Crystal structures of the triple perovskites Ba2K2Te2O9 and Ba2KNaTe2O9, and redetermination of the double perovskite Ba2CaTeO6

Weil, M.

doi:10.1107/S2056989018009064

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Volume 74| Part 7| July 2018| Pages 1006-1009

https://doi.org/10.1107/S2056989018009064

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Crystal structures of the triple perovskites Ba₂K₂Te₂O₉ and Ba₂KNaTe₂O₉, and redetermination of the double perovskite Ba₂CaTeO₆

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 T. J. Prior, University of Hull, England (Received 13 June 2018; accepted 21 June 2018; online 26 June 2018)

Single crystals of Ba₂K₂Te₂O₉ (dibarium dipotassium nonaoxidoditellurate), (I), Ba₂KNaTe₂O₉ (dibarium potassium sodium nonaoxidoditellurate), (II), and Ba₂CaTeO₆ (dibarium calcium hexaoxidotellurate), (III), were obtained from KNO₃/KI or KNO₃/NaNO₃ flux syntheses in platinum crucibles for (I) and (II), or porcelain crucibles for (III). (I) and (II) are isotypic and are members of triple perovskites with general formula A₂^[12co]A′^[12co]B₂^[6o]B′^[6o]O₉. They crystallize in the 6H-BaTiO₃ structure family in space-group type P6₃/mmc, with the A, A′, B and B′ sites being occupied by K, Ba, Te and a second Ba in (I), and in (II) by mixed-occupied (Ba/K), Ba, Te and Na sites, respectively. (III) adopts the A₂^[12co]B′^[6o]B′′^[6o]O₆ double perovskite structure in space-group type Fm $[\overline{3}]$ m, with Ba, Ca and Te located on the A, B′ and B′′ sites, respectively. The current refinement of (III) is based on single-crystal X-ray data. It confirms the previous refinement from X-ray powder diffraction data [Fu et al. (2008). J. Solid State Chem. 181, 2523–2529], but with higher precision.

Keywords: crystal structure; perovskite family; 6H-BaTiO₃ structure type; double perovskite; isotypism.

CCDC references: 1850819; 1850818; 1850817

1. Chemical context

During a recent project on the structure determination of barium oxotellurates(VI), different preparation methods were applied for single-crystal growth of the phases Ba[H₄TeO₆], Ba[H₂TeO₅], Ba[Te₂O₆(OH)₂] and Ba[TeO₄] (Weil et al., 2016 ). Owing to the different water content that defines the thermal stability range of the respective phase, relatively mild temperatures < 600 K had to be adjusted for the three hydrous phases using either a diffusion method in aqueous solutions (room temperature) or hydrothermal methods (ca 470 K), whereas for the anhydrous phase higher temperatures could be employed. However, Ba[TeO₄] decomposes into Ba[TeO₃] with release of oxygen at temperatures above 1000 K, which prevents prolonged heating near this temperature. Although very small crystals of Ba[TeO₄] with a rather poor quality could eventually be grown by heating Ba[H₄TeO₆] at 873 K for some days (Weil et al., 2016), alternative crystal-growth methods were tested with the intention of obtaining larger crystals with better quality. With the upper stability range of the target phase Ba[TeO₄] in mind, KNO₃/KI or KNO₃/NaNO₃ mixtures were used for crystal-growth experiments. Such salt mixtures have low eutectic melting points, e.g. 498 K for a 50:50 mol% mixture of NaNO₃/KNO₃ (Berg & Kerridge, 2004 ). At least for the latter eutectic mixture, crystal-growth experiments from the melt have already been applied successfully for another barium phase, viz. Ba₂As₂O₇ (Weil, 2016 ). However, Ba[TeO₄] did not form under the given conditions because K⁺ or mixtures of K⁺ and Na⁺ were incorporated instead, resulting in the formation of Ba₂K₂Te₂O₉ (I) or Ba₂KNaTe₂O₉ (II) single crystals. In the case a porcelain crucible was employed, Ba₂CaTeO₆ (III) was obtained in form of very few single crystals.

2. Structural commentary

The three title compounds belong to the vast family of perovskites (Tilley, 2016 ). The ideal cubic A^[12co]B^[6o]O₃ perovskite structure comprises of corner-sharing [BO₆] octahedra. In the centre of the resulting ³_∞[BO_6/2] network, the A-site cation occupies a 12-coordinate cuboctahedral site. The 2H hexagonal perovskite structure contains chains of face-sharing [BO₆] octahedra that are separated by chains of A-site cations. In an alternative description, perovskite structures can be derived from closed-packed arrangements of the anions with different stacking sequences (Lufaso & zur Loye, 2005a ; Stöger et al., 2010 ). For example, in the cubic perovskite an ABC stacking and in the hexagonal 2H perovskite an AB stacking is observed. More complex structures that are realized in double perovskites or triple perovskites can include both cubic (c) and hexagonal stacking sequences (h) and consequently structure motifs of corner-sharing and face-sharing [BO₆] octahedra like in the triple perovskites discussed below.

Ba₂K₂Te₂O₉ (I) and Ba₂KNaTe₂O₉ (II) are isotypic and members of the triple perovskite family with general formula A₂^[12co]A′^[12co]B₂^[6o]B′^[6o]O₉. They crystallize in the 6H-BaTiO₃ structure type in space-group type P6₃/mmc with Z = 2. In (I) the A, A′, B and B′ sites are occupied by K1, Ba1, Te1 and Ba2, and in (II) by mixed-occupied (Ba/K)1, Ba1, Te1 and Na2, respectively. The 6H-BaTiO₃ structure type is sometimes also referred to as the BaFeO_2+x structure type with possible values for Z = 2, 3 or 6, dependent on the overall formula sum of the compound. The stacking sequence for this structure type is (cch)₂ (Tilley, 2016). About 240 entries of this structure family are compiled in the recent version of the Inorganic Crystal Structure Database (ICSD, 2018 ), with hexagonal BaTiO₃ being the first phase that has been structurally determined (Burbank & Evans, 1948 ). Only four Te-containing phases have been reported so far to adopt this structure type, viz. Ba₃Fe₂TeO₉ (Harari et al., 1972 ), K₃LaTe₂O₉ (Zhang et al., 2015 ), Ba₃Cr_1.94Te_1.06O₉ (Li et al., 2016 ) and the high-pressure phase Ba₂NiTeO₆ (Z = 3; Aoba et al., 2016 ). A review of this structure type and of perovskites in general was given recently by Tilley (2016). In both structures (I) and (II), Ba1 is situated on Wyckoff position 2b (site symmetry $[\overline{6}]$ m2), the K1 site in (I) and the mixed-occpied (Ba/K)1 site (occupancy ratio 1:1) in (II) on 4f (3m.), Ba2 in (I) and Na2 in (II) on 2a ( $[\overline{3}]$ m.), and in both structures Te1 4f (3m.), O1 on 6h (mm2) and O2 on 12k (.m.), respectively. Hence the smaller Te^VI atoms occupy the face-sharing octahedral B site while the larger barium (Ba2 in (I)) or sodium cations (Na2 in (II)) occupy the corner-sharing octahedral B′ site. The inner angles of the two face-sharing [TeO₆] octahedra in (I) and (II) (Table 1) are more similar than those in isotypic triple perovskites (Lufaso & zur Loye, 2005a), with center shifts of 0.076 Å in (I) and of 0.191 Å in (II). Representative for both (I) and (II), the crystal structure of Ba₂K₂Te₂O₉ is given in Fig. 1. It should be noted that the A (= K1) position in (I) has only nine coordination partners, while in (II) twelve oxygen atoms surround the corresponding site that is statistically occupied by Ba²⁺ and K⁺ (= (Ba/K)1).

Table 1
Selected bond lengths (Å) and angles (°) in the structures (I)–(III)

(I)		(II)		(III)
K1—O1	2.893 (2) [3×]	(Ba/K)1—O2	2.98780 (19) [6×]	Ba—O	2.9577 (5) [12×]
K1—O2	3.0359 (17) [6×]	(Ba/K)1—O2	3.1064 (19) [3×]	Ca—O	2.247 (3) [6x]
		(Ba/K)1—O1	3.1927 (12) [3×]	Te—O	1.930 (3) [6×]
Ba1—O2	2.952 (2) [6×]	Ba1—O2	2.9532 (18) [6×]
Ba1—O1	3.0382 (17) [6×]	Ba1—O1	2.9935 (14) [6×]
Te1—O2	1.8524 (18) [3×]	Te1—O2	1.8481 (16) [3×]
Te1—O1	2.0474 (16) [3×]	Te1—O1	2.0418 (14) [3×]
Ba2—O2	2.5910 (18) [6×]	Na2—O2	2.3037 (16) [6×]

O1—Te1—O1	75.43 (7) [3×]	O1—Te1—O1	75.95 (6) [3×]
Δ^a	0.076	Δ^a	0.191

Note: (a) Δ is the center shift (Å) of the Te atoms in the Te₂O₉ dimer. The center shift is defined as the distance between the Te atoms in the 4f Wyckoff position (z ≃ 1/6) of the actual crystal structure and the ideal high-symmetry 4f Te position (z = 1/6) (Lufaso & zur Loye, 2005a).

Figure 1
Projection of the crystal structure of Ba₂K₂Te₂O₉ (I) along [ $[\overline{1}]$ 00]. [Ba2O₆] octahedra are green, [TeO₆] octahedra are red, potassium sites are blue, Ba1 sites turquoise and O sites shaded pale grey. Displacement ellipsoids are drawn at the 97% probability level.

The current refinement of Ba₂CaTeO₆ (III) is based on single crystal X-ray data and confirms the previous structure determination from X-ray powder diffraction data, but with higher precision (reliability factors for the previous determination: R_wp = 0.159, R_p = 0.112; Fu et al., 2008 ). Ba₂CaTeO₆ (III) is a member of the double perovskite family with general formula A₂^[12co]B′^[6o]B′′^[6o]O₆. Dependent on the cations present at the B′ and B′′ sites, double perovskites are functional oxide materials with interesting electronic and magnetic properties (Vasala & Karppinen, 2015 ). In the crystal structure of (III), Ba, Ca and Te are located on the A, B′ and B′′ sites, respectively. The Wyckoff positions and site symmetries of the four sites present in the structure of (III) are: Ba on 8c ( $[\overline{4}]$ 3m), Ca on 4a (m $[\overline{3}]$ m), Te on 4b (m $[\overline{3}]$ m), and O on 24e (4m.m). Since Ba₂CaTeO₆ represents the highest possible symmetry of a double perovskite structure (cubic elpasolite-type in space group type Fm $[\overline{3}]$ m), tilting of the B′O₆ or B′′O₆ octahedra (Howard et al., 2003 ), like in the monoclinic structure of Sr₂CaTeO₆ (Prior et al., 2005 ), is not observed. The ordering of the CaO₆ and TeO₆ octahedra in a checkerboard arrangement in (III) is displayed in Fig. 2.

Figure 2
Projection of the crystal structure of Ba₂CaTeO₆ (III) along [ $[\overline{1}]$ 00]. [CaO₆] octahedra are turquoise, [TeO₆] octahedra are red, Ba sites blue and O sites pale grey. Displacement ellipsoids are drawn at the 97% probability level.

With the exception of the Na—O bond length, all other bond lengths (Table 1) are characteristic for their respective coordination polyhedra and in good agreement with mean values compiled recently for alkali and alkaline earth cations bonded to oxygen: K—O = 2.955 Å for coordination number (CN) 9, 3.095 Å for CN 12; Ca—O = 2.668 Å for CN 12; Ba—O = 2.689 Å for CN 6, 2.965 Å for CN 12 (Gagné & Hawthorne, 2016 ). The same is valid for the mean value of octahedrally coordinated Te^VI with a mean Te—O bond length of 1.923 Å (Gagné & Hawthorne, 2018 ). As noted above, the Na—O bond length deviates from the mean value. At 2.3037 (16) Å it is considerably shorter than the mean of 2.441 Å for CN 6 (Gagné & Hawthorne, 2016). Such a compression has also been reported for other 6H-BaTiO₃-type structures containing sodium. For example, the Na—O distance in K₃NaOs₂O₉ has nearly the same value [2.313 (6) Å; Mogare et al., 2012 ] but is reported to be significantly shorter in Ba₃NaRuIrO₉ [2.058 (9) Å; Lufaso & zur Loye, 2005b ].

3. Synthesis and crystallization

Ba[H₄TeO₆] was prepared according to a literature protocol (Engelbrecht & Sladky, 1965 ) and its purity checked by X-ray powder diffraction. One gram of dried Ba[H₄TeO₆] was mixed with five grams of a KNO₃/KI mixture (stoichiometric ratio 2:1) for (I) or a KNO₃/NaNO₃ mixture (stoichiometric ratio 1:1) for (II). The mixtures were placed in platinum crucibles and heated within six h to 773 K, held at that temperature for four days and cooled to room temperature within 12 h. The solidified melts were leached out with water and the remaining solid filtered off, washed with water and ethanol. Colourless single crystals with a hexagonal form for both (I) and (II) were selected from the reaction products. In one case a porcelain crucible was used to reproduce the formation of (I). In this batch, very few colourless crystals of Ba₂CaTeO₆ (III) had formed as a minor by-product. The porcelain crucible is an adventitious source of calcium that is present in feldspars such as oligoclase used for manufacturing.

4. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. For refinements of (I) and (II) the coordinates of isotypic Ba₃LaRuO₉ (Doi et al., 2002 ) were used as starting parameters. In the structure of (II), the M1 position with site symmetry 3m. of Wyckoff site 4f is statistically occupied by K⁺ and Ba²⁺ cations. For refinement of (III), the starting parameters were taken from the previous sructure determination based on X-ray powder diffraction data (Fu et al., 2008). The type of element on the metal positions was checked by free refinement of the respective site-occupation factors, which confirmed Ca and Ba, respectively.

Table 2
Experimental details

	(I)	(II)	(III)
Crystal data
Chemical formula	Ba₂K₂Te₂O₉	Ba₂KNaTe₂O₉	Ba₂CaTeO₆
M_r	752.08	735.97	538.36
Crystal system, space group	Hexagonal, P6₃/mmc	Hexagonal, P6₃/mmc	Cubic, Fm $[\overline{3}]$ m
Temperature (K)	298	293	293
a, b, c (Å)	6.047 (3), 6.047 (3), 16.479 (9)	5.9625 (3), 5.9625 (3), 14.9396 (8)	8.3536 (14), 8.3536 (14), 8.3536 (14)
α, β, γ (°)	90, 90, 120	90, 90, 120	90, 90, 90
V (Å³)	521.8 (6)	459.97 (5)	582.9 (3)
Z	2	2	4
Radiation type	Mo Kα	Mo Kα	Mo Kα
μ (mm⁻¹)	13.80	15.25	19.18
Crystal size (mm)	0.09 × 0.09 × 0.01	0.10 × 0.10 × 0.01	0.08 × 0.08 × 0.08

Data collection
Diffractometer	Bruker APEXII CCD	Bruker APEXII CCD	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2015)	Multi-scan (SADABS; Bruker, 2015)	Multi-scan (SADABS; Bruker, 2015)
T_min, T_max	0.488, 0.748	0.540, 0.749	0.514, 0.748
No. of measured, independent and observed [I > 2σ(I)] reflections	21821, 754, 676	11701, 702, 669	11194, 131, 131
R_int	0.041	0.029	0.139
(sin θ/λ)_max (Å⁻¹)	0.943	0.961	0.919

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.015, 0.036, 1.15	0.018, 0.034, 1.49	0.019, 0.049, 1.33
No. of reflections	754	702	131
No. of parameters	22	23	7
Δρ_max, Δρ_min (e Å⁻³)	2.90, −2.02	1.02, −1.63	3.87, −1.68
Computer programs: APEX2 and SAINT (Bruker, 2015 ), SHELXL2017 (Sheldrick, 2015 ), ATOMS for Windows (Dowty, 2006 ) and publCIF (Westrip, 2010 ).

Supporting information

CCDC references: 1850819; 1850818; 1850817

Crystal structure: contains datablocks I, II, III, global. DOI: https://doi.org/10.1107/S2056989018009064/pj2054sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989018009064/pj2054Isup2.hkl

Structure factors: contains datablock II. DOI: https://doi.org/10.1107/S2056989018009064/pj2054IIsup3.hkl

Structure factors: contains datablock III. DOI: https://doi.org/10.1107/S2056989018009064/pj2054IIIsup4.hkl

checkCIF report

Computing details top

For all structures, data collection: APEX2 (Bruker, 2015); cell refinement: SAINT (Bruker, 2015); data reduction: SAINT (Bruker, 2015). Program(s) used to solve structure: coordinates taken from an isotypic compound for (I), (II); coordinates taken from isotypic compound for (III). Program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015) for (I), (II); SHELXL2017 (Sheldrick, 2015) for (III). For all structures, molecular graphics: ATOMS for Windows (Dowty, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Dibarium dipotassium nonaoxidoditellurate (I) top

Crystal data top

Ba₂K₂Te₂O₉	D_x = 4.786 Mg m⁻³
M_r = 752.08	Mo Kα radiation, λ = 0.71073 Å
Hexagonal, P6₃/mmc	Cell parameters from 9371 reflections
a = 6.047 (3) Å	θ = 3.9–42.1°
c = 16.479 (9) Å	µ = 13.80 mm⁻¹
V = 521.8 (6) Å³	T = 298 K
Z = 2	Plate, colourless
F(000) = 652	0.09 × 0.09 × 0.01 mm

Data collection top

Bruker APEXII CCD diffractometer	676 reflections with I > 2σ(I)
ω– and φ–scans	R_int = 0.041
Absorption correction: multi-scan (SADABS; Bruker, 2015)	θ_max = 42.1°, θ_min = 3.9°
T_min = 0.488, T_max = 0.748	h = −11→11
21821 measured reflections	k = −11→11
754 independent reflections	l = −31→30

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	w = 1/[σ²(F_o²) + (0.0151P)² + 0.8791P] where P = (F_o² + 2F_c²)/3
R[F² > 2σ(F²)] = 0.015	(Δ/σ)_max < 0.001
wR(F²) = 0.036	Δρ_max = 2.90 e Å⁻³
S = 1.15	Δρ_min = −2.02 e Å⁻³
754 reflections	Extinction correction: SHELXL2014 (Sheldrick, 2015), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
22 parameters	Extinction coefficient: 0.0138 (4)

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
K1	0.3333	0.6667	0.87422 (7)	0.02257 (17)
Ba1	0.0000	0.0000	0.2500	0.00960 (5)
Te1	0.3333	0.6667	0.16206 (2)	0.00664 (4)
Ba2	0.0000	0.0000	0.0000	0.00851 (5)
O1	0.47142 (19)	0.9428 (4)	0.2500	0.0117 (3)
O2	0.17636 (16)	0.3527 (3)	0.38974 (10)	0.0198 (3)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
K1	0.0158 (2)	0.0158 (2)	0.0360 (5)	0.00792 (10)	0.000	0.000
Ba1	0.00959 (6)	0.00959 (6)	0.00961 (9)	0.00480 (3)	0.000	0.000
Te1	0.00661 (5)	0.00661 (5)	0.00671 (7)	0.00330 (3)	0.000	0.000
Ba2	0.00995 (6)	0.00995 (6)	0.00562 (8)	0.00498 (3)	0.000	0.000
O1	0.0150 (6)	0.0068 (7)	0.0106 (7)	0.0034 (3)	0.000	0.000
O2	0.0264 (6)	0.0116 (6)	0.0165 (6)	0.0058 (3)	0.0037 (3)	0.0075 (5)

Geometric parameters (Å, º) top

K1—O1ⁱ	2.893 (2)	Ba1—O1^xvii	3.0382 (17)
K1—O1ⁱⁱ	2.893 (2)	Ba1—O1^xviii	3.0382 (17)
K1—O1ⁱⁱⁱ	2.893 (2)	Ba1—O1^xix	3.0382 (17)
K1—O2^iv	3.0359 (17)	Ba1—O1^xx	3.0382 (17)
K1—O2^v	3.0359 (17)	Te1—O2^xiii	1.8524 (18)
K1—O2^vi	3.0359 (17)	Te1—O2^xxi	1.8524 (18)
K1—O2^vii	3.0359 (17)	Te1—O2^xxii	1.8525 (18)
K1—O2^viii	3.0360 (17)	Te1—O1	2.0474 (16)
K1—O2^ix	3.0360 (17)	Te1—O1^xvii	2.0474 (16)
Ba1—O2^x	2.952 (2)	Te1—O1^xv	2.0474 (16)
Ba1—O2^xi	2.952 (2)	Ba2—O2^x	2.5910 (18)
Ba1—O2	2.952 (2)	Ba2—O2^xxiii	2.5910 (18)
Ba1—O2^xii	2.952 (2)	Ba2—O2^xiii	2.5911 (18)
Ba1—O2^xiii	2.952 (2)	Ba2—O2^xxiv	2.5911 (18)
Ba1—O2^xiv	2.952 (2)	Ba2—O2^xii	2.5911 (18)
Ba1—O1^xv	3.0382 (17)	Ba2—O2^xxv	2.5911 (18)
Ba1—O1^xvi	3.0382 (17)

O1ⁱ—K1—O1ⁱⁱ	75.48 (6)	O1^xvi—Ba1—O1^xviii	48.69 (7)
O1ⁱ—K1—O1ⁱⁱⁱ	75.48 (6)	O1^xvii—Ba1—O1^xviii	71.31 (7)
O1ⁱⁱ—K1—O1ⁱⁱⁱ	75.48 (6)	O2^x—Ba1—O1^xix	55.25 (3)
O1ⁱ—K1—O2^iv	94.78 (4)	O2^xi—Ba1—O1^xix	55.25 (3)
O1ⁱⁱ—K1—O2^iv	55.82 (4)	O2—Ba1—O1^xix	120.56 (3)
O1ⁱⁱⁱ—K1—O2^iv	131.10 (5)	O2^xii—Ba1—O1^xix	93.53 (2)
O1ⁱ—K1—O2^v	55.82 (4)	O2^xiii—Ba1—O1^xix	120.56 (3)
O1ⁱⁱ—K1—O2^v	94.78 (4)	O2^xiv—Ba1—O1^xix	93.53 (2)
O1ⁱⁱⁱ—K1—O2^v	131.10 (5)	O1^xv—Ba1—O1^xix	120.0
O2^iv—K1—O2^v	63.59 (6)	O1^xvi—Ba1—O1^xix	71.31 (8)
O1ⁱ—K1—O2^vi	131.10 (5)	O1^xvii—Ba1—O1^xix	168.69 (8)
O1ⁱⁱ—K1—O2^vi	55.82 (4)	O1^xviii—Ba1—O1^xix	120.0
O1ⁱⁱⁱ—K1—O2^vi	94.77 (4)	O2^x—Ba1—O1^xx	55.25 (4)
O2^iv—K1—O2^vi	55.94 (7)	O2^xi—Ba1—O1^xx	55.25 (3)
O2^v—K1—O2^vi	119.299 (12)	O2—Ba1—O1^xx	93.53 (2)
O1ⁱ—K1—O2^vii	55.82 (4)	O2^xii—Ba1—O1^xx	120.56 (3)
O1ⁱⁱ—K1—O2^vii	131.10 (5)	O2^xiii—Ba1—O1^xx	93.53 (2)
O1ⁱⁱⁱ—K1—O2^vii	94.78 (4)	O2^xiv—Ba1—O1^xx	120.56 (3)
O2^iv—K1—O2^vii	119.299 (12)	O1^xv—Ba1—O1^xx	71.31 (8)
O2^v—K1—O2^vii	55.94 (7)	O1^xvi—Ba1—O1^xx	120.0
O2^vi—K1—O2^vii	169.60 (8)	O1^xvii—Ba1—O1^xx	120.0
O1ⁱ—K1—O2^viii	131.10 (5)	O1^xviii—Ba1—O1^xx	168.69 (8)
O1ⁱⁱ—K1—O2^viii	94.78 (4)	O1^xix—Ba1—O1^xx	48.69 (8)
O1ⁱⁱⁱ—K1—O2^viii	55.82 (4)	O2^xiii—Te1—O2^xxi	100.46 (7)
O2^iv—K1—O2^viii	119.298 (12)	O2^xiii—Te1—O2^xxii	100.45 (7)
O2^v—K1—O2^viii	169.60 (8)	O2^xxi—Te1—O2^xxii	100.45 (7)
O2^vi—K1—O2^viii	63.59 (6)	O2^xiii—Te1—O1	162.38 (7)
O2^vii—K1—O2^viii	119.297 (12)	O2^xxi—Te1—O1	90.73 (6)
O1ⁱ—K1—O2^ix	94.78 (4)	O2^xxii—Te1—O1	90.73 (6)
O1ⁱⁱ—K1—O2^ix	131.10 (5)	O2^xiii—Te1—O1^xvii	90.73 (6)
O1ⁱⁱⁱ—K1—O2^ix	55.82 (4)	O2^xxi—Te1—O1^xvii	162.38 (7)
O2^iv—K1—O2^ix	169.60 (8)	O2^xxii—Te1—O1^xvii	90.73 (6)
O2^v—K1—O2^ix	119.298 (12)	O1—Te1—O1^xvii	75.43 (7)
O2^vi—K1—O2^ix	119.297 (12)	O2^xiii—Te1—O1^xv	90.73 (6)
O2^vii—K1—O2^ix	63.59 (6)	O2^xxi—Te1—O1^xv	90.73 (6)
O2^viii—K1—O2^ix	55.93 (7)	O2^xxii—Te1—O1^xv	162.38 (7)
O2^x—Ba1—O2^xi	102.53 (7)	O1—Te1—O1^xv	75.43 (7)
O2^x—Ba1—O2	143.54 (3)	O1^xvii—Te1—O1^xv	75.43 (7)
O2^xi—Ba1—O2	65.62 (6)	O2^x—Ba2—O2^xxiii	180.00 (5)
O2^x—Ba1—O2^xii	65.62 (6)	O2^x—Ba2—O2^xiii	76.25 (7)
O2^xi—Ba1—O2^xii	143.54 (3)	O2^xxiii—Ba2—O2^xiii	103.75 (7)
O2—Ba1—O2^xii	143.54 (3)	O2^x—Ba2—O2^xxiv	103.75 (7)
O2^x—Ba1—O2^xiii	65.62 (6)	O2^xxiii—Ba2—O2^xxiv	76.25 (7)
O2^xi—Ba1—O2^xiii	143.54 (3)	O2^xiii—Ba2—O2^xxiv	180.00 (8)
O2—Ba1—O2^xiii	102.53 (7)	O2^x—Ba2—O2^xii	76.25 (7)
O2^xii—Ba1—O2^xiii	65.62 (6)	O2^xxiii—Ba2—O2^xii	103.75 (7)
O2^x—Ba1—O2^xiv	143.54 (3)	O2^xiii—Ba2—O2^xii	76.25 (7)
O2^xi—Ba1—O2^xiv	65.62 (6)	O2^xxiv—Ba2—O2^xii	103.75 (7)
O2—Ba1—O2^xiv	65.62 (6)	O2^x—Ba2—O2^xxv	103.75 (7)
O2^xii—Ba1—O2^xiv	102.53 (7)	O2^xxiii—Ba2—O2^xxv	76.25 (7)
O2^xiii—Ba1—O2^xiv	143.54 (3)	O2^xiii—Ba2—O2^xxv	103.75 (7)
O2^x—Ba1—O1^xv	93.53 (2)	O2^xxiv—Ba2—O2^xxv	76.25 (7)
O2^xi—Ba1—O1^xv	93.53 (2)	O2^xii—Ba2—O2^xxv	180.00 (5)
O2—Ba1—O1^xv	55.25 (3)	Te1^xiii—O1—Te1	90.11 (9)
O2^xii—Ba1—O1^xv	120.56 (3)	Te1^xiii—O1—K1^xxvi	89.91 (5)
O2^xiii—Ba1—O1^xv	55.25 (4)	Te1—O1—K1^xxvi	179.97 (5)
O2^xiv—Ba1—O1^xv	120.56 (3)	Te1^xiii—O1—K1ⁱⁱ	179.97 (12)
O2^x—Ba1—O1^xvi	93.53 (2)	Te1—O1—K1ⁱⁱ	89.91 (5)
O2^xi—Ba1—O1^xvi	93.53 (2)	K1^xxvi—O1—K1ⁱⁱ	90.06 (8)
O2—Ba1—O1^xvi	120.56 (3)	Te1^xiii—O1—Ba1^xxvii	93.99 (2)
O2^xii—Ba1—O1^xvi	55.25 (3)	Te1—O1—Ba1^xxvii	93.99 (2)
O2^xiii—Ba1—O1^xvi	120.56 (3)	K1^xxvi—O1—Ba1^xxvii	86.01 (3)
O2^xiv—Ba1—O1^xvi	55.25 (3)	K1ⁱⁱ—O1—Ba1^xxvii	86.01 (3)
O1^xv—Ba1—O1^xvi	168.69 (7)	Te1^xiii—O1—Ba1^xxviii	93.99 (2)
O2^x—Ba1—O1^xvii	120.56 (3)	Te1—O1—Ba1^xxviii	93.99 (2)
O2^xi—Ba1—O1^xvii	120.56 (3)	K1^xxvi—O1—Ba1^xxviii	86.01 (3)
O2—Ba1—O1^xvii	55.25 (3)	K1ⁱⁱ—O1—Ba1^xxviii	86.01 (3)
O2^xii—Ba1—O1^xvii	93.53 (2)	Ba1^xxvii—O1—Ba1^xxviii	168.69 (7)
O2^xiii—Ba1—O1^xvii	55.24 (3)	Te1^xiii—O2—Ba2^xxix	162.91 (9)
O2^xiv—Ba1—O1^xvii	93.53 (2)	Te1^xiii—O2—Ba1	101.29 (8)
O1^xv—Ba1—O1^xvii	48.69 (8)	Ba2^xxix—O2—Ba1	95.79 (7)
O1^xvi—Ba1—O1^xvii	120.0	Te1^xiii—O2—K1^xxx	89.48 (3)
O2^x—Ba1—O1^xviii	120.56 (3)	Ba2^xxix—O2—K1^xxx	92.02 (3)
O2^xi—Ba1—O1^xviii	120.56 (3)	Ba1—O2—K1^xxx	85.03 (4)
O2—Ba1—O1^xviii	93.53 (2)	Te1^xiii—O2—K1^xxxi	89.48 (3)
O2^xii—Ba1—O1^xviii	55.24 (3)	Ba2^xxix—O2—K1^xxxi	92.02 (3)
O2^xiii—Ba1—O1^xviii	93.53 (2)	Ba1—O2—K1^xxxi	85.03 (4)
O2^xiv—Ba1—O1^xviii	55.24 (3)	K1^xxx—O2—K1^xxxi	169.60 (8)
O1^xv—Ba1—O1^xviii	120.0

Symmetry codes: (i) y−1, −x+y, −z+1; (ii) −x+1, −y+2, −z+1; (iii) x−y+1, x, −z+1; (iv) y, −x+y+1, z+1/2; (v) −x, −y+1, z+1/2; (vi) x−y+1, x+1, z+1/2; (vii) x−y, x, z+1/2; (viii) −x+1, −y+1, z+1/2; (ix) y, −x+y, z+1/2; (x) −x+y, −x, −z+1/2; (xi) −x+y, −x, z; (xii) −y, x−y, −z+1/2; (xiii) x, y, −z+1/2; (xiv) −y, x−y, z; (xv) −x+y, −x+1, z; (xvi) −x+y−1, −x, z; (xvii) −y+1, x−y+1, z; (xviii) x−1, y−1, z; (xix) −y+1, x−y, z; (xx) x, y−1, z; (xxi) −y+1, x−y+1, −z+1/2; (xxii) −x+y, −x+1, −z+1/2; (xxiii) x−y, x, z−1/2; (xxiv) −x, −y, z−1/2; (xxv) y, −x+y, z−1/2; (xxvi) −x+1, −y+2, z−1/2; (xxvii) x, y+1, z; (xxviii) x+1, y+1, z; (xxix) −x, −y, z+1/2; (xxx) −x+1, −y+1, z−1/2; (xxxi) −x, −y+1, z−1/2.

Dibarium potassium sodium nonaoxidoditellurate (II) top

Crystal data top

Ba₂KNaTe₂O₉	D_x = 5.314 Mg m⁻³
M_r = 735.97	Mo Kα radiation, λ = 0.71073 Å
Hexagonal, P6₃/mmc	Cell parameters from 9985 reflections
a = 5.9625 (3) Å	θ = 2.7–42.9°
c = 14.9396 (8) Å	µ = 15.25 mm⁻¹
V = 459.97 (5) Å³	T = 293 K
Z = 2	Plate, colourless
F(000) = 636	0.10 × 0.10 × 0.01 mm

Data collection top

Bruker APEXII CCD diffractometer	669 reflections with I > 2σ(I)
ω– and φ–scans	R_int = 0.029
Absorption correction: multi-scan (SADABS; Bruker, 2015)	θ_max = 43.1°, θ_min = 2.7°
T_min = 0.540, T_max = 0.749	h = −11→11
11701 measured reflections	k = −11→8
702 independent reflections	l = −28→28

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	w = 1/[σ²(F_o²) + (0.0075P)² + 0.5711P] where P = (F_o² + 2F_c²)/3
R[F² > 2σ(F²)] = 0.018	(Δ/σ)_max = 0.001
wR(F²) = 0.034	Δρ_max = 1.02 e Å⁻³
S = 1.49	Δρ_min = −1.63 e Å⁻³
702 reflections	Extinction correction: SHELXL2014 (Sheldrick, 2015), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
23 parameters	Extinction coefficient: 0.0409 (10)

Special details top

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
BaK1	0.3333	0.6667	0.91703 (2)	0.01251 (6)	0.5
KBA1	0.3333	0.6667	0.91703 (2)	0.01251 (6)	0.5
Ba1	0.0000	0.0000	0.2500	0.00953 (5)
Te1	0.3333	0.6667	0.15383 (2)	0.00583 (5)
Na2	0.0000	0.0000	0.0000	0.0110 (3)
O1	0.47381 (18)	0.9476 (4)	0.2500	0.0101 (3)
O2	0.17638 (16)	0.3528 (3)	0.40559 (12)	0.0195 (3)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
BaK1	0.01060 (8)	0.01060 (8)	0.01631 (11)	0.00530 (4)	0.000	0.000
KBA1	0.01060 (8)	0.01060 (8)	0.01631 (11)	0.00530 (4)	0.000	0.000
Ba1	0.00874 (7)	0.00874 (7)	0.01112 (9)	0.00437 (3)	0.000	0.000
Te1	0.00573 (5)	0.00573 (5)	0.00603 (7)	0.00287 (3)	0.000	0.000
Na2	0.0118 (5)	0.0118 (5)	0.0094 (7)	0.0059 (2)	0.000	0.000
O1	0.0107 (5)	0.0060 (6)	0.0121 (6)	0.0030 (3)	0.000	0.000
O2	0.0235 (6)	0.0120 (6)	0.0192 (6)	0.0060 (3)	0.0045 (3)	0.0089 (5)

Geometric parameters (Å, º) top

BaK1—O2ⁱ	2.9878 (2)	Ba1—O1^xviii	2.9935 (14)
BaK1—O2ⁱⁱ	2.9878 (2)	Ba1—O1^xix	2.9935 (14)
BaK1—O2ⁱⁱⁱ	2.9878 (2)	Ba1—O1^xx	2.9935 (14)
BaK1—O2^iv	2.9878 (2)	Ba1—O1^xxi	2.9935 (14)
BaK1—O2^v	2.9878 (2)	Ba1—O1^xxii	2.9935 (14)
BaK1—O2^vi	2.9879 (2)	Ba1—O1^xxiii	2.9935 (14)
BaK1—O2^vii	3.1064 (18)	Te1—O2^xxiv	1.8481 (16)
BaK1—O2^viii	3.1064 (19)	Te1—O2^xiv	1.8481 (16)
BaK1—O2^ix	3.1064 (19)	Te1—O2^xxv	1.8481 (16)
BaK1—O1^x	3.1927 (12)	Te1—O1^xx	2.0418 (14)
BaK1—O1^xi	3.1927 (12)	Te1—O1^xviii	2.0418 (14)
BaK1—O1^xii	3.1927 (12)	Te1—O1	2.0418 (14)
Ba1—O2^xiii	2.9532 (18)	Na2—O2^xiv	2.3037 (16)
Ba1—O2^xiv	2.9532 (18)	Na2—O2^xxvi	2.3037 (16)
Ba1—O2^xv	2.9532 (18)	Na2—O2^xiii	2.3037 (16)
Ba1—O2	2.9532 (18)	Na2—O2^xxvii	2.3037 (16)
Ba1—O2^xvi	2.9532 (18)	Na2—O2^xvi	2.3038 (16)
Ba1—O2^xvii	2.9532 (18)	Na2—O2^xxviii	2.3038 (16)

O2ⁱ—BaK1—O2ⁱⁱ	56.05 (6)	O2^xv—Ba1—O1^xxii	93.19 (2)
O2ⁱ—BaK1—O2ⁱⁱⁱ	63.74 (7)	O2—Ba1—O1^xxii	120.27 (3)
O2ⁱⁱ—BaK1—O2ⁱⁱⁱ	119.677 (7)	O2^xvi—Ba1—O1^xxii	55.95 (3)
O2ⁱ—BaK1—O2^iv	119.677 (7)	O2^xvii—Ba1—O1^xxii	55.95 (3)
O2ⁱⁱ—BaK1—O2^iv	63.74 (7)	O1^xviii—Ba1—O1^xxii	120.0
O2ⁱⁱⁱ—BaK1—O2^iv	172.40 (6)	O1^xix—Ba1—O1^xxii	70.37 (7)
O2ⁱ—BaK1—O2^v	119.676 (7)	O1^xx—Ba1—O1^xxii	169.63 (7)
O2ⁱⁱ—BaK1—O2^v	172.40 (6)	O1^xxi—Ba1—O1^xxii	120.0
O2ⁱⁱⁱ—BaK1—O2^v	56.04 (6)	O2^xiii—Ba1—O1^xxiii	120.27 (3)
O2^iv—BaK1—O2^v	119.675 (7)	O2^xiv—Ba1—O1^xxiii	93.19 (2)
O2ⁱ—BaK1—O2^vi	172.40 (6)	O2^xv—Ba1—O1^xxiii	120.27 (3)
O2ⁱⁱ—BaK1—O2^vi	119.676 (7)	O2—Ba1—O1^xxiii	93.20 (2)
O2ⁱⁱⁱ—BaK1—O2^vi	119.675 (7)	O2^xvi—Ba1—O1^xxiii	55.95 (3)
O2^iv—BaK1—O2^vi	56.04 (6)	O2^xvii—Ba1—O1^xxiii	55.95 (3)
O2^v—BaK1—O2^vi	63.74 (6)	O1^xviii—Ba1—O1^xxiii	70.37 (7)
O2ⁱ—BaK1—O2^vii	120.56 (3)	O1^xix—Ba1—O1^xxiii	120.0
O2ⁱⁱ—BaK1—O2^vii	120.56 (3)	O1^xx—Ba1—O1^xxiii	120.0
O2ⁱⁱⁱ—BaK1—O2^vii	91.79 (4)	O1^xxi—Ba1—O1^xxiii	169.63 (7)
O2^iv—BaK1—O2^vii	91.79 (4)	O1^xxii—Ba1—O1^xxiii	49.63 (7)
O2^v—BaK1—O2^vii	66.84 (5)	O2^xxiv—Te1—O2^xiv	98.85 (7)
O2^vi—BaK1—O2^vii	66.84 (5)	O2^xxiv—Te1—O2^xxv	98.85 (7)
O2ⁱ—BaK1—O2^viii	91.79 (4)	O2^xiv—Te1—O2^xxv	98.85 (7)
O2ⁱⁱ—BaK1—O2^viii	66.84 (5)	O2^xxiv—Te1—O1^xx	91.52 (5)
O2ⁱⁱⁱ—BaK1—O2^viii	120.56 (3)	O2^xiv—Te1—O1^xx	91.51 (5)
O2^iv—BaK1—O2^viii	66.84 (5)	O2^xxv—Te1—O1^xx	163.99 (7)
O2^v—BaK1—O2^viii	120.56 (3)	O2^xxiv—Te1—O1^xviii	163.99 (7)
O2^vi—BaK1—O2^viii	91.79 (4)	O2^xiv—Te1—O1^xviii	91.51 (5)
O2^vii—BaK1—O2^viii	53.73 (5)	O2^xxv—Te1—O1^xviii	91.51 (5)
O2ⁱ—BaK1—O2^ix	66.84 (5)	O1^xx—Te1—O1^xviii	75.95 (6)
O2ⁱⁱ—BaK1—O2^ix	91.79 (4)	O2^xxiv—Te1—O1	91.51 (5)
O2ⁱⁱⁱ—BaK1—O2^ix	66.84 (5)	O2^xiv—Te1—O1	163.99 (7)
O2^iv—BaK1—O2^ix	120.56 (3)	O2^xxv—Te1—O1	91.52 (5)
O2^v—BaK1—O2^ix	91.79 (4)	O1^xx—Te1—O1	75.95 (6)
O2^vi—BaK1—O2^ix	120.56 (3)	O1^xviii—Te1—O1	75.95 (6)
O2^vii—BaK1—O2^ix	53.73 (5)	O2^xiv—Na2—O2^xxvi	180.00 (9)
O2^viii—BaK1—O2^ix	53.73 (5)	O2^xiv—Na2—O2^xiii	86.43 (7)
O2ⁱ—BaK1—O1^x	88.64 (4)	O2^xxvi—Na2—O2^xiii	93.57 (7)
O2ⁱⁱ—BaK1—O1^x	118.94 (4)	O2^xiv—Na2—O2^xxvii	93.57 (7)
O2ⁱⁱⁱ—BaK1—O1^x	53.54 (4)	O2^xxvi—Na2—O2^xxvii	86.43 (7)
O2^iv—BaK1—O1^x	118.94 (4)	O2^xiii—Na2—O2^xxvii	180.00 (9)
O2^v—BaK1—O1^x	53.54 (4)	O2^xiv—Na2—O2^xvi	86.43 (7)
O2^vi—BaK1—O1^x	88.64 (4)	O2^xxvi—Na2—O2^xvi	93.57 (7)
O2^vii—BaK1—O1^x	120.26 (3)	O2^xiii—Na2—O2^xvi	86.43 (7)
O2^viii—BaK1—O1^x	172.86 (4)	O2^xxvii—Na2—O2^xvi	93.57 (7)
O2^ix—BaK1—O1^x	120.26 (3)	O2^xiv—Na2—O2^xxviii	93.57 (7)
O2ⁱ—BaK1—O1^xi	118.94 (4)	O2^xxvi—Na2—O2^xxviii	86.43 (7)
O2ⁱⁱ—BaK1—O1^xi	88.64 (4)	O2^xiii—Na2—O2^xxviii	93.57 (7)
O2ⁱⁱⁱ—BaK1—O1^xi	118.94 (4)	O2^xxvii—Na2—O2^xxviii	86.43 (7)
O2^iv—BaK1—O1^xi	53.54 (4)	O2^xvi—Na2—O2^xxviii	180.00 (7)
O2^v—BaK1—O1^xi	88.64 (4)	Te1^xiv—O1—Te1	89.44 (8)
O2^vi—BaK1—O1^xi	53.54 (4)	Te1^xiv—O1—Ba1^xxix	93.68 (2)
O2^vii—BaK1—O1^xi	120.26 (3)	Te1—O1—Ba1^xxix	93.68 (2)
O2^viii—BaK1—O1^xi	120.26 (3)	Te1^xiv—O1—Ba1^xxx	93.68 (2)
O2^ix—BaK1—O1^xi	172.86 (4)	Te1—O1—Ba1^xxx	93.68 (2)
O1^x—BaK1—O1^xi	65.40 (4)	Ba1^xxix—O1—Ba1^xxx	169.63 (7)
O2ⁱ—BaK1—O1^xii	53.54 (4)	Te1^xiv—O1—BaK1^xxxi	83.874 (13)
O2ⁱⁱ—BaK1—O1^xii	53.54 (4)	Te1—O1—BaK1^xxxi	173.32 (6)
O2ⁱⁱⁱ—BaK1—O1^xii	88.64 (4)	Ba1^xxix—O1—BaK1^xxxi	86.77 (2)
O2^iv—BaK1—O1^xii	88.64 (4)	Ba1^xxx—O1—BaK1^xxxi	86.77 (2)
O2^v—BaK1—O1^xii	118.94 (4)	Te1^xiv—O1—KBA1^xxxi	83.874 (13)
O2^vi—BaK1—O1^xii	118.94 (4)	Te1—O1—KBA1^xxxi	173.32 (6)
O2^vii—BaK1—O1^xii	172.86 (4)	Ba1^xxix—O1—KBA1^xxxi	86.77 (2)
O2^viii—BaK1—O1^xii	120.26 (3)	Ba1^xxx—O1—KBA1^xxxi	86.77 (2)
O2^ix—BaK1—O1^xii	120.26 (3)	BaK1^xxxi—O1—KBA1^xxxi	0.000 (7)
O1^x—BaK1—O1^xii	65.40 (4)	Te1^xiv—O1—BaK1^xi	173.32 (6)
O1^xi—BaK1—O1^xii	65.40 (4)	Te1—O1—BaK1^xi	83.874 (13)
O2^xiii—Ba1—O2^xiv	64.58 (5)	Ba1^xxix—O1—BaK1^xi	86.77 (2)
O2^xiii—Ba1—O2^xv	103.83 (6)	Ba1^xxx—O1—BaK1^xi	86.77 (2)
O2^xiv—Ba1—O2^xv	144.07 (2)	BaK1^xxxi—O1—BaK1^xi	102.81 (5)
O2^xiii—Ba1—O2	144.07 (3)	KBA1^xxxi—O1—BaK1^xi	102.8
O2^xiv—Ba1—O2	103.83 (6)	Te1^xiv—O1—KBA1^xi	173.32 (6)
O2^xv—Ba1—O2	64.58 (5)	Te1—O1—KBA1^xi	83.874 (13)
O2^xiii—Ba1—O2^xvi	64.58 (5)	Ba1^xxix—O1—KBA1^xi	86.77 (2)
O2^xiv—Ba1—O2^xvi	64.58 (5)	Ba1^xxx—O1—KBA1^xi	86.77 (2)
O2^xv—Ba1—O2^xvi	144.07 (2)	BaK1^xxxi—O1—KBA1^xi	102.81 (5)
O2—Ba1—O2^xvi	144.07 (2)	KBA1^xxxi—O1—KBA1^xi	102.81 (5)
O2^xiii—Ba1—O2^xvii	144.07 (3)	BaK1^xi—O1—KBA1^xi	0.000 (7)
O2^xiv—Ba1—O2^xvii	144.07 (3)	Te1^xiv—O2—Na2^xxxii	170.96 (10)
O2^xv—Ba1—O2^xvii	64.58 (5)	Te1^xiv—O2—Ba1	99.37 (7)
O2—Ba1—O2^xvii	64.58 (5)	Na2^xxxii—O2—Ba1	89.67 (6)
O2^xvi—Ba1—O2^xvii	103.83 (6)	Te1^xiv—O2—BaK1^xxxiii	93.26 (3)
O2^xiii—Ba1—O1^xviii	120.27 (3)	Na2^xxxii—O2—BaK1^xxxiii	86.47 (3)
O2^xiv—Ba1—O1^xviii	55.95 (3)	Ba1—O2—BaK1^xxxiii	91.39 (4)
O2^xv—Ba1—O1^xviii	120.27 (3)	Te1^xiv—O2—KBA1^xxxiii	93.26 (3)
O2—Ba1—O1^xviii	55.95 (3)	Na2^xxxii—O2—KBA1^xxxiii	86.47 (3)
O2^xvi—Ba1—O1^xviii	93.20 (2)	Ba1—O2—KBA1^xxxiii	91.39 (4)
O2^xvii—Ba1—O1^xviii	93.19 (2)	BaK1^xxxiii—O2—KBA1^xxxiii	0.000 (13)
O2^xiii—Ba1—O1^xix	55.95 (3)	Te1^xiv—O2—BaK1^xxxiv	93.26 (3)
O2^xiv—Ba1—O1^xix	120.27 (3)	Na2^xxxii—O2—BaK1^xxxiv	86.47 (3)
O2^xv—Ba1—O1^xix	55.95 (3)	Ba1—O2—BaK1^xxxiv	91.39 (4)
O2—Ba1—O1^xix	120.27 (3)	BaK1^xxxiii—O2—BaK1^xxxiv	172.40 (6)
O2^xvi—Ba1—O1^xix	93.20 (2)	KBA1^xxxiii—O2—BaK1^xxxiv	172.4
O2^xvii—Ba1—O1^xix	93.20 (2)	Te1^xiv—O2—KBA1^xxxiv	93.26 (3)
O1^xviii—Ba1—O1^xix	169.63 (7)	Na2^xxxii—O2—KBA1^xxxiv	86.47 (3)
O2^xiii—Ba1—O1^xx	93.20 (2)	Ba1—O2—KBA1^xxxiv	91.39 (4)
O2^xiv—Ba1—O1^xx	55.95 (3)	BaK1^xxxiii—O2—KBA1^xxxiv	172.40 (6)
O2^xv—Ba1—O1^xx	93.20 (2)	KBA1^xxxiii—O2—KBA1^xxxiv	172.40 (6)
O2—Ba1—O1^xx	55.95 (3)	BaK1^xxxiv—O2—KBA1^xxxiv	0.0
O2^xvi—Ba1—O1^xx	120.27 (3)	Te1^xiv—O2—KBA1^ix	87.26 (6)
O2^xvii—Ba1—O1^xx	120.27 (3)	Na2^xxxii—O2—KBA1^ix	83.70 (5)
O1^xviii—Ba1—O1^xx	49.63 (7)	Ba1—O2—KBA1^ix	173.37 (6)
O1^xix—Ba1—O1^xx	120.0	BaK1^xxxiii—O2—KBA1^ix	88.21 (4)
O2^xiii—Ba1—O1^xxi	55.95 (3)	KBA1^xxxiii—O2—KBA1^ix	88.21 (4)
O2^xiv—Ba1—O1^xxi	93.20 (2)	BaK1^xxxiv—O2—KBA1^ix	88.21 (4)
O2^xv—Ba1—O1^xxi	55.95 (3)	KBA1^xxxiv—O2—KBA1^ix	88.21 (4)
O2—Ba1—O1^xxi	93.20 (2)	Te1^xiv—O2—BaK1^ix	87.26 (6)
O2^xvi—Ba1—O1^xxi	120.27 (3)	Na2^xxxii—O2—BaK1^ix	83.70 (5)
O2^xvii—Ba1—O1^xxi	120.27 (3)	Ba1—O2—BaK1^ix	173.37 (6)
O1^xviii—Ba1—O1^xxi	120.0	BaK1^xxxiii—O2—BaK1^ix	88.21 (4)
O1^xix—Ba1—O1^xxi	49.63 (7)	KBA1^xxxiii—O2—BaK1^ix	88.2
O1^xx—Ba1—O1^xxi	70.37 (7)	BaK1^xxxiv—O2—BaK1^ix	88.21 (4)
O2^xiii—Ba1—O1^xxii	93.19 (2)	KBA1^xxxiv—O2—BaK1^ix	88.2
O2^xiv—Ba1—O1^xxii	120.27 (3)	KBA1^ix—O2—BaK1^ix	0.0

Symmetry codes: (i) y, −x+y, z+1/2; (ii) −x+1, −y+1, z+1/2; (iii) x−y, x, z+1/2; (iv) x−y+1, x+1, z+1/2; (v) −x, −y+1, z+1/2; (vi) y, −x+y+1, z+1/2; (vii) −x+y, −x+1, −z+3/2; (viii) −y+1, x−y+1, −z+3/2; (ix) x, y, −z+3/2; (x) y−1, −x+y, −z+1; (xi) −x+1, −y+2, −z+1; (xii) x−y+1, x, −z+1; (xiii) −y, x−y, −z+1/2; (xiv) x, y, −z+1/2; (xv) −y, x−y, z; (xvi) −x+y, −x, −z+1/2; (xvii) −x+y, −x, z; (xviii) −x+y, −x+1, z; (xix) −x+y−1, −x, z; (xx) −y+1, x−y+1, z; (xxi) x−1, y−1, z; (xxii) −y+1, x−y, z; (xxiii) x, y−1, z; (xxiv) −x+y, −x+1, −z+1/2; (xxv) −y+1, x−y+1, −z+1/2; (xxvi) −x, −y, z−1/2; (xxvii) y, −x+y, z−1/2; (xxviii) x−y, x, z−1/2; (xxix) x+1, y+1, z; (xxx) x, y+1, z; (xxxi) −x+1, −y+2, z−1/2; (xxxii) −x, −y, z+1/2; (xxxiii) −x+1, −y+1, z−1/2; (xxxiv) −x, −y+1, z−1/2.

Dibarium calcium hexaoxidotellurate (III) top

Crystal data top

Ba₂CaTeO₆	Mo Kα radiation, λ = 0.71073 Å
M_r = 538.36	Cell parameters from 5256 reflections
Cubic, Fm3m	θ = 4.2–40.4°
a = 8.3536 (14) Å	µ = 19.18 mm⁻¹
V = 582.9 (3) Å³	T = 293 K
Z = 4	Octahedron, colourless
F(000) = 928	0.08 × 0.08 × 0.08 mm
D_x = 6.134 Mg m⁻³

Data collection top

Bruker APEXII CCD diffractometer	131 reflections with I > 2σ(I)
φ– and ω–scans	R_int = 0.139
Absorption correction: multi-scan (SADABS; Bruker, 2015)	θ_max = 40.8°, θ_min = 4.2°
T_min = 0.514, T_max = 0.748	h = −15→15
11194 measured reflections	k = −15→15
131 independent reflections	l = −15→15

Refinement top

Refinement on F²	7 parameters
Least-squares matrix: full	0 restraints
R[F² > 2σ(F²)] = 0.019	w = 1/[σ²(F_o²) + (0.0237P)² + 1.8403P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.049	(Δ/σ)_max < 0.001
S = 1.33	Δρ_max = 3.87 e Å⁻³
131 reflections	Δρ_min = −1.68 e Å⁻³

Special details top

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Ba	0.250000	0.250000	0.250000	0.00957 (13)
Ca	0.000000	0.000000	0.000000	0.0066 (2)
Te	0.500000	0.500000	0.500000	0.00602 (13)
O	0.2690 (4)	0.000000	0.000000	0.0203 (6)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Ba	0.00957 (13)	0.00957 (13)	0.00957 (13)	0.000	0.000	0.000
Ca	0.0066 (2)	0.0066 (2)	0.0066 (2)	0.000	0.000	0.000
Te	0.00602 (13)	0.00602 (13)	0.00602 (13)	0.000	0.000	0.000
O	0.0201 (12)	0.0203 (8)	0.0203 (8)	0.000	0.000	0.000

Geometric parameters (Å, º) top

Ba—Oⁱ	2.9577 (5)	Ca—O	2.247 (3)
Ba—Oⁱⁱ	2.9577 (5)	Ca—O^xii	2.247 (3)
Ba—O	2.9577 (5)	Ca—O^iv	2.247 (3)
Ba—Oⁱⁱⁱ	2.9577 (5)	Ca—O^xiii	2.247 (3)
Ba—O^iv	2.9577 (5)	Ca—O^v	2.247 (3)
Ba—O^v	2.9577 (5)	Ca—O^xiv	2.247 (3)
Ba—O^vi	2.9577 (5)	Te—O^xv	1.930 (3)
Ba—O^vii	2.9577 (5)	Te—Oⁱⁱⁱ	1.930 (3)
Ba—O^viii	2.9577 (5)	Te—O^xvi	1.930 (3)
Ba—O^ix	2.9577 (5)	Te—Oⁱ	1.930 (3)
Ba—O^x	2.9577 (5)	Te—O^xvii	1.930 (3)
Ba—O^xi	2.9577 (5)	Te—Oⁱⁱ	1.930 (3)

Oⁱ—Ba—Oⁱⁱ	54.95 (11)	Oⁱⁱ—Ba—O^xi	90.165 (7)
Oⁱ—Ba—O	119.905 (4)	O—Ba—O^xi	90.165 (7)
Oⁱⁱ—Ba—O	173.85 (13)	Oⁱⁱⁱ—Ba—O^xi	119.905 (4)
Oⁱ—Ba—Oⁱⁱⁱ	54.95 (11)	O^iv—Ba—O^xi	54.95 (11)
Oⁱⁱ—Ba—Oⁱⁱⁱ	54.95 (11)	O^v—Ba—O^xi	119.905 (4)
O—Ba—Oⁱⁱⁱ	119.905 (4)	O^vi—Ba—O^xi	64.99 (11)
Oⁱ—Ba—O^iv	119.905 (4)	O^vii—Ba—O^xi	119.905 (4)
Oⁱⁱ—Ba—O^iv	119.905 (4)	O^viii—Ba—O^xi	119.905 (4)
O—Ba—O^iv	64.99 (11)	O^ix—Ba—O^xi	54.95 (11)
Oⁱⁱⁱ—Ba—O^iv	173.85 (13)	O^x—Ba—O^xi	173.85 (13)
Oⁱ—Ba—O^v	173.85 (13)	O—Ca—O^xii	90.0
Oⁱⁱ—Ba—O^v	119.905 (4)	O—Ca—O^iv	90.0
O—Ba—O^v	64.99 (11)	O^xii—Ca—O^iv	180.0
Oⁱⁱⁱ—Ba—O^v	119.905 (4)	O—Ca—O^xiii	90.0
O^iv—Ba—O^v	64.99 (11)	O^xii—Ca—O^xiii	90.0
Oⁱ—Ba—O^vi	64.99 (11)	O^iv—Ca—O^xiii	90.0
Oⁱⁱ—Ba—O^vi	119.905 (4)	O—Ca—O^v	90.0
O—Ba—O^vi	54.95 (11)	O^xii—Ca—O^v	90.0
Oⁱⁱⁱ—Ba—O^vi	90.165 (7)	O^iv—Ca—O^v	90.0
O^iv—Ba—O^vi	90.165 (7)	O^xiii—Ca—O^v	180.0
O^v—Ba—O^vi	119.905 (4)	O—Ca—O^xiv	180.0
Oⁱ—Ba—O^vii	119.905 (4)	O^xii—Ca—O^xiv	90.0
Oⁱⁱ—Ba—O^vii	64.99 (11)	O^iv—Ca—O^xiv	90.0
O—Ba—O^vii	119.905 (4)	O^xiii—Ca—O^xiv	90.0
Oⁱⁱⁱ—Ba—O^vii	90.165 (7)	O^v—Ca—O^xiv	90.0
O^iv—Ba—O^vii	90.165 (7)	O^xv—Te—Oⁱⁱⁱ	180.0
O^v—Ba—O^vii	54.95 (11)	O^xv—Te—O^xvi	90.0
O^vi—Ba—O^vii	173.85 (13)	Oⁱⁱⁱ—Te—O^xvi	90.0
Oⁱ—Ba—O^viii	90.165 (7)	O^xv—Te—Oⁱ	90.0
Oⁱⁱ—Ba—O^viii	119.905 (4)	Oⁱⁱⁱ—Te—Oⁱ	90.0
O—Ba—O^viii	54.95 (11)	O^xvi—Te—Oⁱ	180.0
Oⁱⁱⁱ—Ba—O^viii	64.99 (11)	O^xv—Te—O^xvii	90.000 (1)
O^iv—Ba—O^viii	119.905 (4)	Oⁱⁱⁱ—Te—O^xvii	90.0
O^v—Ba—O^viii	90.165 (7)	O^xvi—Te—O^xvii	90.000 (1)
O^vi—Ba—O^viii	54.95 (11)	Oⁱ—Te—O^xvii	90.0
O^vii—Ba—O^viii	119.905 (4)	O^xv—Te—Oⁱⁱ	90.0
Oⁱ—Ba—O^ix	90.165 (7)	Oⁱⁱⁱ—Te—Oⁱⁱ	90.000 (1)
Oⁱⁱ—Ba—O^ix	64.99 (11)	O^xvi—Te—Oⁱⁱ	90.0
O—Ba—O^ix	119.905 (4)	Oⁱ—Te—Oⁱⁱ	90.000 (1)
Oⁱⁱⁱ—Ba—O^ix	119.905 (4)	O^xvii—Te—Oⁱⁱ	180.0
O^iv—Ba—O^ix	54.95 (11)	Te^xviii—O—Ca	180.0
O^v—Ba—O^ix	90.165 (7)	Te^xviii—O—Ba^xviii	93.08 (7)
O^vi—Ba—O^ix	119.905 (4)	Ca—O—Ba^xviii	86.92 (7)
O^vii—Ba—O^ix	64.99 (11)	Te^xviii—O—Ba	93.08 (7)
O^viii—Ba—O^ix	173.85 (13)	Ca—O—Ba	86.92 (7)
Oⁱ—Ba—O^x	119.905 (4)	Ba^xviii—O—Ba	173.85 (13)
Oⁱⁱ—Ba—O^x	90.165 (7)	Te^xviii—O—Ba^x	93.08 (7)
O—Ba—O^x	90.165 (7)	Ca—O—Ba^x	86.92 (7)
Oⁱⁱⁱ—Ba—O^x	64.99 (11)	Ba^xviii—O—Ba^x	89.835 (7)
O^iv—Ba—O^x	119.905 (4)	Ba—O—Ba^x	89.835 (7)
O^v—Ba—O^x	54.95 (11)	Te^xviii—O—Ba^xi	93.08 (7)
O^vi—Ba—O^x	119.905 (4)	Ca—O—Ba^xi	86.92 (7)
O^vii—Ba—O^x	54.95 (11)	Ba^xviii—O—Ba^xi	89.835 (7)
O^viii—Ba—O^x	64.99 (11)	Ba—O—Ba^xi	89.835 (7)
O^ix—Ba—O^x	119.905 (4)	Ba^x—O—Ba^xi	173.85 (13)
Oⁱ—Ba—O^xi	64.99 (11)

Symmetry codes: (i) z+1/2, x, y+1/2; (ii) x, y+1/2, z+1/2; (iii) y+1/2, z+1/2, x; (iv) y, z, x; (v) z, x, y; (vi) −y+1/2, −z, −x+1/2; (vii) −y, −z+1/2, −x+1/2; (viii) −z+1/2, −x+1/2, −y; (ix) −z, −x+1/2, −y+1/2; (x) −x+1/2, −y+1/2, −z; (xi) −x+1/2, −y, −z+1/2; (xii) −y, −z, −x; (xiii) −z, −x, −y; (xiv) −x, −y, −z; (xv) −y+1/2, −z+1/2, −x+1; (xvi) −z+1/2, −x+1, −y+1/2; (xvii) −x+1, −y+1/2, −z+1/2; (xviii) x, y−1/2, z−1/2.

Selected bond lengths (Å) and angles (°) in the structures (I)–(III) top

(I)		(II)		(III)
K1—O1	2.893 (2) [3×]	(Ba/K)1—O2	2.98780 (19) [6×]	Ba—O	2.9577 (5) [12×]
K1—O2	3.0359 (17) [6×]	(Ba/K)1—O2	3.1064 (19) [3×]	Ca—O	2.247 (3) [6x]
		(Ba/K)1—O1	3.1927 (12) [3×]	Te—O	1.930 (3) [6×]
Ba1—O2	2.952 (2) [6×]	Ba1—O2	2.9532 (18) [6×]
Ba1—O1	3.0382 (17) [6×]	Ba1—O1	2.9935 (14) [6×]
Te1—O2	1.8524 (18) [3×]	Te1—O2	1.8481 (16) [3×]
Te1—O1	2.0474 (16) [3×]	Te1—O1	2.0418 (14) [3×]
Ba2—O2	2.5910 (18) [6×]	Na2—O2	2.3037 (16) [6×]

O1—Te1—O1	75.43 (7) [3×]	O1—Te1—O1	75.95 (6) [3×]
Δ^a	0.076	Δ^a	0.191

Note: (a) Δ is the center shift (Å) of the Te atoms in the Te₂O₉ dimer. The center shift is defined as the distance between the Te atoms in the 4f Wyckoff position (z ≈ 1/6) of the actual crystal structure and the ideal high-symmetry 4f Te position (z =1/6) (Lufaso & zur Loye, 2005a).

Funding information

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

References

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Volume 74| Part 7| July 2018| Pages 1006-1009

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