Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270108022476/sq3156sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270108022476/sq3156Isup2.hkl |
The title compound was prepared from elemental lithium (rod, 99.9 at.%), copper (ingots, 99.999 at.%) and aluminium (ingots, 99.999 at.%) in the slightly off-stoichiometric 25:35:40 ratio. The reaction mixture was sealed under argon atmosphere in a pure iron crucible and heated to 1370 K, with intensive shaking started approximately at 1270 K. After holding for 10 min at the maximum temperature, the product was cooled rapidly by removing the crucible from the furnace into ambient conditions. In the crushed sample, metallic dark-grey plate-shaped crystals were found using a conventional light microscope. On the basis of previous studies with successive detailed chemical analyses of similar systems (Pauly, 1966; Pauly et al., 1968), a loss of Li up to 1 at.% in nominal composition during sample preparation in hermetically closed crucibles can be expected. A single crystal was protected from air during X-ray data collection in a sealed thin-walled glass capillary (Heidelberg, No. 10).
A statistical test of the distribution of the E values using the program E-STATS from the WinGX system (Farrugia, 1999) suggested with a probability of 60.9% that the structure is centrosymmetric. The analysis of systematic extinctions yielded the space group P4/mbm (No. 127), which was confirmed by the following structure refinement. The structure was solved after the empirical absorption correction. In the first stage of the refinement, the positions of the Cu and Al atoms were obtained correctly by direct methods. The remaining Li atoms were located in subsequent difference Fourier syntheses. The Al2, Al3 and Al6 positions (Wyckoff sites 4g, 8j and 8i, respectively) showed displacement parameters considerably smaller than those of other Al sites, suggesting that these positions are partially occupied by the heavier atom Cu. The attempts to refine all atoms, except for lithium, with anisotropic displacement parameters and Al/Cu statistical distribution for three sites failed because of a very small content of copper in the Al6 site. Assuming this position to be occupied only by aluminium led to unreasonable displacement parameters. The Al:Cu ratio of the Al6 site was varied with fixed displacement parameters and eventually was fixed at 95:5 on the basis of R-factor values. In the final refinement cycles, isotropic and common isotropic displacement parameters for the Al6 position and all Li sites, respectively, were refined. All other atoms were successfully refined with anisotropic displacement parameters without any constraints. The maximum and minimum electron-density features in the final difference map are 1.37 and 0.90 Å from the Cu1 site, respectively.
Data collection: CrysAlis CCD (Oxford Diffraction, 2004); cell refinement: CrysAlis CCD (Oxford Diffraction, 2004); data reduction: CrysAlis RED (Oxford Diffraction, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).
Li12Cu19.21Al22.84 | Dx = 3.971 Mg m−3 |
Mr = 1920.43 | Mo Kα radiation, λ = 0.71073 Å |
Tetragonal, P4/mbm | Cell parameters from 281 reflections |
Hall symbol: -P 4 2ab | θ = 3.2–26.4° |
a = 12.696 (2) Å | µ = 13.05 mm−1 |
c = 4.982 (1) Å | T = 295 K |
V = 803.0 (2) Å3 | Prism, metallic dark grey |
Z = 1 | 0.1 × 0.08 × 0.04 mm |
F(000) = 890.1 |
Oxford Diffraction Xcalibur3 CCD diffractometer | 490 independent reflections |
Radiation source: fine-focus sealed tube | 281 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.091 |
ω scans | θmax = 26.4°, θmin = 3.2° |
Absorption correction: empirical (using intensity measurements) (CrysAlis RED; Oxford Diffraction, 2005) | h = −15→15 |
Tmin = 0.29, Tmax = 0.60 | k = −15→12 |
2572 measured reflections | l = −2→6 |
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)] = 0.049 | w = 1/[σ2(Fo2) + (0.0336P)2] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.098 | (Δ/σ)max < 0.001 |
S = 0.99 | Δρmax = 0.98 e Å−3 |
490 reflections | Δρmin = −1.03 e Å−3 |
36 parameters | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.0005 (1) |
Li12Cu19.21Al22.84 | Z = 1 |
Mr = 1920.43 | Mo Kα radiation |
Tetragonal, P4/mbm | µ = 13.05 mm−1 |
a = 12.696 (2) Å | T = 295 K |
c = 4.982 (1) Å | 0.1 × 0.08 × 0.04 mm |
V = 803.0 (2) Å3 |
Oxford Diffraction Xcalibur3 CCD diffractometer | 490 independent reflections |
Absorption correction: empirical (using intensity measurements) (CrysAlis RED; Oxford Diffraction, 2005) | 281 reflections with I > 2σ(I) |
Tmin = 0.29, Tmax = 0.60 | Rint = 0.091 |
2572 measured reflections |
R[F2 > 2σ(F2)] = 0.049 | 36 parameters |
wR(F2) = 0.098 | 0 restraints |
S = 0.99 | Δρmax = 0.98 e Å−3 |
490 reflections | Δρmin = −1.03 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) | |
Cu1 | 0.24182 (10) | 0.02248 (9) | 0.2491 (4) | 0.0115 (4) | |
Cu2 | 0.3609 (3) | 0.1391 (3) | 0.0000 | 0.0100 (18) | 0.253 (9) |
Al2 | 0.3609 (3) | 0.1391 (3) | 0.0000 | 0.0100 (18) | 0.75 |
Cu3 | 0.0932 (3) | 0.1173 (3) | 0.5000 | 0.0127 (14) | 0.225 (7) |
Al3 | 0.0932 (3) | 0.1173 (3) | 0.5000 | 0.0127 (14) | 0.78 |
Al4 | 0.4269 (4) | 0.0731 (4) | 0.5000 | 0.0116 (17) | |
Al5 | 0.0000 | 0.0000 | 0.0000 | 0.022 (3) | |
Al6 | 0.1535 (3) | 0.1950 (4) | 0.0000 | 0.0136 (12)* | 0.95 |
Cu6 | 0.1535 (3) | 0.1950 (4) | 0.0000 | 0.0136 (12)* | 0.05 |
Li1 | 0.086 (2) | 0.414 (2) | 0.0000 | 0.009 (4)* | |
Li2 | 0.142 (2) | 0.358 (2) | 0.5000 | 0.009 (4)* | |
Li3 | 0.2807 (19) | 0.2193 (19) | 0.5000 | 0.009 (4)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cu1 | 0.0131 (7) | 0.0123 (7) | 0.0091 (6) | −0.0028 (5) | 0.0013 (7) | −0.0016 (10) |
Cu2 | 0.012 (2) | 0.012 (2) | 0.006 (3) | −0.005 (2) | 0.000 | 0.000 |
Al2 | 0.012 (2) | 0.012 (2) | 0.006 (3) | −0.005 (2) | 0.000 | 0.000 |
Cu3 | 0.012 (2) | 0.013 (2) | 0.013 (2) | 0.0037 (16) | 0.000 | 0.000 |
Al3 | 0.012 (2) | 0.013 (2) | 0.013 (2) | 0.0037 (16) | 0.000 | 0.000 |
Al4 | 0.010 (2) | 0.010 (2) | 0.015 (4) | 0.000 (3) | 0.000 | 0.000 |
Al5 | 0.012 (3) | 0.012 (3) | 0.043 (7) | 0.000 | 0.000 | 0.000 |
Cu1—Al2 | 2.4532 (15) | Al6—Cu1i | 2.755 (4) |
Cu1—Cu1i | 2.482 (4) | Al6—Al3vii | 2.786 (3) |
Cu1—Al3ii | 2.494 (3) | Al6—Cu3vii | 2.786 (3) |
Cu1—Cu3ii | 2.494 (3) | Al6—Li1 | 2.92 (3) |
Cu1—Cu1iii | 2.500 (4) | Al6—Li3 | 2.985 (11) |
Cu1—Cu3 | 2.564 (3) | Al6—Li3vii | 2.985 (11) |
Cu1—Cu6iv | 2.624 (4) | Al6—Li2 | 3.243 (18) |
Cu1—Al6iv | 2.624 (4) | Al6—Li2vii | 3.243 (18) |
Cu1—Al4 | 2.738 (3) | Li1—Li2vii | 2.688 (18) |
Cu1—Al6 | 2.755 (4) | Li1—Li2 | 2.688 (18) |
Cu1—Li3 | 2.837 (17) | Li1—Cu1xv | 2.87 (2) |
Cu1—Li2ii | 2.85 (2) | Li1—Cu1ix | 2.87 (2) |
Cu1—Li1iv | 2.87 (2) | Li1—Cu1xvi | 2.87 (2) |
Cu2—Cu1v | 2.4532 (15) | Li1—Cu1xvii | 2.87 (2) |
Cu2—Cu1vi | 2.4532 (15) | Li1—Cu6v | 2.92 (3) |
Cu2—Cu1i | 2.4532 (15) | Li1—Al6v | 2.92 (3) |
Cu2—Cu6v | 2.726 (6) | Li1—Cu2ix | 2.93 (2) |
Cu2—Al6v | 2.726 (6) | Li1—Al2ix | 2.93 (2) |
Cu2—Al6 | 2.726 (6) | Li1—Al2xviii | 2.93 (2) |
Cu2—Al4 | 2.759 (4) | Li1—Cu2xviii | 2.93 (2) |
Cu2—Al4vii | 2.759 (4) | Li1—Li1xix | 3.07 (8) |
Cu2—Li3 | 2.877 (17) | Li1—Al4xx | 3.207 (19) |
Cu2—Li3vii | 2.877 (17) | Li1—Al4ix | 3.207 (19) |
Cu2—Li1iv | 2.93 (2) | Li1—Al4xxi | 3.207 (19) |
Cu2—Li1viii | 2.93 (2) | Li1—Al4xviii | 3.207 (19) |
Al3—Cu1ix | 2.494 (3) | Li2—Li3 | 2.49 (5) |
Cu3—Cu1x | 2.494 (3) | Li2—Li1xi | 2.688 (18) |
Cu3—Cu1iii | 2.564 (3) | Li2—Cu1ix | 2.85 (2) |
Cu3—Al3ii | 2.690 (5) | Li2—Cu1x | 2.85 (2) |
Cu3—Cu3ii | 2.690 (5) | Li2—Cu1xxii | 2.85 (2) |
Cu3—Al3ix | 2.690 (5) | Li2—Cu1xvi | 2.85 (2) |
Cu3—Cu3ix | 2.690 (5) | Li2—Al4ix | 2.86 (3) |
Cu3—Li3 | 2.710 (10) | Li2—Al4xxi | 2.86 (3) |
Cu3—Cu6xi | 2.786 (3) | Li2—Cu3v | 3.12 (2) |
Cu3—Al6xi | 2.786 (3) | Li2—Al3v | 3.12 (2) |
Cu3—Al6 | 2.786 (3) | Li2—Al6xi | 3.243 (18) |
Cu3—Li2 | 3.12 (2) | Li2—Cu6xi | 3.243 (18) |
Al4—Al4xii | 2.624 (14) | Li2—Cu6xxiii | 3.244 (18) |
Al4—Li3 | 2.63 (3) | Li2—Al6xxiii | 3.244 (18) |
Al4—Cu1iii | 2.738 (3) | Li2—Al6v | 3.244 (18) |
Al4—Cu1xiii | 2.738 (3) | Li2—Cu6v | 3.244 (18) |
Al4—Cu1v | 2.738 (3) | Li3—Al3v | 2.710 (10) |
Al4—Al2xi | 2.759 (4) | Li3—Cu3v | 2.710 (10) |
Al4—Cu2xi | 2.759 (4) | Li3—Cu1xiii | 2.837 (17) |
Al4—Li2ii | 2.86 (3) | Li3—Cu1v | 2.837 (17) |
Al4—Li2viii | 2.86 (3) | Li3—Cu1iii | 2.837 (17) |
Al4—Li1iv | 3.207 (19) | Li3—Al2xi | 2.877 (17) |
Al4—Li1ii | 3.207 (19) | Li3—Cu2xi | 2.877 (17) |
Al4—Li1xiv | 3.207 (19) | Li3—Cu6xxiii | 2.985 (11) |
Al4—Li1viii | 3.207 (19) | Li3—Al6xxiii | 2.985 (11) |
Al6—Cu1xv | 2.624 (4) | Li3—Cu6v | 2.985 (11) |
Al6—Cu1ix | 2.624 (4) | Li3—Al6v | 2.985 (11) |
Al6—Cu6v | 2.721 (9) | Li3—Cu6xi | 2.985 (11) |
Al6—Al6v | 2.721 (9) | Li3—Al6xi | 2.985 (11) |
Cu2—Cu1—Cu1i | 59.61 (4) | Cu1v—Al4—Li2viii | 61.0 (3) |
Cu2—Cu1—Al3ii | 178.64 (15) | Al2xi—Al4—Li2viii | 101.36 (13) |
Cu1i—Cu1—Al3ii | 120.08 (6) | Cu2xi—Al4—Li2viii | 101.36 (13) |
Cu2—Cu1—Cu3ii | 178.64 (15) | Cu2—Al4—Li2viii | 101.36 (13) |
Cu1i—Cu1—Cu3ii | 120.08 (6) | Li2ii—Al4—Li2viii | 125.5 (7) |
Al3ii—Cu1—Cu3ii | 0.00 (17) | Cu1xv—Al6—Cu1ix | 56.45 (13) |
Cu2—Cu1—Cu1iii | 120.39 (4) | Cu1xv—Al6—Cu6v | 116.21 (10) |
Cu1i—Cu1—Cu1iii | 180.00 (5) | Cu1ix—Al6—Cu6v | 116.21 (10) |
Al3ii—Cu1—Cu1iii | 59.92 (6) | Cu1xv—Al6—Al6v | 116.21 (10) |
Cu3ii—Cu1—Cu1iii | 59.92 (6) | Cu1ix—Al6—Al6v | 116.21 (10) |
Cu2—Cu1—Cu3 | 114.63 (15) | Cu6v—Al6—Al6v | 0.00 (13) |
Cu1i—Cu1—Cu3 | 119.18 (6) | Cu1xv—Al6—Cu2 | 151.77 (7) |
Al3ii—Cu1—Cu3 | 64.24 (15) | Cu1ix—Al6—Cu2 | 151.77 (7) |
Cu3ii—Cu1—Cu3 | 64.24 (15) | Cu6v—Al6—Cu2 | 60.07 (11) |
Cu1iii—Cu1—Cu3 | 60.82 (6) | Al6v—Al6—Cu2 | 60.07 (11) |
Cu2—Cu1—Cu6iv | 114.48 (12) | Cu1xv—Al6—Cu1i | 108.27 (11) |
Cu1i—Cu1—Cu6iv | 61.77 (7) | Cu1ix—Al6—Cu1i | 137.70 (19) |
Al3ii—Cu1—Cu6iv | 65.91 (9) | Cu6v—Al6—Cu1i | 105.92 (9) |
Cu3ii—Cu1—Cu6iv | 65.91 (9) | Al6v—Al6—Cu1i | 105.92 (9) |
Cu1iii—Cu1—Cu6iv | 118.23 (7) | Cu2—Al6—Cu1i | 53.17 (9) |
Cu3—Cu1—Cu6iv | 117.61 (13) | Cu1xv—Al6—Cu1 | 137.70 (19) |
Cu2—Cu1—Al6iv | 114.48 (12) | Cu1ix—Al6—Cu1 | 108.27 (11) |
Cu1i—Cu1—Al6iv | 61.77 (7) | Cu6v—Al6—Cu1 | 105.92 (9) |
Al3ii—Cu1—Al6iv | 65.91 (9) | Al6v—Al6—Cu1 | 105.92 (9) |
Cu3ii—Cu1—Al6iv | 65.91 (9) | Cu2—Al6—Cu1 | 53.17 (9) |
Cu1iii—Cu1—Al6iv | 118.23 (7) | Cu1i—Al6—Cu1 | 53.55 (12) |
Cu3—Cu1—Al6iv | 117.61 (13) | Cu1xv—Al6—Al3vii | 54.78 (10) |
Cu6iv—Cu1—Al6iv | 0.00 (10) | Cu1ix—Al6—Al3vii | 105.60 (16) |
Cu2—Cu1—Al4 | 63.93 (7) | Cu6v—Al6—Al3vii | 116.40 (11) |
Cu1i—Cu1—Al4 | 117.16 (5) | Al6v—Al6—Al3vii | 116.40 (11) |
Al3ii—Cu1—Al4 | 116.97 (10) | Cu2—Al6—Al3vii | 99.99 (12) |
Cu3ii—Cu1—Al4 | 116.97 (10) | Cu1i—Al6—Al3vii | 55.11 (10) |
Cu1iii—Cu1—Al4 | 62.84 (5) | Cu1—Al6—Al3vii | 103.50 (16) |
Cu3—Cu1—Al4 | 107.41 (15) | Cu1xv—Al6—Cu3vii | 54.78 (10) |
Cu6iv—Cu1—Al4 | 127.60 (15) | Cu1ix—Al6—Cu3vii | 105.60 (16) |
Al6iv—Cu1—Al4 | 127.60 (15) | Cu6v—Al6—Cu3vii | 116.40 (11) |
Cu2—Cu1—Al6 | 62.81 (15) | Al6v—Al6—Cu3vii | 116.40 (11) |
Cu1i—Cu1—Al6 | 63.23 (6) | Cu2—Al6—Cu3vii | 99.99 (12) |
Al3ii—Cu1—Al6 | 115.84 (13) | Cu1i—Al6—Cu3vii | 55.11 (10) |
Cu3ii—Cu1—Al6 | 115.84 (13) | Cu1—Al6—Cu3vii | 103.50 (16) |
Cu1iii—Cu1—Al6 | 116.77 (6) | Al3vii—Al6—Cu3vii | 0.00 (14) |
Cu3—Cu1—Al6 | 63.06 (8) | Cu1xv—Al6—Cu3 | 105.60 (16) |
Cu6iv—Cu1—Al6 | 111.80 (16) | Cu1ix—Al6—Cu3 | 54.78 (10) |
Al6iv—Cu1—Al6 | 111.80 (16) | Cu6v—Al6—Cu3 | 116.40 (11) |
Al4—Cu1—Al6 | 111.62 (15) | Al6v—Al6—Cu3 | 116.40 (11) |
Cu1v—Cu2—Cu1vi | 60.79 (9) | Cu2—Al6—Cu3 | 99.99 (12) |
Cu1v—Cu2—Cu1i | 179.0 (3) | Cu1i—Al6—Cu3 | 103.50 (16) |
Cu1vi—Cu2—Cu1i | 119.20 (9) | Cu1—Al6—Cu3 | 55.11 (10) |
Cu1v—Cu2—Cu1 | 119.20 (9) | Al3vii—Al6—Cu3 | 126.8 (2) |
Cu1vi—Cu2—Cu1 | 179.0 (3) | Cu3vii—Al6—Cu3 | 126.8 (2) |
Cu1i—Cu2—Cu1 | 60.79 (9) | Li2vii—Li1—Li2 | 135.8 (18) |
Cu1v—Cu2—Cu6v | 64.02 (11) | Li2vii—Li1—Cu1xv | 61.5 (3) |
Cu1vi—Cu2—Cu6v | 64.02 (11) | Li2—Li1—Cu1xv | 109.0 (6) |
Cu1i—Cu2—Cu6v | 115.01 (18) | Li2vii—Li1—Cu1ix | 109.0 (6) |
Cu1—Cu2—Cu6v | 115.01 (18) | Li2—Li1—Cu1ix | 61.5 (3) |
Cu1v—Cu2—Al6v | 64.02 (11) | Cu1xv—Li1—Cu1ix | 51.29 (17) |
Cu1vi—Cu2—Al6v | 64.02 (11) | Li2vii—Li1—Cu1xvi | 109.0 (6) |
Cu1i—Cu2—Al6v | 115.01 (18) | Li2—Li1—Cu1xvi | 61.5 (3) |
Cu1—Cu2—Al6v | 115.01 (18) | Cu1xv—Li1—Cu1xvi | 156.7 (15) |
Cu6v—Cu2—Al6v | 0.00 (18) | Cu1ix—Li1—Cu1xvi | 122.9 (6) |
Cu1v—Cu2—Al6 | 115.01 (18) | Li2vii—Li1—Cu1xvii | 61.5 (3) |
Cu1vi—Cu2—Al6 | 115.01 (18) | Li2—Li1—Cu1xvii | 109.0 (6) |
Cu1i—Cu2—Al6 | 64.02 (11) | Cu1xv—Li1—Cu1xvii | 122.9 (6) |
Cu1—Cu2—Al6 | 64.02 (11) | Cu1ix—Li1—Cu1xvii | 156.7 (15) |
Cu6v—Cu2—Al6 | 59.9 (2) | Cu1xvi—Li1—Cu1xvii | 51.29 (17) |
Al6v—Cu2—Al6 | 59.9 (2) | Li2vii—Li1—Al6 | 70.6 (8) |
Cu1v—Cu2—Al4 | 63.06 (6) | Li2—Li1—Al6 | 70.6 (8) |
Cu1vi—Cu2—Al4 | 117.42 (10) | Cu1xv—Li1—Al6 | 53.9 (4) |
Cu1i—Cu2—Al4 | 117.42 (10) | Cu1ix—Li1—Al6 | 53.9 (4) |
Cu1—Cu2—Al4 | 63.06 (6) | Cu1xvi—Li1—Al6 | 103.3 (10) |
Cu6v—Cu2—Al4 | 111.87 (13) | Cu1xvii—Li1—Al6 | 103.3 (10) |
Al6v—Cu2—Al4 | 111.87 (13) | Li2vii—Li1—Cu6v | 70.6 (8) |
Al6—Cu2—Al4 | 111.87 (13) | Li2—Li1—Cu6v | 70.6 (8) |
Cu1v—Cu2—Al4vii | 117.42 (10) | Cu1xv—Li1—Cu6v | 103.3 (10) |
Cu1vi—Cu2—Al4vii | 63.06 (6) | Cu1ix—Li1—Cu6v | 103.3 (10) |
Cu1i—Cu2—Al4vii | 63.06 (6) | Cu1xvi—Li1—Cu6v | 53.9 (4) |
Cu1—Cu2—Al4vii | 117.42 (10) | Cu1xvii—Li1—Cu6v | 53.9 (4) |
Cu6v—Cu2—Al4vii | 111.87 (13) | Al6—Li1—Cu6v | 55.6 (7) |
Al6v—Cu2—Al4vii | 111.87 (13) | Li2vii—Li1—Al6v | 70.6 (8) |
Al6—Cu2—Al4vii | 111.87 (13) | Li2—Li1—Al6v | 70.6 (8) |
Al4—Cu2—Al4vii | 129.1 (3) | Cu1xv—Li1—Al6v | 103.3 (10) |
Cu1v—Cu2—Li3 | 63.74 (17) | Cu1ix—Li1—Al6v | 103.3 (10) |
Cu1vi—Cu2—Li3 | 115.7 (2) | Cu1xvi—Li1—Al6v | 53.9 (4) |
Cu1i—Cu2—Li3 | 115.7 (2) | Cu1xvii—Li1—Al6v | 53.9 (4) |
Cu1—Cu2—Li3 | 63.74 (17) | Al6—Li1—Al6v | 55.6 (7) |
Cu6v—Cu2—Li3 | 64.3 (5) | Cu6v—Li1—Al6v | 0.00 (17) |
Al6v—Cu2—Li3 | 64.3 (5) | Li2vii—Li1—Cu2ix | 101.4 (4) |
Al6—Cu2—Li3 | 64.3 (5) | Li2—Li1—Cu2ix | 101.4 (4) |
Al4—Cu2—Li3 | 55.5 (6) | Cu1xv—Li1—Cu2ix | 50.02 (14) |
Al4vii—Cu2—Li3 | 175.4 (6) | Cu1ix—Li1—Cu2ix | 50.02 (14) |
Cu1v—Cu2—Li3vii | 115.7 (2) | Cu1xvi—Li1—Cu2ix | 148.7 (9) |
Cu1vi—Cu2—Li3vii | 63.74 (17) | Cu1xvii—Li1—Cu2ix | 148.7 (9) |
Cu1i—Cu2—Li3vii | 63.74 (17) | Al6—Li1—Cu2ix | 93.8 (3) |
Cu1—Cu2—Li3vii | 115.7 (2) | Cu6v—Li1—Cu2ix | 149.4 (10) |
Cu6v—Cu2—Li3vii | 64.3 (5) | Al6v—Li1—Cu2ix | 149.4 (10) |
Al6v—Cu2—Li3vii | 64.3 (5) | Li2vii—Li1—Al2ix | 101.4 (4) |
Al6—Cu2—Li3vii | 64.3 (5) | Li2—Li1—Al2ix | 101.4 (4) |
Al4—Cu2—Li3vii | 175.4 (6) | Cu1xv—Li1—Al2ix | 50.02 (14) |
Al4vii—Cu2—Li3vii | 55.5 (6) | Cu1ix—Li1—Al2ix | 50.02 (14) |
Li3—Cu2—Li3vii | 120.0 (12) | Cu1xvi—Li1—Al2ix | 148.7 (9) |
Cu1ix—Cu3—Cu1x | 60.16 (12) | Cu1xvii—Li1—Al2ix | 148.7 (9) |
Cu1ix—Cu3—Cu1 | 119.13 (9) | Al6—Li1—Al2ix | 93.8 (3) |
Cu1x—Cu3—Cu1 | 167.30 (17) | Cu6v—Li1—Al2ix | 149.4 (10) |
Cu1ix—Cu3—Cu1iii | 167.30 (17) | Al6v—Li1—Al2ix | 149.4 (10) |
Cu1x—Cu3—Cu1iii | 119.13 (9) | Cu2ix—Li1—Al2ix | 0.00 (17) |
Cu1—Cu3—Cu1iii | 58.35 (11) | Li3—Li2—Li1xi | 112.1 (9) |
Cu1ix—Cu3—Al3ii | 134.18 (10) | Li3—Li2—Li1 | 112.1 (9) |
Cu1x—Cu3—Al3ii | 134.18 (10) | Li1xi—Li2—Li1 | 135.8 (18) |
Cu1—Cu3—Al3ii | 56.61 (13) | Li3—Li2—Cu1ix | 98.7 (7) |
Cu1iii—Cu3—Al3ii | 56.61 (13) | Li1xi—Li2—Cu1ix | 110.5 (6) |
Cu1ix—Cu3—Cu3ii | 134.18 (10) | Li1—Li2—Cu1ix | 62.4 (2) |
Cu1x—Cu3—Cu3ii | 134.18 (10) | Li3—Li2—Cu1x | 98.7 (7) |
Cu1—Cu3—Cu3ii | 56.61 (13) | Li1xi—Li2—Cu1x | 62.4 (2) |
Cu1iii—Cu3—Cu3ii | 56.61 (13) | Li1—Li2—Cu1x | 110.5 (6) |
Al3ii—Cu3—Cu3ii | 0.000 (17) | Cu1ix—Li2—Cu1x | 52.12 (14) |
Cu1ix—Cu3—Al3ix | 59.14 (13) | Li3—Li2—Cu1xxii | 98.7 (7) |
Cu1x—Cu3—Al3ix | 59.14 (13) | Li1xi—Li2—Cu1xxii | 62.4 (2) |
Cu1—Cu3—Al3ix | 132.68 (10) | Li1—Li2—Cu1xxii | 110.5 (6) |
Cu1iii—Cu3—Al3ix | 132.68 (10) | Cu1ix—Li2—Cu1xxii | 162.6 (15) |
Al3ii—Cu3—Al3ix | 90.0 | Cu1x—Li2—Cu1xxii | 124.6 (4) |
Cu3ii—Cu3—Al3ix | 90.0 | Li3—Li2—Cu1xvi | 98.7 (7) |
Cu1ix—Cu3—Cu3ix | 59.14 (13) | Li1xi—Li2—Cu1xvi | 110.5 (6) |
Cu1x—Cu3—Cu3ix | 59.14 (13) | Li1—Li2—Cu1xvi | 62.4 (2) |
Cu1—Cu3—Cu3ix | 132.68 (10) | Cu1ix—Li2—Cu1xvi | 124.6 (4) |
Cu1iii—Cu3—Cu3ix | 132.68 (10) | Cu1x—Li2—Cu1xvi | 162.6 (15) |
Al3ii—Cu3—Cu3ix | 90.0 | Cu1xxii—Li2—Cu1xvi | 52.11 (14) |
Cu3ii—Cu3—Cu3ix | 90.0 | Li3—Li2—Al4ix | 152.8 (3) |
Al3ix—Cu3—Cu3ix | 0.00 (15) | Li1xi—Li2—Al4ix | 70.5 (8) |
Cu1ix—Cu3—Li3 | 102.4 (6) | Li1—Li2—Al4ix | 70.5 (8) |
Cu1x—Cu3—Li3 | 102.4 (6) | Cu1ix—Li2—Al4ix | 57.3 (4) |
Cu1—Cu3—Li3 | 65.0 (6) | Cu1x—Li2—Al4ix | 57.3 (4) |
Cu1iii—Cu3—Li3 | 65.0 (6) | Cu1xxii—Li2—Al4ix | 105.7 (10) |
Al3ii—Cu3—Li3 | 112.0 (7) | Cu1xvi—Li2—Al4ix | 105.7 (10) |
Cu3ii—Cu3—Li3 | 112.0 (7) | Li3—Li2—Al4xxi | 152.7 (3) |
Al3ix—Cu3—Li3 | 158.0 (7) | Li1xi—Li2—Al4xxi | 70.5 (8) |
Cu3ix—Cu3—Li3 | 158.0 (7) | Li1—Li2—Al4xxi | 70.5 (8) |
Cu1ix—Cu3—Cu6xi | 112.68 (16) | Cu1ix—Li2—Al4xxi | 105.7 (10) |
Cu1x—Cu3—Cu6xi | 59.30 (11) | Cu1x—Li2—Al4xxi | 105.7 (10) |
Cu1—Cu3—Cu6xi | 113.55 (15) | Cu1xxii—Li2—Al4xxi | 57.3 (4) |
Cu1iii—Cu3—Cu6xi | 61.83 (11) | Cu1xvi—Li2—Al4xxi | 57.3 (4) |
Al3ii—Cu3—Cu6xi | 108.68 (13) | Al4ix—Li2—Al4xxi | 54.5 (7) |
Cu3ii—Cu3—Cu6xi | 108.68 (13) | Li3—Li2—Cu3 | 56.4 (6) |
Al3ix—Cu3—Cu6xi | 108.26 (13) | Li1xi—Li2—Cu3 | 102.0 (4) |
Cu3ix—Cu3—Cu6xi | 108.26 (13) | Li1—Li2—Cu3 | 102.0 (4) |
Li3—Cu3—Cu6xi | 65.76 (18) | Cu1ix—Li2—Cu3 | 49.16 (19) |
Cu1ix—Cu3—Al6xi | 112.68 (16) | Cu1x—Li2—Cu3 | 49.16 (19) |
Cu1x—Cu3—Al6xi | 59.30 (11) | Cu1xxii—Li2—Cu3 | 145.2 (9) |
Cu1—Cu3—Al6xi | 113.55 (15) | Cu1xvi—Li2—Cu3 | 145.2 (9) |
Cu1iii—Cu3—Al6xi | 61.83 (11) | Al4ix—Li2—Cu3 | 96.3 (3) |
Al3ii—Cu3—Al6xi | 108.68 (13) | Al4xxi—Li2—Cu3 | 150.8 (9) |
Cu3ii—Cu3—Al6xi | 108.68 (13) | Li3—Li2—Cu3v | 56.4 (6) |
Al3ix—Cu3—Al6xi | 108.26 (13) | Li1xi—Li2—Cu3v | 102.0 (4) |
Cu3ix—Cu3—Al6xi | 108.26 (13) | Li1—Li2—Cu3v | 102.0 (4) |
Li3—Cu3—Al6xi | 65.76 (18) | Cu1ix—Li2—Cu3v | 145.2 (9) |
Cu6xi—Cu3—Al6xi | 0.0 | Cu1x—Li2—Cu3v | 145.2 (9) |
Al4xii—Al4—Li3 | 179.998 (1) | Cu1xxii—Li2—Cu3v | 49.15 (19) |
Al4xii—Al4—Cu1 | 116.17 (13) | Cu1xvi—Li2—Cu3v | 49.15 (19) |
Li3—Al4—Cu1 | 63.8 (5) | Al4ix—Li2—Cu3v | 150.8 (9) |
Al4xii—Al4—Cu1iii | 116.17 (13) | Al4xxi—Li2—Cu3v | 96.3 (3) |
Li3—Al4—Cu1iii | 63.83 (13) | Cu3—Li2—Cu3v | 112.8 (11) |
Cu1—Al4—Cu1iii | 54.31 (11) | Li2—Li3—Al4 | 179.989 (1) |
Al4xii—Al4—Cu1xiii | 116.17 (13) | Li2—Li3—Al3v | 73.6 (7) |
Li3—Al4—Cu1xiii | 63.83 (13) | Al4—Li3—Al3v | 106.5 (7) |
Cu1—Al4—Cu1xiii | 127.7 (3) | Li2—Li3—Cu3v | 73.6 (7) |
Cu1iii—Al4—Cu1xiii | 101.20 (17) | Al4—Li3—Cu3v | 106.5 (7) |
Al4xii—Al4—Cu1v | 116.17 (13) | Al3v—Li3—Cu3v | 0.00 (7) |
Li3—Al4—Cu1v | 63.83 (13) | Li2—Li3—Cu3 | 73.5 (7) |
Cu1—Al4—Cu1v | 101.20 (17) | Al4—Li3—Cu3 | 106.4 (7) |
Cu1iii—Al4—Cu1v | 127.7 (3) | Al3v—Li3—Cu3 | 147.1 (14) |
Cu1xiii—Al4—Cu1v | 54.31 (11) | Cu3v—Li3—Cu3 | 147.1 (14) |
Al4xii—Al4—Al2xi | 115.46 (16) | Li2—Li3—Cu1xiii | 120.0 (6) |
Li3—Al4—Al2xi | 64.54 (16) | Al4—Li3—Cu1xiii | 60.0 (6) |
Cu1—Al4—Al2xi | 102.86 (17) | Al3v—Li3—Cu1xiii | 54.99 (12) |
Cu1iii—Al4—Al2xi | 53.01 (8) | Cu3v—Li3—Cu1xiii | 54.99 (12) |
Cu1xiii—Al4—Al2xi | 53.01 (8) | Cu3—Li3—Cu1xiii | 149.0 (6) |
Cu1v—Al4—Al2xi | 102.86 (17) | Li2—Li3—Cu1v | 120.0 (6) |
Al4xii—Al4—Cu2xi | 115.46 (16) | Al4—Li3—Cu1v | 60.0 (6) |
Li3—Al4—Cu2xi | 64.54 (16) | Al3v—Li3—Cu1v | 54.99 (12) |
Cu1—Al4—Cu2xi | 102.86 (17) | Cu3v—Li3—Cu1v | 54.99 (12) |
Cu1iii—Al4—Cu2xi | 53.01 (8) | Cu3—Li3—Cu1v | 149.0 (6) |
Cu1xiii—Al4—Cu2xi | 53.01 (8) | Cu1xiii—Li3—Cu1v | 52.3 (3) |
Cu1v—Al4—Cu2xi | 102.86 (17) | Li2—Li3—Cu1 | 120.0 (6) |
Al2xi—Al4—Cu2xi | 0.00 (15) | Al4—Li3—Cu1 | 60.0 (6) |
Al4xii—Al4—Cu2 | 115.46 (16) | Al3v—Li3—Cu1 | 149.0 (6) |
Li3—Al4—Cu2 | 64.54 (16) | Cu3v—Li3—Cu1 | 149.0 (6) |
Cu1—Al4—Cu2 | 53.01 (8) | Cu3—Li3—Cu1 | 54.99 (12) |
Cu1iii—Al4—Cu2 | 102.86 (17) | Cu1xiii—Li3—Cu1 | 120.0 (12) |
Cu1xiii—Al4—Cu2 | 102.86 (17) | Cu1v—Li3—Cu1 | 96.4 (8) |
Cu1v—Al4—Cu2 | 53.01 (8) | Li2—Li3—Cu1iii | 120.0 (6) |
Al2xi—Al4—Cu2 | 129.1 (3) | Al4—Li3—Cu1iii | 60.0 (6) |
Cu2xi—Al4—Cu2 | 129.1 (3) | Al3v—Li3—Cu1iii | 149.0 (6) |
Al4xii—Al4—Li2ii | 62.7 (3) | Cu3v—Li3—Cu1iii | 149.0 (6) |
Li3—Al4—Li2ii | 117.3 (3) | Cu3—Li3—Cu1iii | 54.99 (12) |
Cu1—Al4—Li2ii | 61.0 (3) | Cu1xiii—Li3—Cu1iii | 96.4 (8) |
Cu1iii—Al4—Li2ii | 61.0 (3) | Cu1v—Li3—Cu1iii | 120.0 (12) |
Cu1xiii—Al4—Li2ii | 152.74 (5) | Cu1—Li3—Cu1iii | 52.3 (3) |
Cu1v—Al4—Li2ii | 152.74 (5) | Li2—Li3—Cu2 | 120.0 (6) |
Al2xi—Al4—Li2ii | 101.35 (13) | Al4—Li3—Cu2 | 60.0 (6) |
Cu2xi—Al4—Li2ii | 101.35 (13) | Al3v—Li3—Cu2 | 98.15 (19) |
Cu2—Al4—Li2ii | 101.35 (13) | Cu3v—Li3—Cu2 | 98.15 (19) |
Al4xii—Al4—Li2viii | 62.7 (3) | Cu3—Li3—Cu2 | 98.14 (19) |
Li3—Al4—Li2viii | 117.3 (3) | Cu1xiii—Li3—Cu2 | 97.5 (8) |
Cu1—Al4—Li2viii | 152.74 (5) | Cu1v—Li3—Cu2 | 50.8 (3) |
Cu1iii—Al4—Li2viii | 152.74 (5) | Cu1—Li3—Cu2 | 50.8 (3) |
Cu1xiii—Al4—Li2viii | 61.0 (3) | Cu1iii—Li3—Cu2 | 97.5 (8) |
Symmetry codes: (i) x, y, −z; (ii) y, −x, −z+1; (iii) x, y, −z+1; (iv) y, −x, −z; (v) −y+1/2, −x+1/2, z; (vi) −y+1/2, −x+1/2, −z; (vii) x, y, z−1; (viii) −y+1, x, z; (ix) −y, x, z; (x) −y, x, −z+1; (xi) x, y, z+1; (xii) −x+1, −y, −z+1; (xiii) −y+1/2, −x+1/2, −z+1; (xiv) −y+1, x, z+1; (xv) −y, x, −z; (xvi) −x+1/2, y+1/2, z; (xvii) −x+1/2, y+1/2, −z; (xviii) y, −x+1, −z; (xix) −x, −y+1, −z; (xx) −y, x, z−1; (xxi) y, −x+1, −z+1; (xxii) −x+1/2, y+1/2, −z+1; (xxiii) −y+1/2, −x+1/2, z+1. |
Experimental details
Crystal data | |
Chemical formula | Li12Cu19.21Al22.84 |
Mr | 1920.43 |
Crystal system, space group | Tetragonal, P4/mbm |
Temperature (K) | 295 |
a, c (Å) | 12.696 (2), 4.982 (1) |
V (Å3) | 803.0 (2) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 13.05 |
Crystal size (mm) | 0.1 × 0.08 × 0.04 |
Data collection | |
Diffractometer | Oxford Diffraction Xcalibur3 CCD diffractometer |
Absorption correction | Empirical (using intensity measurements) (CrysAlis RED; Oxford Diffraction, 2005) |
Tmin, Tmax | 0.29, 0.60 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2572, 490, 281 |
Rint | 0.091 |
(sin θ/λ)max (Å−1) | 0.625 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.049, 0.098, 0.99 |
No. of reflections | 490 |
No. of parameters | 36 |
Δρmax, Δρmin (e Å−3) | 0.98, −1.03 |
Computer programs: CrysAlis CCD (Oxford Diffraction, 2004), CrysAlis RED (Oxford Diffraction, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 1999).
Cu1—Al2 | 2.4532 (15) | Al6—Cu1i | 2.624 (4) |
Al3—Cu1i | 2.494 (3) | Li1—Li2 | 2.688 (18) |
Al4—Li3 | 2.63 (3) | Li2—Li3 | 2.49 (5) |
Symmetry code: (i) −y, x, z. |
The Li–Cu–Al ternary system has been the subject of intense scientific scrutiny for many decades. The first report on the crystal structures of intermetallides existing in this system was made by Hardy & Silcock (1955–1956), but the majority of papers dedicated to the investigation of these compounds were published beginning in the late 1980s. Intermetallides in this system adopt highly symmetrical structures; Li3CuAl5 (Audier et al., 1988; Guryan et al., 1988), LiCu4Al7.5 (Schneider & von Heimendahl, 1973) and Li3CuAl6 (Dubost et al., 1986; Konno et al., 2002) belong to the cubic system, while LiCuAl2 (Knowles & Stobbs, 1988; Van Smaalen et al., 1990) and Li8Cu12+xAl6-x (Pavlyuk et al., 2008) are hexagonal. The family of quasicrystals of nominal composition close to Li3CuAl6, reviewed by Steurer & Deloudi (2008), has attracted the greatest interest among researchers.
Within the framework of our continuing studies of lithium aluminides, we report here the structure of the new compound, Li12Cu16+xAl26-x (x = 3.2). To our knowledge, it is the first compound with tetragonal symmetry in the Li–Cu–Al system. Moreover this intermetallide crystallizes in a new structure type with the space group P4/mbm (No. 127), Pearson symbol tP54. The structure of Li12Cu16+xAl26-x contains three Li, one Cu, two Al and three Al/Cu statistically mixed positions in the asymmetric unit. For simplicity hereinafter the last positions are designated as Al2, Al3 and Al6, because more Al than Cu is located on these sites. The clinographic projections of the unit cell and coordination polyhedra of atoms are shown in Fig. 1.
Atoms Li1 and Li2 occupy 4g and 4h Wyckoff sites and are surrounded by 15 neighbouring atoms in the form of tri-capped distorted icosahedra, [(Li1)Li2Cu4Al4LiAl4] and [(Li2)Li3Cu4Al8]. The coordination around atom Li3 (4h site) consists of 14 atoms, resulting in a deformed icosahedron with two additional vertices [(Li3)LiAl3Cu4Al6]. The bonding distances for the Li atoms cover the range 2.49 (5)–3.24 (2) Å. The coordination polyhedra around the Cu atoms (in the 16l position) are distorted icosahedra of composition [(Cu1)Al2Cu2Al4Li3Al] with distances to the nearest and farthest atoms of 2.453</span>(2) and 3.324 (1) Å. Atom Al5 (2a site) is surrounded by 20 adjacent atoms [(Al5)Al12Cu8] in the form of a pseudo-Frank–Kasper polyhedron. Atoms Al4 and Al6 (Wyckoff sites 4h and 8i, respectively) are characterized by irregular icosahedra with two extra vertices, [(Al4)LiAlCu4Al2Li6] and [(Al6)Cu2Al2Cu2Al2Li3AlLi2], similar to the Li3 atoms. The coordination environments of atoms Al2 (4g) and Al3 (8j) are distorted (to different degrees) icosahedra, [(Al2)Cu4Al4Li4] and [(Al3)Cu4Al2LiAl2LiAl2]. The shortest and longest contacts for Al atoms in the structure are 2.453 (2) and 3.324 (1) Å. The interatomic distances of the first coordination spheres of the atoms (Table 1) are in good agreement with the atomic radii of constituent elements (Emsley, 1991) and indicate metallic type bonding [the shortest Cu—Al distance, 2.453<span style=" font-weight:600;">(2) Å, is 90.6% of the sum of single-bond radii].
The pseudo-Frank–Kasper polyhedra around atom Al5 are slightly distorted compared with the analogous polyhedra in the CaCu5 structure for the Ca atoms (Haucke, 1940). These 20-vertex polyhedra, sharing their rhombohedral faces in CaCu5 and also in LiCuAl2 (???van or Van Smaalen et al., 1990), form layers with rhombohedral and hexagonal channels between them, respectively. In Li12Cu16+xAl26-x, the same constructive elements, namely pseudo-Frank–Kasper polyhedra connected along the [001] direction and hexagonal channels, can also be recognized (Fig. 2). For all the lithium-containing compounds in this family, including Li8Cu12+xAl6-x (Pavlyuk et al., 2008), a special feature is that the Li atoms are located inside these hexagonal channels, which are connected by sharing edges and faces or byfaces only.