Redetermination of the crystal structure of BaTeO3(H2O), including the localization of the hydrogen atoms

Weil, M.

doi:10.1107/S2414314619007703

inorganic compounds

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ISSN: 2414-3146

Volume 4| Part 5| May 2019| x190770

https://doi.org/10.1107/S2414314619007703

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Redetermination of the crystal structure of BaTeO₃(H₂O), including the localization of the hydrogen atoms

Matthias Weil ^a ^*

^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 22 May 2019; accepted 27 May 2019; online 31 May 2019)

The redetermination of the crystal structure of barium oxidotellurate(IV) monohydrate allowed the localization of the hydrogen atoms that were not determined in the previous study [Nielsen, Hazell & Rasmussen (1971 ). Acta Chem. Scand. 25, 3037–3042], thus making an unambiguous assignment of the hydrogen-bonding scheme possible. The crystal structure shows a layered arrangement parallel to (001), consisting of edge-sharing [BaO₆(H₂O)] polyhedra and flanked by isolated [TeO₃] trigonal pyramids on the top and bottom. O—H⋯O hydrogen bonds of medium strength link adjacent layers along [001].

Keywords: crystal structure; barium oxidotellurate; hydrogen bonding; redetermination.

CCDC reference: 1918972

Structure description

In a recent project it was shown that sulfate or selenate anions can be incorporated into oxidotellurates(IV) of calcium, cadmium or strontium (Weil & Shirkhanlou, 2017 ). In order to expand this series to larger divalent metals, similar experiments with barium were started. Instead of the desired barium compounds with mixed oxidochalcogenate anions, high-quality crystals of BaTeO₃(H₂O) were frequently obtained under the given hydrothermal conditions. The crystal structure of BaTeO₃(H₂O) was determined nearly fifty years ago (Nielsen et al., 1971), however without localization of the hydrogen atoms. For an unambiguous assignment of the hydrogen-bonding scheme, a redetermination of this structure with modern CCD-based diffraction data seemed appropriate. In fact, alongside more precise data in terms of bond lengths and angles (Table 1), the current redetermination clearly revealed the positions of the hydrogen atoms of the water molecule (O4). Numerical data for the hydrogen-bonding interactions are collated in Table 2.

Table 1
Comparison of selected bond lengths (Å) from the current and the previous (Nielsen et al., 1971) refinement of BaTeO₃(H₂O)

	current refinement	previous refinement^a
Ba—O2ⁱ	2.6755 (17)	2.667 (8)
Ba—O1ⁱⁱ	2.6905 (16)	2.675 (8)
Ba—O3ⁱⁱⁱ	2.7064 (15)	2.688 (7)
Ba—O1^iv	2.7867 (16)	2.780 (6)
Ba—O4^iv	2.792 (2)	2.786 (6)
Ba—O1^v	2.7980 (15)	2.781 (6)
Ba—O3^iv	2.8461 (17)	2.823 (6)
Te—O2	1.8571 (16)	1.847 (7)
Te—O3	1.8632 (16)	1.859 (6)
Te—O1	1.8644 (15)	1.858 (6)
O2—Te1—O3	102.18 (8)	102.7 (3)
O2—Te1—O1	99.12 (8)	98.8 (3)
O3—Te1—O1	96.48 (7)	96.5 (3)
Notes (a) a = 8.58 (2), b = 7.53 (2), c = 7.70 (2) Å; β = 106.03 (20)°, T = 298 K; R = 0.039. Symmetry codes: (i) x, y + 1, z; (ii) −x + $[{1\over 2}]$ , y + $[{1\over 2}]$ , −z; (iii) x + $[{1\over 2}]$ , −y + $[{1\over 2}]$ , z; (iv) −x, −y + 1, −z; (v) x + $[{1\over 2}]$ , −y + $[{3\over 2}]$ , z.

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O4—H1⋯O3ⁱ	0.85 (1)	1.86 (1)	2.679 (3)	164 (4)
O4—H2⋯O2ⁱⁱ	0.85 (1)	1.93 (1)	2.761 (3)	167 (4)
Symmetry codes: (i) $[x+{\script{1\over 2}}, -y+{\script{1\over 2}}, z]$ ; (ii) $[-x+{\script{1\over 2}}, y+{\script{1\over 2}}, -z+1]$ .

The crystal structure comprises Ba²⁺ cations with a coordination number of seven by oxygen atoms, and isolated trigonal–pyramidal TeO₃^2– anions. The coordination sphere of the alkaline earth cation is irregular with a Ba—O bond-length distribution from 2.6755 (17) to 2.8461 (17) Å. The Te—O bond lengths and O—Te—O angles are typical for Te^IV bonded to three oxygen atoms (Christy et al., 2016 ). In the crystal structure, [BaO₆(H₂O)] polyhedra share edges and are linked into layers extending parallel to (001). The [TeO₃] trigonal pyramids flank these layers on both sides with the free-electron pair pointing into the interlayer space (Fig. 1). Adjacent layers are held together along [001] by O—H⋯O hydrogen bonds involving one of the water hydrogen atoms (H2). The other hydrogen atom (H1) is engaged in an intralayer hydrogen bond. Judging by the O⋯O contact distances (Table 2), both hydrogen bonds are of medium strength.

Figure 1
The crystal structure of BaTeO₃(H₂O) in a projection along [0 $[\overline{1}]$ 0]. Displacement ellipsoids are drawn at the 74% probability level. [TeO₃] trigonal pyramids are red, hydrogen atoms are of arbitrary size and O—H⋯O hydrogen-bonding interactions are shown as green lines.

Synthesis and crystallization

Ba(OH)₂·8H₂O, H₂SeO₄ (96%_wt), TeO₂ and KOH were mixed in a stoichiometric ratio of 2:1:1:2 (overall load ca 0.3 g) and were placed in a Teflon container with an 8 ml capacity that was filled to about two-thirds of its volume with water. The container was sealed with a Teflon lid, transferred to a steel autoclave and heated at 483 K for one week. A few colourless transparent crystals with a plate-like form of BaTeO₃(H₂O) were separated from microcrystalline material that consisted of BaSeO₄ as the main phase and unknown phase(s) as minor products, as revealed by powder X-ray diffraction.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 3. The same non-standard setting P2₁/a of space group No. 14 (standard setting P2₁/c) and atom-labelling scheme as given in the original structure study (Nielsen et al., 1971) were used. The published atomic coordinates were taken as starting parameters for the refinement. The two H atoms bonded to O4 were clearly discernible from a difference Fourier map. The corresponding O—H distances were treated with restraints d(O—H) = 0.85 (1) Å, and an independent U_iso parameter was refined for each H atom.

Table 3
Experimental details

Crystal data
Chemical formula	BaTeO₃(H₂O)
M_r	330.96
Crystal system, space group	Monoclinic, P2₁/a
Temperature (K)	296
a, b, c (Å)	8.6061 (2), 7.5820 (1), 7.7252 (2)
β (°)	105.8800 (11)
V (Å³)	484.84 (2)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	13.98
Crystal size (mm)	0.18 × 0.09 × 0.01

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2014 )
T_min, T_max	0.541, 0.748
No. of measured, independent and observed [I > 2σ(I)] reflections	24774, 3003, 2535
R_int	0.048
(sin θ/λ)_max (Å⁻¹)	0.904

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.020, 0.042, 1.01
No. of reflections	3003
No. of parameters	63
No. of restraints	3
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	1.36, −1.03
Computer programs: APEX2 and SAINT (Bruker, 2014), SHELXL (Sheldrick, 2015 ), ATOMS (Dowty, 2006 ) and publCIF (Westrip, 2010 ).

Structural data

CCDC reference: 1918972

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S2414314619007703/hb4298sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314619007703/hb4298Isup2.hkl

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2014); cell refinement: SAINT (Bruker, 2014); data reduction: SAINT (Bruker, 2014); program(s) used to solve structure: coordinates from previous model; program(s) used to refine structure: SHELXL (Sheldrick, 2015); molecular graphics: ATOMS (Dowty, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Barium oxidotellurate(IV) monohydrate top

Crystal data top

BaTeO₃(H₂O)	F(000) = 568
M_r = 330.96	D_x = 4.534 Mg m⁻³
Monoclinic, P2₁/a	Mo Kα radiation, λ = 0.71069 Å
a = 8.6061 (2) Å	Cell parameters from 8647 reflections
b = 7.5820 (1) Å	θ = 2.7–39.9°
c = 7.7252 (2) Å	µ = 13.98 mm⁻¹
β = 105.8800 (11)°	T = 296 K
V = 484.84 (2) Å³	Plate, colourless
Z = 4	0.18 × 0.09 × 0.01 mm

Data collection top

Bruker APEXII CCD diffractometer	2535 reflections with I > 2σ(I)
ω– and φ–scans	R_int = 0.048
Absorption correction: multi-scan (SADABS; Bruker, 2014)	θ_max = 40.0°, θ_min = 2.7°
T_min = 0.541, T_max = 0.748	h = −15→15
24774 measured reflections	k = −13→13
3003 independent reflections	l = −13→13

Refinement top

Refinement on F²	3 restraints
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F² > 2σ(F²)] = 0.020	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.042	w = 1/[σ²(F_o²) + (0.013P)² + 0.3124P] where P = (F_o² + 2F_c²)/3
S = 1.01	(Δ/σ)_max = 0.001
3003 reflections	Δρ_max = 1.36 e Å⁻³
63 parameters	Δρ_min = −1.03 e Å⁻³

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

	x	y	z	U_iso*/U_eq
Ba	0.33203 (2)	0.84905 (2)	0.11771 (2)	0.01402 (3)
Te	0.00420 (2)	0.18710 (2)	0.28883 (2)	0.01247 (3)
O1	−0.0478 (2)	0.31565 (19)	0.0749 (2)	0.0166 (3)
O2	0.2033 (2)	0.0987 (2)	0.2807 (2)	0.0234 (3)
O3	−0.1331 (2)	−0.0024 (2)	0.2030 (2)	0.0198 (3)
O4	0.1377 (3)	0.6040 (3)	0.3567 (3)	0.0361 (5)
H1	0.210 (3)	0.553 (5)	0.319 (5)	0.047 (11)*
H2	0.172 (4)	0.608 (5)	0.4705 (14)	0.048 (11)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Ba	0.01206 (5)	0.01126 (5)	0.01810 (6)	−0.00019 (3)	0.00307 (4)	0.00052 (4)
Te	0.01224 (6)	0.01311 (5)	0.01221 (5)	0.00006 (4)	0.00361 (4)	−0.00102 (4)
O1	0.0191 (7)	0.0155 (6)	0.0155 (7)	−0.0003 (5)	0.0055 (6)	0.0029 (5)
O2	0.0145 (7)	0.0298 (8)	0.0266 (9)	0.0050 (6)	0.0065 (6)	−0.0042 (7)
O3	0.0192 (7)	0.0147 (6)	0.0248 (8)	−0.0040 (5)	0.0050 (6)	0.0002 (6)
O4	0.0224 (9)	0.0602 (14)	0.0215 (9)	0.0147 (9)	−0.0012 (7)	−0.0131 (10)

Geometric parameters (Å, º) top

Ba—O2ⁱ	2.6755 (17)	Ba—O3^iv	2.8461 (17)
Ba—O1ⁱⁱ	2.6905 (16)	Te—O2	1.8571 (16)
Ba—O3ⁱⁱⁱ	2.7064 (15)	Te—O3	1.8632 (16)
Ba—O1^iv	2.7867 (16)	Te—O1	1.8644 (15)
Ba—O4^v	2.792 (2)	O4—H1	0.846 (10)
Ba—O1^v	2.7980 (15)	O4—H2	0.849 (10)

O2ⁱ—Ba—O1ⁱⁱ	139.83 (5)	O4^v—Ba—O3^iv	139.19 (5)
O2ⁱ—Ba—O3ⁱⁱⁱ	127.23 (5)	O1^v—Ba—O3^iv	71.32 (5)
O1ⁱⁱ—Ba—O3ⁱⁱⁱ	89.77 (5)	O2—Te—O3	102.18 (8)
O2ⁱ—Ba—O1^iv	98.76 (5)	O2—Te—O1	99.12 (8)
O1ⁱⁱ—Ba—O1^iv	107.47 (5)	O3—Te—O1	96.48 (7)
O3ⁱⁱⁱ—Ba—O1^iv	73.59 (5)	Te—O1—Ba^vi	120.32 (7)
O2ⁱ—Ba—O4^v	92.01 (7)	Te—O1—Ba^iv	101.64 (6)
O1ⁱⁱ—Ba—O4^v	73.13 (6)	Ba^vi—O1—Ba^iv	112.62 (6)
O3ⁱⁱⁱ—Ba—O4^v	86.63 (6)	Te—O1—Ba^vii	112.15 (7)
O1^iv—Ba—O4^v	160.17 (6)	Ba^vi—O1—Ba^vii	108.25 (5)
O2ⁱ—Ba—O1^v	68.09 (5)	Ba^iv—O1—Ba^vii	99.87 (5)
O1ⁱⁱ—Ba—O1^v	71.75 (5)	Te—O2—Ba^viii	140.90 (9)
O3ⁱⁱⁱ—Ba—O1^v	153.03 (5)	Te—O3—Ba^ix	148.51 (8)
O1^iv—Ba—O1^v	130.01 (4)	Te—O3—Ba^iv	99.59 (6)
O4^v—Ba—O1^v	69.54 (6)	Ba^ix—O3—Ba^iv	100.63 (5)
O2ⁱ—Ba—O3^iv	83.85 (5)	Ba^vii—O4—H1	119 (2)
O1ⁱⁱ—Ba—O3^iv	84.18 (5)	Ba^vii—O4—H2	133 (3)
O3ⁱⁱⁱ—Ba—O3^iv	127.51 (4)	H1—O4—H2	107 (3)
O1^iv—Ba—O3^iv	59.15 (4)

Symmetry codes: (i) x, y+1, z; (ii) −x+1/2, y+1/2, −z; (iii) x+1/2, −y+1/2, z; (iv) −x, −y+1, −z; (v) x+1/2, −y+3/2, z; (vi) −x+1/2, y−1/2, −z; (vii) x−1/2, −y+3/2, z; (viii) x, y−1, z; (ix) x−1/2, −y+1/2, z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O4—H1···O3ⁱⁱⁱ	0.85 (1)	1.86 (1)	2.679 (3)	164 (4)
O4—H2···O2^x	0.85 (1)	1.93 (1)	2.761 (3)	167 (4)

Symmetry codes: (iii) x+1/2, −y+1/2, z; (x) −x+1/2, y+1/2, −z+1.

Comparison of selected bond lengths (Å) from the current and the previous (Nielsen et al., 1971) refinement of BaTeO₃(H₂O) top

	current refinement	previous refinement^a
Ba—O2ⁱ	2.6755 (17)	2.667 (8)
Ba—O1ⁱⁱ	2.6905 (16)	2.675 (8)
Ba—O3ⁱⁱⁱ	2.7064 (15)	2.688 (7)
Ba—O1^iv	2.7867 (16)	2.780 (6)
Ba—O4^iv	2.792 (2)	2.786 (6)
Ba—O1^v	2.7980 (15)	2.781 (6)
Ba—O3^iv	2.8461 (17)	2.823 (6)
Te—O2	1.8571 (16)	1.847 (7)
Te—O3	1.8632 (16)	1.859 (6)
Te—O1	1.8644 (15)	1.858 (6)
O2—Te1—O3	102.18 (8)	102.7 (3)
O2—Te1—O1	99.12 (8)	98.8 (3)
O3—Te1—O1	96.48 (7)	96.5 (3)

Notes (a) a = 8.58 (2), b = 7.53 (2), c = 7.70 (2) Å; β = 106.03 (20)°, T = 298 K; R = 0.039. Symmetry codes: (i) x, y + 1, z; (ii) -x + 1/2, y + 1/2, -z; (iii) x + 1/2, -y + 1/2, z; (iv) -x, -y + 1, -z; (v) x + 1/2, -y + 3/2, z.

Acknowledgements

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

References

Bruker (2014). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Christy, A. G., Mills, S. J. & Kampf, A. R. (2016). Miner. Mag. 80, 415–545. Web of Science CrossRef CAS Google Scholar
Dowty, E. (2006). ATOMS. Shape Software, Kingsport, Tennessee, USA. Google Scholar
Nielsen, B. R., Hazell, R. G. & Rasmussen, S. E. (1971). Acta Chem. Scand. 25, 3037–3042. CrossRef Google Scholar
Sheldrick, G. M. (2015). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Weil, M. & Shirkhanlou, M. (2017). Z. Anorg. Allg. Chem. 643, 330–339. CrossRef CAS Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar

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