Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801010935/br6026sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536801010935/br6026Isup2.hkl |
The compound was crystallized from a solid-state reaction between a mixture of BaH2 (Ba rods 99.9+%, Aldrich Chemical Company Inc.; heated under 50 bar of H2 pressure at 723 K for 4 h) and Pd (powder < 60 µm, claimed purity 99.9+%, Chempur) in a nominal molar ratio Ba:Pd = 2:1 mixed and heated (T ≈ 973 K) in an Al2O3 crucible in a stainless-steel reactor under a H2 pressure of 35 bar. All materials were handled in an argon-filled glove-box. The reason for using hydrogen was that the initial intention was to synthesize hydrides. The most probable sources of oxygen are either residual impurities in the glove-box atmosphere or a solid-state reaction with the crucible material (Al2O3). Assuming the conditions of Ellingham diagrams (Wulfsberg, 1987) to be true, one can imagine that the reduction of Al2O3 with Ba metal would be spontaneous at the synthesis temperature, thus a possible source of oxygen is the crucible material. Small single crystals were obtained from the solidified reaction product.
The O atoms in the center of barium octahedra were located from difference-density maps. Without the O atoms, residual densities of 12.2, 7.4 and 2.9 e Å-3 were located in the center of the Ba octahedra. Adding the O atoms further decreased the conventional R1 from 0.040 to 0.029. A l l O atoms were refined with a common isotropic displacement parameter and the occupancy of O3 were let free to refine. Adding hydrogen as central atoms to describe the residual intensities invariably led to negative displacement parameters and the only reasonable model that fitted the diffraction data was the one described with the oxygen atoms in the center of the octahedra. The corresponding refinement of the occupancy parameters of O1 and O2 did not yield any significant deviation from full occupancy, thus they were locked at full occupancy. The use of a common isotropic displacement parameter was found to be the model that gave the most stable refinement. No chemical analysis of the O content were done, thus the only indication of the presence of O atoms is the better fit to the structural data.
Data collection: DIF4 (Stoe & Cie, 1988); cell refinement: DIF4; data reduction: REDU4 (Stoe & Cie, 1988); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Bergerhof, 1996).
Ba2.125PdO0.422 | Mo Kα radiation, λ = 0.71073 Å |
Mr = 404.91 | Cell parameters from 32 reflections |
Cubic, F43m | θ = 15.0–19.2° |
a = 15.878 (1) Å | µ = 19.89 mm−1 |
V = 4003.0 (4) Å3 | T = 293 K |
Z = 32 | Prism, metallic light grey |
F(000) = 5344 | 0.14 × 0.09 × 0.07 mm |
Dx = 5.340 Mg m−3 |
Stoe AED4 diffractometer | 270 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.079 |
Graphite monochromator | θmax = 27.9°, θmin = 2.2° |
ω/2θ scans | h = −1→20 |
Absorption correction: numerical (X-RED; Stoe & Cie, 1997) | k = −1→20 |
Tmin = 0.060, Tmax = 0.259 | l = −1→20 |
1671 measured reflections | 3 standard reflections every 240 min |
336 independent reflections | intensity decay: 1% |
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)] = 0.029 | w = 1/[σ2(Fo2) + (0.01P)2] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.042 | (Δ/σ)max < 0.001 |
S = 1.16 | Δρmax = 1.65 e Å−3 |
336 reflections | Δρmin = −1.32 e Å−3 |
22 parameters | Absolute structure: Flack (1983), XXXX Friedel pairs |
0 restraints | Absolute structure parameter: −0.08 (11) |
Ba2.125PdO0.422 | Z = 32 |
Mr = 404.91 | Mo Kα radiation |
Cubic, F43m | µ = 19.89 mm−1 |
a = 15.878 (1) Å | T = 293 K |
V = 4003.0 (4) Å3 | 0.14 × 0.09 × 0.07 mm |
Stoe AED4 diffractometer | 270 reflections with I > 2σ(I) |
Absorption correction: numerical (X-RED; Stoe & Cie, 1997) | Rint = 0.079 |
Tmin = 0.060, Tmax = 0.259 | 3 standard reflections every 240 min |
1671 measured reflections | intensity decay: 1% |
336 independent reflections |
R[F2 > 2σ(F2)] = 0.029 | 0 restraints |
wR(F2) = 0.042 | Δρmax = 1.65 e Å−3 |
S = 1.16 | Δρmin = −1.32 e Å−3 |
336 reflections | Absolute structure: Flack (1983), XXXX Friedel pairs |
22 parameters | Absolute structure parameter: −0.08 (11) |
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. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
Ba1 | 0.92634 (10) | 0.2500 | 0.2500 | 0.0160 (5) | |
Ba2 | 0.32977 (8) | 0.0000 | 0.0000 | 0.0153 (5) | |
Ba3 | 0.09949 (6) | 0.09949 (6) | 0.09949 (6) | 0.0128 (4) | |
Ba4 | 0.2500 | 0.2500 | 0.2500 | 0.0119 (7) | |
Pd1 | 0.35502 (11) | 0.35502 (11) | 0.35502 (11) | 0.0140 (5) | |
Pd2 | 0.89303 (10) | 0.89303 (10) | 0.89303 (10) | 0.0114 (6) | |
O1 | 0.7500 | 0.7500 | 0.7500 | 0.011 (5)* | |
O2 | 0.5000 | 0.5000 | 0.5000 | 0.011 (5)* | |
O3 | 0.879 (2) | 0.379 (2) | 0.121 (2) | 0.011 (5)* | 0.34 (3) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Ba1 | 0.0113 (9) | 0.0184 (6) | 0.0184 (6) | 0.000 | 0.000 | −0.0105 (7) |
Ba2 | 0.0087 (8) | 0.0187 (5) | 0.0187 (5) | 0.000 | 0.000 | 0.0000 (10) |
Ba3 | 0.0128 (4) | 0.0128 (4) | 0.0128 (4) | 0.0015 (5) | 0.0015 (5) | 0.0015 (5) |
Ba4 | 0.0119 (7) | 0.0119 (7) | 0.0119 (7) | 0.000 | 0.000 | 0.000 |
Pd1 | 0.0140 (5) | 0.0140 (5) | 0.0140 (5) | −0.0032 (7) | −0.0032 (7) | −0.0032 (7) |
Pd2 | 0.0114 (6) | 0.0114 (6) | 0.0114 (6) | −0.0014 (7) | −0.0014 (7) | −0.0014 (7) |
Ba1—O1i | 2.7999 (16) | Ba3—Ba3xxv | 4.468 (3) |
Ba1—O3 | 3.00 (4) | Ba4—Pd1 | 2.888 (3) |
Ba1—O3ii | 3.00 (4) | Ba4—Pd1ii | 2.888 (3) |
Ba1—Pd2iii | 3.255 (2) | Ba4—Pd1xxvi | 2.888 (3) |
Ba1—Pd2i | 3.255 (2) | Ba4—Pd1xxvii | 2.888 (3) |
Ba1—Ba1iv | 3.960 (2) | Ba4—Ba3xxvii | 4.1393 (18) |
Ba1—Ba1v | 3.960 (2) | Ba4—Ba3xxvi | 4.1393 (18) |
Ba1—Ba1vi | 3.960 (2) | Ba4—Ba3ii | 4.1393 (18) |
Ba1—Ba1vii | 3.960 (2) | Pd1—Ba2xxviii | 3.280 (2) |
Ba1—Ba2viii | 4.3277 (6) | Pd1—Ba2xxix | 3.280 (2) |
Ba1—Ba2ix | 4.3277 (6) | Pd1—Ba2xxx | 3.280 (2) |
Ba1—Ba2x | 4.3277 (6) | Pd2—Ba1xxviii | 3.255 (2) |
Ba2—O2i | 2.7029 (13) | Pd2—Ba1xxx | 3.255 (2) |
Ba2—O3xi | 2.82 (3) | Pd2—Ba1xxix | 3.255 (2) |
Ba2—O3xii | 2.82 (3) | Pd2—Ba3xxxi | 3.2825 (17) |
Ba2—Pd1ii | 3.280 (2) | Pd2—Ba3xxxii | 3.2825 (17) |
Ba2—Pd1i | 3.280 (2) | Pd2—Ba3xxxiii | 3.2825 (17) |
Ba2—Ba2xiii | 3.8225 (18) | O1—Ba1xxxiv | 2.7999 (16) |
Ba2—Ba2xiv | 3.8225 (18) | O1—Ba1xxx | 2.7999 (16) |
Ba2—Ba2vi | 3.8225 (18) | O1—Ba1xxviii | 2.7999 (16) |
Ba2—Ba2vii | 3.8225 (18) | O1—Ba1xxix | 2.7999 (16) |
Ba2—Ba3xv | 4.2849 (11) | O1—Ba1xxxv | 2.7999 (16) |
Ba2—Ba3 | 4.2849 (11) | O1—Ba1xxxvi | 2.7999 (16) |
Ba2—Ba1xvi | 4.3277 (6) | O2—Ba2xxxvii | 2.7029 (13) |
Ba3—Pd2xvii | 3.2825 (17) | O2—Ba2xxviii | 2.7029 (13) |
Ba3—Pd2xviii | 3.2825 (17) | O2—Ba2xxxviii | 2.7029 (13) |
Ba3—Pd2xix | 3.2825 (17) | O2—Ba2xxix | 2.7029 (13) |
Ba3—Ba4 | 4.1393 (18) | O2—Ba2iv | 2.7029 (13) |
Ba3—Ba2xx | 4.2849 (11) | O2—Ba2xxx | 2.7029 (13) |
Ba3—Ba2xxi | 4.2849 (11) | O3—Ba2viii | 2.82 (3) |
Ba3—Ba1xxii | 4.3567 (11) | O3—Ba2xxxix | 2.82 (3) |
Ba3—Ba1xxiii | 4.3567 (11) | O3—Ba2x | 2.82 (3) |
Ba3—Ba1xxiv | 4.3567 (11) | O3—Ba1v | 3.00 (4) |
Ba3—Ba3xv | 4.468 (3) | O3—Ba1vi | 3.00 (4) |
O1i—Ba1—O3 | 75.6 (8) | Ba2—Ba3—Ba2xx | 119.556 (6) |
O1i—Ba1—O3ii | 75.6 (8) | Pd2xvii—Ba3—Ba2xxi | 67.311 (13) |
O3—Ba1—O3ii | 151.3 (16) | Pd2xviii—Ba3—Ba2xxi | 151.51 (7) |
O1i—Ba1—Pd2iii | 80.65 (4) | Pd2xix—Ba3—Ba2xxi | 67.311 (13) |
O3—Ba1—Pd2iii | 87.69 (13) | Ba4—Ba3—Ba2xxi | 86.16 (3) |
O3ii—Ba1—Pd2iii | 87.69 (13) | Ba2—Ba3—Ba2xxi | 119.556 (6) |
O1i—Ba1—Pd2i | 80.65 (4) | Ba2xx—Ba3—Ba2xxi | 119.556 (6) |
O3—Ba1—Pd2i | 87.69 (13) | Pd2xvii—Ba3—Ba1xxii | 123.422 (14) |
O3ii—Ba1—Pd2i | 87.69 (13) | Pd2xviii—Ba3—Ba1xxii | 123.422 (14) |
Pd2iii—Ba1—Pd2i | 161.30 (9) | Pd2xix—Ba3—Ba1xxii | 47.94 (4) |
O1i—Ba1—Ba1iv | 45.0 | Ba4—Ba3—Ba1xxii | 74.39 (3) |
O3—Ba1—Ba1iv | 108.0 (7) | Ba2—Ba3—Ba1xxii | 60.099 (5) |
O3ii—Ba1—Ba1iv | 48.7 (6) | Ba2xx—Ba3—Ba1xxii | 160.55 (5) |
Pd2iii—Ba1—Ba1iv | 52.54 (3) | Ba2xxi—Ba3—Ba1xxii | 60.099 (5) |
Pd2i—Ba1—Ba1iv | 112.24 (4) | Pd2xvii—Ba3—Ba1xxiii | 123.422 (14) |
O1i—Ba1—Ba1v | 45.0 | Pd2xviii—Ba3—Ba1xxiii | 47.94 (4) |
O3—Ba1—Ba1v | 48.7 (6) | Pd2xix—Ba3—Ba1xxiii | 123.422 (14) |
O3ii—Ba1—Ba1v | 108.0 (7) | Ba4—Ba3—Ba1xxiii | 74.39 (3) |
Pd2iii—Ba1—Ba1v | 52.54 (3) | Ba2—Ba3—Ba1xxiii | 60.099 (5) |
Pd2i—Ba1—Ba1v | 112.24 (4) | Ba2xx—Ba3—Ba1xxiii | 60.099 (5) |
Ba1iv—Ba1—Ba1v | 60.0 | Ba2xxi—Ba3—Ba1xxiii | 160.55 (5) |
O1i—Ba1—Ba1vi | 45.0 | Ba1xxii—Ba3—Ba1xxiii | 113.04 (2) |
O3—Ba1—Ba1vi | 48.7 (6) | Pd2xvii—Ba3—Ba1xxiv | 47.94 (4) |
O3ii—Ba1—Ba1vi | 108.0 (7) | Pd2xviii—Ba3—Ba1xxiv | 123.422 (14) |
Pd2iii—Ba1—Ba1vi | 112.24 (4) | Pd2xix—Ba3—Ba1xxiv | 123.422 (14) |
Pd2i—Ba1—Ba1vi | 52.54 (3) | Ba4—Ba3—Ba1xxiv | 74.39 (3) |
Ba1iv—Ba1—Ba1vi | 90.0 | Ba2—Ba3—Ba1xxiv | 160.55 (5) |
Ba1v—Ba1—Ba1vi | 60.0 | Ba2xx—Ba3—Ba1xxiv | 60.099 (5) |
O1i—Ba1—Ba1vii | 45.0 | Ba2xxi—Ba3—Ba1xxiv | 60.099 (5) |
O3—Ba1—Ba1vii | 108.0 (7) | Ba1xxii—Ba3—Ba1xxiv | 113.04 (2) |
O3ii—Ba1—Ba1vii | 48.7 (6) | Ba1xxiii—Ba3—Ba1xxiv | 113.04 (2) |
Pd2iii—Ba1—Ba1vii | 112.24 (4) | Pd2xvii—Ba3—Ba3xv | 92.93 (5) |
Pd2i—Ba1—Ba1vii | 52.54 (3) | Pd2xviii—Ba3—Ba3xv | 47.11 (4) |
Ba1iv—Ba1—Ba1vii | 60.0 | Pd2xix—Ba3—Ba3xv | 47.11 (4) |
Ba1v—Ba1—Ba1vii | 90.0 | Ba4—Ba3—Ba3xv | 144.7 |
Ba1vi—Ba1—Ba1vii | 60.0 | Ba2—Ba3—Ba3xv | 58.58 (3) |
O1i—Ba1—Ba2viii | 105.68 (2) | Ba2xx—Ba3—Ba3xv | 110.04 (2) |
O3—Ba1—Ba2viii | 40.4 (6) | Ba2xxi—Ba3—Ba3xv | 110.04 (2) |
O3ii—Ba1—Ba2viii | 153.62 (9) | Ba1xxii—Ba3—Ba3xv | 86.66 (2) |
Pd2iii—Ba1—Ba2viii | 118.664 (16) | Ba1xxiii—Ba3—Ba3xv | 86.66 (2) |
Pd2i—Ba1—Ba2viii | 66.93 (2) | Ba1xxiv—Ba3—Ba3xv | 140.87 (3) |
Ba1iv—Ba1—Ba2viii | 147.11 (2) | Pd2xvii—Ba3—Ba3xxv | 47.11 (4) |
Ba1v—Ba1—Ba2viii | 89.09 (2) | Pd2xviii—Ba3—Ba3xxv | 47.11 (4) |
Ba1vi—Ba1—Ba2viii | 62.776 (19) | Pd2xix—Ba3—Ba3xxv | 92.93 (5) |
Ba1vii—Ba1—Ba2viii | 113.456 (15) | Ba4—Ba3—Ba3xxv | 144.7 |
O1i—Ba1—Ba2ix | 105.68 (2) | Ba2—Ba3—Ba3xxv | 110.04 (2) |
O3—Ba1—Ba2ix | 153.62 (9) | Ba2xx—Ba3—Ba3xxv | 58.58 (3) |
O3ii—Ba1—Ba2ix | 40.4 (6) | Ba2xxi—Ba3—Ba3xxv | 110.04 (2) |
Pd2iii—Ba1—Ba2ix | 118.664 (16) | Ba1xxii—Ba3—Ba3xxv | 140.87 (3) |
Pd2i—Ba1—Ba2ix | 66.93 (2) | Ba1xxiii—Ba3—Ba3xxv | 86.66 (2) |
Ba1iv—Ba1—Ba2ix | 89.09 (2) | Ba1xxiv—Ba3—Ba3xxv | 86.66 (2) |
Ba1v—Ba1—Ba2ix | 147.11 (2) | Ba3xv—Ba3—Ba3xxv | 60.0 |
Ba1vi—Ba1—Ba2ix | 113.456 (15) | Pd1—Ba4—Pd1ii | 109.5 |
Ba1vii—Ba1—Ba2ix | 62.776 (19) | Pd1—Ba4—Pd1xxvi | 109.5 |
Ba2viii—Ba1—Ba2ix | 117.64 (4) | Pd1ii—Ba4—Pd1xxvi | 109.5 |
O1i—Ba1—Ba2x | 105.68 (2) | Pd1—Ba4—Pd1xxvii | 109.5 |
O3—Ba1—Ba2x | 40.4 (6) | Pd1ii—Ba4—Pd1xxvii | 109.5 |
O3ii—Ba1—Ba2x | 153.62 (9) | Pd1xxvi—Ba4—Pd1xxvii | 109.5 |
Pd2iii—Ba1—Ba2x | 66.93 (2) | Pd1—Ba4—Ba3 | 180.00 (3) |
Pd2i—Ba1—Ba2x | 118.664 (16) | Pd1ii—Ba4—Ba3 | 70.5 |
Ba1iv—Ba1—Ba2x | 113.456 (15) | Pd1xxvi—Ba4—Ba3 | 70.5 |
Ba1v—Ba1—Ba2x | 62.776 (19) | Pd1xxvii—Ba4—Ba3 | 70.5 |
Ba1vi—Ba1—Ba2x | 89.09 (2) | Pd1—Ba4—Ba3xxvii | 70.5 |
Ba1vii—Ba1—Ba2x | 147.11 (2) | Pd1ii—Ba4—Ba3xxvii | 70.5 |
Ba2viii—Ba1—Ba2x | 52.42 (3) | Pd1xxvi—Ba4—Ba3xxvii | 70.5 |
Ba2ix—Ba1—Ba2x | 148.64 (4) | Pd1xxvii—Ba4—Ba3xxvii | 180.00 (3) |
O2i—Ba2—O3xi | 73.8 (9) | Ba3—Ba4—Ba3xxvii | 109.5 |
O2i—Ba2—O3xii | 73.8 (9) | Pd1—Ba4—Ba3xxvi | 70.5 |
O3xi—Ba2—O3xii | 147.5 (18) | Pd1ii—Ba4—Ba3xxvi | 70.5 |
O2i—Ba2—Pd1ii | 82.98 (4) | Pd1xxvi—Ba4—Ba3xxvi | 180.00 (3) |
O3xi—Ba2—Pd1ii | 88.04 (10) | Pd1xxvii—Ba4—Ba3xxvi | 70.5 |
O3xii—Ba2—Pd1ii | 88.04 (10) | Ba3—Ba4—Ba3xxvi | 109.5 |
O2i—Ba2—Pd1i | 82.98 (4) | Ba3xxvii—Ba4—Ba3xxvi | 109.5 |
O3xi—Ba2—Pd1i | 88.04 (10) | Pd1—Ba4—Ba3ii | 70.5 |
O3xii—Ba2—Pd1i | 88.04 (10) | Pd1ii—Ba4—Ba3ii | 180.00 (8) |
Pd1ii—Ba2—Pd1i | 165.96 (9) | Pd1xxvi—Ba4—Ba3ii | 70.5 |
O2i—Ba2—Ba2xiii | 45.0 | Pd1xxvii—Ba4—Ba3ii | 70.5 |
O3xi—Ba2—Ba2xiii | 106.4 (7) | Ba3—Ba4—Ba3ii | 109.5 |
O3xii—Ba2—Ba2xiii | 47.3 (6) | Ba3xxvii—Ba4—Ba3ii | 109.5 |
Pd1ii—Ba2—Ba2xiii | 54.36 (4) | Ba3xxvi—Ba4—Ba3ii | 109.5 |
Pd1i—Ba2—Ba2xiii | 114.20 (4) | Ba4—Pd1—Ba2xxviii | 137.72 (4) |
O2i—Ba2—Ba2xiv | 45.0 | Ba4—Pd1—Ba2xxix | 137.72 (4) |
O3xi—Ba2—Ba2xiv | 47.3 (6) | Ba2xxviii—Pd1—Ba2xxix | 71.28 (7) |
O3xii—Ba2—Ba2xiv | 106.4 (7) | Ba4—Pd1—Ba2xxx | 137.72 (4) |
Pd1ii—Ba2—Ba2xiv | 54.36 (4) | Ba2xxviii—Pd1—Ba2xxx | 71.28 (7) |
Pd1i—Ba2—Ba2xiv | 114.20 (4) | Ba2xxix—Pd1—Ba2xxx | 71.28 (7) |
Ba2xiii—Ba2—Ba2xiv | 60.0 | Ba1xxviii—Pd2—Ba1xxx | 74.93 (7) |
O2i—Ba2—Ba2vi | 45.0 | Ba1xxviii—Pd2—Ba1xxix | 74.93 (7) |
O3xi—Ba2—Ba2vi | 106.4 (7) | Ba1xxx—Pd2—Ba1xxix | 74.93 (7) |
O3xii—Ba2—Ba2vi | 47.3 (6) | Ba1xxviii—Pd2—Ba3xxxi | 135.74 (2) |
Pd1ii—Ba2—Ba2vi | 114.20 (4) | Ba1xxx—Pd2—Ba3xxxi | 83.58 (4) |
Pd1i—Ba2—Ba2vi | 54.36 (4) | Ba1xxix—Pd2—Ba3xxxi | 135.74 (2) |
Ba2xiii—Ba2—Ba2vi | 60.0 | Ba1xxviii—Pd2—Ba3xxxii | 83.58 (4) |
Ba2xiv—Ba2—Ba2vi | 90.0 | Ba1xxx—Pd2—Ba3xxxii | 135.74 (2) |
O2i—Ba2—Ba2vii | 45.0 | Ba1xxix—Pd2—Ba3xxxii | 135.74 (2) |
O3xi—Ba2—Ba2vii | 47.3 (6) | Ba3xxxi—Pd2—Ba3xxxii | 85.78 (8) |
O3xii—Ba2—Ba2vii | 106.4 (7) | Ba1xxviii—Pd2—Ba3xxxiii | 135.74 (2) |
Pd1ii—Ba2—Ba2vii | 114.20 (4) | Ba1xxx—Pd2—Ba3xxxiii | 135.74 (2) |
Pd1i—Ba2—Ba2vii | 54.36 (4) | Ba1xxix—Pd2—Ba3xxxiii | 83.58 (4) |
Ba2xiii—Ba2—Ba2vii | 90.0 | Ba3xxxi—Pd2—Ba3xxxiii | 85.78 (8) |
Ba2xiv—Ba2—Ba2vii | 60.0 | Ba3xxxii—Pd2—Ba3xxxiii | 85.78 (8) |
Ba2vi—Ba2—Ba2vii | 60.0 | Ba1xxxiv—O1—Ba1xxx | 90.0 |
O2i—Ba2—Ba3xv | 148.58 (3) | Ba1xxxiv—O1—Ba1xxviii | 180.0 |
O3xi—Ba2—Ba3xv | 103.8 (7) | Ba1xxx—O1—Ba1xxviii | 90.0 |
O3xii—Ba2—Ba3xv | 103.8 (7) | Ba1xxxiv—O1—Ba1xxix | 90.0 |
Pd1ii—Ba2—Ba3xv | 128.44 (6) | Ba1xxx—O1—Ba1xxix | 90.0 |
Pd1i—Ba2—Ba3xv | 65.59 (4) | Ba1xxviii—O1—Ba1xxix | 90.0 |
Ba2xiii—Ba2—Ba3xv | 149.778 (3) | Ba1xxxiv—O1—Ba1xxxv | 90.0 |
Ba2xiv—Ba2—Ba3xv | 149.778 (3) | Ba1xxx—O1—Ba1xxxv | 90.0 |
Ba2vi—Ba2—Ba3xv | 110.04 (2) | Ba1xxviii—O1—Ba1xxxv | 90.0 |
Ba2vii—Ba2—Ba3xv | 110.04 (2) | Ba1xxix—O1—Ba1xxxv | 180.0 |
O2i—Ba2—Ba3 | 148.58 (3) | Ba1xxxiv—O1—Ba1xxxvi | 90.0 |
O3xi—Ba2—Ba3 | 103.8 (7) | Ba1xxx—O1—Ba1xxxvi | 180.0 |
O3xii—Ba2—Ba3 | 103.8 (7) | Ba1xxviii—O1—Ba1xxxvi | 90.0 |
Pd1ii—Ba2—Ba3 | 65.59 (4) | Ba1xxix—O1—Ba1xxxvi | 90.0 |
Pd1i—Ba2—Ba3 | 128.44 (6) | Ba1xxxv—O1—Ba1xxxvi | 90.0 |
Ba2xiii—Ba2—Ba3 | 110.04 (2) | Ba2xxxvii—O2—Ba2xxviii | 180.0 |
Ba2xiv—Ba2—Ba3 | 110.04 (2) | Ba2xxxvii—O2—Ba2xxxviii | 90.0 |
Ba2vi—Ba2—Ba3 | 149.778 (3) | Ba2xxviii—O2—Ba2xxxviii | 90.0 |
Ba2vii—Ba2—Ba3 | 149.778 (3) | Ba2xxxvii—O2—Ba2xxix | 90.0 |
Ba3xv—Ba2—Ba3 | 62.85 (5) | Ba2xxviii—O2—Ba2xxix | 90.0 |
O2i—Ba2—Ba1xvi | 107.018 (16) | Ba2xxxviii—O2—Ba2xxix | 90.0 |
O3xi—Ba2—Ba1xvi | 43.6 (7) | Ba2xxxvii—O2—Ba2iv | 90.0 |
O3xii—Ba2—Ba1xvi | 152.63 (9) | Ba2xxviii—O2—Ba2iv | 90.0 |
Pd1ii—Ba2—Ba1xvi | 119.33 (2) | Ba2xxxviii—O2—Ba2iv | 90.0 |
Pd1i—Ba2—Ba1xvi | 65.27 (2) | Ba2xxix—O2—Ba2iv | 180.0 |
Ba2xiii—Ba2—Ba1xvi | 148.818 (19) | Ba2xxxvii—O2—Ba2xxx | 90.0 |
Ba2xiv—Ba2—Ba1xvi | 90.91 (2) | Ba2xxviii—O2—Ba2xxx | 90.0 |
Ba2vi—Ba2—Ba1xvi | 113.456 (15) | Ba2xxxviii—O2—Ba2xxx | 180.0 |
Ba2vii—Ba2—Ba1xvi | 63.792 (15) | Ba2xxix—O2—Ba2xxx | 90.0 |
Ba3xv—Ba2—Ba1xvi | 60.774 (19) | Ba2iv—O2—Ba2xxx | 90.0 |
Ba3—Ba2—Ba1xvi | 89.36 (2) | Ba2viii—O3—Ba2xxxix | 85.3 (13) |
Pd2xvii—Ba3—Pd2xviii | 94.07 (7) | Ba2viii—O3—Ba2x | 85.3 (13) |
Pd2xvii—Ba3—Pd2xix | 94.07 (7) | Ba2xxxix—O3—Ba2x | 85.3 (13) |
Pd2xviii—Ba3—Pd2xix | 94.07 (7) | Ba2viii—O3—Ba1v | 178.1 (17) |
Pd2xvii—Ba3—Ba4 | 122.33 (5) | Ba2xxxix—O3—Ba1v | 96.02 (7) |
Pd2xviii—Ba3—Ba4 | 122.33 (5) | Ba2x—O3—Ba1v | 96.02 (7) |
Pd2xix—Ba3—Ba4 | 122.33 (5) | Ba2viii—O3—Ba1vi | 96.02 (7) |
Pd2xvii—Ba3—Ba2 | 151.51 (7) | Ba2xxxix—O3—Ba1vi | 96.02 (7) |
Pd2xviii—Ba3—Ba2 | 67.311 (13) | Ba2x—O3—Ba1vi | 178.1 (17) |
Pd2xix—Ba3—Ba2 | 67.311 (13) | Ba1v—O3—Ba1vi | 82.6 (12) |
Ba4—Ba3—Ba2 | 86.16 (3) | Ba2viii—O3—Ba1 | 96.02 (7) |
Pd2xvii—Ba3—Ba2xx | 67.311 (13) | Ba2xxxix—O3—Ba1 | 178.1 (17) |
Pd2xviii—Ba3—Ba2xx | 67.311 (13) | Ba2x—O3—Ba1 | 96.02 (7) |
Pd2xix—Ba3—Ba2xx | 151.51 (7) | Ba1v—O3—Ba1 | 82.6 (12) |
Ba4—Ba3—Ba2xx | 86.16 (3) | Ba1vi—O3—Ba1 | 82.6 (12) |
Symmetry codes: (i) x, y−1/2, z−1/2; (ii) x, −y+1/2, −z+1/2; (iii) x, −y+1, −z+1; (iv) z+1/2, −x+1, −y+1/2; (v) −y+1, z, −x+1; (vi) z+1/2, x−1/2, y; (vii) y+1/2, z, x−1/2; (viii) −y+1, z+1/2, −x+1/2; (ix) z+1, −x+1/2, −y+1/2; (x) z+1, x, y; (xi) x−1/2, −y+1/2, −z; (xii) x−1/2, y−1/2, z; (xiii) −y+1/2, z, −x+1/2; (xiv) z+1/2, −x+1/2, −y; (xv) x, −y, −z; (xvi) z, −x+1, −y; (xvii) x−1, −y+1, −z+1; (xviii) −x+1, y−1, −z+1; (xix) −x+1, −y+1, z−1; (xx) y, z, x; (xxi) z, x, y; (xxii) y, z, x−1; (xxiii) z, x−1, y; (xxiv) x−1, y, z; (xxv) −x, −y, z; (xxvi) −x+1/2, y, −z+1/2; (xxvii) −x+1/2, −y+1/2, z; (xxviii) y+1/2, z+1/2, x; (xxix) z+1/2, x, y+1/2; (xxx) x, y+1/2, z+1/2; (xxxi) x+1, −y+1, −z+1; (xxxii) −x+1, −y+1, z+1; (xxxiii) −x+1, y+1, −z+1; (xxxiv) −y+1, z+1/2, −x+3/2; (xxxv) z+1/2, −x+3/2, −y+1; (xxxvi) −x+3/2, −y+1, z+1/2; (xxxvii) −y+1/2, z+1/2, −x+1; (xxxviii) −x+1, −y+1/2, z+1/2; (xxxix) x+1/2, y+1/2, z. |
Experimental details
Crystal data | |
Chemical formula | Ba2.125PdO0.422 |
Mr | 404.91 |
Crystal system, space group | Cubic, F43m |
Temperature (K) | 293 |
a (Å) | 15.878 (1) |
V (Å3) | 4003.0 (4) |
Z | 32 |
Radiation type | Mo Kα |
µ (mm−1) | 19.89 |
Crystal size (mm) | 0.14 × 0.09 × 0.07 |
Data collection | |
Diffractometer | Stoe AED4 diffractometer |
Absorption correction | Numerical (X-RED; Stoe & Cie, 1997) |
Tmin, Tmax | 0.060, 0.259 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 1671, 336, 270 |
Rint | 0.079 |
(sin θ/λ)max (Å−1) | 0.658 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.029, 0.042, 1.16 |
No. of reflections | 336 |
No. of parameters | 22 |
Δρmax, Δρmin (e Å−3) | 1.65, −1.32 |
Absolute structure | Flack (1983), XXXX Friedel pairs |
Absolute structure parameter | −0.08 (11) |
Computer programs: DIF4 (Stoe & Cie, 1988), DIF4, REDU4 (Stoe & Cie, 1988), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), DIAMOND (Bergerhof, 1996).
Ba1—O1i | 2.7999 (16) | Ba2—Ba2vii | 3.8225 (18) |
Ba1—O3 | 3.00 (4) | Ba2—Ba3 | 4.2849 (11) |
Ba1—Pd2ii | 3.255 (2) | Ba3—Pd2viii | 3.2825 (17) |
Ba1—Ba1iii | 3.960 (2) | Ba3—Ba4 | 4.1393 (18) |
Ba1—Ba2iv | 4.3277 (6) | Ba3—Ba1ix | 4.3567 (11) |
Ba2—O2i | 2.7029 (13) | Ba3—Ba3x | 4.468 (3) |
Ba2—O3v | 2.82 (3) | Ba4—Pd1 | 2.888 (3) |
Ba2—Pd1vi | 3.280 (2) |
Symmetry codes: (i) x, y−1/2, z−1/2; (ii) x, −y+1, −z+1; (iii) z+1/2, −x+1, −y+1/2; (iv) −y+1, z+1/2, −x+1/2; (v) x−1/2, −y+1/2, −z; (vi) x, −y+1/2, −z+1/2; (vii) −y+1/2, z, −x+1/2; (viii) x−1, −y+1, −z+1; (ix) y, z, x−1; (x) x, −y, −z. |
The title compound was synthesized as part of a search for intermetallic compounds for use as hydrogen storage materials. The compound is composed of a network of face sharing O–Ba6 octahedra with the residual Ba atoms and all Pd atoms located in the tunnels of the octahedra network. O atoms were assigned to model quite large residual densities in the centre of the octahedra. This network of O—Ba6 is closely related to the pyrochlore structure (Gaertner, 1930). Removing the O1 atom (Fig. 1) gives a good resemblance between the pyrochlore Nb—O6 octahedra and the network of O2—Ba26 octahedra in the title compound. Barium suboxides, with similar arrangements of O—Ba octahedra, have been observed earlier (Röhr, 1995). The main difference in the present compound are the slightly longer Ba—O and Ba—Ba distances. This may be due to partial occupation of the O-atom positions giving a weaker attraction but may also be an effect of the excess Ba and Pd in the structure. In addition to the network of O—Ba6 octahedra as shown in Fig. 2, one can construct a complementary network of tetrahedraly coordinated Ba3 around Ba4 with an extra tetrahedron of Pd1 around Ba4 connected to each other through squares of 2 × Ba3 and 2 × Pd2. This additional network is shown in Fig. 3. It must be emphasized that the only indication that the title compound contains oxygen is the much better fit of the diffraction data when the model includes O atoms. Removing the O atoms from the structure model gives a pure intermetallic compound with the composition Ba68Pd32. This is, however, probably not correct. The oxygen stoichiometry cannot be stated with particularly high accuracy as it is a result from refinement.