Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270111005889/fn3073sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270111005889/fn3073Isup2.hkl |
For related literature, see: Brown (1996); Fornasini & Palenzona (1983); Gulay & Daszkiewicz (2011); Ijjaali et al. (2004); Julien-Pouzol & Guittard (1968); Julien-Pouzol & Guittard (1972); Julien-Pouzol et al. (1985); Mitchell & Ibers (2002); Sheldrick (2008); Spek (2009); Wiberg (1995).
The sample of composition La3Cu4.88Se7 was prepared by melting of high-purity (better than 99.9 wt%) elements in an evacuated silica tube. The ampoule was heated at a rate of 30 K h-1 in a tube furnace to a temperature of 1420 K and kept at this temperature for 3 h. Afterwards the ampoule was cooled slowly (at a rate of 10 K h-1) to 870 K and annealed at this temperature for 720 h. After annealing, the sample was quenched in air. A diffraction-quality single crystal was selected from the sample.
Two positions for La, six for Cu and four for Se were determined. The site-occupancy factor for each Cu position was refined as a free parameter. Attempts to use a SUMP restraint to make the total number of Cu atoms integral always resulted in non-positive definite anisotropic displacement parameters. The structure was checked with PLATON (Spek, 2009) and no additional symmetry elements were found.
Data collection: CrysAlis (Oxford Diffraction, 2007); cell refinement: CrysAlis (Oxford Diffraction, 2007); data reduction: CrysAlis (Oxford Diffraction, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2009); software used to prepare material for publication: publCIF (Westrip, 2010).
La3Cu4.88Se7 | F(000) = 2202 |
Mr = 1279.53 | Dx = 6.516 Mg m−3 |
Orthorhombic, Pnma | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ac 2n | Cell parameters from 1058 reflections |
a = 7.6785 (11) Å | θ = 3.1–27.5° |
b = 24.523 (3) Å | µ = 36.88 mm−1 |
c = 6.9265 (10) Å | T = 295 K |
V = 1304.3 (3) Å3 | Prism, black |
Z = 4 | 0.06 × 0.06 × 0.03 mm |
Kuma KM-4 with CCD area-detector diffractometer | 1518 independent reflections |
Radiation source: fine-focus sealed tube | 1058 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.102 |
Detector resolution: 1024x1024 with blocks 2x2, 33.133pixel/mm pixels mm-1 | θmax = 27.5°, θmin = 3.1° |
ω scans | h = −9→9 |
Absorption correction: numerical (CrysAlis; Oxford Diffraction, 2007) | k = −31→31 |
Tmin = 0.110, Tmax = 0.384 | l = −8→8 |
13882 measured reflections |
Refinement on F2 | 0 restraints |
Least-squares matrix: full | Primary atom site location: structure-invariant direct methods |
R[F2 > 2σ(F2)] = 0.041 | Secondary atom site location: difference Fourier map |
wR(F2) = 0.051 | w = 1/[σ2(Fo2) + (0.005P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.01 | (Δ/σ)max < 0.001 |
1518 reflections | Δρmax = 2.36 e Å−3 |
99 parameters | Δρmin = −1.56 e Å−3 |
La3Cu4.88Se7 | V = 1304.3 (3) Å3 |
Mr = 1279.53 | Z = 4 |
Orthorhombic, Pnma | Mo Kα radiation |
a = 7.6785 (11) Å | µ = 36.88 mm−1 |
b = 24.523 (3) Å | T = 295 K |
c = 6.9265 (10) Å | 0.06 × 0.06 × 0.03 mm |
Kuma KM-4 with CCD area-detector diffractometer | 1518 independent reflections |
Absorption correction: numerical (CrysAlis; Oxford Diffraction, 2007) | 1058 reflections with I > 2σ(I) |
Tmin = 0.110, Tmax = 0.384 | Rint = 0.102 |
13882 measured reflections |
R[F2 > 2σ(F2)] = 0.041 | 99 parameters |
wR(F2) = 0.051 | 0 restraints |
S = 1.01 | Δρmax = 2.36 e Å−3 |
1518 reflections | Δρmin = −1.56 e Å−3 |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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) | |
La1 | 0.46018 (11) | 0.2500 | 0.06060 (14) | 0.0154 (2) | |
La2 | 0.86253 (8) | 0.40400 (3) | 0.06238 (10) | 0.01810 (18) | |
Se1 | 0.15956 (14) | 0.32583 (4) | 0.17598 (15) | 0.0136 (3) | |
Se2 | 0.80196 (18) | 0.2500 | 0.8402 (2) | 0.0162 (4) | |
Se3 | 0.52329 (13) | 0.38421 (5) | 0.84856 (16) | 0.0194 (3) | |
Se4 | 0.18567 (14) | 0.47656 (5) | 0.13470 (16) | 0.0194 (3) | |
Cu1 | 0.7505 (11) | 0.4402 (6) | 0.6517 (14) | 0.051 (5) | 0.215 (8) |
Cu2 | 0.7424 (5) | 0.3983 (3) | 0.5779 (8) | 0.027 (2) | 0.347 (7) |
Cu3 | 0.7208 (4) | 0.33687 (14) | 0.6662 (4) | 0.0287 (14) | 0.469 (5) |
Cu4 | 0.5874 (4) | 0.29581 (15) | 0.6447 (4) | 0.0393 (14) | 0.528 (5) |
Cu5 | 0.5543 (3) | 0.47845 (8) | 0.7816 (4) | 0.0741 (13) | 0.880 (6) |
U11 | U22 | U33 | U12 | U13 | U23 | |
La1 | 0.0105 (5) | 0.0224 (6) | 0.0133 (5) | 0.000 | −0.0013 (4) | 0.000 |
La2 | 0.0130 (3) | 0.0206 (4) | 0.0207 (4) | 0.0000 (3) | −0.0009 (3) | 0.0014 (4) |
Se1 | 0.0117 (5) | 0.0149 (6) | 0.0141 (6) | −0.0003 (5) | −0.0005 (5) | −0.0004 (5) |
Se2 | 0.0104 (9) | 0.0235 (11) | 0.0146 (9) | 0.000 | 0.0024 (7) | 0.000 |
Se3 | 0.0171 (6) | 0.0219 (7) | 0.0192 (7) | −0.0042 (5) | −0.0054 (5) | 0.0033 (5) |
Se4 | 0.0151 (6) | 0.0175 (7) | 0.0257 (7) | 0.0003 (5) | −0.0050 (5) | 0.0003 (5) |
Cu1 | 0.052 (6) | 0.070 (11) | 0.032 (6) | 0.011 (5) | −0.022 (4) | 0.006 (6) |
Cu2 | 0.015 (2) | 0.040 (5) | 0.027 (3) | 0.004 (2) | −0.006 (2) | 0.000 (3) |
Cu3 | 0.031 (2) | 0.036 (3) | 0.019 (2) | 0.0141 (16) | 0.0021 (15) | −0.0061 (16) |
Cu4 | 0.024 (2) | 0.069 (3) | 0.025 (2) | 0.0088 (17) | 0.0080 (13) | 0.0242 (18) |
Cu5 | 0.0709 (18) | 0.0292 (16) | 0.122 (2) | −0.0232 (12) | −0.0733 (16) | 0.0306 (14) |
La1—Se1i | 3.0217 (13) | Se3—La2xiv | 3.0354 (12) |
La1—Se1ii | 3.0217 (13) | Se3—La2iii | 3.1403 (13) |
La1—Se2iii | 3.0306 (18) | Se4—Cu1iii | 2.232 (8) |
La1—Se2iv | 3.0359 (17) | Se4—Cu5xvi | 2.354 (2) |
La1—Se1v | 3.0700 (13) | Se4—Cu5xvii | 2.376 (2) |
La1—Se1 | 3.0700 (13) | Se4—Cu2iii | 2.458 (5) |
La1—Cu3vi | 3.222 (3) | Se4—Cu1xvi | 2.569 (15) |
La1—Cu3iii | 3.222 (3) | Se4—La2iii | 3.0680 (14) |
La1—Cu4vii | 3.243 (3) | Se4—La2xi | 3.0941 (13) |
La1—Cu4iv | 3.243 (3) | Se4—La2ix | 3.2528 (13) |
La1—Cu4vi | 3.388 (3) | Cu1—Cu2 | 1.148 (11) |
La1—Cu4iii | 3.388 (3) | Cu1—Cu5 | 1.990 (11) |
La2—Se3iv | 3.0354 (12) | Cu1—Se4i | 2.232 (8) |
La2—Se1i | 3.0640 (13) | Cu1—Se3xii | 2.504 (10) |
La2—Se4i | 3.0680 (13) | Cu1—Cu3 | 2.545 (15) |
La2—Cu2i | 3.078 (4) | Cu1—Cu5xii | 2.557 (10) |
La2—Se1viii | 3.0816 (13) | Cu1—Se4xvi | 2.569 (15) |
La2—Se4viii | 3.0941 (13) | Cu1—La2xiv | 3.101 (8) |
La2—Cu1iv | 3.101 (8) | Cu1—La2iii | 3.444 (10) |
La2—Se3i | 3.1403 (13) | Cu2—Cu3 | 1.635 (7) |
La2—Se4ix | 3.2528 (13) | Cu2—Se3xii | 2.243 (4) |
La2—Cu5x | 3.320 (2) | Cu2—Se4i | 2.458 (5) |
La2—Cu5i | 3.343 (2) | Cu2—Se1i | 2.580 (7) |
La2—Cu3iv | 3.380 (3) | Cu2—Cu5 | 2.818 (7) |
Se1—Cu4iii | 2.405 (3) | Cu2—Cu4 | 2.820 (7) |
Se1—Cu3iii | 2.431 (3) | Cu2—La2iii | 3.078 (4) |
Se1—Cu2iii | 2.580 (7) | Cu2—La2xiv | 3.483 (5) |
Se1—La1iii | 3.0217 (13) | Cu3—Cu4 | 1.444 (4) |
Se1—La2iii | 3.0640 (13) | Cu3—Se1i | 2.431 (3) |
Se1—La2xi | 3.0816 (13) | Cu3—Se3xii | 2.599 (4) |
Se2—Cu4v | 2.410 (3) | Cu3—La1i | 3.222 (3) |
Se2—Cu4 | 2.410 (3) | Cu3—La2xiv | 3.380 (3) |
Se2—Cu4xii | 2.465 (3) | Cu3—La2iii | 3.576 (3) |
Se2—Cu4xiii | 2.465 (3) | Cu4—Cu4v | 2.247 (7) |
Se2—Cu3v | 2.526 (3) | Cu4—Se1i | 2.405 (3) |
Se2—Cu3 | 2.526 (3) | Cu4—Se2xv | 2.465 (3) |
Se2—La1i | 3.0306 (18) | Cu4—La1xiv | 3.243 (3) |
Se2—La1xiv | 3.0359 (17) | Cu4—La1i | 3.388 (3) |
Se3—Cu2xv | 2.243 (4) | Cu4—La2iii | 3.476 (3) |
Se3—Cu3 | 2.290 (3) | Cu5—Se4xvi | 2.354 (2) |
Se3—Cu5 | 2.369 (2) | Cu5—Se4xviii | 2.376 (2) |
Se3—Cu1xv | 2.504 (10) | Cu5—Cu1xv | 2.557 (10) |
Se3—Cu2 | 2.543 (5) | Cu5—Cu5xix | 3.311 (6) |
Se3—Cu3xv | 2.599 (4) | Cu5—La2xx | 3.320 (2) |
Se3—Cu1 | 2.605 (10) | Cu5—La2iii | 3.343 (2) |
Se3—Cu4 | 2.634 (4) | Cu5—La2xiv | 3.566 (2) |
Se1i—La1—Se1ii | 75.96 (5) | Cu1xvi—Se4—La2iii | 89.0 (2) |
Se1i—La1—Se2iii | 139.14 (3) | Cu1iii—Se4—La2xi | 78.7 (3) |
Se1ii—La1—Se2iii | 139.14 (3) | Cu5xvi—Se4—La2xi | 171.77 (7) |
Se1i—La1—Se2iv | 82.28 (4) | Cu5xvii—Se4—La2xi | 73.42 (6) |
Se1ii—La1—Se2iv | 82.28 (4) | Cu2iii—Se4—La2xi | 66.19 (10) |
Se2iii—La1—Se2iv | 83.45 (3) | Cu1xvi—Se4—La2xi | 134.7 (2) |
Se1i—La1—Se1v | 126.62 (4) | La2iii—Se4—La2xi | 97.59 (4) |
Se1ii—La1—Se1v | 81.43 (3) | Cu1iii—Se4—La2ix | 90.7 (4) |
Se2iii—La1—Se1v | 86.39 (4) | Cu5xvi—Se4—La2ix | 77.16 (6) |
Se2iv—La1—Se1v | 141.34 (3) | Cu5xvii—Se4—La2ix | 70.94 (6) |
Se1i—La1—Se1 | 81.43 (3) | Cu2iii—Se4—La2ix | 118.14 (17) |
Se1ii—La1—Se1 | 126.62 (4) | Cu1xvi—Se4—La2ix | 63.1 (2) |
Se2iii—La1—Se1 | 86.39 (4) | La2iii—Se4—La2ix | 149.28 (4) |
Se2iv—La1—Se1 | 141.34 (3) | La2xi—Se4—La2ix | 111.02 (4) |
Se1v—La1—Se1 | 74.56 (5) | Cu2—Cu1—Cu5 | 125.6 (7) |
Se1i—La1—Cu3vi | 171.95 (7) | Cu2—Cu1—Se4i | 87.1 (6) |
Se1ii—La1—Cu3vi | 100.17 (7) | Cu5—Cu1—Se4i | 92.6 (4) |
Se2iii—La1—Cu3vi | 47.53 (6) | Cu2—Cu1—Se3xii | 63.6 (5) |
Se2iv—La1—Cu3vi | 104.36 (7) | Cu5—Cu1—Se3xii | 153.1 (4) |
Se1v—La1—Cu3vi | 45.38 (6) | Se4i—Cu1—Se3xii | 113.9 (4) |
Se1—La1—Cu3vi | 95.65 (7) | Cu2—Cu1—Cu3 | 28.7 (4) |
Se1i—La1—Cu3iii | 100.17 (7) | Cu5—Cu1—Cu3 | 112.6 (4) |
Se1ii—La1—Cu3iii | 171.95 (7) | Se4i—Cu1—Cu3 | 114.4 (5) |
Se2iii—La1—Cu3iii | 47.53 (6) | Se3xii—Cu1—Cu3 | 61.9 (3) |
Se2iv—La1—Cu3iii | 104.36 (7) | Cu2—Cu1—Cu5xii | 117.2 (6) |
Se1v—La1—Cu3iii | 95.65 (7) | Cu5—Cu1—Cu5xii | 115.8 (6) |
Se1—La1—Cu3iii | 45.38 (6) | Se4i—Cu1—Cu5xii | 102.5 (4) |
Cu3vi—La1—Cu3iii | 82.76 (13) | Se3xii—Cu1—Cu5xii | 55.82 (17) |
Se1i—La1—Cu4vii | 126.65 (6) | Cu3—Cu1—Cu5xii | 116.1 (4) |
Se1ii—La1—Cu4vii | 99.82 (7) | Cu2—Cu1—Se4xvi | 167.7 (6) |
Se2iii—La1—Cu4vii | 46.13 (6) | Cu5—Cu1—Se4xvi | 60.6 (4) |
Se2iv—La1—Cu4vii | 45.00 (6) | Se4i—Cu1—Se4xvi | 103.7 (5) |
Se1v—La1—Cu4vii | 104.36 (6) | Se3xii—Cu1—Se4xvi | 106.0 (3) |
Se1—La1—Cu4vii | 131.89 (7) | Cu3—Cu1—Se4xvi | 141.8 (4) |
Cu3vi—La1—Cu4vii | 60.65 (7) | Cu5xii—Cu1—Se4xvi | 55.2 (3) |
Cu3iii—La1—Cu4vii | 88.16 (9) | Cu2—Cu1—Se3 | 74.1 (6) |
Se1i—La1—Cu4iv | 99.82 (7) | Cu5—Cu1—Se3 | 60.3 (2) |
Se1ii—La1—Cu4iv | 126.65 (6) | Se4i—Cu1—Se3 | 121.8 (4) |
Se2iii—La1—Cu4iv | 46.13 (6) | Se3xii—Cu1—Se3 | 105.8 (4) |
Se2iv—La1—Cu4iv | 45.00 (6) | Cu3—Cu1—Se3 | 52.8 (3) |
Se1v—La1—Cu4iv | 131.89 (7) | Cu5xii—Cu1—Se3 | 135.2 (3) |
Se1—La1—Cu4iv | 104.36 (6) | Se4xvi—Cu1—Se3 | 104.2 (4) |
Cu3vi—La1—Cu4iv | 88.16 (9) | Cu2—Cu1—La2xiv | 99.6 (6) |
Cu3iii—La1—Cu4iv | 60.65 (7) | Cu5—Cu1—La2xiv | 86.0 (3) |
Cu4vii—La1—Cu4iv | 40.54 (13) | Se4i—Cu1—La2xiv | 172.6 (6) |
Se1i—La1—Cu4vi | 152.32 (7) | Se3xii—Cu1—La2xiv | 67.17 (19) |
Se1ii—La1—Cu4vi | 118.52 (6) | Cu3—Cu1—La2xiv | 72.8 (2) |
Se2iii—La1—Cu4vi | 43.68 (5) | Cu5xii—Cu1—La2xiv | 71.7 (2) |
Se2iv—La1—Cu4vi | 121.29 (6) | Se4xvi—Cu1—La2xiv | 69.3 (2) |
Se1v—La1—Cu4vi | 43.38 (5) | Se3—Cu1—La2xiv | 63.58 (19) |
Se1—La1—Cu4vi | 71.03 (7) | Cu2—Cu1—La2iii | 62.1 (4) |
Cu3vi—La1—Cu4vi | 25.07 (8) | Cu5—Cu1—La2iii | 70.2 (2) |
Cu3iii—La1—Cu4vi | 62.14 (10) | Se4i—Cu1—La2iii | 61.8 (2) |
Cu4vii—La1—Cu4vi | 76.52 (5) | Se3xii—Cu1—La2iii | 125.6 (5) |
Cu4iv—La1—Cu4vi | 89.80 (6) | Cu3—Cu1—La2iii | 71.5 (3) |
Se1i—La1—Cu4iii | 118.52 (6) | Cu5xii—Cu1—La2iii | 164.1 (3) |
Se1ii—La1—Cu4iii | 152.32 (7) | Se4xvi—Cu1—La2iii | 128.2 (4) |
Se2iii—La1—Cu4iii | 43.68 (5) | Se3—Cu1—La2iii | 60.7 (2) |
Se2iv—La1—Cu4iii | 121.29 (6) | La2xiv—Cu1—La2iii | 124.1 (3) |
Se1v—La1—Cu4iii | 71.03 (7) | Cu1—Cu2—Cu3 | 131.5 (6) |
Se1—La1—Cu4iii | 43.38 (5) | Cu1—Cu2—Se3xii | 89.2 (5) |
Cu3vi—La1—Cu4iii | 62.14 (10) | Cu3—Cu2—Se3xii | 82.6 (2) |
Cu3iii—La1—Cu4iii | 25.07 (8) | Cu1—Cu2—Se4i | 65.1 (5) |
Cu4vii—La1—Cu4iii | 89.80 (6) | Cu3—Cu2—Se4i | 157.8 (3) |
Cu4iv—La1—Cu4iii | 76.52 (5) | Se3xii—Cu2—Se4i | 115.3 (2) |
Cu4vi—La1—Cu4iii | 38.73 (12) | Cu1—Cu2—Se3 | 80.2 (5) |
Se3iv—La2—Se1i | 75.64 (3) | Cu3—Cu2—Se3 | 62.07 (17) |
Se3iv—La2—Se4i | 92.67 (3) | Se3xii—Cu2—Se3 | 116.62 (19) |
Se1i—La2—Se4i | 74.53 (3) | Se4i—Cu2—Se3 | 115.5 (2) |
Se3iv—La2—Cu2i | 130.69 (9) | Cu1—Cu2—Se1i | 158.8 (5) |
Se1i—La2—Cu2i | 129.83 (14) | Cu3—Cu2—Se1i | 66.1 (3) |
Se4i—La2—Cu2i | 131.43 (10) | Se3xii—Cu2—Se1i | 106.6 (2) |
Se3iv—La2—Se1viii | 131.32 (4) | Se4i—Cu2—Se1i | 94.91 (17) |
Se1i—La2—Se1viii | 80.57 (3) | Se3—Cu2—Se1i | 104.21 (19) |
Se4i—La2—Se1viii | 120.91 (4) | Cu1—Cu2—Cu5 | 35.0 (5) |
Cu2i—La2—Se1viii | 49.54 (14) | Cu3—Cu2—Cu5 | 113.8 (2) |
Se3iv—La2—Se4viii | 149.22 (4) | Se3xii—Cu2—Cu5 | 119.1 (3) |
Se1i—La2—Se4viii | 132.22 (4) | Se4i—Cu2—Cu5 | 70.41 (17) |
Se4i—La2—Se4viii | 84.88 (3) | Se3—Cu2—Cu5 | 52.15 (12) |
Cu2i—La2—Se4viii | 46.93 (10) | Se1i—Cu2—Cu5 | 134.05 (15) |
Se1viii—La2—Se4viii | 73.91 (3) | Cu1—Cu2—Cu4 | 138.3 (6) |
Se3iv—La2—Cu1iv | 50.22 (18) | Cu3—Cu2—Cu4 | 22.15 (15) |
Se1i—La2—Cu1iv | 125.5 (2) | Se3xii—Cu2—Cu4 | 103.4 (2) |
Se4i—La2—Cu1iv | 109.8 (2) | Se4i—Cu2—Cu4 | 136.0 (2) |
Cu2i—La2—Cu1iv | 89.22 (18) | Se3—Cu2—Cu4 | 58.56 (12) |
Se1viii—La2—Cu1iv | 128.1 (2) | Se1i—Cu2—Cu4 | 52.66 (14) |
Se4viii—La2—Cu1iv | 101.9 (2) | Cu5—Cu2—Cu4 | 108.86 (15) |
Se3iv—La2—Se3i | 82.55 (2) | Cu1—Cu2—La2iii | 98.7 (5) |
Se1i—La2—Se3i | 129.74 (4) | Cu3—Cu2—La2iii | 93.6 (2) |
Se4i—La2—Se3i | 152.07 (4) | Se3xii—Cu2—La2iii | 171.9 (3) |
Cu2i—La2—Se3i | 48.26 (9) | Se4i—Cu2—La2iii | 66.88 (10) |
Se1viii—La2—Se3i | 81.05 (3) | Se3—Cu2—La2iii | 67.15 (9) |
Se4viii—La2—Se3i | 85.43 (3) | Se1i—Cu2—La2iii | 65.31 (12) |
Cu1iv—La2—Se3i | 47.3 (2) | Cu5—Cu2—La2iii | 68.93 (10) |
Se3iv—La2—Se4ix | 80.89 (3) | Cu4—Cu2—La2iii | 72.07 (13) |
Se1i—La2—Se4ix | 138.92 (4) | Cu1—Cu2—La2xiv | 61.4 (5) |
Se4i—La2—Se4ix | 73.40 (2) | Cu3—Cu2—La2xiv | 72.8 (2) |
Cu2i—La2—Se4ix | 90.92 (14) | Se3xii—Cu2—La2xiv | 62.15 (12) |
Se1viii—La2—Se4ix | 138.73 (3) | Se4i—Cu2—La2xiv | 126.4 (3) |
Se4viii—La2—Se4ix | 68.98 (4) | Se3—Cu2—La2xiv | 58.02 (11) |
Cu1iv—La2—Se4ix | 47.6 (3) | Se1i—Cu2—La2xiv | 138.6 (2) |
Se3i—La2—Se4ix | 78.67 (4) | Cu5—Cu2—La2xiv | 68.01 (14) |
Se3iv—La2—Cu5x | 121.81 (5) | Cu4—Cu2—La2xiv | 89.39 (13) |
Se1i—La2—Cu5x | 111.75 (5) | La2iii—Cu2—La2xiv | 123.60 (15) |
Se4i—La2—Cu5x | 43.02 (4) | Cu4—Cu3—Cu2 | 132.6 (3) |
Cu2i—La2—Cu5x | 90.08 (11) | Cu4—Cu3—Se3 | 86.61 (19) |
Se1viii—La2—Cu5x | 106.31 (6) | Cu2—Cu3—Se3 | 78.8 (2) |
Se4viii—La2—Cu5x | 43.31 (4) | Cu4—Cu3—Se1i | 71.62 (17) |
Cu1iv—La2—Cu5x | 103.0 (3) | Cu2—Cu3—Se1i | 76.0 (2) |
Se3i—La2—Cu5x | 118.24 (5) | Se3—Cu3—Se1i | 117.79 (13) |
Se4ix—La2—Cu5x | 55.39 (5) | Cu4—Cu3—Se2 | 68.65 (18) |
Se3iv—La2—Cu5i | 96.75 (5) | Cu2—Cu3—Se2 | 158.6 (2) |
Se1i—La2—Cu5i | 170.81 (5) | Se3—Cu3—Se2 | 109.13 (13) |
Se4i—La2—Cu5i | 111.44 (5) | Se1i—Cu3—Se2 | 114.78 (13) |
Cu2i—La2—Cu5i | 51.86 (14) | Cu4—Cu3—Cu1 | 138.9 (3) |
Se1viii—La2—Cu5i | 101.29 (5) | Cu2—Cu3—Cu1 | 19.7 (2) |
Se4viii—La2—Cu5i | 56.51 (5) | Se3—Cu3—Cu1 | 64.9 (2) |
Cu1iv—La2—Cu5i | 46.56 (19) | Se1i—Cu3—Cu1 | 95.2 (2) |
Se3i—La2—Cu5i | 42.72 (4) | Se2—Cu3—Cu1 | 146.7 (2) |
Se4ix—La2—Cu5i | 42.20 (4) | Cu4—Cu3—Se3xii | 160.3 (2) |
Cu5x—La2—Cu5i | 76.53 (7) | Cu2—Cu3—Se3xii | 58.84 (17) |
Se3iv—La2—Cu3iv | 41.39 (5) | Se3—Cu3—Se3xii | 112.78 (14) |
Se1i—La2—Cu3iv | 90.67 (7) | Se1i—Cu3—Se3xii | 100.62 (12) |
Se4i—La2—Cu3iv | 134.04 (6) | Se2—Cu3—Se3xii | 100.08 (11) |
Cu2i—La2—Cu3iv | 91.53 (10) | Cu1—Cu3—Se3xii | 58.3 (2) |
Se1viii—La2—Cu3iv | 98.20 (6) | Cu4—Cu3—La1i | 83.87 (18) |
Se4viii—La2—Cu3iv | 132.05 (7) | Cu2—Cu3—La1i | 111.7 (2) |
Cu1iv—La2—Cu3iv | 46.0 (3) | Se3—Cu3—La1i | 169.07 (16) |
Se3i—La2—Cu3iv | 46.80 (6) | Se1i—Cu3—La1i | 63.99 (7) |
Se4ix—La2—Cu3iv | 93.51 (6) | Se2—Cu3—La1i | 62.25 (7) |
Cu5x—La2—Cu3iv | 148.89 (8) | Cu1—Cu3—La1i | 126.0 (2) |
Cu5i—La2—Cu3iv | 80.16 (7) | Se3xii—Cu3—La1i | 76.49 (8) |
Cu4iii—Se1—Cu2iii | 68.78 (14) | Cu4—Cu3—La2xiv | 130.7 (2) |
Cu4iii—Se1—La1iii | 104.64 (9) | Cu2—Cu3—La2xiv | 79.7 (2) |
Cu3iii—Se1—La1iii | 139.03 (10) | Se3—Cu3—La2xiv | 61.21 (7) |
Cu2iii—Se1—La1iii | 163.84 (10) | Se1i—Cu3—La2xiv | 155.21 (15) |
Cu4iii—Se1—La2iii | 148.76 (10) | Se2—Cu3—La2xiv | 86.78 (9) |
Cu3iii—Se1—La2iii | 114.11 (9) | Cu1—Cu3—La2xiv | 61.2 (2) |
Cu2iii—Se1—La2iii | 81.18 (10) | Se3xii—Cu3—La2xiv | 61.74 (7) |
La1iii—Se1—La2iii | 106.59 (4) | La1i—Cu3—La2xiv | 122.28 (10) |
Cu4iii—Se1—La1 | 75.36 (8) | Cu4—Cu3—La2iii | 74.33 (16) |
Cu3iii—Se1—La1 | 70.63 (8) | Cu2—Cu3—La2iii | 59.22 (16) |
Cu2iii—Se1—La1 | 93.12 (10) | Se3—Cu3—La2iii | 60.09 (7) |
La1iii—Se1—La1 | 99.52 (4) | Se1i—Cu3—La2iii | 58.05 (7) |
La2iii—Se1—La1 | 98.66 (4) | Se2—Cu3—La2iii | 142.14 (13) |
Cu4iii—Se1—La2xi | 77.53 (8) | Cu1—Cu3—La2iii | 66.00 (19) |
Cu3iii—Se1—La2xi | 79.92 (8) | Se3xii—Cu3—La2iii | 117.68 (12) |
Cu2iii—Se1—La2xi | 65.16 (9) | La1i—Cu3—La2iii | 121.83 (9) |
La1iii—Se1—La2xi | 99.33 (4) | La2xiv—Cu3—La2iii | 112.52 (9) |
La2iii—Se1—La2xi | 97.95 (4) | Cu3—Cu4—Cu4v | 134.22 (17) |
La1—Se1—La2xi | 150.09 (4) | Cu3—Cu4—Se1i | 73.64 (17) |
Cu4v—Se2—Cu4 | 55.56 (18) | Cu4v—Cu4—Se1i | 107.83 (9) |
Cu4v—Se2—Cu4xii | 147.54 (8) | Cu3—Cu4—Se2 | 77.44 (17) |
Cu4—Se2—Cu4xii | 114.78 (14) | Cu4v—Cu4—Se2 | 62.22 (9) |
Cu4v—Se2—Cu4xiii | 114.78 (14) | Se1i—Cu4—Se2 | 120.29 (12) |
Cu4—Se2—Cu4xiii | 147.54 (8) | Cu3—Cu4—Se2xv | 160.7 (2) |
Cu4xii—Se2—Cu4xiii | 54.21 (16) | Cu4v—Cu4—Se2xv | 62.89 (8) |
Cu4—Se2—Cu3v | 87.49 (14) | Se1i—Cu4—Se2xv | 112.54 (12) |
Cu4xii—Se2—Cu3v | 128.60 (11) | Se2—Cu4—Se2xv | 111.81 (12) |
Cu4xiii—Se2—Cu3v | 81.68 (12) | Cu3—Cu4—Se3 | 60.22 (17) |
Cu4v—Se2—Cu3 | 87.49 (14) | Cu4v—Cu4—Se3 | 145.40 (7) |
Cu4xii—Se2—Cu3 | 81.68 (12) | Se1i—Cu4—Se3 | 106.64 (13) |
Cu4xiii—Se2—Cu3 | 128.60 (11) | Se2—Cu4—Se3 | 102.13 (12) |
Cu3v—Se2—Cu3 | 115.00 (16) | Se2xv—Cu4—Se3 | 100.72 (10) |
Cu4v—Se2—La1i | 76.06 (8) | Cu3—Cu4—Cu2 | 25.27 (16) |
Cu4—Se2—La1i | 76.06 (8) | Cu4v—Cu4—Cu2 | 153.08 (12) |
Cu4xii—Se2—La1i | 71.48 (7) | Se1i—Cu4—Cu2 | 58.56 (14) |
Cu4xiii—Se2—La1i | 71.48 (7) | Se2—Cu4—Cu2 | 102.66 (14) |
Cu3v—Se2—La1i | 70.22 (7) | Se2xv—Cu4—Cu2 | 142.04 (15) |
Cu3—Se2—La1i | 70.22 (7) | Se3—Cu4—Cu2 | 55.46 (14) |
Cu4v—Se2—La1xiv | 72.05 (8) | Cu3—Cu4—La1xiv | 111.3 (2) |
Cu4—Se2—La1xiv | 72.05 (8) | Cu4v—Cu4—La1xiv | 69.73 (6) |
Cu4xii—Se2—La1xiv | 138.36 (8) | Se1i—Cu4—La1xiv | 174.90 (14) |
Cu4xiii—Se2—La1xiv | 138.36 (8) | Se2—Cu4—La1xiv | 62.95 (7) |
Cu3v—Se2—La1xiv | 91.53 (8) | Se2xv—Cu4—La1xiv | 62.40 (7) |
Cu3—Se2—La1xiv | 91.53 (8) | Se3—Cu4—La1xiv | 75.67 (7) |
La1i—Se2—La1xiv | 143.81 (6) | Cu2—Cu4—La1xiv | 125.57 (16) |
Cu2xv—Se3—Cu3 | 147.17 (16) | Cu3—Cu4—La1i | 71.06 (15) |
Cu2xv—Se3—Cu5 | 89.45 (19) | Cu4v—Cu4—La1i | 70.63 (6) |
Cu3—Se3—Cu5 | 108.67 (12) | Se1i—Cu4—La1i | 61.26 (7) |
Cu3—Se3—Cu1xv | 146.2 (2) | Se2—Cu4—La1i | 60.26 (7) |
Cu5—Se3—Cu1xv | 63.2 (3) | Se2xv—Cu4—La1i | 128.16 (13) |
Cu2xv—Se3—Cu2 | 141.51 (18) | Se3—Cu4—La1i | 131.00 (12) |
Cu5—Se3—Cu2 | 69.91 (17) | Cu2—Cu4—La1i | 82.54 (12) |
Cu1xv—Se3—Cu2 | 118.6 (3) | La1xiv—Cu4—La1i | 120.84 (9) |
Cu3—Se3—Cu3xv | 110.11 (13) | Cu3—Cu4—La2iii | 82.10 (18) |
Cu5—Se3—Cu3xv | 121.18 (9) | Cu4v—Cu4—La2iii | 139.76 (6) |
Cu1xv—Se3—Cu3xv | 59.8 (3) | Se1i—Cu4—La2iii | 59.97 (7) |
Cu2—Se3—Cu3xv | 128.56 (16) | Se2—Cu4—La2iii | 158.01 (15) |
Cu2xv—Se3—Cu1 | 133.0 (4) | Se2xv—Cu4—La2iii | 85.61 (8) |
Cu3—Se3—Cu1 | 62.3 (3) | Se3—Cu4—La2iii | 60.00 (7) |
Cu5—Se3—Cu1 | 46.9 (3) | Cu2—Cu4—La2iii | 57.41 (10) |
Cu1xv—Se3—Cu1 | 105.7 (5) | La1xiv—Cu4—La2iii | 118.77 (9) |
Cu3xv—Se3—Cu1 | 144.4 (2) | La1i—Cu4—La2iii | 119.98 (8) |
Cu2xv—Se3—Cu4 | 115.37 (16) | Cu1—Cu5—Se4xvi | 72.0 (4) |
Cu5—Se3—Cu4 | 132.79 (11) | Cu1—Cu5—Se3 | 72.8 (4) |
Cu1xv—Se3—Cu4 | 127.4 (2) | Se4xvi—Cu5—Se3 | 119.61 (9) |
Cu2—Se3—Cu4 | 65.98 (18) | Cu1—Cu5—Se4xviii | 127.8 (3) |
Cu3xv—Se3—Cu4 | 77.19 (10) | Se4xvi—Cu5—Se4xviii | 123.06 (10) |
Cu1—Se3—Cu4 | 91.6 (3) | Se3—Cu5—Se4xviii | 117.32 (8) |
Cu2xv—Se3—La2xiv | 133.61 (13) | Cu1—Cu5—Cu1xv | 126.8 (6) |
Cu3—Se3—La2xiv | 77.40 (9) | Se4xvi—Cu5—Cu1xv | 154.4 (2) |
Cu5—Se3—La2xiv | 81.57 (5) | Se3—Cu5—Cu1xv | 61.0 (3) |
Cu1xv—Se3—La2xiv | 129.1 (2) | Se4xviii—Cu5—Cu1xv | 62.6 (3) |
Cu2—Se3—La2xiv | 76.70 (11) | Cu1—Cu5—Cu2 | 19.3 (3) |
Cu3xv—Se3—La2xiv | 149.05 (8) | Se4xvi—Cu5—Cu2 | 90.87 (13) |
Cu1—Se3—La2xiv | 66.20 (19) | Se3—Cu5—Cu2 | 57.93 (12) |
Cu4—Se3—La2xiv | 103.46 (7) | Se4xviii—Cu5—Cu2 | 120.46 (13) |
Cu2xv—Se3—La2iii | 78.69 (15) | Cu1xv—Cu5—Cu2 | 107.6 (3) |
Cu3—Se3—La2iii | 80.71 (9) | Cu1—Cu5—La2xx | 93.3 (3) |
Cu5—Se3—La2iii | 73.22 (6) | Se4xvi—Cu5—La2xx | 62.77 (5) |
Cu1xv—Se3—La2iii | 65.5 (2) | Se3—Cu5—La2xx | 162.89 (12) |
Cu2—Se3—La2iii | 64.59 (10) | Se4xviii—Cu5—La2xx | 63.27 (5) |
Cu3xv—Se3—La2iii | 71.46 (7) | Cu1xv—Cu5—La2xx | 125.2 (3) |
Cu1—Se3—La2iii | 72.99 (19) | Cu2—Cu5—La2xx | 106.13 (13) |
Cu4—Se3—La2iii | 73.43 (7) | Cu1—Cu5—La2iii | 75.7 (3) |
La2xiv—Se3—La2iii | 139.01 (4) | Se4xvi—Cu5—La2iii | 143.61 (12) |
Cu1iii—Se4—Cu5xvi | 102.5 (3) | Se3—Cu5—La2iii | 64.06 (5) |
Cu1iii—Se4—Cu5xvii | 137.7 (2) | Se4xviii—Cu5—La2iii | 66.86 (5) |
Cu5xvi—Se4—Cu5xvii | 109.55 (8) | Cu1xv—Cu5—La2iii | 61.73 (19) |
Cu5xvi—Se4—Cu2iii | 111.29 (12) | Cu2—Cu5—La2iii | 59.21 (11) |
Cu5xvii—Se4—Cu2iii | 139.16 (11) | La2xx—Cu5—La2iii | 103.47 (7) |
Cu1iii—Se4—Cu1xvi | 141.9 (3) | Cu1—Cu5—La2xiv | 60.2 (2) |
Cu5xvi—Se4—Cu1xvi | 47.44 (19) | Se4xvi—Cu5—La2xiv | 62.78 (5) |
Cu5xvii—Se4—Cu1xvi | 62.12 (19) | Se3—Cu5—La2xiv | 57.35 (5) |
Cu2iii—Se4—Cu1xvi | 158.7 (2) | Se4xviii—Cu5—La2xiv | 170.33 (11) |
Cu1iii—Se4—La2iii | 106.1 (3) | Cu1xv—Cu5—La2xiv | 108.6 (3) |
Cu5xvi—Se4—La2iii | 74.21 (6) | Cu2—Cu5—La2xiv | 64.89 (10) |
Cu5xvii—Se4—La2iii | 108.63 (8) | La2xx—Cu5—La2xiv | 124.48 (6) |
Cu2iii—Se4—La2iii | 83.03 (15) | La2iii—Cu5—La2xiv | 113.66 (7) |
Symmetry codes: (i) x+1/2, y, −z+1/2; (ii) x+1/2, −y+1/2, −z+1/2; (iii) x−1/2, y, −z+1/2; (iv) x, y, z−1; (v) x, −y+1/2, z; (vi) x−1/2, −y+1/2, −z+1/2; (vii) x, −y+1/2, z−1; (viii) x+1, y, z; (ix) −x+1, −y+1, −z; (x) −x+3/2, −y+1, z−1/2; (xi) x−1, y, z; (xii) x+1/2, y, −z+3/2; (xiii) x+1/2, −y+1/2, −z+3/2; (xiv) x, y, z+1; (xv) x−1/2, y, −z+3/2; (xvi) −x+1, −y+1, −z+1; (xvii) −x+1/2, −y+1, z−1/2; (xviii) −x+1/2, −y+1, z+1/2; (xix) −x+1, −y+1, −z+2; (xx) −x+3/2, −y+1, z+1/2. |
Experimental details
Crystal data | |
Chemical formula | La3Cu4.88Se7 |
Mr | 1279.53 |
Crystal system, space group | Orthorhombic, Pnma |
Temperature (K) | 295 |
a, b, c (Å) | 7.6785 (11), 24.523 (3), 6.9265 (10) |
V (Å3) | 1304.3 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 36.88 |
Crystal size (mm) | 0.06 × 0.06 × 0.03 |
Data collection | |
Diffractometer | Kuma KM-4 with CCD area-detector diffractometer |
Absorption correction | Numerical (CrysAlis; Oxford Diffraction, 2007) |
Tmin, Tmax | 0.110, 0.384 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 13882, 1518, 1058 |
Rint | 0.102 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.041, 0.051, 1.01 |
No. of reflections | 1518 |
No. of parameters | 99 |
Δρmax, Δρmin (e Å−3) | 2.36, −1.56 |
Computer programs: CrysAlis (Oxford Diffraction, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2009), publCIF (Westrip, 2010).
Atom | CN | BVS | atom | CN | BVS |
Cu1 | 3 | 1.103 | Cu4 | 3 | 1.041 |
Cu1 | 4 | 1.317 | Cu4 | 4 | 1.238 |
Cu2 | 3 | 1.139 | Cu5 | 2 | 0.825 |
Cu2 | 4 | 1.368 | Cu5 | 3 | 1.221 |
Cu3 | 3 | 1.107 | La1 | 6 | 2.845 |
Cu3 | 4 | 1.324 | La2 | 7 | 2.835 |
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The design of functional materials with increasingly complex compositions has become a primary direction in modern science and technology. Among multicomponent systems much attention has been paid to complex rare-earth-based chalcogenides, owing to their specific thermal, electrical, magnetic and optical properties. An example is prospective applications of various chalcogenide materials in the field of infrared and nonlinear optics (Gulay & Daszkiewicz, 2011; Mitchell & Ibers, 2002).
So far, only La5CuSe8 and LaCuSe2 have been synthesized from the La2Se3–Cu2Se system (Julien-Pouzol & Guittard, 1968; Ijjaali et al., 2004) and been fully characterized. They crystallize in space groups I43d and P21/c, respectively. Julien-Pouzol & Guittard (1972) reported the existence of crystals of a compound with orthorhombic symmetry. Lattice parameters a = 7.74 Å, b = 24.67 Å, c = 7.01 Å were determined using the Weissenberg method and a formula La5Cu13Se14 was proposed. However, its crystal structure was never reported until now.
The asymmetric unit of La3Cu4.88Se7 contains two La sites, five Cu sites and four Se sites. The site of each copper atom is partially occupied. The non-stoichiometry here can be explained by the presence of mixed-valence CuI/CuII. The La1 and Se2 atoms lie on a mirror plane. Each of the formally LaIII and Cu atoms is surrounded by four Se2– anions at distances that agree well with the sum of the respective ionic radii (Wiberg, 1995). The selenium atoms form a distorted trigonal prism around the La1 atom and a distorted mono-capped trigonal prism around the La2 atom. Two trigonal prisms centred by La1 are surrounded on two sides by two mono-capped trigonal prisms centred by La2. These six trigonal prisms (2La1 + 4La2) form a large structural building block [La6Se28] which is related by inversion (Fig. 1). Since each lanthanum atom is connected to the adjacent lanthanum atom by two bridging selenium atoms, the crystal lattice is built by the edge-sharing [LaSe6] and [LaSe7] polyhedra. On the other hand, the Se atoms exhibit distorted tetrahedral coordination around the Cu1 to Cu4 atoms. The remaining Cu5 atom has triangular surroundings and it is located very close to the plane built by three Se atoms.
Overall, the crystal structure of La3Cu4.88Se7 is structurally related to Pt3Sr7 (Fornasini & Palenzona, 1983; ICSD, 2010) (Fig. 1). In Pt3Sr7, the Pt1 atom is surrounded by seven Sr atoms which form a mono-capped trigonal prism [PtSr7], and each Pt2 atom is surrounded by six Sr atoms which form a trigonal prism [PtSr6]. Those polyhedra are connected to each other by edges creating a Pt6Sr28 building block. Since the position of platinum and strontium atoms corresponds to the position of lanthanum and selenium ions in the title compound, an identical building block of [La6Se28] exists in La3Cu4.88Se7. Furthermore, since this building block is created by edge-sharing polyhedra, voids exist inside the block near the faces of [LaSe6] and [LaSe7] polyhedra. These voids are filled by the copper ions, because Cu+ has a relatively small ionic radius and the [La6Se28] building block is deficient in positive charge. So it appears that the role of voids in the stiff structural base of [La6Se28] is as important as the copper ions occupying disordered positions (Gulay & Daszkiewicz, 2011).
From the bond-valence-sum (BVS) point of view, the five copper ions are overbonded, because the BVS for these ions is greater than the formal oxidation state, +1 (Table 1) (Brown, 1996). These values remain greater than 1 even if the longest Cu–Se distance is not taken into the calculation of BVS for Cu1–Cu4. In the case of Cu5, BVS is less than 1 for two coordination spheres. However, the longest Cu–Se distance for each copper position should have to be included in the coordination sphere, because the longest Cu–Se distance still contributes 0.198 (for Cu4)–0.396 (for Cu5) of a valence unit. All the copper positions create a ring with the nearest copper–copper distances falling within the range 1.148 (11) (for Cu1–Cu2)–2.557 (10) Å [for Cu1–Cu5i; symmetry code: (i) 1/2+x, y, 3/2–z] (Fig. 2). The total occupation of the copper in the ring is 8.0 over 18 positions. The adjacent rings are joined together forming a ribbon along the a axis. The longest copper–copper distance along this direction corresponds to the longest distance in the ring, 2.557 (10) Å (for Cu1–Cu5i). The ribbon is transformed by the inversion and the shortest interribbon distance is 3.311 (6) Å [for Cu5i–Cu5iv symmetry code: (iv) 3/2–x, 1–y, z-1/2] (Fig. 2). If the copper ions move through the Cu1–Cu5 positions, the intra-ring (Cu1–Cu5) and interribbon (Cu5–Cu5) distances appear to play an important role in ionic diffusion. If the energy barriers associated with these distances are overcome, ionic condctivity of the La3Cu4.88Se7 compound will be observed.