Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270103006693/sk1623sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270103006693/sk1623Isup2.hkl | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270103006693/sk1623IIsup3.hkl |
Single crystals of Sr2Ru1 − xTixO4 were grown by the floating zone melting technique (Ikeda et al., 2002; Mao et al., 2000) in a CSI FZ—T-10000-H furnace equipped with four power lamps of 1500 W each. Polycrystalline starting materials with x = 0.1 and 1/5, respectively, were synthesized by conventional solid-state reactions from SrCO3, RuO2 and TiO2. To take into account the evaporation of some RuO2 during crystal growth, a 10% excess of ruthenium oxide was used. Rods of the polycrystalline compounds, approximately 7 mm in diameter and 100 mm in length, were pressed and sintered at 1623 K for 24 h. Crystal growth was performed in flowing air (1 l h−1) with a growth rate of 5 mm h−1. Seed- and feed-rods were counter-rotated at 35 r min−1. The resulting boules could be easily cleaved, and single crystals of appropriate sizes were selected for structure analysis.
Because of the plate-like shape and high linear absorption coefficient of the crystals, an absorption correction was mandatory. The crystal faces and distances were thoroughly determined, and the analytical absorption-correction procedure (Alcock, 1970) implemented in PLATON (Spek, 2003) was used.
Equal thermal displacement parameters were used for Ru and Ti, and the sum of their site-occupancy factors was fixed to yield a complete occupation of the corresponding site.
For both compounds, program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997).
Fig. 1. The crystal structure of Sr2Ru1 − xTixO4, showing the Ru/Ti–O6 octahedra and Sr–O9 capped tetragonal antiprisms. |
Sr2Ru0.93Ti0.07O4 | Dx = 5.829 Mg m−3 |
Mr = 334.99 | Mo Kα radiation, λ = 0.71073 Å |
Tetragonal, I4/mmm | Cell parameters from 25 reflections |
Hall symbol: -I 4 2 | θ = 9.7–18.0° |
a = 3.8736 (3) Å | µ = 31.43 mm−1 |
c = 12.720 (7) Å | T = 293 K |
V = 190.87 (10) Å3 | Triangular plate, black |
Z = 2 | 0.20 × 0.09 × 0.03 mm |
F(000) = 300 |
Siemens Syntex P21 diffractometer | 247 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.031 |
Graphite monochromator | θmax = 42.5°, θmin = 3.2° |
ω/2θ scans | h = −7→7 |
Absorption correction: analytical de Meulenaer & Tompa (1965) | k = −7→7 |
Tmin = 0.077, Tmax = 0.453 | l = −24→24 |
2882 measured reflections | 3 standard reflections every 100 reflections |
247 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)] = 0.014 | w = 1/[σ2(Fo2) + (0.0158P)2 + 0.1824P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.033 | (Δ/σ)max < 0.001 |
S = 1.31 | Δρmax = 1.62 e Å−3 |
247 reflections | Δρmin = −1.43 e Å−3 |
14 parameters | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.064 (3) |
Sr2Ru0.93Ti0.07O4 | Z = 2 |
Mr = 334.99 | Mo Kα radiation |
Tetragonal, I4/mmm | µ = 31.43 mm−1 |
a = 3.8736 (3) Å | T = 293 K |
c = 12.720 (7) Å | 0.20 × 0.09 × 0.03 mm |
V = 190.87 (10) Å3 |
Siemens Syntex P21 diffractometer | 247 reflections with I > 2σ(I) |
Absorption correction: analytical de Meulenaer & Tompa (1965) | Rint = 0.031 |
Tmin = 0.077, Tmax = 0.453 | 3 standard reflections every 100 reflections |
2882 measured reflections | intensity decay: < 1% |
247 independent reflections |
R[F2 > 2σ(F2)] = 0.014 | 14 parameters |
wR(F2) = 0.033 | 0 restraints |
S = 1.31 | Δρmax = 1.62 e Å−3 |
247 reflections | Δρmin = −1.43 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 > 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) | |
Ru | 0.0000 | 0.0000 | 0.0000 | 0.00345 (8) | 0.929 (2) |
Ti | 0.0000 | 0.0000 | 0.0000 | 0.00345 (8) | 0.071 (2) |
Sr | 0.0000 | 0.0000 | 0.353311 (19) | 0.00653 (8) | |
O1 | 0.5000 | 0.0000 | 0.0000 | 0.0084 (3) | |
O2 | 0.0000 | 0.0000 | 0.16130 (18) | 0.0083 (3) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Ru | 0.00334 (9) | 0.00334 (9) | 0.00366 (11) | 0.000 | 0.000 | 0.000 |
Ti | 0.00334 (9) | 0.00334 (9) | 0.00366 (11) | 0.000 | 0.000 | 0.000 |
Sr | 0.00752 (9) | 0.00752 (9) | 0.00456 (11) | 0.000 | 0.000 | 0.000 |
O1 | 0.0045 (6) | 0.0117 (8) | 0.0090 (7) | 0.000 | 0.000 | 0.000 |
O2 | 0.0103 (5) | 0.0103 (5) | 0.0043 (6) | 0.000 | 0.000 | 0.000 |
Ru—O1i | 1.9368 (2) | Sr—O2viii | 2.7453 (3) |
Ru/Ti—O1 | 1.9368 (2) | Sr—O2vi | 2.7453 (3) |
Ru—O1ii | 1.9368 (2) | Sr—O2xv | 2.7453 (3) |
Ru—O1iii | 1.9368 (2) | Sr—O2xvi | 2.7453 (3) |
Ru—O2iv | 2.052 (3) | Sr—Tixvii | 3.3142 (6) |
Ru/Ti—O2 | 2.052 (3) | Sr—Ruxvii | 3.3142 (6) |
Ru—Srv | 3.3142 (6) | Sr—Tixviii | 3.3142 (6) |
Ru/Ti—Srvi | 3.3142 (6) | O1—Tixix | 1.9368 (2) |
Ru—Srvii | 3.3142 (6) | O1—Ruxix | 1.9368 (2) |
Ru—Srviii | 3.3142 (6) | O1—Srvi | 2.6894 (7) |
Ru—Srix | 3.3142 (6) | O1—Srx | 2.6894 (7) |
Ru—Srx | 3.3142 (6) | O1—Srvii | 2.6894 (7) |
Sr—O2 | 2.443 (3) | O1—Srxvi | 2.6894 (7) |
Sr—O1xi | 2.6894 (7) | O2—Srviii | 2.7453 (3) |
Sr—O1xii | 2.6894 (7) | O2—Srvi | 2.7453 (3) |
Sr—O1xiii | 2.6894 (7) | O2—Srxvi | 2.7453 (3) |
Sr—O1xiv | 2.6894 (7) | O2—Srxv | 2.7453 (3) |
O1i—Ru—O1 | 90.0 | O1xiii—Sr—O2vi | 123.71 (4) |
O1i—Ru—O1ii | 180.0 | O1xiv—Sr—O2vi | 123.71 (4) |
O1—Ru—O1ii | 90.0 | O2viii—Sr—O2vi | 172.24 (9) |
O1i—Ru—O1iii | 90.0 | O2—Sr—O2xv | 86.12 (5) |
O1—Ru—O1iii | 180.0 | O1xi—Sr—O2xv | 123.71 (4) |
O1ii—Ru—O1iii | 90.0 | O1xii—Sr—O2xv | 62.54 (4) |
O1i—Ru—O2iv | 90.0 | O1xiii—Sr—O2xv | 62.54 (4) |
O1—Ru—O2iv | 90.0 | O1xiv—Sr—O2xv | 123.71 (4) |
O1ii—Ru—O2iv | 90.0 | O2viii—Sr—O2xv | 89.738 (6) |
O1iii—Ru—O2iv | 90.0 | O2vi—Sr—O2xv | 89.738 (6) |
O1i—Ru—O2 | 90.0 | O2—Sr—O2xvi | 86.12 (5) |
O1—Ru—O2 | 90.0 | O1xi—Sr—O2xvi | 62.54 (4) |
O1ii—Ru—O2 | 90.0 | O1xii—Sr—O2xvi | 123.71 (4) |
O1iii—Ru—O2 | 90.0 | O1xiii—Sr—O2xvi | 123.71 (4) |
O2iv—Ru—O2 | 180.0 | O1xiv—Sr—O2xvi | 62.54 (4) |
O1i—Ru—Srv | 125.760 (7) | O2viii—Sr—O2xvi | 89.738 (6) |
O1—Ru—Srv | 125.760 (7) | O2vi—Sr—O2xvi | 89.738 (6) |
O1ii—Ru—Srv | 54.240 (7) | O2xv—Sr—O2xvi | 172.24 (9) |
O1iii—Ru—Srv | 54.240 (7) | O2—Sr—Tixvii | 124.264 (15) |
O2iv—Ru—Srv | 55.736 (15) | O1xi—Sr—Tixvii | 35.760 (7) |
O2—Ru—Srv | 124.264 (15) | O1xii—Sr—Tixvii | 35.760 (7) |
O1i—Ru—Srvi | 54.240 (7) | O1xiii—Sr—Tixvii | 91.73 (3) |
O1—Ru—Srvi | 54.240 (7) | O1xiv—Sr—Tixvii | 91.73 (3) |
O1ii—Ru—Srvi | 125.760 (7) | O2viii—Sr—Tixvii | 149.62 (5) |
O1iii—Ru—Srvi | 125.760 (7) | O2vi—Sr—Tixvii | 38.15 (5) |
O2iv—Ru—Srvi | 124.264 (15) | O2xv—Sr—Tixvii | 92.18 (3) |
O2—Ru—Srvi | 55.736 (15) | O2xvi—Sr—Tixvii | 92.18 (3) |
Srv—Ru—Srvi | 180.000 (7) | O2—Sr—Ruxvii | 124.264 (15) |
O1i—Ru—Srvii | 54.240 (7) | O1xi—Sr—Ruxvii | 35.760 (7) |
O1—Ru—Srvii | 54.240 (7) | O1xii—Sr—Ruxvii | 35.760 (7) |
O1ii—Ru—Srvii | 125.760 (7) | O1xiii—Sr—Ruxvii | 91.73 (3) |
O1iii—Ru—Srvii | 125.760 (7) | O1xiv—Sr—Ruxvii | 91.73 (3) |
O2iv—Ru—Srvii | 55.736 (15) | O2viii—Sr—Ruxvii | 149.62 (5) |
O2—Ru—Srvii | 124.264 (15) | O2vi—Sr—Ruxvii | 38.15 (5) |
Srv—Ru—Srvii | 111.47 (3) | O2xv—Sr—Ruxvii | 92.18 (3) |
Srvi—Ru—Srvii | 68.53 (3) | O2xvi—Sr—Ruxvii | 92.18 (3) |
O1i—Ru—Srviii | 125.760 (7) | Tixvii—Sr—Ruxvii | 0.0 |
O1—Ru—Srviii | 125.760 (7) | O2—Sr—Tixviii | 124.264 (15) |
O1ii—Ru—Srviii | 54.240 (7) | O1xi—Sr—Tixviii | 35.760 (7) |
O1iii—Ru—Srviii | 54.240 (7) | O1xii—Sr—Tixviii | 91.73 (3) |
O2iv—Ru—Srviii | 124.264 (15) | O1xiii—Sr—Tixviii | 91.73 (3) |
O2—Ru—Srviii | 55.736 (15) | O1xiv—Sr—Tixviii | 35.760 (7) |
Srv—Ru—Srviii | 68.53 (3) | O2viii—Sr—Tixviii | 92.18 (3) |
Srvi—Ru—Srviii | 111.47 (3) | O2vi—Sr—Tixviii | 92.18 (3) |
Srvii—Ru—Srviii | 180.000 (7) | O2xv—Sr—Tixviii | 149.62 (5) |
O1i—Ru—Srix | 54.240 (7) | O2xvi—Sr—Tixviii | 38.15 (5) |
O1—Ru—Srix | 125.760 (7) | Tixvii—Sr—Tixviii | 71.519 (15) |
O1ii—Ru—Srix | 125.760 (7) | Ruxvii—Sr—Tixviii | 71.519 (15) |
O1iii—Ru—Srix | 54.240 (7) | Tixix—O1—Ru | 180.0 |
O2iv—Ru—Srix | 55.736 (15) | Ru—O1—Ruxix | 180.0 |
O2—Ru—Srix | 124.264 (15) | Tixix—O1—Srvi | 90.0 |
Srv—Ru—Srix | 71.519 (14) | Ru—O1—Srvi | 90.0 |
Srvi—Ru—Srix | 108.481 (15) | Ruxix—O1—Srvi | 90.0 |
Srvii—Ru—Srix | 71.519 (15) | Tixix—O1—Srx | 90.0 |
Srviii—Ru—Srix | 108.481 (15) | Ru—O1—Srx | 90.0 |
O1i—Ru—Srx | 125.760 (7) | Ruxix—O1—Srx | 90.0 |
O1—Ru—Srx | 54.240 (7) | Srvi—O1—Srx | 180.000 (8) |
O1ii—Ru—Srx | 54.240 (7) | Tixix—O1—Srvii | 90.0 |
O1iii—Ru—Srx | 125.760 (7) | Ru—O1—Srvii | 90.0 |
O2iv—Ru—Srx | 55.736 (15) | Ruxix—O1—Srvii | 90.0 |
O2—Ru—Srx | 124.264 (15) | Srvi—O1—Srvii | 87.87 (3) |
Srv—Ru—Srx | 71.519 (14) | Srx—O1—Srvii | 92.13 (3) |
Srvi—Ru—Srx | 108.481 (15) | Tixix—O1—Srxvi | 90.0 |
Srvii—Ru—Srx | 71.519 (15) | Ru—O1—Srxvi | 90.0 |
Srviii—Ru—Srx | 108.481 (15) | Ruxix—O1—Srxvi | 90.0 |
Srix—Ru—Srx | 111.47 (3) | Srvi—O1—Srxvi | 92.13 (3) |
O2—Sr—O1xi | 133.933 (16) | Srx—O1—Srxvi | 87.87 (3) |
O2—Sr—O1xii | 133.933 (16) | Srvii—O1—Srxvi | 180.000 (8) |
O1xi—Sr—O1xii | 61.225 (18) | Ru—O2—Sr | 180.0 |
O2—Sr—O1xiii | 133.933 (16) | Ru—O2—Srviii | 86.12 (5) |
O1xi—Sr—O1xiii | 92.13 (3) | Sr—O2—Srviii | 93.88 (5) |
O1xii—Sr—O1xiii | 61.225 (18) | Ru—O2—Srvi | 86.12 (5) |
O2—Sr—O1xiv | 133.933 (16) | Sr—O2—Srvi | 93.88 (5) |
O1xi—Sr—O1xiv | 61.225 (18) | Srviii—O2—Srvi | 172.24 (9) |
O1xii—Sr—O1xiv | 92.13 (3) | Ru—O2—Srxvi | 86.12 (5) |
O1xiii—Sr—O1xiv | 61.225 (18) | Sr—O2—Srxvi | 93.88 (5) |
O2—Sr—O2viii | 86.12 (5) | Srviii—O2—Srxvi | 89.738 (6) |
O1xi—Sr—O2viii | 123.71 (4) | Srvi—O2—Srxvi | 89.738 (6) |
O1xii—Sr—O2viii | 123.71 (4) | Ru—O2—Srxv | 86.12 (5) |
O1xiii—Sr—O2viii | 62.54 (4) | Sr—O2—Srxv | 93.88 (5) |
O1xiv—Sr—O2viii | 62.54 (4) | Srviii—O2—Srxv | 89.738 (6) |
O2—Sr—O2vi | 86.12 (5) | Srvi—O2—Srxv | 89.738 (6) |
O1xi—Sr—O2vi | 62.54 (4) | Srxvi—O2—Srxv | 172.24 (9) |
O1xii—Sr—O2vi | 62.54 (4) |
Symmetry codes: (i) −y, x, z; (ii) −y, x−1, z; (iii) x−1, y, z; (iv) −x, −y, −z; (v) x−1/2, y−1/2, z−1/2; (vi) −x+1/2, −y+1/2, −z+1/2; (vii) x+1/2, y+1/2, z−1/2; (viii) −x−1/2, −y−1/2, −z+1/2; (ix) x−1/2, y+1/2, z−1/2; (x) x+1/2, y−1/2, z−1/2; (xi) −y+1/2, x−1/2, z+1/2; (xii) x−1/2, y+1/2, z+1/2; (xiii) −y−1/2, x−1/2, z+1/2; (xiv) x−1/2, y−1/2, z+1/2; (xv) −x−1/2, −y+1/2, −z+1/2; (xvi) −x+1/2, −y−1/2, −z+1/2; (xvii) x+1/2, y+1/2, z+1/2; (xviii) x+1/2, y−1/2, z+1/2; (xix) x+1, y, z. |
Sr2Ru0.81Ti0.19O4 | Dx = 5.747 Mg m−3 |
Mr = 330.21 | Mo Kα radiation, λ = 0.71073 Å |
Tetragonal, I4/mmm | Cell parameters from 25 reflections |
Hall symbol: -I 4 2 | θ = 7.1–18.0° |
a = 3.8767 (5) Å | µ = 31.27 mm−1 |
c = 12.698 (3) Å | T = 293 K |
V = 190.83 (6) Å3 | Rectangular plate, black |
Z = 2 | 0.15 × 0.09 × 0.02 mm |
F(000) = 296 |
Siemens Syntex P21 diffractometer | 246 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.038 |
Graphite monochromator | θmax = 42.5°, θmin = 3.2° |
ω/2θ scans | h = −7→7 |
Absorption correction: analytical de Meulenaer & Tompa (1965) | k = −7→7 |
Tmin = 0.074, Tmax = 0.529 | l = −24→24 |
2882 measured reflections | 3 standard reflections every 100 reflections |
247 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)] = 0.019 | w = 1/[σ2(Fo2) + (0.0183P)2 + 0.4584P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.045 | (Δ/σ)max = 0.001 |
S = 1.41 | Δρmax = 1.40 e Å−3 |
247 reflections | Δρmin = −2.97 e Å−3 |
14 parameters | Extinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.047 (3) |
Sr2Ru0.81Ti0.19O4 | Z = 2 |
Mr = 330.21 | Mo Kα radiation |
Tetragonal, I4/mmm | µ = 31.27 mm−1 |
a = 3.8767 (5) Å | T = 293 K |
c = 12.698 (3) Å | 0.15 × 0.09 × 0.02 mm |
V = 190.83 (6) Å3 |
Siemens Syntex P21 diffractometer | 246 reflections with I > 2σ(I) |
Absorption correction: analytical de Meulenaer & Tompa (1965) | Rint = 0.038 |
Tmin = 0.074, Tmax = 0.529 | 3 standard reflections every 100 reflections |
2882 measured reflections | intensity decay: < 1% |
247 independent reflections |
R[F2 > 2σ(F2)] = 0.019 | 14 parameters |
wR(F2) = 0.045 | 0 restraints |
S = 1.41 | Δρmax = 1.40 e Å−3 |
247 reflections | Δρmin = −2.97 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 > 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) | |
Ru | 0.0000 | 0.0000 | 0.0000 | 0.00326 (13) | 0.810 (4) |
Ti | 0.0000 | 0.0000 | 0.0000 | 0.00326 (13) | 0.190 (4) |
Sr | 0.0000 | 0.0000 | 0.35362 (3) | 0.00642 (11) | |
O1 | 0.5000 | 0.0000 | 0.0000 | 0.0079 (4) | |
O2 | 0.0000 | 0.0000 | 0.1608 (2) | 0.0084 (5) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Ru | 0.00320 (14) | 0.00320 (14) | 0.00338 (17) | 0.000 | 0.000 | 0.000 |
Ti | 0.00320 (14) | 0.00320 (14) | 0.00338 (17) | 0.000 | 0.000 | 0.000 |
Sr | 0.00744 (13) | 0.00744 (13) | 0.00439 (15) | 0.000 | 0.000 | 0.000 |
O1 | 0.0049 (10) | 0.0106 (11) | 0.0082 (9) | 0.000 | 0.000 | 0.000 |
O2 | 0.0106 (7) | 0.0106 (7) | 0.0041 (8) | 0.000 | 0.000 | 0.000 |
Ru—O1i | 1.9383 (2) | Sr—O2viii | 2.7474 (4) |
Ru/Ti—O1 | 1.9383 (2) | Sr—O2vi | 2.7474 (4) |
Ru—O1ii | 1.9383 (2) | Sr—O2xv | 2.7474 (4) |
Ru—O1iii | 1.9383 (2) | Sr—O2xvi | 2.7474 (4) |
Ru—O2iv | 2.042 (3) | Sr—Tixvii | 3.3120 (4) |
Ru/Ti—O2 | 2.042 (3) | Sr—Ruxvii | 3.3120 (4) |
Ru/Ti—Srv | 3.3120 (4) | Sr—Tixiv | 3.3120 (4) |
Ru—Srvi | 3.3120 (4) | O1—Tixviii | 1.9383 (2) |
Ru—Srvii | 3.3120 (4) | O1—Ruxviii | 1.9383 (2) |
Ru—Srviii | 3.3120 (4) | O1—Srvi | 2.6855 (4) |
Ru—Srix | 3.3120 (4) | O1—Srx | 2.6855 (4) |
Ru—Srx | 3.3120 (4) | O1—Srvii | 2.6855 (4) |
Sr—O2 | 2.448 (3) | O1—Srxvi | 2.6855 (4) |
Sr—O1xi | 2.6855 (4) | O2—Srviii | 2.7474 (4) |
Sr—O1xii | 2.6855 (4) | O2—Srvi | 2.7474 (4) |
Sr—O1xiii | 2.6855 (4) | O2—Srxvi | 2.7474 (4) |
Sr—O1xiv | 2.6855 (4) | O2—Srxv | 2.7474 (4) |
O1i—Ru—O1 | 90.0 | O1xiii—Sr—O2vi | 123.74 (5) |
O1i—Ru—O1ii | 180.0 | O1xiv—Sr—O2vi | 123.74 (5) |
O1—Ru—O1ii | 90.0 | O2viii—Sr—O2vi | 172.35 (13) |
O1i—Ru—O1iii | 90.0 | O2—Sr—O2xv | 86.18 (7) |
O1—Ru—O1iii | 180.0 | O1xi—Sr—O2xv | 123.74 (5) |
O1ii—Ru—O1iii | 90.0 | O1xii—Sr—O2xv | 62.41 (5) |
O1i—Ru—O2iv | 90.0 | O1xiii—Sr—O2xv | 62.41 (5) |
O1—Ru—O2iv | 90.0 | O1xiv—Sr—O2xv | 123.74 (5) |
O1ii—Ru—O2iv | 90.0 | O2viii—Sr—O2xv | 89.745 (9) |
O1iii—Ru—O2iv | 90.0 | O2vi—Sr—O2xv | 89.745 (9) |
O1i—Ru—O2 | 90.0 | O2—Sr—O2xvi | 86.18 (7) |
O1—Ru—O2 | 90.0 | O1xi—Sr—O2xvi | 62.41 (5) |
O1ii—Ru—O2 | 90.0 | O1xii—Sr—O2xvi | 123.74 (5) |
O1iii—Ru—O2 | 90.0 | O1xiii—Sr—O2xvi | 123.74 (5) |
O2iv—Ru—O2 | 180.0 | O1xiv—Sr—O2xvi | 62.41 (5) |
O1i—Ru—Srv | 125.821 (4) | O2viii—Sr—O2xvi | 89.745 (9) |
O1—Ru—Srv | 125.821 (4) | O2vi—Sr—O2xvi | 89.745 (9) |
O1ii—Ru—Srv | 54.179 (4) | O2xv—Sr—O2xvi | 172.35 (13) |
O1iii—Ru—Srv | 54.179 (4) | O2—Sr—Tixvii | 124.140 (9) |
O2iv—Ru—Srv | 55.860 (9) | O1xi—Sr—Tixvii | 35.821 (4) |
O2—Ru—Srv | 124.140 (9) | O1xii—Sr—Tixvii | 35.821 (4) |
O1i—Ru—Srvi | 54.179 (4) | O1xiii—Sr—Tixvii | 91.948 (16) |
O1—Ru—Srvi | 54.179 (4) | O1xiv—Sr—Tixvii | 91.948 (16) |
O1ii—Ru—Srvi | 125.821 (4) | O2viii—Sr—Tixvii | 149.68 (7) |
O1iii—Ru—Srvi | 125.821 (4) | O2vi—Sr—Tixvii | 37.96 (7) |
O2iv—Ru—Srvi | 124.140 (9) | O2xv—Sr—Tixvii | 92.14 (4) |
O2—Ru—Srvi | 55.860 (9) | O2xvi—Sr—Tixvii | 92.14 (4) |
Srv—Ru—Srvi | 180.000 (10) | O2—Sr—Ruxvii | 124.140 (9) |
O1i—Ru—Srvii | 54.179 (4) | O1xi—Sr—Ruxvii | 35.821 (4) |
O1—Ru—Srvii | 54.179 (4) | O1xii—Sr—Ruxvii | 35.821 (4) |
O1ii—Ru—Srvii | 125.821 (4) | O1xiii—Sr—Ruxvii | 91.948 (16) |
O1iii—Ru—Srvii | 125.821 (4) | O1xiv—Sr—Ruxvii | 91.948 (16) |
O2iv—Ru—Srvii | 55.861 (9) | O2viii—Sr—Ruxvii | 149.68 (7) |
O2—Ru—Srvii | 124.140 (9) | O2vi—Sr—Ruxvii | 37.96 (7) |
Srv—Ru—Srvii | 111.721 (18) | O2xv—Sr—Ruxvii | 92.14 (4) |
Srvi—Ru—Srvii | 68.279 (18) | O2xvi—Sr—Ruxvii | 92.14 (4) |
O1i—Ru—Srviii | 125.821 (4) | Tixvii—Sr—Ruxvii | 0.0 |
O1—Ru—Srviii | 125.821 (4) | O2—Sr—Tixiv | 124.140 (9) |
O1ii—Ru—Srviii | 54.179 (4) | O1xi—Sr—Tixiv | 91.948 (16) |
O1iii—Ru—Srviii | 54.179 (4) | O1xii—Sr—Tixiv | 91.948 (16) |
O2iv—Ru—Srviii | 124.140 (9) | O1xiii—Sr—Tixiv | 35.821 (4) |
O2—Ru—Srviii | 55.861 (9) | O1xiv—Sr—Tixiv | 35.821 (4) |
Srv—Ru—Srviii | 68.279 (18) | O2viii—Sr—Tixiv | 37.96 (7) |
Srvi—Ru—Srviii | 111.721 (18) | O2vi—Sr—Tixiv | 149.68 (7) |
Srvii—Ru—Srviii | 180.000 (10) | O2xv—Sr—Tixiv | 92.14 (4) |
O1i—Ru—Srix | 54.179 (4) | O2xvi—Sr—Tixiv | 92.14 (4) |
O1—Ru—Srix | 125.821 (4) | Tixvii—Sr—Tixiv | 111.721 (18) |
O1ii—Ru—Srix | 125.821 (4) | Ruxvii—Sr—Tixiv | 111.721 (18) |
O1iii—Ru—Srix | 54.179 (4) | Tixviii—O1—Ru | 180.0 |
O2iv—Ru—Srix | 55.860 (9) | Ru—O1—Ruxviii | 180.0 |
O2—Ru—Srix | 124.140 (9) | Tixviii—O1—Srvi | 90.0 |
Srv—Ru—Srix | 71.642 (9) | Ru—O1—Srvi | 90.0 |
Srvi—Ru—Srix | 108.358 (9) | Ruxviii—O1—Srvi | 90.0 |
Srvii—Ru—Srix | 71.642 (9) | Tixviii—O1—Srx | 90.0 |
Srviii—Ru—Srix | 108.358 (9) | Ru—O1—Srx | 90.0 |
O1i—Ru—Srx | 125.821 (4) | Ruxviii—O1—Srx | 90.0 |
O1—Ru—Srx | 54.179 (4) | Srvi—O1—Srx | 180.000 (10) |
O1ii—Ru—Srx | 54.179 (4) | Tixviii—O1—Srvii | 90.0 |
O1iii—Ru—Srx | 125.821 (4) | Ru—O1—Srvii | 90.0 |
O2iv—Ru—Srx | 55.860 (9) | Ruxviii—O1—Srvii | 90.0 |
O2—Ru—Srx | 124.140 (9) | Srvi—O1—Srvii | 87.597 (19) |
Srv—Ru—Srx | 71.642 (9) | Srx—O1—Srvii | 92.40 (2) |
Srvi—Ru—Srx | 108.358 (9) | Tixviii—O1—Srxvi | 90.0 |
Srvii—Ru—Srx | 71.642 (9) | Ru—O1—Srxvi | 90.0 |
Srviii—Ru—Srx | 108.358 (9) | Ruxviii—O1—Srxvi | 90.0 |
Srix—Ru—Srx | 111.721 (18) | Srvi—O1—Srxvi | 92.40 (2) |
O2—Sr—O1xi | 133.799 (10) | Srx—O1—Srxvi | 87.597 (19) |
O2—Sr—O1xii | 133.799 (10) | Srvii—O1—Srxvi | 180.000 (10) |
O1xi—Sr—O1xii | 61.377 (11) | Ru—O2—Sr | 180.0 |
O2—Sr—O1xiii | 133.799 (10) | Ru—O2—Srviii | 86.18 (7) |
O1xi—Sr—O1xiii | 92.403 (19) | Sr—O2—Srviii | 93.82 (7) |
O1xii—Sr—O1xiii | 61.377 (11) | Ru—O2—Srvi | 86.18 (7) |
O2—Sr—O1xiv | 133.799 (10) | Sr—O2—Srvi | 93.82 (7) |
O1xi—Sr—O1xiv | 61.377 (11) | Srviii—O2—Srvi | 172.35 (13) |
O1xii—Sr—O1xiv | 92.403 (19) | Ru—O2—Srxvi | 86.18 (7) |
O1xiii—Sr—O1xiv | 61.377 (11) | Sr—O2—Srxvi | 93.82 (7) |
O2—Sr—O2viii | 86.18 (7) | Srviii—O2—Srxvi | 89.745 (9) |
O1xi—Sr—O2viii | 123.74 (5) | Srvi—O2—Srxvi | 89.745 (9) |
O1xii—Sr—O2viii | 123.74 (5) | Ru—O2—Srxv | 86.18 (7) |
O1xiii—Sr—O2viii | 62.41 (5) | Sr—O2—Srxv | 93.82 (7) |
O1xiv—Sr—O2viii | 62.41 (5) | Srviii—O2—Srxv | 89.745 (9) |
O2—Sr—O2vi | 86.18 (7) | Srvi—O2—Srxv | 89.745 (9) |
O1xi—Sr—O2vi | 62.41 (5) | Srxvi—O2—Srxv | 172.35 (13) |
O1xii—Sr—O2vi | 62.41 (5) |
Symmetry codes: (i) −y, x, z; (ii) −y, x−1, z; (iii) x−1, y, z; (iv) −x, −y, −z; (v) x−1/2, y−1/2, z−1/2; (vi) −x+1/2, −y+1/2, −z+1/2; (vii) x+1/2, y+1/2, z−1/2; (viii) −x−1/2, −y−1/2, −z+1/2; (ix) x−1/2, y+1/2, z−1/2; (x) x+1/2, y−1/2, z−1/2; (xi) −y+1/2, x−1/2, z+1/2; (xii) x−1/2, y+1/2, z+1/2; (xiii) −y−1/2, x−1/2, z+1/2; (xiv) x−1/2, y−1/2, z+1/2; (xv) −x−1/2, −y+1/2, −z+1/2; (xvi) −x+1/2, −y−1/2, −z+1/2; (xvii) x+1/2, y+1/2, z+1/2; (xviii) x+1, y, z. |
Experimental details
(I) | (II) | |
Crystal data | ||
Chemical formula | Sr2Ru0.93Ti0.07O4 | Sr2Ru0.81Ti0.19O4 |
Mr | 334.99 | 330.21 |
Crystal system, space group | Tetragonal, I4/mmm | Tetragonal, I4/mmm |
Temperature (K) | 293 | 293 |
a, c (Å) | 3.8736 (3), 12.720 (7) | 3.8767 (5), 12.698 (3) |
V (Å3) | 190.87 (10) | 190.83 (6) |
Z | 2 | 2 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 31.43 | 31.27 |
Crystal size (mm) | 0.20 × 0.09 × 0.03 | 0.15 × 0.09 × 0.02 |
Data collection | ||
Diffractometer | Siemens Syntex P21 diffractometer | Siemens Syntex P21 diffractometer |
Absorption correction | Analytical de Meulenaer & Tompa (1965) | Analytical de Meulenaer & Tompa (1965) |
Tmin, Tmax | 0.077, 0.453 | 0.074, 0.529 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2882, 247, 247 | 2882, 247, 246 |
Rint | 0.031 | 0.038 |
(sin θ/λ)max (Å−1) | 0.950 | 0.951 |
Refinement | ||
R[F2 > 2σ(F2)], wR(F2), S | 0.014, 0.033, 1.31 | 0.019, 0.045, 1.41 |
No. of reflections | 247 | 247 |
No. of parameters | 14 | 14 |
Δρmax, Δρmin (e Å−3) | 1.62, −1.43 | 1.40, −2.97 |
Computer programs: SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997).
Ru/Ti—O1 | 1.9368 (2) | Sr—O2 | 2.443 (3) |
Ru/Ti—O2 | 2.052 (3) | Sr—O1ii | 2.6894 (7) |
Ru/Ti—Sri | 3.3142 (6) | Sr—O2i | 2.7453 (3) |
Symmetry codes: (i) −x+1/2, −y+1/2, −z+1/2; (ii) x−1/2, y+1/2, z+1/2. |
Ru/Ti—O1 | 1.9383 (2) | Sr—O2 | 2.448 (3) |
Ru/Ti—O2 | 2.042 (3) | Sr—O1ii | 2.6855 (4) |
Ru/Ti—Sri | 3.3120 (4) | Sr—O2iii | 2.7474 (4) |
Symmetry codes: (i) x−1/2, y−1/2, z−1/2; (ii) x−1/2, y−1/2, z+1/2; (iii) −x+1/2, −y+1/2, −z+1/2. |
The origin of superconductivity in Sr2RuO4 (Maeno et al., 1994) still remains an unsolved problem. In contrast to the isostructural (La, Sr)2CuO4, superconductivity in Sr2RuO4 is easily suppressed, even by traces of impurities (Mackenzie et al., 1998). Although this effect is rather undesired, it offers the unique opportunity to study the normal state of distrontium ruthenate and thus can help us to understand the mechanism of superconductivity in this unusual material.
Single crystals of undoped Sr2RuO4 have been examined in detail by Walz & Lichtenberg (1993) and Müller-Buschbaum & Wilkens (1990).
Titanium doping was found to alter dramatically the physical characteristics of Sr2RuO4 (Minakata & Maeno, 2001; Braden et al., 2002), and extensive investigations of electrical resistivity, magnetism, heat capacity and infrared spectroscopy have been reported recently (Pucher et al., 2002). It is therefore important to study the effect of doping on the crystallographic structure.
Sr2RuO4 and its Ti-substituted analogues crystallizes in the so-called K2NiF4-type structure. This structure consists of perovskite monolayers, stacked along the c axis and separated by rock-salt-type layers. The coordination of the Ru atoms is typical for perovskites, consisting of an O-atom octahedron in the first coordination sphere, followed by a cube of eight Sr atoms. For the Sr atoms, the 12-fold cubic–octahedral coordination geometry in perovskites is replaced by a ninefold coordination, which can be described as a capped tetragonal antiprism. The different structural elements are shown in Fig. 1.
The structure refinements converged smoothly and led to small s.u. values for both fractional coordinates and anisotropic displacement parameters. The obtained titanium contents of 7.1 (2) and 19.0 (4)% are close to the expected values of x = 0.1 and 1/5, resepctively, indicating that there was no severe loss of titanium during the growth procedure.
Ti doping leads to a systematic modification of the crystal structure. With increasing Ti content, the cell parameter a increases while c decreases. At the same time, the Ru/Ti—O2 distance decreases, and consequently the elongation of the Ru/TiO6-octahedra is reduced. This result is in agreement with the expected behavior; Ru4+ is a Jahn–Teller-active ion, therefore a significant distortion of the RuO6-octahedra is expected. Ti4+, on the other hand, is not a Jahn-Teller ion. Consequently, a substitution of titanium for ruthenium should reduce the elongation of the octahedra.
The SrO9 unit shows only minor modifications. While the Sr–O1 distance decreases upon Ti doping, the distance of the equatorial O2 atoms (1/2, 1/2, 1/2 − zO2) increases. The interatomic distance to the capping O2 atom (0,0,zO2) also slightly increases. The deviations of the latter three values, on the other hand, are quite small (0.002–0.006 Å) and barely significant within a tolerance range of 3σ.