research papers
Single crystals of Sr2CaWO6 have been prepared by sintering at high temperature. Powder samples were compressed into rods and heated up to 1953 K. This seems a promising new route for further studies of the structure and physical properties of double perovskites. The structural model of Sr2CaWO6 includes a quantitative description of the twinning shown by the diffraction pattern that should be present in almost any single-crystal specimen for this type of compound.
Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108768110002041/ck5040sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108768110002041/ck5040Isup2.hkl |
Computing details top
Program(s) used to refine structure: Jana2000 (Petricek, Dusek & Palatinus, 2000); software used to prepare material for publication: Jana2000 (Petricek, Dusek & Palatinus, 2000).
(I) top
Crystal data top
Ca0.5O3SrW0.5 | Z = 4 |
Mr = 247.6 | F(000) = 436 |
Monoclinic, P21/n | Dx = 5.941 Mg m−3 |
Hall symbol: -P 2yn | Mo Kα radiation, λ = 0.71069 Å |
a = 5.800 (2) Å | µ = 40.83 mm−1 |
b = 5.813 (2) Å | T = 293 K |
c = 8.207 (5) Å | Irregular prism, light orange |
β = 89.966 (5)° | 0.12 × 0.08 × 0.05 mm |
V = 276.7 (2) Å3 |
Data collection top
Stoe IPDS I diffractometer | 566 independent reflections |
Radiation source: sealed X-ray tube | 350 reflections with I > 3σ(I) |
Graphite monochromator | Rint = 0.096 |
150 images at 2o stepwise rotation in phi, 16min./frame scans | θmax = 25.9°, θmin = 4.3° |
Absorption correction: analytical (see. N.W. Alcock (1970). Cryst. Computing, p271) | h = −7→7 |
Tmin = 0.071, Tmax = 0.178 | k = −7→7 |
1910 measured reflections | l = −10→10 |
Refinement top
Refinement on F2 | 12 restraints |
Least-squares matrix: full | Primary atom site location: structure-invariant direct methods |
R[F2 > 2σ(F2)] = 0.042 | Secondary atom site location: difference Fourier map |
wR(F2) = 0.134 | Weighting scheme based on measured s.u.'s w = 1/(σ2(I) + 0.0081I2) |
S = 1.04 | (Δ/σ)max = 0.001 |
566 reflections | Δρmax = 2.32 e Å−3 |
25 parameters | Δρmin = −2.51 e Å−3 |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
x | y | z | Uiso*/Ueq | ||
Sr | 0.0010 (19) | 0.5358 (10) | 0.2502 (10) | 0.0086 (16) | |
Ca | 0 | 0 | 0.5 | 0.0053 (11)* | |
W | 0 | 0 | 0 | 0.0027 (4)* | |
O1 | 0.079 (5) | 0.018 (4) | −0.224 (5) | 0.038 (4)* | |
O2 | 0.277 (3) | −0.169 (4) | 0.042 (3) | 0.038 (4)* | |
O3 | 0.161 (4) | 0.283 (3) | 0.040 (3) | 0.038 (4)* |
Geometric parameters (Å, º) top
Sr—O1i | 2.64 (3) | Ca—O2viii | 2.34 (2) |
Sr—O1ii | 2.48 (3) | W—O1 | 1.90 (4) |
Sr—O3 | 2.45 (3) | W—O1vi | 1.90 (4) |
Sr—O3i | 2.77 (3) | W—O3 | 1.917 (18) |
Sr—O3iii | 2.98 (3) | W—O3vi | 1.917 (18) |
Sr—O2iv | 2.90 (2) | W—O2 | 1.92 (2) |
Sr—O2iii | 2.45 (2) | W—O2vi | 1.92 (2) |
Sr—O2ii | 2.83 (3) | O1—O3 | 2.70 (4) |
Ca—O1v | 2.31 (4) | O1—O3vi | 2.70 (4) |
Ca—O1vi | 2.31 (4) | O1—O2 | 2.70 (4) |
Ca—O3vii | 2.36 (2) | O1—O2vi | 2.70 (4) |
Ca—O3ii | 2.36 (2) | O3—O2 | 2.71 (3) |
Ca—O2iii | 2.34 (2) | O3—O2vi | 2.71 (3) |
O1i—Sr—O1ii | 87.6 (9) | Cax—O1—O2vi | 114.0 (12) |
O1i—Sr—O3 | 126.7 (10) | W—O1—O3 | 45.3 (9) |
O1i—Sr—O3i | 59.8 (9) | W—O1—O3vi | 45.3 (8) |
O1i—Sr—O3iii | 71.9 (8) | W—O1—O2 | 45.3 (9) |
O1i—Sr—O2iv | 58.0 (9) | W—O1—O2vi | 45.3 (8) |
O1i—Sr—O2iii | 128.8 (10) | O3—O1—O3vi | 90.6 (13) |
O1i—Sr—O2ii | 73.7 (10) | O3—O1—O2 | 60.4 (10) |
O1ii—Sr—O1i | 87.6 (9) | O3—O1—O2vi | 60.3 (10) |
O1ii—Sr—O3 | 110.9 (10) | O3vi—O1—O3 | 90.6 (13) |
O1ii—Sr—O3i | 77.7 (10) | O3vi—O1—O2 | 60.3 (10) |
O1ii—Sr—O3iii | 131.5 (10) | O3vi—O1—O2vi | 60.4 (10) |
O1ii—Sr—O2iv | 132.1 (9) | O2—O1—O2vi | 90.6 (13) |
O1ii—Sr—O2iii | 113.4 (10) | O2vi—O1—O2 | 90.6 (13) |
O1ii—Sr—O2ii | 60.7 (10) | Sr—O3—Sri | 104.4 (7) |
O3—Sr—O3i | 75.6 (7) | Sr—O3—Srvii | 97.5 (9) |
O3—Sr—O3iii | 116.6 (8) | Sr—O3—Caiii | 95.2 (7) |
O3—Sr—O2iv | 74.4 (7) | Sr—O3—W | 116.9 (11) |
O3—Sr—O2iii | 90.0 (8) | Sr—O3—O1 | 147.3 (11) |
O3—Sr—O2ii | 159.0 (8) | Sr—O3—O1vi | 78.5 (10) |
O3i—Sr—O3 | 75.6 (7) | Sr—O3—O2 | 132.2 (12) |
O3i—Sr—O3iii | 122.5 (6) | Sr—O3—O2vi | 88.1 (9) |
O3i—Sr—O2iv | 57.0 (6) | Sri—O3—Sr | 104.4 (7) |
O3i—Sr—O2iii | 164.5 (8) | Sri—O3—Srvii | 154.7 (10) |
O3i—Sr—O2ii | 117.9 (7) | Sri—O3—Caiii | 87.7 (8) |
O3iii—Sr—O3 | 116.6 (8) | Sri—O3—W | 90.9 (10) |
O3iii—Sr—O3i | 122.5 (6) | Sri—O3—O1 | 57.8 (8) |
O3iii—Sr—O2iv | 72.1 (7) | Sri—O3—O1vi | 123.7 (11) |
O3iii—Sr—O2iii | 59.0 (7) | Sri—O3—O2 | 117.3 (10) |
O3iii—Sr—O2ii | 71.4 (7) | Sri—O3—O2vi | 64.0 (8) |
O2iv—Sr—O2iii | 114.1 (7) | Srvii—O3—Sr | 97.5 (9) |
O2iv—Sr—O2ii | 126.1 (7) | Srvii—O3—Sri | 154.7 (10) |
O2iii—Sr—O2iv | 114.1 (7) | Srvii—O3—Caiii | 77.8 (7) |
O2iii—Sr—O2ii | 77.6 (7) | Srvii—O3—W | 90.3 (7) |
O2ii—Sr—O2iv | 126.1 (7) | Srvii—O3—O1 | 107.8 (8) |
O2ii—Sr—O2iii | 77.6 (7) | Srvii—O3—O1vi | 72.7 (9) |
O1v—Ca—O1vi | 180 | Srvii—O3—O2 | 50.6 (6) |
O1v—Ca—O3vii | 89.7 (10) | Srvii—O3—O2vi | 130.1 (9) |
O1v—Ca—O3ii | 90.3 (10) | Caiii—O3—W | 147.1 (12) |
O1v—Ca—O2iii | 89.8 (9) | Caiii—O3—O1 | 109.9 (12) |
O1v—Ca—O2viii | 90.2 (9) | Caiii—O3—O1vi | 148.6 (13) |
O1vi—Ca—O1v | 180 | Caiii—O3—O2 | 108.1 (9) |
O1vi—Ca—O3vii | 90.3 (10) | Caiii—O3—O2vi | 151.4 (12) |
O1vi—Ca—O3ii | 89.7 (10) | W—O3—O2vi | 45.1 (7) |
O1vi—Ca—O2iii | 90.2 (9) | O1—O3—O1vi | 89.4 (11) |
O1vi—Ca—O2viii | 89.8 (9) | O1—O3—O2 | 59.8 (9) |
O3vii—Ca—O3ii | 180 | O1—O3—O2vi | 59.8 (9) |
O3vii—Ca—O2iii | 87.6 (7) | O1vi—O3—O1 | 89.4 (11) |
O3vii—Ca—O2viii | 92.4 (7) | O1vi—O3—O2 | 59.8 (8) |
O3ii—Ca—O3vii | 180 | O1vi—O3—O2vi | 59.9 (10) |
O3ii—Ca—O2iii | 92.4 (7) | O2—O3—O2vi | 90 |
O3ii—Ca—O2viii | 87.6 (7) | O2vi—O3—O2 | 90 |
O2iii—Ca—O2viii | 180 | Srxi—O2—Srvii | 99.6 (8) |
O2viii—Ca—O2iii | 180 | Srxi—O2—Srix | 155.9 (10) |
O1—W—O1vi | 180 | Srxi—O2—Cavii | 84.6 (8) |
O1—W—O3 | 90.0 (11) | Srxi—O2—W | 86.9 (7) |
O1—W—O3vi | 90.0 (11) | Srxi—O2—O1 | 118.6 (9) |
O1—W—O2 | 90.0 (11) | Srxi—O2—O1vi | 56.1 (7) |
O1—W—O2vi | 90.0 (11) | Srxi—O2—O3 | 115.9 (9) |
O1vi—W—O1 | 180 | Srxi—O2—O3vi | 59.0 (7) |
O1vi—W—O3 | 90.0 (11) | Srvii—O2—Srxi | 99.6 (8) |
O1vi—W—O3vi | 90.0 (11) | Srvii—O2—Srix | 102.4 (8) |
O1vi—W—O2 | 90.0 (11) | Srvii—O2—Cavii | 102.3 (8) |
O1vi—W—O2vi | 90.0 (11) | Srvii—O2—W | 108.4 (11) |
O3—W—O3vi | 180 | Srvii—O2—O1 | 126.3 (12) |
O3—W—O2 | 90.1 (10) | Srvii—O2—O1vi | 81.8 (10) |
O3—W—O2vi | 89.9 (10) | Srvii—O2—O3 | 70.3 (9) |
O3vi—W—O3 | 180 | Srvii—O2—O3vi | 141.6 (11) |
O3vi—W—O2 | 89.9 (10) | Srix—O2—Srxi | 155.9 (10) |
O3vi—W—O2vi | 90.1 (10) | Srix—O2—Srvii | 102.4 (8) |
O2—W—O2vi | 180 | Srix—O2—Cavii | 81.3 (7) |
O2vi—W—O2 | 180 | Srix—O2—W | 95.3 (10) |
Sri—O1—Srix | 106.9 (10) | Srix—O2—O1 | 53.2 (8) |
Sri—O1—Cax | 86.0 (10) | Srix—O2—O1vi | 136.9 (12) |
Sri—O1—W | 95.3 (12) | Srix—O2—O3 | 81.0 (9) |
Sri—O1—O3 | 62.4 (8) | Srix—O2—O3vi | 106.7 (10) |
Sri—O1—O3vi | 126.3 (13) | Cavii—O2—W | 149.2 (12) |
Sri—O1—O2 | 122.5 (14) | Cavii—O2—O1 | 116.7 (12) |
Sri—O1—O2vi | 65.9 (9) | Cavii—O2—O1vi | 140.4 (12) |
Srix—O1—Sri | 106.9 (10) | Cavii—O2—O3 | 158.8 (11) |
Srix—O1—Cax | 96.1 (12) | Cavii—O2—O3vi | 106.3 (10) |
Srix—O1—W | 108.2 (14) | W—O2—O3vi | 45.1 (5) |
Srix—O1—O3 | 88.1 (11) | O1—O2—O1vi | 89.4 (12) |
Srix—O1—O3vi | 118.3 (12) | O1—O2—O3 | 59.8 (10) |
Srix—O1—O2 | 66.1 (9) | O1—O2—O3vi | 59.8 (9) |
Srix—O1—O2vi | 147.7 (16) | O1vi—O2—O1 | 89.4 (12) |
Cax—O1—W | 154.0 (15) | O1vi—O2—O3 | 59.8 (9) |
Cax—O1—O3 | 147.9 (12) | O1vi—O2—O3vi | 59.9 (9) |
Cax—O1—O3vi | 114.6 (12) | O3—O2—O3vi | 90 |
Cax—O1—O2 | 149.0 (13) | O3vi—O2—O3 | 90 |
Symmetry codes: (i) −x, −y+1, −z; (ii) x−1/2, −y+1/2, z+1/2; (iii) −x+1/2, y+1/2, −z+1/2; (iv) x, y+1, z; (v) x, y, z+1; (vi) −x, −y, −z; (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, y, z−1; (xi) x, y−1, z. |