer | 904 independent reflections |
Absorption correction: numerical
(NUMABS; Higashi, 2000) | 899 reflections with I > 2σ(I) |
| Tmin = 0.482, Tmax = 0.625 | Rint = 0.081 |
| 3351 measured reflections | θmax = 27.5° |
Refinement top
| R[F2 > 2σ(F2)] = 0.036 | 1 restraint |
| wR(F2) = 0.080 | Δρmax = 1.40 e Å−3 |
| S = 1.07 | Δρmin = −2.31 e Å−3 |
| 904 reflections | Absolute structure: Flack (1983), 420 Friedel pairs |
| 38 parameters | Flack parameter: −0.01 (3) |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top| | x | y | z | Uiso*/Ueq | |
| Zr | 0.0000 | 0.34835 (8) | 0.77333 (11) | 0.0065 (3) | |
| Ge | 0.0000 | 0.22779 (8) | 0.96377 (13) | 0.0077 (3) | |
| Te1 | 0.5000 | 0.48455 (5) | 0.74420 (8) | 0.0083 (2) | |
| Te2 | 0.5000 | 0.39999 (5) | 0.96079 (7) | 0.0084 (2) | |
| Te3 | 0.5000 | 0.22096 (6) | 0.69689 (7) | 0.0070 (2) | |
| Te4 | 0.0000 | 0.38129 (5) | 0.50002 (7) | 0.0073 (2) | |
Atomic displacement parameters (Å2) top| | U11 | U22 | U33 | U12 | U13 | U23 |
| Zr | 0.0068 (5) | 0.0086 (6) | 0.0042 (5) | 0.000 | 0.000 | 0.0001 (5) |
| Ge | 0.0079 (5) | 0.0108 (7) | 0.0044 (5) | 0.000 | 0.000 | 0.0008 (5) |
| Te1 | 0.0089 (3) | 0.0097 (5) | 0.0065 (4) | 0.000 | 0.000 | 0.0001 (3) |
| Te2 | 0.0087 (3) | 0.0117 (5) | 0.0048 (4) | 0.000 | 0.000 | −0.0012 (3) |
| Te3 | 0.0082 (3) | 0.0087 (4) | 0.0042 (4) | 0.000 | 0.000 | −0.0010 (3) |
| Te4 | 0.0071 (3) | 0.0094 (4) | 0.0053 (4) | 0.000 | 0.000 | 0.0006 (3) |
Geometric parameters (Å, °) top
| Zr—Ge | 2.8413 (17) | Ge—Te4iii | 2.6716 (10) |
| Zr—Te1 | 2.9612 (11) | Ge—Te3iii | 2.6903 (16) |
| Zr—Te1i | 2.9612 (11) | Te1—Te2 | 2.7361 (12) |
| Zr—Te3i | 2.9637 (11) | Te1—Zriv | 2.9612 (11) |
| Zr—Te3 | 2.9637 (11) | Te2—Zriv | 2.9806 (11) |
| Zr—Te2 | 2.9806 (11) | Te3—Gev | 2.6903 (16) |
| Zr—Te2i | 2.9806 (11) | Te3—Zriv | 2.9637 (11) |
| Zr—Te4 | 3.0507 (15) | Te4—Gevi | 2.6716 (10) |
| Ge—Te4ii | 2.6716 (10) | Te4—Gev | 2.6716 (10) |
| | | |
| Ge—Zr—Te1 | 125.10 (4) | Te1i—Zr—Te4 | 76.55 (4) |
| Ge—Zr—Te1i | 125.10 (4) | Te3i—Zr—Te4 | 80.70 (3) |
| Te1—Zr—Te1i | 84.43 (4) | Te3—Zr—Te4 | 80.70 (3) |
| Ge—Zr—Te3i | 75.30 (4) | Te2—Zr—Te4 | 129.33 (3) |
| Te1—Zr—Te3i | 157.24 (5) | Te2i—Zr—Te4 | 129.33 (3) |
| Te1i—Zr—Te3i | 91.14 (2) | Te4ii—Ge—Te4iii | 96.28 (5) |
| Ge—Zr—Te3 | 75.30 (4) | Te4ii—Ge—Te3iii | 93.17 (5) |
| Te1—Zr—Te3 | 91.14 (2) | Te4iii—Ge—Te3iii | 93.17 (5) |
| Te1i—Zr—Te3 | 157.24 (5) | Te4ii—Ge—Zr | 123.34 (4) |
| Te3i—Zr—Te3 | 84.34 (4) | Te4iii—Ge—Zr | 123.34 (4) |
| Ge—Zr—Te2 | 71.15 (3) | Te3iii—Ge—Zr | 119.81 (6) |
| Te1—Zr—Te2 | 54.84 (3) | Te2—Te1—Zr | 62.94 (3) |
| Te1i—Zr—Te2 | 108.73 (5) | Te2—Te1—Zriv | 62.94 (3) |
| Te3i—Zr—Te2 | 146.43 (5) | Zr—Te1—Zriv | 84.43 (4) |
| Te3—Zr—Te2 | 86.38 (2) | Te1—Te2—Zr | 62.22 (3) |
| Ge—Zr—Te2i | 71.15 (3) | Te1—Te2—Zriv | 62.22 (3) |
| Te1—Zr—Te2i | 108.73 (5) | Zr—Te2—Zriv | 83.76 (4) |
| Te1i—Zr—Te2i | 54.84 (3) | Gev—Te3—Zriv | 93.58 (4) |
| Te3i—Zr—Te2i | 86.38 (2) | Gev—Te3—Zr | 93.58 (4) |
| Te3—Zr—Te2i | 146.43 (5) | Zriv—Te3—Zr | 84.34 (4) |
| Te2—Zr—Te2i | 83.76 (4) | Gevi—Te4—Gev | 96.28 (5) |
| Ge—Zr—Te4 | 147.38 (6) | Gevi—Te4—Zr | 92.01 (4) |
| Te1—Zr—Te4 | 76.55 (4) | Gev—Te4—Zr | 92.01 (4) |
| Symmetry codes: (i) x−1, y, z; (ii) −x−1/2, −y+1/2, z+1/2; (iii) −x+1/2, −y+1/2, z+1/2; (iv) x+1, y, z; (v) −x+1/2, −y+1/2, z−1/2; (vi) −x−1/2, −y+1/2, z−1/2. |
Table 1
Selected geometric parameters (Å, °) top| Zr—Ge | 2.8413 (17) | Zr—Te2i | 2.9806 (11) |
| Zr—Te1 | 2.9612 (11) | Zr—Te4 | 3.0507 (15) |
| Zr—Te1i | 2.9612 (11) | Ge—Te4ii | 2.6716 (10) |
| Zr—Te3i | 2.9637 (11) | Ge—Te4iii | 2.6716 (10) |
| Zr—Te3 | 2.9637 (11) | Ge—Te3iii | 2.6903 (16) |
| Zr—Te2 | 2.9806 (11) | Te1—Te2 | 2.7361 (12) |
| | | |
| Te4ii—Ge—Te4iii | 96.28 (5) | Te4iii—Ge—Zr | 123.34 (4) |
| Te4iii—Ge—Te3iii | 93.17 (5) | Te3iii—Ge—Zr | 119.81 (6) |
| Symmetry codes: (i) x−1, y, z; (ii) −x−1/2, −y+1/2, z+1/2; (iii) −x+1/2, −y+1/2, z+1/2. |
This research was supported by the Korean Research Foundation (KRF-2006–521-C00088). Use was made of the X-ray facilities supported by Ajou University.
Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.
Flack, H. D. (1983). Acta Cryst. A39, 876–881.
Furuseth, S., Brattås, L. & Kjekshus, A. (1973). Acta Chem. Scand. 27, 2367–2374.
Higashi, T. (2000). NUMABS. Rigaku Corporation, Tokyo, Japan.
Johnson, C. K. (1965). ORTEP. Report ORNL-3794. Oak Ridge National Laboratory, Tennessee, USA.
Mar, A. & Ibers, J. (1993). J. Am. Chem. Soc. 115, 3227–3238.
Rigaku (2006). RAPID-AUTO. Rigaku Corporation, Tokyo, Japan.
Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.
![[Figure 1]](./fi2044fig1thm.gif)
![[Figure 2]](./fi2044fig2thm.gif)
The title compound is isostructural with Hf0.85GeTe4 (Mar & Ibers, 1993). A view of the structure down the a axis in Fig. 1 shows the layered nature of the compound. Fig 2. shows that an individual layer is composed of two unique one-dimensional chains of face-sharing Zr-centered bicapped trigonal prisms and corner-sharing Ge-centered tetrahedra.
The Zr atom is surrounded by six Te atoms in a trigonal prismatic manner, the vertices of two base sides of the prism are composed of six Te atoms. Atoms Te1, Te2, and Te3 form a triangle that is isosceles, the Te1—Te2 distance (2.736 (1) Å) being much shorter than the other two (> 3.0 Å). This short Te1—Te2 separation is typical of (Te—Te)2− pair (Furuseth et al., 1973). Te4 and Ge cap two of the rectangular faces of the trigonal prism to complete the Zr-centered bicapped trigonal prismatic coordination. These trigonal prisms share their triangular faces to form an infinite chain, ∞1[ZrGeTe4] along the direction of the a axis.
The Ge atom is surrounded by three Te and one Zr atoms in a distorted tetrahedral fashion. These tetrahedra share their corners through the Te4 atom to form an infinite chain. The bicapped trigonal prismatic and the tetrahedral chains are fused through Zr—Ge bonds to form a double chain and finally these chains are connected along the c axis to complete the two-dimensional layer. These layers then stack on top of each other to form the three-dimensional structure with an undulating van der Waals gap shown in Fig. 1.
We have checked many crystals from different reactions with various starting Zr/Te and Hf/Te ratios. We were not able to find nonstoichiometric M0.85GeTe4 (M=Zr, Hf) phases and we believe that the nature of the nonstoichiometry varies depending on the synthetic method.