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Acta Crystallogr C. 2010 March 15; 66(Pt 3): e9.
Published online 2010 February 27. doi:  10.1107/S0108270109054286
PMCID: PMC2855578

Strontium tetra­fluoro­borate. Erratum


In the paper by Bunič, Tavčar, Goreshnik & Žemva [Acta Cryst. (2007 [triangle]), C63, i75–i76], the structure reported as Sr(BF4)2 is actually that of Cd(BF4)2. The correct structure of Sr(BF4)2 is now reported.


This erratum is to correct the report of the crystal structure of strontium tetra­fluoro­borate (Bunič et al., 2007 [triangle]). The investigated compound was Cd(BF4)2 and not the reported Sr(BF4)2 because of experimental error. We report here the correct structure of strontium tetra­fluoro­borate, which appears to be isomorphous with the previously published structures of Ca(BF4)2 (Jordan et al., 1975 [triangle]) and Cd(BF4)2 (Tavčar & Žemva, 2005 [triangle]). In the Sr(BF4)2 structure, the metal atom possesses a coordination number of eight with a square-anti­prismatic coordination polyhedron. The Sr—F distances lie in the narrow range 2.490 (4)–2.538 (4) Å, compared with Ca—F distances in the range 2.330 (2)–2.401 (2) Å in Ca(BF4)2 and Cd—F distances in the range 2.296 (2)–2.381 (3) Å in Cd(BF4)2. The Sr metal center is bonded to eight BF4 units. In turn, each anion is connected to four Sr atoms. All four F atoms in each anion act as μ2-bridges between B and Sr atoms, resulting in similar B—F bond lengths of 1.376 (7)–1.402 (7) Å.


Routine crystallization of strontium tetra­fluoro­borate from different solvents usually gives crystals of various solvates. However, crystals of the anhydrous salt were grown by dissolving Sr(BF4)2·2H2O, prepared by the reaction between SrCO3 (Aldrich, 99.99%) and excess aqueous HF (Aldrich, 40%), in acetone and further very slow crystallization.

Crystal data

  • Sr(BF4)2
  • M r = 261.24
  • Orthorhombic, An external file that holds a picture, illustration, etc.
Object name is c-66-000e9-efi1.jpg
  • a = 9.602 (5) Å
  • b = 9.259 (5) Å
  • c = 13.890 (6) Å
  • V = 1235.0 (10) Å3
  • Z = 8
  • Mo Kα radiation
  • μ = 8.83 mm−1
  • T = 296 K
  • 0.1 × 0.1 × 0.08 mm

Data collection

  • Rigaku Mercury CCD (2×2 bin mode) diffractometer
  • Absorption correction: multi-scan (Blessing, 1995 [triangle]) T min = 0.427, T max = 0.504
  • 9319 measured reflections
  • 1534 independent reflections
  • 1348 reflections with I > 2σ(I)
  • R int = 0.055


  • R[F 2 > 2σ(F 2)] = 0.059
  • wR(F 2) = 0.111
  • S = 1.34
  • 1534 reflections
  • 101 parameters
  • Δρmax = 1.49 e Å−3
  • Δρmin = −0.76 e Å−3

Data collection: CrystalClear (Rigaku, 1999 [triangle]); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SIR92 (Altomare et al., 1993 [triangle]) and TEXSAN (Molecular Structure Corporation, 1999 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); software used to prepare material for publication: WinGX (Version 1.70; Farrugia, 1999 [triangle]) and enCIFer (Version 1.2; Allen et al., 2004 [triangle]).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S0108270109054286/ln3136sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S0108270109054286/ln3136Isup2.hkl


The authors gratefully acknowledge Dr Stefan Adams (Department of Materials Science and Engineering, National University of Singapore), who first noted some discrepancies in the structure, erroneously entitled as strontium tetra­fluoro­borate, and to the Slovenian Research Agency (ARRS) for the financial support of the Research Program P1-0045 (Inorganic Chemistry and Technology).


Supplementary data for this paper are available from the IUCr electronic archives (Reference: LN3136). Services for accessing these data are described at the back of the journal.


  • Allen, F. H., Johnson, O., Shields, G. P., Smith, B. R. & Towler, M. (2004). J. Appl. Cryst.37, 335–338.
  • Altomare, A., Cascarano, G., Giacovazzo, C. & Guagliardi, A. (1993). J. Appl. Cryst.26, 343–350.
  • Blessing, R. H. (1995). Acta Cryst. A51, 33–38. [PubMed]
  • Bunič, T., Tavčar, G., Goreshnik, E. & Žemva, B. (2007). Acta Cryst. C63, i75–i76.
  • Farrugia, L. J. (1999). J. Appl. Cryst.32, 837–838.
  • Jordan, T. H., Dickens, B., Schroeder, L. W. & Brown, W. E. (1975). Acta Cryst. B31, 669–672.
  • Molecular Structure Corporation (1999). TEXSAN for Windows Version 1.06. MSC, The Woodlands, Texas, USA.
  • Rigaku (1999). CrystalClear Rigaku Corporation, Tokyo, Japan.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Tavčar, G. & Žemva, B. (2005). Inorg. Chem.44, 1525–1529. [PubMed]

Articles from Acta Crystallographica Section C: Crystal Structure Communications are provided here courtesy of International Union of Crystallography