Barium bis­[tetra­fluorido­bromate(III)]

Ivlev, S.I.; Kraus, F.

doi:10.1107/S2414314621007355

inorganic compounds

IUCrDATA

ISSN: 2414-3146

Volume 6| Part 7| July 2021| x210735

https://doi.org/10.1107/S2414314621007355

Open

access

Barium bis[tetrafluoridobromate(III)]

Sergei I. Ivlev ^a and Florian Kraus ^a ^*

^aPhilipps-Universität Marburg, Fachbereich Chemie, Hans-Meerwein-Str. 4, 35032 Marburg, Germany
^*Correspondence e-mail: f.kraus@uni-marburg.de

Edited by M. Weil, Vienna University of Technology, Austria (Received 22 June 2021; accepted 15 July 2021; online 20 July 2021)

Single crystals of barium bis[tetrafluoridobromate(III)], Ba[BrF₄]₂, were obtained in the form of tiny blocks. Crystal-structure refinement of Ba[BrF₄]₂ from single-crystal X-ray diffraction data confirmed the previous model obtained on the basis of powder data [Ivlev et al. (2014 ). Eur. J. Inorg. Chem. pp. 6261–6267], but with all atoms refined with anisotropic displacement parameters. The crystal structure consists of two symmetry-independent barium cations that are each coordinated by twelve fluorine atoms, forming edge-sharing polyhedra, and an almost square-planar [BrF₄]⁻ anion. The compound crystallizes in the Ba[AuF₄]₂ structure type.

Keywords: crystal structure; barium; tetrafluoridobromate(III); re-refinement.

CCDC reference: 2096684

Structure description

The first synthesis of Ba[BrF₄]₂ was performed by Sharpe & Emeléus (1948 ) by treating anhydrous barium chloride or barium fluoride with bromine trifluoride. The product was, however, only characterized by means of a quantitative elemental analysis. The thermal properties of Ba[BrF₄]₂ were later studied by Kiselev and co-workers, who investigated the thermal decomposition of Ba[BrF₄]₂ to yield barium fluoride (Kiselev et al., 1987 ). To the best of our knowledge, our report on the crystal structure of Ba[BrF₄]₂ determined from X-ray and neutron powder diffraction data at 300 K was the first structural investigation of the title compound (Ivlev et al., 2014). We showed that Ba[BrF₄]₂ crystallizes in the space group I $[\overline{4}]$ and adopts the Ba[AuF₄]₂ structure type. Here we present our results on the re-refinement of the crystal structure of Ba[BrF₄]₂ from single-crystal X-ray diffraction data at 100 K.

As expected, the unit-cell parameters of the single-crystal study at 100 K (Table 1) are smaller than those determined during the powder study at 300 K, a = 9.65081 (11), c = 8.03453 (13) Å, V = 748.32 (2) Å³ (Ivlev et al., 2014). The crystal structure contains two symmetry-independent Ba²⁺ cations on special Wyckoff positions 2a (site symmetry $[\overline{4}]$ ..) and 2d ( $[\overline{4}]$ ..), respectively. Each Ba site is coordinated by twelve F atoms forming edge-sharing polyhedra. The Ba⋯F distances lie in the range of 2.680 (14)–3.324 (16) Å [powder data at RT yielded the range of 2.696 (3)–3.376 (3) Å]. The bromine atom occupies the general Wyckoff position 8g and is coordinated by four fluorine atoms also located on general positions in an almost square-planar shape. The resulting Br—F bond lengths are 1.829 (13), 1.861 (12), 1.934 (13), and 1.935 (13) Å, which is comparable with our previous model on basis of powder data [cf.: 1.800 (4), 1.856 (4), 1.902 (4), 1.935 (2) Å]. The two longer Br—F bond lengths correspond to the F atoms coordinating two barium cations each. The two other fluorine atoms coordinate only to one barium cation each and thus have shorter Br—F bond lengths. The F—Br—F cis-angles are 84.9 (6), 89.6 (6), 92.6 (6) and 92.9 (6)°, which corresponds with the previously published results: 85.14 (16), 90.02 (13), 91.80 (15), 93.04 (18)°. Fig. 1 shows the closest contacts between one [BrF₄]⁻ anion and its surrounding Ba²⁺ cations, and Fig. 2 shows the packing of the cations and anions in the crystal structure.

Table 1
Experimental details

Crystal data
Chemical formula	Ba[BrF₄]₂
M_r	449.16
Crystal system, space group	Tetragonal, I $[\overline{4}]$
Temperature (K)	100
a, c (Å)	9.5823 (6), 8.0380 (11)
V (Å³)	738.05 (14)
Z	4
Radiation type	Cu Kα
μ (mm⁻¹)	55.60
Crystal size (mm)	0.02 × 0.02 × 0.01

Data collection
Diffractometer	Stoe Stadivari
Absorption correction	Multi-scan [X-AREA (Stoe, 2020 ) based on Koziskova et al., (2016 )]
T_min, T_max	0.068, 0.362
No. of measured, independent and observed [I > 2σ(I)] reflections	2012, 746, 688
R_int	0.038
(sin θ/λ)_max (Å⁻¹)	0.637

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.049, 0.127, 1.08
No. of reflections	746
No. of parameters	50
Δρ_max, Δρ_min (e Å⁻³)	1.84, −1.05
Absolute structure	Flack x determined using 266 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al., 2013 )
Absolute structure parameter	−0.012 (17)
Computer programs: X-AREA (Stoe, 2020), SHELXT (Sheldrick, 2015a ), SHELXL (Sheldrick, 2015b ), DIAMOND (Brandenburg, 2020 ) and publCIF (Westrip, 2010 ).

Figure 1
The closest contacts between one [BrF₄]⁻ anion and surrounding Ba²⁺ cations. Displacement ellipsoids are shown at the 50% probability level. [Symmetry codes: (xiii) x + $[{1\over 2}]$ , y + $[{1\over 2}]$ , z + $[{1\over 2}]$ ; (xiv) x + $[{1\over 2}]$ , y − $[{1\over 2}]$ , z + $[{1\over 2}]$ .]

Figure 2
The crystal structure of Ba[BrF₄]₂ in a projection along the b axis. Displacement ellipsoids are shown at the 50% probability level.

Synthesis and crystallization

Tiny crystals of barium tetrafluoridobromate(III) were obtained by direct reaction of bromine trifluoride with barium fluoride in a closed Teflon vessel. In contrast to Rb[BrF₄] (Malin et al., 2019 ) and Cs[BrF₄] (Malin et al., 2020 ), it was not possible to improve the crystal quality by melting and recrystallization since Ba[BrF₄]₂ decomposes before reaching its melting point.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. Because of very small size of the crystals, we had to employ a diffractometer with a Cu source to improve the reflection intensities at the cost of a more complicated absorption correction.

Structural data

CCDC reference: 2096684

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314621007355/wm4148sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314621007355/wm4148Isup2.hkl

pdf file with requested changes and comments. DOI: https://doi.org/10.1107/S2414314621007355/wm4148sup3.pdf

checkCIF report

Computing details top

Data collection: X-AREA (Stoe, 2020); cell refinement: X-AREA (Stoe, 2020); data reduction: X-AREA (Stoe, 2020); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL (Sheldrick, 2015b); molecular graphics: DIAMOND (Brandenburg, 2020); software used to prepare material for publication: publCIF (Westrip, 2010).

Barium bis[tetrafluoridobromate(III)] top

Crystal data top

Ba²⁺·2BrF₄⁻	D_x = 4.042 Mg m⁻³
M_r = 449.16	Cu Kα radiation, λ = 1.54186 Å
Tetragonal, I4	Cell parameters from 2706 reflections
a = 9.5823 (6) Å	θ = 6.5–79.3°
c = 8.0380 (11) Å	µ = 55.60 mm⁻¹
V = 738.05 (14) Å³	T = 100 K
Z = 4	Block, colorless
F(000) = 792	0.02 × 0.02 × 0.01 mm

Data collection top

Stoe Stadivari diffractometer	746 independent reflections
Radiation source: GeniX 3D HF Cu	688 reflections with I > 2σ(I)
Graded multilayer mirror monochromator	R_int = 0.038
Detector resolution: 5.81 pixels mm^-1	θ_max = 79.1°, θ_min = 6.5°
rotation method, ω scans	h = −11→12
Absorption correction: multi-scan [X-AREA (Stoe, 2020) based on Koziskova et al., (2016)]	k = −10→6
T_min = 0.068, T_max = 0.362	l = −10→9
2012 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	w = 1/[σ²(F_o²) + (0.091P)² + 5.3796P] where P = (F_o² + 2F_c²)/3
R[F² > 2σ(F²)] = 0.049	(Δ/σ)_max < 0.001
wR(F²) = 0.127	Δρ_max = 1.84 e Å⁻³
S = 1.08	Δρ_min = −1.05 e Å⁻³
746 reflections	Absolute structure: Flack x determined using 266 quotients [(I⁺)-(I^-)]/[(I⁺)+(I^-)] (Parsons et al., 2013)
50 parameters	Absolute structure parameter: −0.012 (17)
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

	x	y	z	U_iso*/U_eq
Ba1	0.500000	0.500000	0.500000	0.0243 (6)
Br1	0.77576 (19)	0.84257 (18)	0.6325 (2)	0.0238 (5)
F1	0.7435 (16)	0.6574 (14)	0.5444 (17)	0.041 (3)
Ba2	0.500000	1.000000	0.250000	0.0293 (6)
F2	0.6192 (14)	0.9136 (15)	0.5334 (19)	0.041 (3)
F3	0.8236 (13)	1.0143 (13)	0.7242 (17)	0.036 (3)
F4	0.9413 (13)	0.7748 (13)	0.744 (2)	0.040 (3)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Ba1	0.0219 (7)	0.0219 (7)	0.0291 (12)	0.000	0.000	0.000
Br1	0.0251 (10)	0.0197 (9)	0.0267 (9)	−0.0021 (7)	−0.0004 (8)	0.0000 (7)
F1	0.050 (8)	0.030 (7)	0.043 (7)	−0.013 (6)	0.008 (6)	−0.008 (5)
Ba2	0.0257 (8)	0.0257 (8)	0.0364 (13)	0.000	0.000	0.000
F2	0.033 (7)	0.042 (7)	0.048 (8)	0.004 (6)	−0.009 (6)	−0.004 (6)
F3	0.042 (7)	0.027 (6)	0.038 (8)	−0.001 (5)	−0.006 (6)	−0.003 (5)
F4	0.034 (7)	0.029 (6)	0.057 (8)	0.003 (6)	−0.017 (7)	−0.006 (6)

Geometric parameters (Å, º) top

Ba1—F3ⁱ	2.791 (13)	Br1—F2	1.829 (13)
Ba1—F3ⁱⁱ	2.791 (13)	Br1—F3	1.861 (12)
Ba1—F3ⁱⁱⁱ	2.791 (13)	Br1—F4	1.934 (13)
Ba1—F3^iv	2.791 (13)	Br1—F1	1.935 (13)
Ba1—F1^v	2.801 (14)	Ba2—F2^viii	2.680 (14)
Ba1—F1^vi	2.801 (14)	Ba2—F2^ix	2.680 (14)
Ba1—F1^vii	2.801 (14)	Ba2—F2^x	2.680 (14)
Ba1—F1	2.801 (14)	Ba2—F2	2.680 (14)
Ba1—F4ⁱⁱ	3.034 (14)	Ba2—F4^xi	2.693 (12)
Ba1—F4^iv	3.034 (14)	Ba2—F4^vii	2.693 (12)
Ba1—F4ⁱⁱⁱ	3.034 (14)	Ba2—F4ⁱⁱⁱ	2.693 (12)
Ba1—F4ⁱ	3.034 (14)	Ba2—F4^xii	2.693 (12)

F3ⁱ—Ba1—F3ⁱⁱ	129.1 (3)	F4ⁱⁱ—Ba1—F4ⁱⁱⁱ	94.6 (6)
F3ⁱ—Ba1—F3ⁱⁱⁱ	129.1 (3)	F4^iv—Ba1—F4ⁱⁱⁱ	117.4 (3)
F3ⁱⁱ—Ba1—F3ⁱⁱⁱ	74.9 (6)	F3ⁱ—Ba1—F4ⁱ	52.0 (4)
F3ⁱ—Ba1—F3^iv	74.9 (6)	F3ⁱⁱ—Ba1—F4ⁱ	95.7 (4)
F3ⁱⁱ—Ba1—F3^iv	129.1 (3)	F3ⁱⁱⁱ—Ba1—F4ⁱ	168.1 (4)
F3ⁱⁱⁱ—Ba1—F3^iv	129.1 (3)	F3^iv—Ba1—F4ⁱ	62.5 (4)
F3ⁱ—Ba1—F1^v	105.4 (4)	F1^v—Ba1—F4ⁱ	54.6 (4)
F3ⁱⁱ—Ba1—F1^v	67.9 (4)	F1^vi—Ba1—F4ⁱ	128.6 (4)
F3ⁱⁱⁱ—Ba1—F1^v	125.4 (4)	F1^vii—Ba1—F4ⁱ	63.2 (4)
F3^iv—Ba1—F1^v	62.1 (4)	F1—Ba1—F4ⁱ	114.0 (4)
F3ⁱ—Ba1—F1^vi	125.4 (4)	F4ⁱⁱ—Ba1—F4ⁱ	117.4 (3)
F3ⁱⁱ—Ba1—F1^vi	105.4 (4)	F4^iv—Ba1—F4ⁱ	94.6 (6)
F3ⁱⁱⁱ—Ba1—F1^vi	62.1 (4)	F4ⁱⁱⁱ—Ba1—F4ⁱ	117.4 (3)
F3^iv—Ba1—F1^vi	67.9 (4)	F2—Br1—F3	92.6 (6)
F1^v—Ba1—F1^vi	90.93 (7)	F2—Br1—F4	177.3 (6)
F3ⁱ—Ba1—F1^vii	67.9 (4)	F3—Br1—F4	84.9 (6)
F3ⁱⁱ—Ba1—F1^vii	62.1 (4)	F2—Br1—F1	92.9 (6)
F3ⁱⁱⁱ—Ba1—F1^vii	105.4 (4)	F3—Br1—F1	174.4 (6)
F3^iv—Ba1—F1^vii	125.4 (4)	F4—Br1—F1	89.6 (6)
F1^v—Ba1—F1^vii	90.93 (7)	Br1—F1—Ba1	132.3 (7)
F1^vi—Ba1—F1^vii	165.4 (5)	F2^viii—Ba2—F2^ix	136.3 (4)
F3ⁱ—Ba1—F1	62.1 (4)	F2^viii—Ba2—F2^x	63.5 (6)
F3ⁱⁱ—Ba1—F1	125.4 (4)	F2^ix—Ba2—F2^x	136.3 (4)
F3ⁱⁱⁱ—Ba1—F1	67.9 (4)	F2^viii—Ba2—F2	136.3 (4)
F3^iv—Ba1—F1	105.4 (4)	F2^ix—Ba2—F2	63.5 (6)
F1^v—Ba1—F1	165.4 (5)	F2^x—Ba2—F2	136.3 (4)
F1^vi—Ba1—F1	90.93 (7)	F2^viii—Ba2—F4^xi	114.0 (5)
F1^vii—Ba1—F1	90.93 (7)	F2^ix—Ba2—F4^xi	109.7 (5)
F3ⁱ—Ba1—F4ⁱⁱ	168.1 (4)	F2^x—Ba2—F4^xi	67.9 (5)
F3ⁱⁱ—Ba1—F4ⁱⁱ	52.0 (4)	F2—Ba2—F4^xi	68.4 (5)
F3ⁱⁱⁱ—Ba1—F4ⁱⁱ	62.5 (4)	F2^viii—Ba2—F4^vii	67.9 (5)
F3^iv—Ba1—F4ⁱⁱ	95.7 (4)	F2^ix—Ba2—F4^vii	68.4 (5)
F1^v—Ba1—F4ⁱⁱ	63.2 (4)	F2^x—Ba2—F4^vii	114.0 (5)
F1^vi—Ba1—F4ⁱⁱ	54.6 (4)	F2—Ba2—F4^vii	109.7 (5)
F1^vii—Ba1—F4ⁱⁱ	114.0 (4)	F4^xi—Ba2—F4^vii	178.0 (7)
F1—Ba1—F4ⁱⁱ	128.6 (4)	F2^viii—Ba2—F4ⁱⁱⁱ	68.4 (5)
F3ⁱ—Ba1—F4^iv	62.5 (4)	F2^ix—Ba2—F4ⁱⁱⁱ	114.0 (5)
F3ⁱⁱ—Ba1—F4^iv	168.1 (4)	F2^x—Ba2—F4ⁱⁱⁱ	109.7 (5)
F3ⁱⁱⁱ—Ba1—F4^iv	95.7 (4)	F2—Ba2—F4ⁱⁱⁱ	67.9 (5)
F3^iv—Ba1—F4^iv	52.0 (4)	F4^xi—Ba2—F4ⁱⁱⁱ	90.018 (16)
F1^v—Ba1—F4^iv	114.0 (4)	F4^vii—Ba2—F4ⁱⁱⁱ	90.018 (15)
F1^vi—Ba1—F4^iv	63.2 (4)	F2^viii—Ba2—F4^xii	109.7 (5)
F1^vii—Ba1—F4^iv	128.6 (4)	F2^ix—Ba2—F4^xii	67.9 (5)
F1—Ba1—F4^iv	54.6 (4)	F2^x—Ba2—F4^xii	68.4 (5)
F4ⁱⁱ—Ba1—F4^iv	117.4 (3)	F2—Ba2—F4^xii	114.0 (5)
F3ⁱ—Ba1—F4ⁱⁱⁱ	95.7 (4)	F4^xi—Ba2—F4^xii	90.018 (15)
F3ⁱⁱ—Ba1—F4ⁱⁱⁱ	62.5 (4)	F4^vii—Ba2—F4^xii	90.018 (15)
F3ⁱⁱⁱ—Ba1—F4ⁱⁱⁱ	52.0 (4)	F4ⁱⁱⁱ—Ba2—F4^xii	178.0 (7)
F3^iv—Ba1—F4ⁱⁱⁱ	168.1 (4)	Br1—F2—Ba2	146.6 (8)
F1^v—Ba1—F4ⁱⁱⁱ	128.6 (4)	Br1—F3—Ba1^xiii	114.9 (6)
F1^vi—Ba1—F4ⁱⁱⁱ	114.0 (4)	Br1—F4—Ba2^xiv	120.5 (6)
F1^vii—Ba1—F4ⁱⁱⁱ	54.6 (4)	Br1—F4—Ba1^xiii	103.2 (5)
F1—Ba1—F4ⁱⁱⁱ	63.2 (4)	Ba2^xiv—F4—Ba1^xiii	130.1 (5)

F3—Br1—F2—Ba2	103.8 (13)	F2—Br1—F3—Ba1^xiii	158.2 (7)
F1—Br1—F2—Ba2	−75.4 (13)	F4—Br1—F3—Ba1^xiii	−20.9 (7)

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

Funding information

We thank the Deutsche Forschungsgemeinschaft for generous funding.

References

Brandenburg, K. (2020). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Ivlev, S., Sobolev, V., Hoelzel, M., Karttunen, A. J., Müller, T., Gerin, I., Ostvald, R. & Kraus, F. (2014). Eur. J. Inorg. Chem. pp. 6261–6267. Web of Science CrossRef ICSD Google Scholar
Kiselev, N. I., Lapshin, O. N., Sadikova, A. T., Sukhoverkhov, V. F. & Churbanov, M. F. (1987). Visok. Veschestva, 3, 178–182. Google Scholar
Koziskova, J., Hahn, F., Richter, J. & Kožíšek, J. (2016). Acta Chim. Slov. 9, 136–140. Web of Science CrossRef CAS Google Scholar
Malin, A. V., Ivlev, S. I., Ostvald, R. V. & Kraus, F. (2019). IUCrData, 4, x191595. Google Scholar
Malin, A. V., Ivlev, S. I., Ostvald, R. V. & Kraus, F. (2020). IUCrData, 5, x200114. Google Scholar
Parsons, S., Flack, H. D. & Wagner, T. (2013). Acta Cryst. B69, 249–259. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Sharpe, A. G. & Emeléus, H. J. (1948). J. Chem. Soc. pp. 2135–2138. CrossRef Google Scholar
Sheldrick, G. M. (2015a). Acta Cryst. A71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2015b). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Stoe (2020). X-AREA. Stoe & Cie GmbH, Darmstadt, Germany. Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar