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inorganic compounds
Redetermination of Ba2CdTe3 from single-crystal X-ray data
aState Key Laboratory of Crystal Materials, Institute of Crystal Materials, Shandong University, Jinan, Shandong 250100, People's Republic of China
*Correspondence e-mail: shqxia@sdu.edu.cn
The previous ). J. Solid State Chem. 148, 464–467]. In the current redetermination from single-crystal X-ray data, all atoms were refined with anisotropic displacement parameters. The previous structure report is generally confirmed, but with some differences in bond lengths. Ba2CdTe3 is isotypic with Ba2MX3 (M = Mn, Cd; X = S, Se) and features 1∞[CdTe2/2Te2/1]4− chains of corner-sharing CdTe4 tetrahedra running parallel [010]. The two Ba2+ cations are located between the chains, both within distorted monocapped trigonal–prismatic coordination polyhedra. All atoms in the structure are located on a mirror plane.
Related literature
For the previous determination of Ba2CdTe3, see: Wang & DiSalvo (1999). For isotypic compounds, see: Grey & Steinfink (1971
) for Ba2MnS3 and Ba2MnSe3; Iglesias et al. (1974
) for Ba2CdSe3 and Ba2CdS3.
Experimental
Crystal data
|
Data collection: APEX2 (Bruker, 2005); cell SAINT (Bruker, 2005
); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008
); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.
Supporting information
https://doi.org/10.1107/S1600536812038974/wm2681sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536812038974/wm2681Isup2.hkl
The title compound was synthesized through a high temperature metal
reaction. All starting elements were handled inside an Argon-filled with controlled oxygen and moisture levels below 0.1 p.p.m.. The reaction conditions were optimized as follows: Ba, Cd, Te and Bi in a molar ratio of 2:1:3:10 were loaded in an alumina crucible, which were subsequently flame-sealed in a fused silica tube. The reactants were heated quickly to 973 K and allowed to dwell at this temperature for 20 h. After a slow cooling process down to 773 K at a rate of 5 K/h and the removal of the Bi by centrifugation, high-quality single crystals of Ba2CdTe3 were obtained.The full occupancies for all sites were verified by freeing the site occupation factor for an individual atom, while other remaining parameters were kept fixed. This proved that all positions are fully occupied with corresponding deviations from full occupancy within 3σ. The residual electron densities show a maximum peak of 1.44 e/Å3 and a minimum hole of -1.27 e/Å3, which are 0.86 and 0.81 Å from Te3 and Te2, respectively.
Single crystals of Ba2CdTe3 were obtained unintentionally from a Bi-flux reactions for exploration of possible new ternary phases in the Ba—Cd—Te system.
The structure of Ba2CdTe3 is isotypic with Ba2MnX3 (X = S, Se; Grey & Steinfink, 1971) and Ba2CdX3 (X = S, Se; Iglesias et al., 1974). The structural set-up can be described as a packing of polyanionic chains composed of corner-sharing CdTe4 tetrahedra. These chains run parallel to [010]; inbetween the chains the two Ba2+ cations are located (Fig. 1), both with a
of 7 and surrounded in form of monocapped trigonal-prismatic polyhedra of Te atoms. All atoms are located on a mirror plane x, 1/4, z (Wyckoff symbol 4c).In comparison with the previous structure model on basis of powder X-ray data (Wang & DiSalvo, 1999), the most important improvement of the current redetermination is reflected in the higher precision of the atomic coordinates and the use of anisotropic displacemenet parameters for all atoms. Although the coordination spheres of Cd and the two Ba atoms can still be described as a distorted CdTe4 tetrahedron and two distorted monocapped trigonal BaTe7 prisms, respectively, the results of the redetermination indicate some differences in terms of Cd—Te and Ba—Te bond lengths (mean σ for the bond length of the powder model in the range 0.003 Å; 0.0006 for the current model). For example, the longest Ba—Te bonds are 3.6722 (8) and 3.6796 (8) Å for Ba1 and Ba2. The previous powder study revealed distances of 3.638 (5) and 3.500 (5) Å, respectively.
For the previous determination of Ba2CdTe3, see: Wang & DiSalvo (1999). For isotypic compounds, see: Grey & Steinfink (1971) for Ba2MnS3 and Ba2MnSe3; Iglesias et al. (1974) for Ba2CdSe3 and Ba2CdS3.
Data collection: APEX2 (Bruker, 2005); cell
SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).Ba2CdTe3 | F(000) = 1264 |
Mr = 769.88 | Dx = 5.727 Mg m−3 |
Orthorhombic, Pnma | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ac 2n | Cell parameters from 1715 reflections |
a = 9.8405 (2) Å | θ = 3.0–28.2° |
b = 4.7502 (1) Å | µ = 20.59 mm−1 |
c = 19.1008 (4) Å | T = 293 K |
V = 892.85 (3) Å3 | Needle, red |
Z = 4 | 0.07 × 0.03 × 0.03 mm |
Bruker APEXII CCD diffractometer | 1098 independent reflections |
Radiation source: fine-focus sealed tube | 858 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.031 |
φ and ω scans | θmax = 27.1°, θmin = 2.1° |
Absorption correction: multi-scan (SADABS; Bruker, 2005) | h = −12→9 |
Tmin = 0.348, Tmax = 0.627 | k = −3→6 |
4014 measured reflections | l = −24→15 |
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)] = 0.025 | w = 1/[σ2(Fo2) + (0.0142P)2] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.041 | (Δ/σ)max = 0.001 |
S = 0.99 | Δρmax = 1.44 e Å−3 |
1098 reflections | Δρmin = −1.27 e Å−3 |
38 parameters | Extinction correction: SHELXTL (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.00112 (6) |
Ba2CdTe3 | V = 892.85 (3) Å3 |
Mr = 769.88 | Z = 4 |
Orthorhombic, Pnma | Mo Kα radiation |
a = 9.8405 (2) Å | µ = 20.59 mm−1 |
b = 4.7502 (1) Å | T = 293 K |
c = 19.1008 (4) Å | 0.07 × 0.03 × 0.03 mm |
Bruker APEXII CCD diffractometer | 1098 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2005) | 858 reflections with I > 2σ(I) |
Tmin = 0.348, Tmax = 0.627 | Rint = 0.031 |
4014 measured reflections |
R[F2 > 2σ(F2)] = 0.025 | 38 parameters |
wR(F2) = 0.041 | 0 restraints |
S = 0.99 | Δρmax = 1.44 e Å−3 |
1098 reflections | Δρmin = −1.27 e Å−3 |
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 | Uiso*/Ueq | ||
Ba1 | 0.07317 (6) | 0.2500 | 0.78653 (3) | 0.01857 (16) | |
Ba2 | 0.24597 (6) | 0.2500 | 0.03873 (3) | 0.01918 (16) | |
Cd1 | 0.12996 (7) | 0.2500 | 0.36470 (3) | 0.01947 (18) | |
Te1 | 0.01147 (6) | 0.2500 | 0.59692 (3) | 0.01802 (17) | |
Te2 | 0.19335 (6) | 0.2500 | 0.22108 (3) | 0.01748 (16) | |
Te3 | 0.38656 (6) | 0.2500 | 0.42865 (3) | 0.01745 (17) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Ba1 | 0.0190 (3) | 0.0171 (3) | 0.0196 (4) | 0.000 | −0.0003 (3) | 0.000 |
Ba2 | 0.0209 (3) | 0.0191 (3) | 0.0175 (3) | 0.000 | −0.0013 (3) | 0.000 |
Cd1 | 0.0197 (4) | 0.0201 (4) | 0.0186 (4) | 0.000 | 0.0014 (3) | 0.000 |
Te1 | 0.0187 (4) | 0.0154 (3) | 0.0200 (4) | 0.000 | 0.0024 (3) | 0.000 |
Te2 | 0.0178 (4) | 0.0203 (3) | 0.0144 (4) | 0.000 | −0.0008 (3) | 0.000 |
Te3 | 0.0158 (4) | 0.0200 (3) | 0.0165 (4) | 0.000 | 0.0004 (3) | 0.000 |
Ba1—Te2i | 3.5331 (6) | Cd1—Te1iii | 2.8488 (5) |
Ba1—Te2ii | 3.5331 (6) | Cd1—Te1iv | 2.8488 (5) |
Ba1—Te2iii | 3.5413 (6) | Te1—Cd1iii | 2.8488 (5) |
Ba1—Te2iv | 3.5413 (6) | Te1—Cd1iv | 2.8488 (5) |
Ba1—Te3i | 3.6287 (6) | Te1—Ba2i | 3.5459 (6) |
Ba1—Te3ii | 3.6287 (6) | Te1—Ba2ii | 3.5459 (6) |
Ba1—Te1 | 3.6722 (8) | Te1—Ba2vii | 3.6796 (8) |
Ba2—Te3v | 3.4297 (6) | Te2—Ba1vi | 3.5331 (6) |
Ba2—Te3vi | 3.4297 (6) | Te2—Ba1v | 3.5331 (6) |
Ba2—Te2 | 3.5213 (8) | Te2—Ba1iii | 3.5413 (6) |
Ba2—Te1vi | 3.5459 (6) | Te2—Ba1iv | 3.5413 (6) |
Ba2—Te1v | 3.5459 (6) | Te3—Ba2i | 3.4297 (6) |
Ba2—Te3vii | 3.5913 (8) | Te3—Ba2ii | 3.4297 (6) |
Ba2—Te1viii | 3.6796 (8) | Te3—Ba2viii | 3.5913 (8) |
Cd1—Te3 | 2.8050 (9) | Te3—Ba1v | 3.6287 (6) |
Cd1—Te2 | 2.8133 (9) | Te3—Ba1vi | 3.6287 (6) |
Te2i—Ba1—Te2ii | 84.480 (18) | Te1iii—Cd1—Te1iv | 112.97 (3) |
Te2i—Ba1—Te2iii | 156.629 (18) | Cd1iii—Te1—Cd1iv | 112.97 (3) |
Te2ii—Ba1—Te2iii | 90.930 (5) | Cd1iii—Te1—Ba2i | 165.46 (2) |
Te2i—Ba1—Te2iv | 90.930 (5) | Cd1iv—Te1—Ba2i | 81.436 (14) |
Te2ii—Ba1—Te2iv | 156.629 (18) | Cd1iii—Te1—Ba2ii | 81.436 (14) |
Te2iii—Ba1—Te2iv | 84.241 (18) | Cd1iv—Te1—Ba2ii | 165.46 (2) |
Te2i—Ba1—Te3i | 75.741 (13) | Ba2i—Te1—Ba2ii | 84.104 (18) |
Te2ii—Ba1—Te3i | 129.32 (2) | Cd1iii—Te1—Ba1 | 80.038 (19) |
Te2iii—Ba1—Te3i | 123.41 (2) | Cd1iv—Te1—Ba1 | 80.038 (19) |
Te2iv—Ba1—Te3i | 70.888 (14) | Ba2i—Te1—Ba1 | 101.413 (18) |
Te2i—Ba1—Te3ii | 129.32 (2) | Ba2ii—Te1—Ba1 | 101.413 (18) |
Te2ii—Ba1—Te3ii | 75.741 (13) | Cd1iii—Te1—Ba2vii | 80.46 (2) |
Te2iii—Ba1—Te3ii | 70.888 (14) | Cd1iv—Te1—Ba2vii | 80.46 (2) |
Te2iv—Ba1—Te3ii | 123.41 (2) | Ba2i—Te1—Ba2vii | 104.904 (17) |
Te3i—Ba1—Te3ii | 81.769 (17) | Ba2ii—Te1—Ba2vii | 104.904 (17) |
Te2i—Ba1—Te1 | 76.026 (15) | Ba1—Te1—Ba2vii | 144.28 (2) |
Te2ii—Ba1—Te1 | 76.026 (15) | Cd1—Te2—Ba2 | 175.65 (3) |
Te2iii—Ba1—Te1 | 80.624 (16) | Cd1—Te2—Ba1vi | 78.412 (18) |
Te2iv—Ba1—Te1 | 80.624 (16) | Ba2—Te2—Ba1vi | 104.737 (17) |
Te3i—Ba1—Te1 | 139.101 (8) | Cd1—Te2—Ba1v | 78.412 (18) |
Te3ii—Ba1—Te1 | 139.101 (8) | Ba2—Te2—Ba1v | 104.737 (17) |
Te3v—Ba2—Te3vi | 87.658 (19) | Ba1vi—Te2—Ba1v | 84.480 (18) |
Te3v—Ba2—Te2 | 123.399 (16) | Cd1—Te2—Ba1iii | 82.866 (18) |
Te3vi—Ba2—Te2 | 123.399 (16) | Ba2—Te2—Ba1iii | 93.918 (17) |
Te3v—Ba2—Te1vi | 155.78 (2) | Ba1vi—Te2—Ba1iii | 161.261 (19) |
Te3vi—Ba2—Te1vi | 89.100 (12) | Ba1v—Te2—Ba1iii | 92.594 (5) |
Te2—Ba2—Te1vi | 77.814 (17) | Cd1—Te2—Ba1iv | 82.866 (18) |
Te3v—Ba2—Te1v | 89.100 (12) | Ba2—Te2—Ba1iv | 93.918 (17) |
Te3vi—Ba2—Te1v | 155.78 (2) | Ba1vi—Te2—Ba1iv | 92.594 (5) |
Te2—Ba2—Te1v | 77.814 (17) | Ba1v—Te2—Ba1iv | 161.261 (19) |
Te1vi—Ba2—Te1v | 84.104 (18) | Ba1iii—Te2—Ba1iv | 84.240 (18) |
Te3v—Ba2—Te3vii | 74.447 (16) | Cd1—Te3—Ba2i | 85.679 (19) |
Te3vi—Ba2—Te3vii | 74.447 (16) | Cd1—Te3—Ba2ii | 85.679 (19) |
Te2—Ba2—Te3vii | 71.552 (17) | Ba2i—Te3—Ba2ii | 87.658 (19) |
Te1vi—Ba2—Te3vii | 127.482 (15) | Cd1—Te3—Ba2viii | 164.18 (3) |
Te1v—Ba2—Te3vii | 127.482 (15) | Ba2i—Te3—Ba2viii | 105.553 (16) |
Te3v—Ba2—Te1viii | 80.695 (16) | Ba2ii—Te3—Ba2viii | 105.553 (16) |
Te3vi—Ba2—Te1viii | 80.695 (16) | Cd1—Te3—Ba1v | 76.852 (18) |
Te2—Ba2—Te1viii | 143.22 (2) | Ba2i—Te3—Ba1v | 162.44 (2) |
Te1vi—Ba2—Te1viii | 75.096 (17) | Ba2ii—Te3—Ba1v | 92.687 (10) |
Te1v—Ba2—Te1viii | 75.096 (17) | Ba2viii—Te3—Ba1v | 91.275 (17) |
Te3vii—Ba2—Te1viii | 145.23 (2) | Cd1—Te3—Ba1vi | 76.852 (18) |
Te3—Cd1—Te2 | 103.01 (3) | Ba2i—Te3—Ba1vi | 92.687 (10) |
Te3—Cd1—Te1iii | 109.13 (2) | Ba2ii—Te3—Ba1vi | 162.44 (2) |
Te2—Cd1—Te1iii | 111.05 (2) | Ba2viii—Te3—Ba1vi | 91.275 (17) |
Te3—Cd1—Te1iv | 109.13 (2) | Ba1v—Te3—Ba1vi | 81.769 (17) |
Te2—Cd1—Te1iv | 111.05 (2) |
Symmetry codes: (i) −x+1/2, −y+1, z+1/2; (ii) −x+1/2, −y, z+1/2; (iii) −x, −y, −z+1; (iv) −x, −y+1, −z+1; (v) −x+1/2, −y, z−1/2; (vi) −x+1/2, −y+1, z−1/2; (vii) x−1/2, y, −z+1/2; (viii) x+1/2, y, −z+1/2. |
Experimental details
Crystal data | |
Chemical formula | Ba2CdTe3 |
Mr | 769.88 |
Crystal system, space group | Orthorhombic, Pnma |
Temperature (K) | 293 |
a, b, c (Å) | 9.8405 (2), 4.7502 (1), 19.1008 (4) |
V (Å3) | 892.85 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 20.59 |
Crystal size (mm) | 0.07 × 0.03 × 0.03 |
Data collection | |
Diffractometer | Bruker APEXII CCD |
Absorption correction | Multi-scan (SADABS; Bruker, 2005) |
Tmin, Tmax | 0.348, 0.627 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4014, 1098, 858 |
Rint | 0.031 |
(sin θ/λ)max (Å−1) | 0.640 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.025, 0.041, 0.99 |
No. of reflections | 1098 |
No. of parameters | 38 |
Δρmax, Δρmin (e Å−3) | 1.44, −1.27 |
Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 2008).
Acknowledgements
The authors acknowledge financial support by the National Natural Science Foundation of China (20901047) and the Shandong Provincial Natural Science Foundation (ZR2010BM003).
References
Bruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Grey, I. E. & Steinfink, H. (1971). Inorg. Chem. 10, 691–696. Google Scholar
Iglesias, J. E., Pachali, K. E. & Steinfink, H. (1974). J. Solid State Chem. 9, 6–14. CrossRef CAS Web of Science Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Wang, Y. C. & DiSalvo, F. J. (1999). J. Solid State Chem. 148, 464–467. Web of Science CrossRef CAS Google Scholar
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Single crystals of Ba2CdTe3 were obtained unintentionally from a Bi-flux reactions for exploration of possible new ternary phases in the Ba—Cd—Te system.
The structure of Ba2CdTe3 is isotypic with Ba2MnX3 (X = S, Se; Grey & Steinfink, 1971) and Ba2CdX3 (X = S, Se; Iglesias et al., 1974). The structural set-up can be described as a packing of polyanionic chains composed of corner-sharing CdTe4 tetrahedra. These chains run parallel to [010]; inbetween the chains the two Ba2+ cations are located (Fig. 1), both with a coordination number of 7 and surrounded in form of monocapped trigonal-prismatic polyhedra of Te atoms. All atoms are located on a mirror plane x, 1/4, z (Wyckoff symbol 4c).
In comparison with the previous structure model on basis of powder X-ray data (Wang & DiSalvo, 1999), the most important improvement of the current redetermination is reflected in the higher precision of the atomic coordinates and the use of anisotropic displacemenet parameters for all atoms. Although the coordination spheres of Cd and the two Ba atoms can still be described as a distorted CdTe4 tetrahedron and two distorted monocapped trigonal BaTe7 prisms, respectively, the results of the redetermination indicate some differences in terms of Cd—Te and Ba—Te bond lengths (mean σ for the bond length of the powder model in the range 0.003 Å; 0.0006 for the current model). For example, the longest Ba—Te bonds are 3.6722 (8) and 3.6796 (8) Å for Ba1 and Ba2. The previous powder study revealed distances of 3.638 (5) and 3.500 (5) Å, respectively.