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ISSN: 2414-3146

Redetermination of the γ-form of tellurium dioxide

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aInstitute for Chemical Technologies and Analytics, Division of Structural Chemistry, TU Wien, Getreidemarkt 9/164-SC, A-1060 Vienna, Austria
*Correspondence e-mail: matthias.weil@tuwien.ac.at

Edited by W. T. A. Harrison, University of Aberdeen, Scotland (Received 5 December 2017; accepted 7 December 2017; online 12 December 2017)

The crystal structure of γ-TeO2 was redetermined on the basis of single-crystal X-ray diffraction data. The previous structure determination of this modification was based on laboratory powder X-ray diffraction data [Champarnaud-Mesjard et al. (2000[Champarnaud-Mesjard, J. C., Blanchandin, S., Thomas, P., Mirgorodsky, A., Merle-Méjean, T. & Frit, B. (2000). J. Phys. Chem. Solids, 61, 1499-1507.]). J. Phys. Chem. Solids, 61, 1499–1507]. The current redetermination revealed all atoms with anisotropic displacement parameters, accompanied with a much higher accuracy and precision in terms of bond lengths and angles, and the determination of the absolute structure. The crystal structure consists of TeO4 bis­phenoids that combine through corner-sharing of all their oxygen atoms into a three-dimensional framework.

3D view (loading...)
[Scheme 3D1]

Structure description

In a continuation of hydro­thermal phase formation studies to incorporate tetra­hedral XO4 groups (X = S, Se) into framework structures of divalent metal oxotellurates(IV) (metal = Ca, Cd, Hg, Mg, Pb, Sr, Zn; Weil & Shirkhanlou, 2015[Weil, M. & Shirkhanlou, M. (2015). Z. Anorg. Allg. Chem. 641, 1459-1466.], 2017a[Weil, M. & Shirkhanlou, M. (2017a). Z. Anorg. Allg. Chem. 643, 330-339.],b[Weil, M. & Shirkhanlou, M. (2017b). Z. Anorg. Allg. Chem. 643, 749-756.],c[Weil, M. & Shirkhanlou, M. (2017c). Z. Anorg. Allg. Chem. 643, 757-765.]), the system Mn/Se/Te/O was investigated. In one of these experiments, single crystals of γ-TeO2 were obtained serendipitously as a minor by-product.

Tellurium dioxide is polymorphic, with three reported crystalline forms at ambient pressure: the α-form (Lindqvist, 1968[Lindqvist, O. (1968). Acta Chem. Scand. 22, 977-982.]), the β-form (Beyer, 1967[Beyer, H. (1967). Z. Kristallogr. 124, 228-237.]) and the γ-form (Champarnaud-Mesjard et al., 2000[Champarnaud-Mesjard, J. C., Blanchandin, S., Thomas, P., Mirgorodsky, A., Merle-Méjean, T. & Frit, B. (2000). J. Phys. Chem. Solids, 61, 1499-1507.]). Whereas the α- and β-forms can be found in nature as the rare minerals paratellurite and tellurite, respectively, the γ-form is synthetic and can usually be obtained as a polycrystalline material by recrystallizing TeO2 glasses at low temperatures. This was also the procedure to prepare material for the previous structure determination of γ-TeO2 that was based on laboratory X-ray diffraction data and refined using the Rietveld method (Champarnaud-Mesjard et al., 2000[Champarnaud-Mesjard, J. C., Blanchandin, S., Thomas, P., Mirgorodsky, A., Merle-Méjean, T. & Frit, B. (2000). J. Phys. Chem. Solids, 61, 1499-1507.]). The results of the current rerefinement using modern CCD data are reported here. The previous structure model is confirmed, however, with higher accuracy and precision, as exemplified by a comparison of the bond lengths and angles (Table 1[link]). Moreover, the absolute structure of γ-TeO2 was determined (Table 2[link]).

Table 1
Comparison of bond lengths (Å) and angles (°) in the current and the previous refinement of γ-TeO2

  Current refinement Previous refinement a
Te1—O1 1.839 (3) 1.86 (2)
Te1—O2i 1.906 (3) 1.94 (2)
Te1—O2ii 2.048 (3) 2.02 (2)
Te1—O1iii 2.241 (4) 2.20 (2)
O1—Te1—O2i 100.36 (17) 99.2 (4)
O1—Te1—O2ii 93.14 (17) 91.8 (5)
O1—Te1—O1iii 91.69 (9) 91.9 (5)
O2i—Te1—O2ii 78.68 (9) 77.6 (5)
O2i—Te1—O1iii 75.60 (14) 76.1 (4)
O2ii—Te1—O1iii 154.28 (13) 153.6 (5)
Te1—O1—Te1iv 131.6 (2) 133.1 (5)
Te1v—O2—Te1vi 125.18 (18) 125.1 (5)
Symmetry codes: (i) x, y, z − 1; (ii) −x + [{3\over 2}], −y, z − [{1\over 2}]; (iii) x + [{1\over 2}], −y + [{1\over 2}], −z; (iv) x − [{1\over 2}], −y + [{1\over 2}], −z; (v) x, y, z + 1; (vi) −x + [{3\over 2}], −y, z + [{1\over 2}]. Notes: (a) Champarnaud-Mesjard et al. (2000[Champarnaud-Mesjard, J. C., Blanchandin, S., Thomas, P., Mirgorodsky, A., Merle-Méjean, T. & Frit, B. (2000). J. Phys. Chem. Solids, 61, 1499-1507.]); lattice parameters a = 4.898 (3), b = 8.576 (4), c = 4.351 (2) Å at room temperature.

Table 2
Experimental details

Crystal data
Chemical formula TeO2
Mr 159.60
Crystal system, space group Orthorhombic, P212121
Temperature (K) 296
a, b, c (Å) 4.8809 (2), 8.5668 (4), 4.3433 (2)
V3) 181.61 (1)
Z 4
Radiation type Mo Kα
μ (mm−1) 15.91
Crystal size (mm) 0.18 × 0.01 × 0.01
 
Data collection
Diffractometer Bruker APEXII CCD
Absorption correction Multi-scan (SADABS; Bruker, 2015[Bruker (2015). APEX2, SAINT and SADABS. Bruker AXS Inc. Madison, Wisconsin, USA.])
Tmin, Tmax 0.552, 0.747
No. of measured, independent and observed [I > 2σ(I)] reflections 7370, 893, 816
Rint 0.056
(sin θ/λ)max−1) 0.844
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.025, 0.037, 1.02
No. of reflections 893
No. of parameters 28
Δρmax, Δρmin (e Å−3) 1.81, −1.28
Absolute structure Flack x determined using 296 quotients [(I+)−(I)]/[(I+)+(I)] (Parsons et al., 2013[Parsons, S., Flack, H. D. & Wagner, T. (2013). Acta Cryst. B69, 249-259.])
Absolute structure parameter −0.03 (4)
Coordinates were taken from a previous refinement. Computer programs: APEX2 and SAINT (Bruker, 2015[Bruker (2015). APEX2, SAINT and SADABS. Bruker AXS Inc. Madison, Wisconsin, USA.]), SHELXL2014/7 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]), ATOMS (Dowty, 2006[Dowty, E. (2006). ATOMS. Shape Software, Kingsport, Tennessee, USA.]) and publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

In the crystal structure, the tellurium atom is surrounded by four oxygen atoms in the shape of a bis­phenoid, with a Te—O bond lengths range of 1.839 (3) – 2.241 (4) Å. Each TeO4 polyhedron is linked to four symmetry-related TeO4 polyhedra by sharing corners, which leads to the formation of a three-dimensional framework structure. Characteristic for the crystal chemistry of tellurium(IV) oxides or oxotellurates(IV) (Christy et al., 2016[Christy, A. G., Mills, S. J. & Kampf, A. R. (2016). Mineral. Mag. 80, 415-545.]), the 5s2 electron lone pair situated at the TeIV atom is stereochemically active and points towards the open space of this arrangement (Fig. 1[link]).

[Figure 1]
Figure 1
Projection of the crystal structure of γ-TeO2 along [101]. TeO4 groups are given as polyhedra (Te atoms red, O atoms colourless) with anisotropic displacement ellipsoids drawn at the 74% probability level.

Synthesis and crystallization

100 mg TeO2, 350 mg MnSeO4·H2O and 70 mg KOH were mixed and placed in a 5 ml capacity Teflon container that was subsequently filled with 2 ml water. The container was closed with a Teflon lid and placed in a steel autoclave for ten days at 483 K under autogenous pressure. After cooling down to room temperature, the solid reaction product was filtered off and washed with water and ethanol. The obtained material consisted of a dark-brown to black powder as the main product besides few light-brown plate-like crystals and very few colourless needles. Powder X-ray diffraction of the dark-brown material revealed Mn2TeO6 (Hund, 1971[Hund, F. (1971). Naturwissenschaften, 58, 323.]), and single-crystal X-ray diffraction showed the plate-like crystals to be spiro­ffite-type Mn2Te3O8 (Cooper & Hawthorne, 1996[Cooper, M. A. & Hawthorne, F. C. (1996). Can. Mineral. 34, 821-826.]); the colourless needles correspond to the title compound.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2[link]. Coordinates and atom labels were taken from the previous refinement (Champarnaud-Mesjard et al., 2000[Champarnaud-Mesjard, J. C., Blanchandin, S., Thomas, P., Mirgorodsky, A., Merle-Méjean, T. & Frit, B. (2000). J. Phys. Chem. Solids, 61, 1499-1507.]). The maximum and minimum electron density peaks are located 0.68 and 0.73 Å, respectively, from atom Te1.

Structural data


Computing details top

Data collection: APEX2 (Bruker, 2015); cell refinement: SAINT (Bruker, 2015); data reduction: SAINT (Bruker, 2015); program(s) used to solve structure: coordinates from previous refinement; program(s) used to refine structure: SHELXL2014/7 (Sheldrick, 2015); molecular graphics: ATOMS (Dowty, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

(I) top
Crystal data top
O2TeDx = 5.837 Mg m3
Mr = 159.60Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, P212121Cell parameters from 2511 reflections
a = 4.8809 (2) Åθ = 4.8–32.2°
b = 8.5668 (4) ŵ = 15.91 mm1
c = 4.3433 (2) ÅT = 296 K
V = 181.61 (1) Å3Needle, colourless
Z = 40.18 × 0.01 × 0.01 mm
F(000) = 272
Data collection top
Bruker APEXII CCD
diffractometer
816 reflections with I > 2σ(I)
ω–scans'Rint = 0.056
Absorption correction: multi-scan
(SADABS; Bruker, 2015)
θmax = 36.9°, θmin = 4.8°
Tmin = 0.552, Tmax = 0.747h = 88
7370 measured reflectionsk = 1414
893 independent reflectionsl = 77
Refinement top
Refinement on F2Primary atom site location: isomorphous structure methods
Least-squares matrix: full w = 1/[σ2(Fo2) + (0.014P)2 + 0.0171P]
where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.025(Δ/σ)max < 0.001
wR(F2) = 0.037Δρmax = 1.81 e Å3
S = 1.02Δρmin = 1.28 e Å3
893 reflectionsAbsolute structure: Flack x determined using 296 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013)
28 parametersAbsolute structure parameter: 0.03 (4)
0 restraints
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Te10.96976 (6)0.10122 (4)0.13698 (7)0.01056 (7)
O10.7704 (7)0.2822 (4)0.1778 (9)0.0147 (8)
O20.8602 (7)0.0379 (4)0.7347 (8)0.0140 (7)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Te10.01128 (12)0.00983 (11)0.01058 (11)0.00182 (11)0.00163 (11)0.00096 (13)
O10.0143 (16)0.0114 (17)0.018 (2)0.0056 (12)0.0012 (14)0.0006 (15)
O20.0144 (18)0.0200 (19)0.0075 (15)0.0067 (14)0.0006 (13)0.0036 (14)
Geometric parameters (Å, º) top
Te1—O11.839 (3)O1—Te1iv2.241 (3)
Te1—O2i1.906 (3)O2—Te1v1.906 (3)
Te1—O2ii2.048 (3)O2—Te1vi2.048 (3)
Te1—O1iii2.241 (4)
O1—Te1—O2i100.36 (17)O2i—Te1—O1iii75.60 (14)
O1—Te1—O2ii93.14 (17)O2ii—Te1—O1iii154.28 (13)
O2i—Te1—O2ii78.68 (9)Te1—O1—Te1iv131.6 (2)
O1—Te1—O1iii91.69 (9)Te1v—O2—Te1vi125.18 (18)
Symmetry codes: (i) x, y, z1; (ii) x+3/2, y, z1/2; (iii) x+1/2, y+1/2, z; (iv) x1/2, y+1/2, z; (v) x, y, z+1; (vi) x+3/2, y, z+1/2.
Comparison of bond lengths (Å) and angles (°) in the current and the previous refinement of γ-TeO2 top
Current refinementPrevious refinement a
Te1—O11.839 (3)1.86 (2)
Te1—O2i1.906 (3)1.94 (2)
Te1—O2ii2.048 (3)2.02 (2)
Te1—O1iii2.241 (4)2.20 (2)
O1—Te1—O2i100.36 (17)99.2 (4)
O1—Te1—O2ii93.14 (17)91.8 (5)
O1—Te1—O1iii91.69 (9)91.9 (5)
O2i—Te1—O2ii78.68 (9)77.6 (5)
O2i—Te1—O1iii75.60 (14)76.1 (4)
O2ii—Te1—O1iii154.28 (13)153.6 (5)
Te1—O1—Te1iv131.6 (2)133.1 (5)
Te1v—O2—Te1vi125.18 (18)125.1 (5)
Symmetry codes: (i) x, y, z - 1; (ii) -x + 3/2, -y, z - 1/2; (iii) x + 1/2, -y + 1/2, -z; (iv) x - 1/2, -y + 1/2, -z; (v) x, y, z + 1; (vi) -x + 3/2, -y, z + 1/2. Notes: (a) Champarnaud-Mesjard et al. (2000); lattice parameters a = 4.898 (3), b = 8.576 (4), c = 4.351 (2) Å at room temperature.
 

Acknowledgements

The X-ray centre of TU Wien is acknowledged for financial support and for providing access to the single-crystal and powder X-ray diffractometers.

References

First citationBeyer, H. (1967). Z. Kristallogr. 124, 228–237.  CrossRef CAS Google Scholar
First citationBruker (2015). APEX2, SAINT and SADABS. Bruker AXS Inc. Madison, Wisconsin, USA.  Google Scholar
First citationChamparnaud-Mesjard, J. C., Blanchandin, S., Thomas, P., Mirgorodsky, A., Merle-Méjean, T. & Frit, B. (2000). J. Phys. Chem. Solids, 61, 1499–1507.  CAS Google Scholar
First citationChristy, A. G., Mills, S. J. & Kampf, A. R. (2016). Mineral. Mag. 80, 415–545.  Web of Science CrossRef CAS Google Scholar
First citationCooper, M. A. & Hawthorne, F. C. (1996). Can. Mineral. 34, 821–826.  CAS Google Scholar
First citationDowty, E. (2006). ATOMS. Shape Software, Kingsport, Tennessee, USA.  Google Scholar
First citationHund, F. (1971). Naturwissenschaften, 58, 323.  CrossRef Google Scholar
First citationLindqvist, O. (1968). Acta Chem. Scand. 22, 977–982.  CrossRef CAS Web of Science Google Scholar
First citationParsons, S., Flack, H. D. & Wagner, T. (2013). Acta Cryst. B69, 249–259.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSheldrick, G. M. (2015). Acta Cryst. C71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar
First citationWeil, M. & Shirkhanlou, M. (2015). Z. Anorg. Allg. Chem. 641, 1459–1466.  CrossRef CAS Google Scholar
First citationWeil, M. & Shirkhanlou, M. (2017a). Z. Anorg. Allg. Chem. 643, 330–339.  CrossRef CAS Google Scholar
First citationWeil, M. & Shirkhanlou, M. (2017b). Z. Anorg. Allg. Chem. 643, 749–756.  CrossRef CAS Google Scholar
First citationWeil, M. & Shirkhanlou, M. (2017c). Z. Anorg. Allg. Chem. 643, 757–765.  CrossRef CAS Google Scholar
First citationWestrip, S. P. (2010). J. Appl. Cryst. 43, 920–925.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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