Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807057583/pk2063sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807057583/pk2063Isup2.hkl |
Key indicators
- Single-crystal X-ray study
- T = 296 K
- Mean (r-O) = 0.001 Å
- R factor = 0.021
- wR factor = 0.051
- Data-to-parameter ratio = 48.8
checkCIF/PLATON results
No syntax errors found
Alert level C PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ .... ? PLAT731_ALERT_1_C Bond Calc 2.9267(5), Rep 2.9268(2) ...... 2.50 su-Ra BA2 -O1 1.555 7.454 PLAT731_ALERT_1_C Bond Calc 2.9267(5), Rep 2.9268(2) ...... 2.50 su-Ra BA2 -O1 1.555 7.344 PLAT731_ALERT_1_C Bond Calc 2.9267(6), Rep 2.9268(2) ...... 3.00 su-Ra BA2 -O1 1.555 9.564 PLAT731_ALERT_1_C Bond Calc 2.9267(7), Rep 2.9268(2) ...... 3.50 su-Ra BA2 -O1 1.555 8.544 PLAT731_ALERT_1_C Bond Calc 2.9267(7), Rep 2.9268(2) ...... 3.50 su-Ra BA2 -O1 1.555 8.444 PLAT731_ALERT_1_C Bond Calc 2.9267(6), Rep 2.9268(2) ...... 3.00 su-Ra BA2 -O1 1.555 9.554 PLAT731_ALERT_1_C Bond Calc 2.9267(5), Rep 2.9268(2) ...... 2.50 su-Ra O1 -BA2 1.555 13.545 PLAT731_ALERT_1_C Bond Calc 2.9267(5), Rep 2.9268(2) ...... 2.50 su-Ra O1 -BA2 1.555 13.655
Alert level G PLAT794_ALERT_5_G Check Predicted Bond Valency for Cr1 (5) 4.66
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 9 ALERT level C = Check and explain 1 ALERT level G = General alerts; check 9 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 0 ALERT type 2 Indicator that the structure model may be wrong or deficient 0 ALERT type 3 Indicator that the structure quality may be low 0 ALERT type 4 Improvement, methodology, query or suggestion 1 ALERT type 5 Informative message, check
For details of the first single-crystal growth of Ba3Cr2O8 (X-ray size crystals), see Mattausch & Muller-Buschbaum (1972). For a more recent synthesis of Ba3Cr2O8 and some measurements of magnetic properties, see Nakajima et al. (2006). Additional details describing the growth of large single crystals by the traveling solvent floating-zone method and subsequent magnetic characterization measurements, see Aczel et al. (2007).
Large single crystals of the title compound were grown by the traveling solvent floating zone method in an Ar enviroment, using BaCO3 and Cr2O3 as starting materials. The growth rate was fast (both 27 mm/h and 18 mm/h were applied), which was necessary to maintain zone stability. The feed and seed rods were rotating in opposite directions at 20 rpm throughout the growth, and a 3 cm boule of the desired Ba3Cr2O8 phase was obtained on the seed rod. Due to the very fast growth, the as-obtained boule consisted of many well oriented crystalline grains.
Data collection: APEX2 (Bruker, 2006); cell refinement: APEX2 (Bruker, 2006); data reduction: APEX2 (Bruker, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: GRETEP (Laugier & Bochu, 2003); software used to prepare material for publication: SHELXTL (Sheldrick, 1997b).
Fig. 1. 50% displacement ellipsoid plot of the unit cell. Ba ions are shown in dark blue, Cr ions are shown in blue, and O ions are shown in red. |
Ba3Cr2O8 | Dx = 5.248 Mg m−3 |
Mr = 644.02 | Mo Kα radiation, λ = 0.71073 Å |
Trigonal, R3m | Cell parameters from 2788 reflections |
Hall symbol: -R 3 2" | θ = 2.9–42.1° |
a = 5.7450 (2) Å | µ = 16.87 mm−1 |
c = 21.3883 (10) Å | T = 296 K |
V = 611.35 (4) Å3 | Rod, blue |
Z = 3 | 0.30 × 0.05 × 0.02 mm |
F(000) = 840 |
Bruker APEXII CCD area-detector diffractometer | 928 independent reflections |
Radiation source: fine-focus sealed tube | 779 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.034 |
ϕ and ω scans | θmax = 52.2°, θmin = 2.9° |
Absorption correction: numerical (face correction; APEX2; Bruker, 2006) | h = −8→12 |
Tmin = 0.38, Tmax = 0.77 | k = −12→10 |
9434 measured reflections | l = −47→46 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.021 | w = 1/[σ2(Fo2) + (0.0269P)2] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.051 | (Δ/σ)max = 0.001 |
S = 1.07 | Δρmax = 1.98 e Å−3 |
928 reflections | Δρmin = −2.01 e Å−3 |
19 parameters | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.0065 (3) |
Ba3Cr2O8 | Z = 3 |
Mr = 644.02 | Mo Kα radiation |
Trigonal, R3m | µ = 16.87 mm−1 |
a = 5.7450 (2) Å | T = 296 K |
c = 21.3883 (10) Å | 0.30 × 0.05 × 0.02 mm |
V = 611.35 (4) Å3 |
Bruker APEXII CCD area-detector diffractometer | 928 independent reflections |
Absorption correction: numerical (face correction; APEX2; Bruker, 2006) | 779 reflections with I > 2σ(I) |
Tmin = 0.38, Tmax = 0.77 | Rint = 0.034 |
9434 measured reflections |
R[F2 > 2σ(F2)] = 0.021 | 19 parameters |
wR(F2) = 0.051 | 0 restraints |
S = 1.07 | Δρmax = 1.98 e Å−3 |
928 reflections | Δρmin = −2.01 e Å−3 |
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 > 2σ(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. |
x | y | z | Uiso*/Ueq | ||
Ba1 | 0.0000 | 0.0000 | 0.0000 | 0.01420 (5) | |
Ba2 | 0.0000 | 0.0000 | 0.205924 (6) | 0.00918 (5) | |
Cr1 | 0.0000 | 0.0000 | 0.407042 (18) | 0.00721 (6) | |
O1 | 0.82832 (9) | 0.17168 (9) | 0.89871 (5) | 0.01272 (17) | |
O2 | 0.0000 | 0.0000 | 0.32872 (9) | 0.0273 (5) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Ba1 | 0.01762 (7) | 0.01762 (7) | 0.00736 (7) | 0.00881 (3) | 0.000 | 0.000 |
Ba2 | 0.00956 (5) | 0.00956 (5) | 0.00841 (6) | 0.00478 (3) | 0.000 | 0.000 |
Cr1 | 0.00723 (8) | 0.00723 (8) | 0.00718 (11) | 0.00361 (4) | 0.000 | 0.000 |
O1 | 0.0143 (3) | 0.0143 (3) | 0.0137 (4) | 0.0102 (3) | 0.00047 (14) | −0.00047 (14) |
O2 | 0.0366 (8) | 0.0366 (8) | 0.0085 (7) | 0.0183 (4) | 0.000 | 0.000 |
Ba1—O1i | 2.7589 (10) | Ba2—Cr1xix | 3.5101 (2) |
Ba1—O1ii | 2.7589 (10) | Ba2—Cr1xx | 3.5101 (2) |
Ba1—O1iii | 2.7589 (10) | Cr1—O2 | 1.675 (2) |
Ba1—O1iv | 2.7589 (10) | Cr1—O1xxi | 1.7133 (9) |
Ba1—O1v | 2.7589 (10) | Cr1—O1xxii | 1.7133 (9) |
Ba1—O1vi | 2.7589 (10) | Cr1—O1xxiii | 1.7134 (9) |
Ba1—O2vii | 3.3183 (1) | Cr1—Ba2xx | 3.5101 (2) |
Ba1—O2viii | 3.3183 (1) | Cr1—Ba2xxiv | 3.5101 (2) |
Ba1—O2ix | 3.3183 (1) | Cr1—Ba2xix | 3.5101 (2) |
Ba1—O2x | 3.3183 (1) | Cr1—Ba1xxv | 3.6724 (2) |
Ba1—O2xi | 3.3184 (1) | Cr1—Ba1xxvi | 3.6724 (2) |
Ba1—O2xii | 3.3184 (1) | Cr1—Ba1xxvii | 3.6725 (2) |
Ba2—O2 | 2.626 (2) | Cr1—Cr1xxiv | 4.5764 (6) |
Ba2—O1i | 2.8155 (10) | Cr1—Cr1xx | 4.5764 (6) |
Ba2—O1v | 2.8155 (10) | O2—Ba1xxvi | 3.3183 (1) |
Ba2—O1iii | 2.8155 (10) | O2—Ba1xxv | 3.3183 (1) |
Ba2—O1xiii | 2.9268 (2) | O2—Ba1xxvii | 3.3184 (1) |
Ba2—O1xiv | 2.9268 (2) | O1—Cr1xxiii | 1.7133 (9) |
Ba2—O1xv | 2.9268 (2) | O1—Ba1xxviii | 2.7589 (10) |
Ba2—O1xvi | 2.9268 (2) | O1—Ba2i | 2.8155 (10) |
Ba2—O1xvii | 2.9268 (2) | O1—Ba2xxix | 2.9268 (2) |
Ba2—O1xviii | 2.9268 (2) | O1—Ba2xxx | 2.9268 (2) |
O1i—Ba1—O1ii | 180.00 (3) | O1xvi—Ba2—O1xviii | 56.85 (4) |
O1i—Ba1—O1iii | 64.86 (3) | O1xvii—Ba2—O1xviii | 116.445 (13) |
O1ii—Ba1—O1iii | 115.14 (3) | O2—Ba2—Cr1xix | 70.902 (7) |
O1i—Ba1—O1iv | 115.14 (3) | O1i—Ba2—Cr1xix | 71.74 (2) |
O1ii—Ba1—O1iv | 64.86 (3) | O1v—Ba2—Cr1xix | 123.145 (7) |
O1iii—Ba1—O1iv | 180.00 (3) | O1iii—Ba2—Cr1xix | 123.145 (7) |
O1i—Ba1—O1v | 64.86 (3) | O1xiii—Ba2—Cr1xix | 87.343 (18) |
O1ii—Ba1—O1v | 115.14 (3) | O1xiv—Ba2—Cr1xix | 87.343 (18) |
O1iii—Ba1—O1v | 64.86 (3) | O1xv—Ba2—Cr1xix | 137.11 (2) |
O1iv—Ba1—O1v | 115.14 (3) | O1xvi—Ba2—Cr1xix | 29.108 (18) |
O1i—Ba1—O1vi | 115.14 (3) | O1xvii—Ba2—Cr1xix | 137.11 (2) |
O1ii—Ba1—O1vi | 64.86 (3) | O1xviii—Ba2—Cr1xix | 29.109 (18) |
O1iii—Ba1—O1vi | 115.14 (3) | O2—Ba2—Cr1xx | 70.900 (7) |
O1iv—Ba1—O1vi | 64.86 (3) | O1i—Ba2—Cr1xx | 123.146 (7) |
O1v—Ba1—O1vi | 180.00 (3) | O1v—Ba2—Cr1xx | 123.146 (7) |
O1i—Ba1—O2vii | 70.56 (3) | O1iii—Ba2—Cr1xx | 71.74 (2) |
O1ii—Ba1—O2vii | 109.44 (3) | O1xiii—Ba2—Cr1xx | 29.109 (18) |
O1iii—Ba1—O2vii | 70.56 (3) | O1xiv—Ba2—Cr1xx | 137.11 (2) |
O1iv—Ba1—O2vii | 109.44 (3) | O1xv—Ba2—Cr1xx | 29.109 (18) |
O1v—Ba1—O2vii | 126.55 (4) | O1xvi—Ba2—Cr1xx | 87.343 (18) |
O1vi—Ba1—O2vii | 53.45 (4) | O1xvii—Ba2—Cr1xx | 87.343 (18) |
O1i—Ba1—O2viii | 70.56 (3) | O1xviii—Ba2—Cr1xx | 137.11 (2) |
O1ii—Ba1—O2viii | 109.44 (3) | Cr1xix—Ba2—Cr1xx | 109.841 (7) |
O1iii—Ba1—O2viii | 126.55 (4) | O2—Cr1—O1xxi | 110.14 (4) |
O1iv—Ba1—O2viii | 53.45 (4) | O2—Cr1—O1xxii | 110.14 (4) |
O1v—Ba1—O2viii | 70.56 (3) | O1xxi—Cr1—O1xxii | 108.80 (4) |
O1vi—Ba1—O2viii | 109.44 (3) | O2—Cr1—O1xxiii | 110.14 (4) |
O2vii—Ba1—O2viii | 119.913 (4) | O1xxi—Cr1—O1xxiii | 108.79 (4) |
O1i—Ba1—O2ix | 109.44 (3) | O1xxii—Cr1—O1xxiii | 108.79 (4) |
O1ii—Ba1—O2ix | 70.56 (3) | O2—Cr1—Ba2xx | 109.099 (7) |
O1iii—Ba1—O2ix | 53.45 (4) | O1xxi—Cr1—Ba2xx | 56.202 (7) |
O1iv—Ba1—O2ix | 126.55 (4) | O1xxii—Cr1—Ba2xx | 140.76 (4) |
O1v—Ba1—O2ix | 109.44 (3) | O1xxiii—Cr1—Ba2xx | 56.204 (7) |
O1vi—Ba1—O2ix | 70.56 (3) | O2—Cr1—Ba2xxiv | 109.099 (7) |
O2vii—Ba1—O2ix | 60.087 (4) | O1xxi—Cr1—Ba2xxiv | 140.76 (4) |
O2viii—Ba1—O2ix | 180.00 (7) | O1xxii—Cr1—Ba2xxiv | 56.202 (7) |
O1i—Ba1—O2x | 109.44 (3) | O1xxiii—Cr1—Ba2xxiv | 56.204 (7) |
O1ii—Ba1—O2x | 70.56 (3) | Ba2xx—Cr1—Ba2xxiv | 109.842 (7) |
O1iii—Ba1—O2x | 109.44 (3) | O2—Cr1—Ba2xix | 109.098 (7) |
O1iv—Ba1—O2x | 70.56 (3) | O1xxi—Cr1—Ba2xix | 56.205 (7) |
O1v—Ba1—O2x | 53.45 (4) | O1xxii—Cr1—Ba2xix | 56.205 (7) |
O1vi—Ba1—O2x | 126.55 (4) | O1xxiii—Cr1—Ba2xix | 140.76 (4) |
O2vii—Ba1—O2x | 180.00 (7) | Ba2xx—Cr1—Ba2xix | 109.841 (7) |
O2viii—Ba1—O2x | 60.087 (4) | Ba2xxiv—Cr1—Ba2xix | 109.841 (7) |
O2ix—Ba1—O2x | 119.913 (4) | O2—Cr1—Ba1xxv | 64.579 (6) |
O1i—Ba1—O2xi | 126.55 (4) | O1xxi—Cr1—Ba1xxv | 124.876 (11) |
O1ii—Ba1—O2xi | 53.45 (4) | O1xxii—Cr1—Ba1xxv | 45.56 (4) |
O1iii—Ba1—O2xi | 70.56 (3) | O1xxiii—Cr1—Ba1xxv | 124.874 (11) |
O1iv—Ba1—O2xi | 109.44 (3) | Ba2xx—Cr1—Ba1xxv | 173.677 (12) |
O1v—Ba1—O2xi | 70.56 (3) | Ba2xxiv—Cr1—Ba1xxv | 73.364 (2) |
O1vi—Ba1—O2xi | 109.44 (3) | Ba2xix—Cr1—Ba1xxv | 73.365 (2) |
O2vii—Ba1—O2xi | 119.912 (4) | O2—Cr1—Ba1xxvi | 64.579 (6) |
O2viii—Ba1—O2xi | 119.912 (4) | O1xxi—Cr1—Ba1xxvi | 45.56 (4) |
O2ix—Ba1—O2xi | 60.088 (4) | O1xxii—Cr1—Ba1xxvi | 124.876 (11) |
O2x—Ba1—O2xi | 60.088 (4) | O1xxiii—Cr1—Ba1xxvi | 124.874 (11) |
O1i—Ba1—O2xii | 53.45 (4) | Ba2xx—Cr1—Ba1xxvi | 73.364 (2) |
O1ii—Ba1—O2xii | 126.55 (4) | Ba2xxiv—Cr1—Ba1xxvi | 173.677 (12) |
O1iii—Ba1—O2xii | 109.44 (3) | Ba2xix—Cr1—Ba1xxvi | 73.365 (2) |
O1iv—Ba1—O2xii | 70.56 (3) | Ba1xxv—Cr1—Ba1xxvi | 102.921 (7) |
O1v—Ba1—O2xii | 109.44 (3) | O2—Cr1—Ba1xxvii | 64.579 (6) |
O1vi—Ba1—O2xii | 70.56 (3) | O1xxi—Cr1—Ba1xxvii | 124.873 (11) |
O2vii—Ba1—O2xii | 60.088 (4) | O1xxii—Cr1—Ba1xxvii | 124.873 (11) |
O2viii—Ba1—O2xii | 60.088 (4) | O1xxiii—Cr1—Ba1xxvii | 45.56 (4) |
O2ix—Ba1—O2xii | 119.912 (4) | Ba2xx—Cr1—Ba1xxvii | 73.365 (2) |
O2x—Ba1—O2xii | 119.912 (4) | Ba2xxiv—Cr1—Ba1xxvii | 73.365 (2) |
O2xi—Ba1—O2xii | 180.00 (7) | Ba2xix—Cr1—Ba1xxvii | 173.678 (12) |
O2—Ba2—O1i | 142.65 (2) | Ba1xxv—Cr1—Ba1xxvii | 102.920 (7) |
O2—Ba2—O1v | 142.64 (2) | Ba1xxvi—Cr1—Ba1xxvii | 102.920 (7) |
O1i—Ba2—O1v | 63.40 (3) | O2—Cr1—Cr1xxiv | 46.451 (7) |
O2—Ba2—O1iii | 142.64 (2) | O1xxi—Cr1—Cr1xxiv | 156.59 (4) |
O1i—Ba2—O1iii | 63.40 (3) | O1xxii—Cr1—Cr1xxiv | 84.09 (3) |
O1v—Ba2—O1iii | 63.40 (3) | O1xxiii—Cr1—Cr1xxiv | 84.09 (3) |
O2—Ba2—O1xiii | 78.99 (2) | Ba2xx—Cr1—Cr1xxiv | 124.602 (5) |
O1i—Ba2—O1xiii | 99.33 (2) | Ba2xxiv—Cr1—Cr1xxiv | 62.648 (3) |
O1v—Ba2—O1xiii | 131.476 (10) | Ba2xix—Cr1—Cr1xxiv | 124.602 (5) |
O1iii—Ba2—O1xiii | 68.34 (4) | Ba1xxv—Cr1—Cr1xxiv | 51.460 (3) |
O2—Ba2—O1xiv | 78.99 (2) | Ba1xxvi—Cr1—Cr1xxiv | 111.030 (13) |
O1i—Ba2—O1xiv | 99.33 (2) | Ba1xxvii—Cr1—Cr1xxiv | 51.460 (3) |
O1v—Ba2—O1xiv | 68.34 (4) | O2—Cr1—Cr1xx | 46.451 (7) |
O1iii—Ba2—O1xiv | 131.476 (10) | O1xxi—Cr1—Cr1xx | 84.09 (3) |
O1xiii—Ba2—O1xiv | 157.90 (4) | O1xxii—Cr1—Cr1xx | 156.59 (4) |
O2—Ba2—O1xv | 78.99 (2) | O1xxiii—Cr1—Cr1xx | 84.09 (3) |
O1i—Ba2—O1xv | 131.476 (10) | Ba2xx—Cr1—Cr1xx | 62.648 (3) |
O1v—Ba2—O1xv | 99.33 (2) | Ba2xxiv—Cr1—Cr1xx | 124.602 (5) |
O1iii—Ba2—O1xv | 68.34 (4) | Ba2xix—Cr1—Cr1xx | 124.602 (5) |
O1xiii—Ba2—O1xv | 56.85 (4) | Ba1xxv—Cr1—Cr1xx | 111.030 (13) |
O1xiv—Ba2—O1xv | 116.445 (13) | Ba1xxvi—Cr1—Cr1xx | 51.460 (3) |
O2—Ba2—O1xvi | 78.99 (2) | Ba1xxvii—Cr1—Cr1xx | 51.460 (4) |
O1i—Ba2—O1xvi | 68.34 (4) | Cr1xxiv—Cr1—Cr1xx | 77.758 (11) |
O1v—Ba2—O1xvi | 131.476 (10) | Cr1—O2—Ba2 | 180.0 |
O1iii—Ba2—O1xvi | 99.33 (2) | Cr1—O2—Ba1xxvi | 88.29 (4) |
O1xiii—Ba2—O1xvi | 60.73 (4) | Ba2—O2—Ba1xxvi | 91.71 (4) |
O1xiv—Ba2—O1xvi | 116.445 (13) | Cr1—O2—Ba1xxv | 88.29 (4) |
O1xv—Ba2—O1xvi | 116.445 (13) | Ba2—O2—Ba1xxv | 91.71 (4) |
O2—Ba2—O1xvii | 78.99 (2) | Ba1xxvi—O2—Ba1xxv | 119.913 (4) |
O1i—Ba2—O1xvii | 131.475 (10) | Cr1—O2—Ba1xxvii | 88.29 (4) |
O1v—Ba2—O1xvii | 68.34 (4) | Ba2—O2—Ba1xxvii | 91.71 (4) |
O1iii—Ba2—O1xvii | 99.33 (2) | Ba1xxvi—O2—Ba1xxvii | 119.912 (4) |
O1xiii—Ba2—O1xvii | 116.445 (13) | Ba1xxv—O2—Ba1xxvii | 119.912 (4) |
O1xiv—Ba2—O1xvii | 56.85 (4) | Cr1xxiii—O1—Ba1xxviii | 108.12 (5) |
O1xv—Ba2—O1xvii | 60.73 (4) | Cr1xxiii—O1—Ba2i | 147.49 (5) |
O1xvi—Ba2—O1xvii | 157.90 (4) | Ba1xxviii—O1—Ba2i | 104.39 (3) |
O2—Ba2—O1xviii | 78.99 (2) | Cr1xxiii—O1—Ba2xxix | 94.688 (19) |
O1i—Ba2—O1xviii | 68.34 (4) | Ba1xxviii—O1—Ba2xxix | 98.010 (19) |
O1v—Ba2—O1xviii | 99.33 (2) | Ba2i—O1—Ba2xxix | 80.67 (2) |
O1iii—Ba2—O1xviii | 131.476 (10) | Cr1xxiii—O1—Ba2xxx | 94.688 (19) |
O1xiii—Ba2—O1xviii | 116.445 (13) | Ba1xxviii—O1—Ba2xxx | 98.009 (19) |
O1xiv—Ba2—O1xviii | 60.73 (4) | Ba2i—O1—Ba2xxx | 80.67 (2) |
O1xv—Ba2—O1xviii | 157.90 (4) | Ba2xxix—O1—Ba2xxx | 157.90 (4) |
Symmetry codes: (i) −x+1, −y, −z+1; (ii) x−1, y, z−1; (iii) y, −x+y+1, −z+1; (iv) −y, x−y−1, z−1; (v) x−y−1, x−1, −z+1; (vi) −x+y+1, −x+1, z−1; (vii) −x+2/3, −y+1/3, −z+1/3; (viii) −x−1/3, −y−2/3, −z+1/3; (ix) x+1/3, y+2/3, z−1/3; (x) x−2/3, y−1/3, z−1/3; (xi) −x−1/3, −y+1/3, −z+1/3; (xii) x+1/3, y−1/3, z−1/3; (xiii) x−1/3, y+1/3, z−2/3; (xiv) x−4/3, y−2/3, z−2/3; (xv) −x+y+2/3, −x+4/3, z−2/3; (xvi) −y+2/3, x−y−2/3, z−2/3; (xvii) −y−1/3, x−y−2/3, z−2/3; (xviii) −x+y+2/3, −x+1/3, z−2/3; (xix) −x+1/3, −y−1/3, −z+2/3; (xx) −x+1/3, −y+2/3, −z+2/3; (xxi) x−y−1/3, x−2/3, −z+4/3; (xxii) y−1/3, −x+y+1/3, −z+4/3; (xxiii) −x+2/3, −y+1/3, −z+4/3; (xxiv) −x−2/3, −y−1/3, −z+2/3; (xxv) x−1/3, y−2/3, z+1/3; (xxvi) x+2/3, y+1/3, z+1/3; (xxvii) x−1/3, y+1/3, z+1/3; (xxviii) x+1, y, z+1; (xxix) x+1/3, y−1/3, z+2/3; (xxx) x+4/3, y+2/3, z+2/3. |
Experimental details
Crystal data | |
Chemical formula | Ba3Cr2O8 |
Mr | 644.02 |
Crystal system, space group | Trigonal, R3m |
Temperature (K) | 296 |
a, c (Å) | 5.7450 (2), 21.3883 (10) |
V (Å3) | 611.35 (4) |
Z | 3 |
Radiation type | Mo Kα |
µ (mm−1) | 16.87 |
Crystal size (mm) | 0.30 × 0.05 × 0.02 |
Data collection | |
Diffractometer | Bruker APEXII CCD area-detector diffractometer |
Absorption correction | Numerical (face correction; APEX2; Bruker, 2006) |
Tmin, Tmax | 0.38, 0.77 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 9434, 928, 779 |
Rint | 0.034 |
(sin θ/λ)max (Å−1) | 1.112 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.021, 0.051, 1.07 |
No. of reflections | 928 |
No. of parameters | 19 |
Δρmax, Δρmin (e Å−3) | 1.98, −2.01 |
Computer programs: APEX2 (Bruker, 2006), SHELXS97 (Sheldrick, 1997a), SHELXL97 (Sheldrick, 1997a), GRETEP (Laugier & Bochu, 2003), SHELXTL (Sheldrick, 1997b).
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The system Ba3Cr2O8 was recently synthesized in polycrystalline form to study its magnetic properties (Nakajima et al., 2006). Susceptibility and high-field magnetization measurements have provided evidence that this material is a new spin dimer system. The interesting magnetic properties observed motivated our growth of large single crystals up to 6 mm x 4 mm x 1 mm in size. Fig.1 shows the structure of Ba3Cr2O8, which consists of a series of CrO43- tetrahedra and Ba2+ ions.
Smaller single crystals of Ba3Cr2O8 (suitable for X-ray work) were previously grown using a flux method (Mattausch and Muller-Buschbaum, 1972), but the magnetic properties of these crystals were never investigated. The authors did solve the crystallographic structure, but the reported R values were quite high (> 0.08) and both the isotropic and anisotropic displacement parameters were not presented. It follows that the purpose of this work is to present a more accurate and complete solution of the crystallographic structure of this system. This work also proves that single crystals of materials containing the difficult-to-stabilize Cr5+ ion can be grown by the traveling solvent floating zone technique.