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inorganic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 66| Part 9| September 2010| Page i67
https://doi.org/10.1107/S1600536810032538

Redetermination of tantalum penta­bromide, (TaBr5)2

Katja Habermehl,a Ingo Pantenburga and Gerd Meyera*

aUniversität zu Köln, Institut für Anorganische Chemie, Greinstrasse 6, D 50939 Köln, Germany
*Correspondence e-mail: gerd.meyer@uni-koeln.de

(Received 26 July 2010; accepted 12 August 2010; online 21 August 2010)

Crystals of di-μ-bromido-bis­[tetra­bromidotantalum(V)], (TaBr5)2, were obtained by recrystallization at 773 K. A first crystal structure study of (TaBr5)2 was reported by Rolsten [J. Am. Chem. Soc. (1958)[Rolsten, R. F. (1958a). J. Am. Chem. Soc. 80, 2952-2953.], 80, 2952–2953], who analysed the powder diffraction pattern and came to the conclusion that it crystallizes isotypically with (NbBr5)2 in a primitive ortho­rhom­bic cell. These findings are not in agreement with our current results of a monoclinic C-centred structure. (TaBr5)2 is isotypic with α-(NbCl5)2. The crystal structure contains [TaBr6] octa­hedra sharing common edges forming [TaBr5]2 dimers. Two crystallographically independent dimers with symmetries m and 2/m and Ta⋯Ta distances of 4.1574 (11) and 4.1551 (15) Å, respectively, are present in the structure.

Related literature

For a previous study of (TaBr5)2, see: Rolsten (1958a[Rolsten, R. F. (1958a). J. Am. Chem. Soc. 80, 2952-2953.]), who also reported the crystal structure of (NbBr5)2 (Rolsten, 1958b[Rolsten, R. F. (1958b). J. Phys. Chem. 62, 126-127.]). (TaBr5)2 is isotypic with α-(NbCl5)2, the structure of which was first described by Zalkin & Sands (1958[Zalkin, A. & Sands, D. E. (1958). Acta Cryst. 11, 615-619.]) and was redetermined by Hoenle & von Schnering (1990[Hoenle, W. & von Schnering, H. G. (1990). Z. Kristallogr. 191, 139-140.]). For a summary of all possible stackings of double octa­hedral mol­ecules in penta­halides of Nb and Ta, see: Müller (1978[Müller, U. (1978). Acta Cryst. A34, 256-267.]). Experimental details can be found in Brauer's handbook (Brauer, 1962[Brauer, G. (1962). Handbuch der präparativen Anorganischen Chemie, Band II, p. 1152. Stuttgart: F. Enke-Verlag.]). For data analysis, see: Spek (2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Experimental

Crystal data

  • Ta2Br10

  • Mr = 1161.00

  • Monoclinic, C 2/m

  • a = 19.433 (3) Å

  • b = 18.775 (2) Å

  • c = 6.2034 (10) Å

  • β = 90.716 (13)°

  • V = 2263.2 (6) Å3

  • Z = 6

  • Mo Kα radiation

  • μ = 40.93 mm−1

  • T = 293 K

  • 0.14 × 0.09 × 0.04 mm
Data collection

  • Stoe IPDS 2 diffractometer

  • Absorption correction: numerical (X-SHAPE; Stoe & Cie, 1999[Stoe & Cie (1999). X-SHAPE. Stoe & Cie, Darmstadt, Germany.]) Tmin = 0.014, Tmax = 0.089

  • 17962 measured reflections

  • 2605 independent reflections

  • 1678 reflections with I > 2σ(I)

  • Rint = 0.125
Refinement

  • R[F2 > 2σ(F2)] = 0.042

  • wR(F2) = 0.109

  • S = 0.95

  • 2605 reflections

  • 88 parameters

  • Δρmax = 1.71 e Å−3

  • Δρmin = −1.53 e Å−3

Data collection: X-AREA (Stoe & Cie, 2002[Stoe & Cie (2002). X-AREA and X-RED. Stoe & Cie, Darmstadt, Germany.]); cell refinement: X-RED (Stoe & Cie, 2002[Stoe & Cie (2002). X-AREA and X-RED. Stoe & Cie, Darmstadt, Germany.]); data reduction: X-RED; program(s) used to solve structure: SIR92 (Altomare et al., 1994[Altomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: DIAMOND (Brandenburg, 2005[Brandenburg, K. (2005). DIAMOND. Crystal Impact GbR, Bonn, Germany.]); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S1600536810032538/wm2384sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810032538/wm2384Isup2.hkl

checkCIF report


Comment top

(TaBr5)2 was first described by Rolsten (Rolsten, 1958a). He compared the powder diffraction pattern of (TaBr5)2 with orthorhombic NbBr5 (space group Pbam) and came to the conclusion that the structures are alike. The structure of (NbBr5)2 was already known from single-crystal structure analysis (Rolsten, 1958b). However, the apparent isotypism between (TaBr5)2 and (NbBr5)2 is not in agreement with our result that shows (TaBr5)2 to crystallize in the monoclinic space goup C2/m.

The crystal structures of all pentahalides besides the fluorides contain [MX6] octahedra (M = Nb, Ta; X = Cl, B, I) sharing common edges forming [MX5]2 dimers. These double octahedra can be stacked in different ways, resulting in different structure types. In the title compound, the stacking of the (TaBr5)2 layers along b can be described as A1B1A1B1··· . Within one layer the molecules are stacked in a "2 1" stacking scheme (Fig. 1). A summary of all possible stacking possibilities has been given by Müller (1978). The [TaBr6] octahedra are distorted due to the repulsive forces of the highly charged metal atoms centering the octahedra with d(Ta—Ta) = 4.1574 (11) Å for the (Ta1Br5)2 dimer (m symmetry) and 4.1551 (15) Å for the (Ta2Br5)2 dimer (2/m symmetry).

(TaBr5)2 is isotypic with α-(NbCl5)2 (Zalkin & Sands, 1958; Hoenle & von Schnering, 1990).

Related literature top

For a previous study of (TaBr5)2, see: Rolsten (1958a), who also reported the crystal structure of (NbBr5)2 (Rolsten, 1958b). (TaBr5)2 is isotypic with α-(NbCl5)2, the structure of which was first described by Zalkin & Sands (1958) and was redetermined by Hoenle & von Schnering (1990). For a summary of all possible stackings of double octahedral molecules in pentahalides of Nb and Ta, see: Müller (1978). Experimental details can be found in Brauer's handbook (Brauer, 1962). For data analysis, see: Spek (2009).

Experimental top

TaBr5 was synthesized according to an experimental procedure reported in Brauer's handbook (Brauer, 1962). Orange polyhedric crystals were obtained by recrystallization of TaBr5 in a silica ampoule. The ampoule was heated with 50 K per hour to 773 K and annealed for 12 h, after which it was slowly cooled to room temperature with 2 K per hour. Single crystals of TaBr5 were selected under a microscope in an argon-filled glove box.

Refinement top

PLATON (Spek, 2009) indicates higher (pseudo)-symmetry and suggests a change of the crystal system from monoclinic C to orthorhombic C, but the experimentally determined unit cell angles differ with 0.72° considerably from orthogonality. The maximum residual density lies 1.29Å from Ta1 and the density minimum lies at the Br4 atom.

Structure description top

(TaBr5)2 was first described by Rolsten (Rolsten, 1958a). He compared the powder diffraction pattern of (TaBr5)2 with orthorhombic NbBr5 (space group Pbam) and came to the conclusion that the structures are alike. The structure of (NbBr5)2 was already known from single-crystal structure analysis (Rolsten, 1958b). However, the apparent isotypism between (TaBr5)2 and (NbBr5)2 is not in agreement with our result that shows (TaBr5)2 to crystallize in the monoclinic space goup C2/m.

The crystal structures of all pentahalides besides the fluorides contain [MX6] octahedra (M = Nb, Ta; X = Cl, B, I) sharing common edges forming [MX5]2 dimers. These double octahedra can be stacked in different ways, resulting in different structure types. In the title compound, the stacking of the (TaBr5)2 layers along b can be described as A1B1A1B1··· . Within one layer the molecules are stacked in a "2 1" stacking scheme (Fig. 1). A summary of all possible stacking possibilities has been given by Müller (1978). The [TaBr6] octahedra are distorted due to the repulsive forces of the highly charged metal atoms centering the octahedra with d(Ta—Ta) = 4.1574 (11) Å for the (Ta1Br5)2 dimer (m symmetry) and 4.1551 (15) Å for the (Ta2Br5)2 dimer (2/m symmetry).

(TaBr5)2 is isotypic with α-(NbCl5)2 (Zalkin & Sands, 1958; Hoenle & von Schnering, 1990).

For a previous study of (TaBr5)2, see: Rolsten (1958a), who also reported the crystal structure of (NbBr5)2 (Rolsten, 1958b). (TaBr5)2 is isotypic with α-(NbCl5)2, the structure of which was first described by Zalkin & Sands (1958) and was redetermined by Hoenle & von Schnering (1990). For a summary of all possible stackings of double octahedral molecules in pentahalides of Nb and Ta, see: Müller (1978). Experimental details can be found in Brauer's handbook (Brauer, 1962). For data analysis, see: Spek (2009).

Computing details top

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-RED (Stoe & Cie, 2002); data reduction: X-RED (Stoe & Cie, 2002); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2005); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. Unit cell of TaBr5 in a view along [001]. Double octahedral molecules are coloured in orange or blue for depth perception. Thermal ellipsoids are given on the 99% probability level.
di-µ-bromido-bis[tetrabromidotantalum(V)] top
Crystal data top
Ta2Br10F(000) = 2976
Mr = 1161.00none
Monoclinic, C2/mDx = 5.111 Mg m−3
Hall symbol: -C 2yMo Kα radiation, λ = 0.71073 Å
a = 19.433 (3) ÅCell parameters from 7929 reflections
b = 18.775 (2) Åθ = 2.1–27.1°
c = 6.2034 (10) ŵ = 40.93 mm−1
β = 90.716 (13)°T = 293 K
V = 2263.2 (6) Å3Polyhedron, orange
Z = 60.14 × 0.09 × 0.04 mm
Data collection top
Stoe IPDS 2
diffractometer		2605 independent reflections
Radiation source: fine-focus sealed tube1678 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.125
Detector resolution: 0 pixels mm-1θmax = 27.3°, θmin = 1.5°
oscillation scansh = −24→24
Absorption correction: numerical
(X-SHAPE; Stoe & Cie, 1999)		k = −24→24
Tmin = 0.014, Tmax = 0.089l = −7→7
17962 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.042 w = 1/[σ2(Fo2) + (0.0563P)2]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.109(Δ/σ)max = 0.001
S = 0.95Δρmax = 1.71 e Å−3
2605 reflectionsΔρmin = −1.53 e Å−3
88 parametersExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraintsExtinction coefficient: 0.00064 (4)
0 constraints
Crystal data top
Ta2Br10V = 2263.2 (6) Å3
Mr = 1161.00Z = 6
Monoclinic, C2/mMo Kα radiation
a = 19.433 (3) ŵ = 40.93 mm−1
b = 18.775 (2) ÅT = 293 K
c = 6.2034 (10) Å0.14 × 0.09 × 0.04 mm
β = 90.716 (13)°
Data collection top
Stoe IPDS 2
diffractometer		2605 independent reflections
Absorption correction: numerical
(X-SHAPE; Stoe & Cie, 1999)		1678 reflections with I > 2σ(I)
Tmin = 0.014, Tmax = 0.089Rint = 0.125
17962 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.04288 parameters
wR(F2) = 0.1090 restraints
S = 0.95Δρmax = 1.71 e Å−3
2605 reflectionsΔρmin = −1.53 e Å−3
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 > σ(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
xyzUiso*/Ueq
Ta11.00000.38934 (4)0.50000.0296 (2)
Ta20.66677 (3)0.38928 (3)0.97909 (7)0.02938 (18)
Br10.61422 (10)0.50001.2034 (3)0.0326 (4)
Br20.61078 (9)0.30802 (8)1.2210 (2)0.0430 (4)
Br30.56469 (8)0.40167 (8)0.7436 (2)0.0406 (3)
Br40.72279 (9)0.30797 (8)0.7378 (2)0.0430 (4)
Br50.71903 (11)0.50000.7544 (3)0.0321 (4)
Br60.89789 (8)0.40192 (8)0.7271 (2)0.0421 (3)
Br70.76900 (8)0.40188 (8)1.2143 (2)0.0415 (3)
Br81.05614 (9)0.30768 (8)0.7446 (2)0.0451 (4)
Br91.05245 (11)0.50000.7294 (3)0.0323 (4)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Ta10.0289 (4)0.0278 (4)0.0320 (4)0.0000.0032 (3)0.000
Ta20.0292 (3)0.0280 (3)0.0310 (3)0.0002 (2)0.00055 (19)−0.00014 (18)
Br10.0353 (11)0.0314 (9)0.0312 (8)0.0000.0070 (7)0.000
Br20.0464 (10)0.0408 (8)0.0419 (7)−0.0076 (6)0.0083 (6)0.0062 (5)
Br30.0338 (8)0.0460 (8)0.0419 (7)−0.0012 (6)−0.0074 (5)−0.0021 (5)
Br40.0465 (10)0.0396 (7)0.0431 (7)0.0060 (7)0.0079 (6)−0.0087 (6)
Br50.0343 (11)0.0316 (9)0.0305 (8)0.0000.0067 (7)0.000
Br60.0353 (8)0.0457 (8)0.0455 (7)−0.0017 (6)0.0125 (6)0.0023 (6)
Br70.0349 (8)0.0453 (8)0.0440 (7)0.0008 (6)−0.0079 (5)0.0031 (6)
Br80.0464 (10)0.0400 (7)0.0487 (8)0.0075 (7)−0.0038 (6)0.0096 (6)
Br90.0360 (11)0.0305 (8)0.0303 (8)0.000−0.0039 (7)0.000
Geometric parameters (Å, º) top
Ta1—Br8i2.4087 (15)Ta2—Br32.4598 (16)
Ta1—Br82.4087 (15)Ta2—Br72.4613 (17)
Ta1—Br62.4591 (14)Ta2—Br52.7075 (12)
Ta1—Br6i2.4591 (14)Ta2—Br12.7084 (12)
Ta1—Br92.7100 (13)Br1—Ta2iii2.7084 (12)
Ta1—Br9ii2.7100 (13)Br5—Ta2iii2.7075 (12)
Ta2—Br42.4075 (14)Br9—Ta1ii2.7100 (13)
Ta2—Br22.4092 (15)
Br8i—Ta1—Br8100.93 (9)Br2—Ta2—Br393.59 (6)
Br8i—Ta1—Br693.41 (6)Br4—Ta2—Br793.53 (6)
Br8—Ta1—Br693.60 (6)Br2—Ta2—Br793.39 (6)
Br8i—Ta1—Br6i93.60 (6)Br3—Ta2—Br7169.06 (5)
Br8—Ta1—Br6i93.41 (6)Br4—Ta2—Br589.51 (5)
Br6—Ta1—Br6i168.98 (8)Br2—Ta2—Br5169.14 (5)
Br8i—Ta1—Br9169.48 (6)Br3—Ta2—Br585.79 (6)
Br8—Ta1—Br989.59 (5)Br7—Ta2—Br585.77 (6)
Br6—Ta1—Br985.78 (6)Br4—Ta2—Br1169.22 (5)
Br6i—Ta1—Br985.77 (6)Br2—Ta2—Br189.43 (5)
Br8i—Ta1—Br9ii89.59 (5)Br3—Ta2—Br185.76 (6)
Br8—Ta1—Br9ii169.48 (6)Br7—Ta2—Br185.90 (6)
Br6—Ta1—Br9ii85.77 (6)Br5—Ta2—Br179.71 (4)
Br6i—Ta1—Br9ii85.78 (6)Ta2—Br1—Ta2iii100.26 (6)
Br9—Ta1—Br9ii79.90 (6)Ta2—Br5—Ta2iii100.31 (6)
Br4—Ta2—Br2101.35 (6)Ta1—Br9—Ta1ii100.10 (6)
Br4—Ta2—Br393.34 (6)
Symmetry codes: (i) −x+2, y, −z+1; (ii) −x+2, −y+1, −z+1; (iii) x, −y+1, z.

Experimental details

Crystal data
Chemical formulaTa2Br10
Mr1161.00
Crystal system, space groupMonoclinic, C2/m
Temperature (K)293
a, b, c (Å)19.433 (3), 18.775 (2), 6.2034 (10)
β (°) 90.716 (13)
V (Å3)2263.2 (6)
Z6
Radiation typeMo Kα
µ (mm−1)40.93
Crystal size (mm)0.14 × 0.09 × 0.04
Data collection
DiffractometerStoe IPDS 2
Absorption correctionNumerical
(X-SHAPE; Stoe & Cie, 1999)
Tmin, Tmax0.014, 0.089
No. of measured, independent and
observed [I > 2σ(I)] reflections		17962, 2605, 1678
Rint0.125
(sin θ/λ)max (Å−1)0.646
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.042, 0.109, 0.95
No. of reflections2605
No. of parameters88
Δρmax, Δρmin (e Å−3)1.71, −1.53

Computer programs: X-AREA (Stoe & Cie, 2002), X-RED (Stoe & Cie, 2002), SIR92 (Altomare et al., 1994), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2005).

 

Acknowledgements

Financial support from the State of Nordrhein-Westfalen and Universität zu Köln is greatly appreciated.

References

First citationAltomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435.  CrossRef Web of Science IUCr Journals Google Scholar
 First citationBrandenburg, K. (2005). DIAMOND. Crystal Impact GbR, Bonn, Germany.  Google Scholar
 First citationBrauer, G. (1962). Handbuch der präparativen Anorganischen Chemie, Band II, p. 1152. Stuttgart: F. Enke-Verlag.  Google Scholar
 First citationHoenle, W. & von Schnering, H. G. (1990). Z. Kristallogr. 191, 139–140.  CAS Google Scholar
 First citationMüller, U. (1978). Acta Cryst. A34, 256–267.  CrossRef IUCr Journals Web of Science Google Scholar
 First citationRolsten, R. F. (1958a). J. Am. Chem. Soc. 80, 2952–2953.  CrossRef CAS Web of Science Google Scholar
 First citationRolsten, R. F. (1958b). J. Phys. Chem. 62, 126–127.  CrossRef CAS Web of Science Google Scholar
 First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationStoe & Cie (1999). X-SHAPE. Stoe & Cie, Darmstadt, Germany.  Google Scholar
 First citationStoe & Cie (2002). X-AREA and X-RED. Stoe & Cie, Darmstadt, Germany.  Google Scholar
 First citationZalkin, A. & Sands, D. E. (1958). Acta Cryst. 11, 615–619.  CrossRef CAS IUCr Journals Web of Science Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 66| Part 9| September 2010| Page i67
https://doi.org/10.1107/S1600536810032538
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