supplementary materials
Ga2(TeO3)3(H2O)3
The title compound, digallium(III) tris[tellurate(IV)] trihydrate, was obtained under hydrothermal conditions. It is isotypic with the analogous selenates(IV) of formula type MIII2(SeO3)3(H2O)3 (MIII = Al, Cr, Fe, Sc, Ga) and comprises isolated GaO6 and GaO3(H2O)3 octahedra as well as TeO3 trigonal pyramids as single building units. These polyhedra share corners and thereby establish a network structure. Additional hydrogen bonding between the water molecules and O atoms helps to stabilize this arrangement. Both crystallographically independent Ga atoms are located on threefold rotation axes. The crystal used was an inversion twin.
All chemicals used were of analytical grade (Merck) and employed without further purification. 159.6 mg TeO2 and 400 mg Ga2(SO4)3.xH2O were placed in a Teflon inlay with 5 ml capacity. The inlay was charged with two-thirds of a 20%wt NH4OH solution, sealed, placed in a steel autoclave and heated at 493 K for 6 d. The obtained material consisted of colourless crystals with unspecific habit. X-ray powder diffraction of the bulk revealed (I) as the main product, TeO2 (paratellurite) as a minor product, and a few additional reflections which could not be assigned to any known phase.
The coordinates of all non-H atoms of the isotypic compound Fe2(SeO3)3(H2O)3 (Giester & Pertlik, 1994) were used as starting parameters. Both H positions were found in difference Fourier maps. Their positions were refined freely with a common Uiso parameter. The measured crystal was racemically twinned, with an approximate twin ratio of 1:1 (Flack parameter 0.542 (16)). The highest remaining peak in the final difference Fourier map is 0.03 away from Te and the deepest hole is 0.59 Å away from the same atom.
Data collection: CAD-4 Software (Enraf–Nonius, 1989); cell refinement: CAD-4 Software (Enraf–Nonius, 1989); data reduction: HELENA implemented in PLATON (Spek, 2003); program(s) used to solve structure: coordinates taken from an isotypic structure (Giester & Pertlik, 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ATOMS (Dowty, 2006); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).
digallium(III) tris[tellurate(IV)] trihydrate
top
Crystal data top
| Ga2(TeO3)3(H2O)3 | Z = 6 |
| Mr = 720.29 | F000 = 1920 |
| Hexagonal, R3c | Dx = 4.474 Mg m−3 |
| Hall symbol: R 3 -2"c | Mo Kα radiation
λ = 0.71073 Å |
| a = 9.5404 (13) Å | Cell parameters from 25 reflections |
| b = 9.5404 (13) Å | θ = 10.0–17.1º |
| c = 20.3472 (19) Å | µ = 13.12 mm−1 |
| α = 90º | T = 295 (2) K |
| β = 90º | Fragment, colourless |
| γ = 120º | 0.24 × 0.23 × 0.21 mm |
| V = 1603.9 (3) Å3 | |
Data collection top
Enraf–Nonius CAD-4
diffractometer | Rint = 0.069 |
| Radiation source: fine-focus sealed tube | θmax = 35.0º |
| Monochromator: graphite | θmin = 3.2º |
| T = 293(2) K | h = −15→15 |
| ω/2θ scans | k = −15→15 |
Absorption correction: numerical
(HABITUS; Herrendorf, 1997) | l = −32→32 |
| Tmin = 0.106, Tmax = 0.197 | 3 standard reflections |
| 8621 measured reflections | every 180 reflections |
| 1569 independent reflections | intensity decay: none |
| 1563 reflections with I > 2σ(I) | |
Refinement top
| Refinement on F2 | H atoms treated by a mixture of
independent and constrained refinement |
| Least-squares matrix: full | w = 1/[σ2(Fo2) + (0.0129P)2 + 4.6051P]
where P = (Fo2 + 2Fc2)/3 |
| R[F2 > 2σ(F2)] = 0.020 | (Δ/σ)max = 0.001 |
| wR(F2) = 0.040 | Δρmax = 1.47 e Å−3 |
| S = 1.16 | Δρmin = −1.31 e Å−3 |
| 1569 reflections | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
| 61 parameters | Extinction coefficient: 0.00111 (4) |
| 4 restraints | Absolute structure: Flack (1983), 780 Friedel pairs |
| Primary atom site location: isomorphous structure methods | Flack parameter: 0.542 (16) |
| Hydrogen site location: difference Fourier map | |
Crystal data top
| Ga2(TeO3)3(H2O)3 | γ = 120º |
| Mr = 720.29 | V = 1603.9 (3) Å3 |
| Hexagonal, R3c | Z = 6 |
| a = 9.5404 (13) Å | Mo Kα |
| b = 9.5404 (13) Å | µ = 13.12 mm−1 |
| c = 20.3472 (19) Å | T = 295 (2) K |
| α = 90º | 0.24 × 0.23 × 0.21 mm |
| β = 90º | |
Data collection top
Enraf–Nonius CAD-4
diffractometer | 1563 reflections with I > 2σ(I) |
Absorption correction: numerical
(HABITUS; Herrendorf, 1997) | Rint = 0.069 |
| Tmin = 0.106, Tmax = 0.197 | 3 standard reflections |
| 8621 measured reflections | every 180 reflections |
| 1569 independent reflections | intensity decay: none |
Refinement top
| R[F2 > 2σ(F2)] = 0.020 | H atoms treated by a mixture of
independent and constrained refinement |
| wR(F2) = 0.040 | Δρmax = 1.47 e Å−3 |
| S = 1.16 | Δρmin = −1.31 e Å−3 |
| 1569 reflections | Absolute structure: Flack (1983), 780 Friedel pairs |
| 61 parameters | Flack parameter: 0.542 (16) |
| 4 restraints | |
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 > 2sigma(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| | x | y | z | Uiso*/Ueq | |
| Ga1 | 0.0000 | 0.0000 | 0.09638 (2) | 0.00750 (10) | |
| Ga2 | 0.3333 | 0.6667 | 0.00547 (2) | 0.00893 (10) | |
| Te | 0.38972 (2) | 0.23787 (2) | 0.053606 (9) | 0.00860 (5) | |
| O1 | 0.1896 (3) | 0.0480 (3) | 0.04221 (10) | 0.0117 (4) | |
| O2 | 0.1524 (3) | 0.1845 (3) | 0.15207 (11) | 0.0146 (4) | |
| O3 | 0.4808 (3) | 0.1732 (3) | 0.12004 (11) | 0.0138 (4) | |
| O4 | 0.1786 (4) | 0.4827 (4) | 0.06755 (13) | 0.0238 (5) | |
| H1 | 0.208 (5) | 0.467 (5) | 0.1097 (16) | 0.017 (6)* | |
| H2 | 0.118 (5) | 0.378 (4) | 0.0461 (19) | 0.017 (6)* | |
Atomic displacement parameters (Å2) top| | U11 | U22 | U33 | U12 | U13 | U23 |
| Ga1 | 0.00780 (14) | 0.00780 (14) | 0.00689 (18) | 0.00390 (7) | 0.000 | 0.000 |
| Ga2 | 0.00992 (15) | 0.00992 (15) | 0.00694 (17) | 0.00496 (7) | 0.000 | 0.000 |
| Te | 0.00799 (9) | 0.00895 (9) | 0.00906 (6) | 0.00439 (7) | 0.00024 (5) | 0.00030 (5) |
| O1 | 0.0065 (8) | 0.0117 (10) | 0.0117 (8) | 0.0005 (7) | 0.0016 (7) | −0.0044 (7) |
| O2 | 0.0122 (10) | 0.0144 (10) | 0.0140 (8) | 0.0042 (8) | −0.0016 (7) | −0.0091 (8) |
| O3 | 0.0148 (10) | 0.0122 (10) | 0.0135 (8) | 0.0061 (9) | −0.0060 (8) | −0.0016 (7) |
| O4 | 0.0221 (13) | 0.0249 (14) | 0.0206 (11) | 0.0088 (11) | 0.0053 (10) | 0.0078 (10) |
Geometric parameters (Å, °) top
| Ga1—O1i | 1.966 (2) | Ga2—O4vi | 2.065 (3) |
| Ga1—O1 | 1.966 (2) | Ga2—O4 | 2.065 (3) |
| Ga1—O1ii | 1.966 (2) | Ga2—O4vii | 2.065 (3) |
| Ga1—O2 | 1.984 (2) | Te—O2viii | 1.865 (2) |
| Ga1—O2ii | 1.984 (2) | Te—O3 | 1.871 (2) |
| Ga1—O2i | 1.984 (2) | Te—O1 | 1.877 (2) |
| Ga2—O3iii | 1.973 (2) | O4—H1 | 0.94 (3) |
| Ga2—O3iv | 1.973 (2) | O4—H2 | 0.97 (3) |
| Ga2—O3v | 1.973 (2) | | |
| | | |
| O1i—Ga1—O1 | 91.65 (9) | O3v—Ga2—O4vi | 89.04 (12) |
| O1i—Ga1—O1ii | 91.65 (9) | O3iii—Ga2—O4 | 89.04 (12) |
| O1—Ga1—O1ii | 91.65 (9) | O3iv—Ga2—O4 | 174.70 (11) |
| O1i—Ga1—O2 | 176.01 (11) | O3v—Ga2—O4 | 90.39 (12) |
| O1—Ga1—O2 | 86.13 (9) | O4vi—Ga2—O4 | 86.49 (12) |
| O1ii—Ga1—O2 | 91.73 (11) | O3iii—Ga2—O4vii | 90.39 (12) |
| O1i—Ga1—O2ii | 91.73 (11) | O3iv—Ga2—O4vii | 89.04 (12) |
| O1—Ga1—O2ii | 176.01 (11) | O3v—Ga2—O4vii | 174.70 (11) |
| O1ii—Ga1—O2ii | 86.13 (9) | O4vi—Ga2—O4vii | 86.49 (12) |
| O2—Ga1—O2ii | 90.61 (10) | O4—Ga2—O4vii | 86.49 (12) |
| O1i—Ga1—O2i | 86.13 (9) | O2viii—Te—O3 | 94.37 (10) |
| O1—Ga1—O2i | 91.73 (11) | O2viii—Te—O1 | 91.62 (10) |
| O1ii—Ga1—O2i | 176.01 (11) | O3—Te—O1 | 100.80 (11) |
| O2—Ga1—O2i | 90.61 (10) | Te—O1—Ga1 | 121.95 (11) |
| O2ii—Ga1—O2i | 90.61 (10) | Teix—O2—Ga1 | 125.93 (14) |
| O3iii—Ga2—O3iv | 93.85 (10) | Te—O3—Ga2x | 121.25 (13) |
| O3iii—Ga2—O3v | 93.85 (10) | Ga2—O4—H1 | 124 (3) |
| O3iv—Ga2—O3v | 93.85 (10) | Ga2—O4—H2 | 114 (3) |
| O3iii—Ga2—O4vi | 174.70 (11) | H1—O4—H2 | 109 (3) |
| O3iv—Ga2—O4vi | 90.39 (12) | | |
| Symmetry codes: (i) −x+y, −x, z; (ii) −y, x−y, z; (iii) −x+y+2/3, y+1/3, z−1/6; (iv) −y+2/3, −x+4/3, z−1/6; (v) x−1/3, x−y+1/3, z−1/6; (vi) −x+y, −x+1, z; (vii) −y+1, x−y+1, z; (viii) −y+2/3, −x+1/3, z−1/6; (ix) −y+1/3, −x+2/3, z+1/6; (x) −y+4/3, −x+2/3, z+1/6. |
Hydrogen-bond geometry (Å, °) top
| D—H···A | D—H | H···A | D···A | D—H···A |
| O4—H1···O2 | 0.94 (3) | 2.62 (4) | 3.226 (4) | 123 (3) |
| O4—H1···O1ix | 0.94 (3) | 2.14 (3) | 3.060 (3) | 170 (4) |
| O4—H2···O1ii | 0.97 (3) | 2.01 (4) | 2.915 (4) | 154 (4) |
| Symmetry codes: (ix) −y+1/3, −x+2/3, z+1/6; (ii) −y, x−y, z. |
Selected geometric parameters (Å, °) top| Ga1—O1 | 1.966 (2) | Te—O2ii | 1.865 (2) |
| Ga1—O2 | 1.984 (2) | Te—O3 | 1.871 (2) |
| Ga2—O3i | 1.973 (2) | Te—O1 | 1.877 (2) |
| Ga2—O4 | 2.065 (3) | | |
| | | |
| O2ii—Te—O3 | 94.37 (10) | O3—Te—O1 | 100.80 (11) |
| O2ii—Te—O1 | 91.62 (10) | | |
| Symmetry codes: (i) −y+2/3, −x+4/3, z−1/6; (ii) −y+2/3, −x+1/3, z−1/6. |
Hydrogen-bond geometry (Å, °) top
| D—H···A | D—H | H···A | D···A | D—H···A |
| O4—H1···O2 | 0.94 (3) | 2.62 (4) | 3.226 (4) | 123 (3) |
| O4—H1···O1iii | 0.94 (3) | 2.14 (3) | 3.060 (3) | 170 (4) |
| O4—H2···O1iv | 0.97 (3) | 2.01 (4) | 2.915 (4) | 154 (4) |
| Symmetry codes: (iii) −y+1/3, −x+2/3, z+1/6; (iv) −y, x−y, z. |
Financial support of the FWF (Fonds zur Förderung der wissenschaftlichen Forschung; project No. P19099-N17) is gratefully acknowledged.
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![[Figure 1]](./mg2042fig1thm.gif)
![[Figure 2]](./mg2042fig2thm.gif)
In continuation of our studies concerning synthesis and crystal chemistry of tellurate(IV) compounds formed under hydrothermal conditions (e.g. Weil, 2005; 2007)), we report here on crystallization and the structure of Ga2(TeO3)3(H2O)3, (I). Compound (I) is the first tellurate(IV) crystallizing in the M2(SeO3)3(H2O)3 structure type (M = Al (Harrison, Stucky, Morris & Cheetham, 1992), Cr (Harrison, Stucky & Cheetham, 1992), Fe (Giester & Pertlik, 1994), Sc (Johnston & Harrison, 2004), Ga (Rastsvetaeva et al., 1986)).
(I) contains two Ga, one Te, four O and two H atoms in the asymmetric unit. The single building units are rather regular GaO6 and GaO3(H2O)3 octahedra and a trigonal–pyramidal TeO3 group (Fig. 1). The average Ga—O bond length of 1.975 Å for the GaO6 octahedron is slightly smaller than that of 2.019 Å for the GaO3(H2O)3 octahedron which is caused by the longer Ga—OH2 distance in comparison with the Ga—O distances (see Table). Whereas the Ga—O bond lengths in (I) are nearly the same as in the isotypic Ga2(SeO3)3(H2O)3 structure, the average Te—O bond lengths are significantly longer than the corresponding average bond length in the selenate(IV), viz. 1.871 Å versus 1.708 Å. However, the Te—O bond lengths as well as the O—Te—O angles (average 95.5 °) are in the typical ranges as observed for the structures of other tellurate(IV) compounds (Dolgikh, 1991).
The two types of isolated octahedra are stacked along [001], forming an hexagonal array of rods. The TeO3 units bridge the octahedra within one rod and cross-link adjacent rods which leads to the formation of a 3-D network (Fig. 2). Hydrogen bonding between water molecules and neighbouring O atoms stabilizes the structure both along the stacking direction [d(O···O) = 3.060 (3) Å] and between adjacent moieties (see Hydrogen bonding Table).