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New ternary dodeca­lithium dodeca­copper tetra­deca­aluminium, Li12Cu12.60Al14.37 (trigonal, R\overline{3}m, hR39), crystallizes as a new structure type and belongs to the structural family that derives from binary Laves phases. The Li atoms are enclosed in 15- and 16-vertex and the Al3 atom in 14-vertex pseudo-Frank-Kasper polyhedra. The polyhedra around the statistical mixtures of (Cu,Al)1 and (Al,Cu)2 are distorted icosa­hedra. The electronic structure was calculated by the TB-LMTO-ASA (tight-binding linear muffin-tin orbital atomic spheres approximation) method. The electron localization function, which indicates bond formation, is mostly located at the Al atoms. Thus, Al-Al bonding is much stronger than Li-Al or Cu-Al bonding. This indicates that, besides metallic bonding which is dominant in this compound, weak covalent Al-Al inter­actions also exist.

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Comment top

In the search for new electrode materials for lithium batteries, we carried out extensive studies of the interactions of the components in the ternary systems that consist of lithium, transition metals and p-elements [?]. Thus, we synthesized and studied the crystal structure of new compounds from the Li–Cu–Si ternary system, such as LiCu3Si2 (Pavlyuk et al., 1995a), Li7Cu7Si5 (Pavlyuk et al., 1995b), Li113Cu54Si57 (Pavlyuk et al., 1995c) and Li119Cu145Si177 (Pavlyuk et al., 1995d). The structure of the Li5Cu2Ge2 ternary germanide from the Li–Cu–Ge ternary system was also investigated (Pavlyuk & Bodak, 1992).

In this paper, we present new results for a ternary phase of the Li–Cu–Al system. The first report on the crystal structures of intermetallides of the Li–Cu–Al system was made by Hardy & Silcock (1955). Note that the majority of scientific papers on these compounds were published in the early 1990s. A characteristic feature is that the intermetallides in this system adopt high symmetrical [high-symmetry?] 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) are cubic, while LiCuAl2 (Knowles & Stobbs, 1988; Van Smaalen et al., 1990) is hexagonal. Stable Li3CuAl6 was initially reported by Hardy & Silcock (1955), but was later identified as an icosahedral quasicrystalline phase (Ball & Lloyd, 1985). We synthesized and described the crystal structures of two previously unknown ternary phases, viz. Li8Cu12+xAl6-x (Pavlyuk et al., 2008a) and Li12Cu16 +xAl26-x (Pavlyuk et al., 2008b), which crystallize with hexagonal and tetragonal symmetries, respectively.

During the systematic study of ternary alloys of the Li–Cu–Al system in the region between the Li50Cu25Al25 and Li35Cu35Al30 compositions, we detected a new ternary compound. The powder diffraction pattern of this compound is not similar to the powder patterns of the earlier investigated phases from this system. Therefore, a full structure analysis was performed using single-crystal X-ray diffraction.

The obtained single-crystal data show that the title compound crystallizes with a new trigonal structure type (space group R3m). A projection of the unit cell and the coordination polyhedra of the atoms are shown in Fig. 1. The number of neighbouring atoms correlates well with the sizes of the central atoms.

The coordination polyhedra around the statistical mixtures of (Cu,Al)1 and (Al,Cu)2 (on the 18h and 3a sites, respectively) are distorted icosahedra of compositions [(Cu,Al)1(Cu,Al)4(Al,Cu)Al2Li2Li3] and [(Al,Cu)2(Cu,Al)6Li6]. The Al3 atom, corresponding to 6c site symmetry, is surrounded by 14 adjacent atoms [Al3Al(Cu,Al)6LiLi6] in the form of pseudo-Frank–Kasper polyhedra. The Li atoms are enclosed in 15- and 16-vertex polyhedra that can be treated as distorted pseudo-Frank–Kasper polyhedra of compositions [Li4(Cu,Al)6Li3Al6] and [Li5Al(Al,Cu)3(Cu,Al)6Li3(Cu,Al)3].

A detailed crystal chemical analysis shows (Fig. 2) that the title structure is a derivative of the binary Laves phases, such as MgZn2 and MgNi2 (Villars, 1997). As a result of the unit-cell deformation of the initial MgZn2 and MgNi2 Laves phases, the structure types of W6Fe7 (Arnfelt & Westgren, 1935) and Cs6K7 (Simon et al., 1976) can be obtained, respectively. By the systematic replacement of some atoms by atoms of a third component in the deformed binary derivatives, the ternary phases Li12Cu12.60Al14.37 and Li8Cu12+xAl6-x are obtained. The main features of both these compounds are channels of hexagonal prisms with Li atoms inside. Further displacement of some atoms, as a result of internal deformation, leads to a structure similar to the K4Au7Ge2 type (Zachwieja, 1995). As a result, in this structure half of the above-mentioned hexagonal prisms are transformed into octagonal prisms (Fig. 2).

The electronic structure of the title compound was calculated using the tight-binding linear muffin-tin orbital (TB–LMTO) method in the atomic spheres approximation (TB–LMTO–ASA; Andersen, 1975; Andersen & Jepsen, 1984; Andersen et al., 1985, 1986), using the experimental crystallographic data which are presented here. The exchange and correlation were interpreted in the local density approximation (von Barth & Hedin, 1972).

The TB–LMTO–ASA calculations were performed on an ordered Li12Cu13Al14 model of the title compound with the statistical mixture on the (Cu,Al)1 site approximated by a pure Cu occupation and on the (Cu,Al)2 site by a pure Al occupation, taking into account the refined proportions of atoms in these mixtures. The chemical bonding in the Li12Cu13Al14 intermetallic compound is visualized by means of the electron localization function (ELF) mapping, which is shown in Fig. 3(a), where the blue regions indicate zero electron localization around Li atoms, indicating that they are positively polarized. The electron concentration is higher around Ńu [?] atoms (light-blue regions) and the maximum ELFs are observed between Al–Al atoms (red regions). This indicates that, besides metallic bonding which is dominant in this compound, the weak covalent Al···Al interaction also exists. This is also highlighted by the isosurfaces of the ELF around the cited atom types (Fig. 3b). The rest of the crystal space has free electron-like behaviour (green region). The isosurfaces of the ELF around the atoms for the title compound are shown in Fig. 3(b). The total and partial densities of states (DOS) of Li12Cu13Al14 calculated by the TB–LMTO–ASA method are shown in Fig. 4(a). The Fermi level (EF) lies in a continuous DOS region indicating a metallic character for the title compound. The DOS is low over the entire energy range near the Fermi level and confirms its relative stability. The DOS [values] indicate that for the title compound the Cu atoms mainly contribute to the valence band. The chemical bonding (iCOHP curve) exhibits strong Al···Al interactions between -3 and -2 eV (Fig. 4b). These interactions are between Al3—Al3 (2.678 Å and -iCOHP = 0.1717 Ry cell-1). An almost twice weaker interaction is observed between Al and Cu atoms, for example, for Al3—Cu1 at a distance of 2.696 Å, the integrated crystal orbital Hamilton populations value is equal: -iCOHP = 0.0857 Ry cell-1. The interaction between the closest Cu atoms (Cu1···Cu1) is 2.461 Å and -iCOHP = 0.0691 Ry cell-1 (Fig. 4c). The weakest is the Li1—Li1 interaction (2.848 Å and -iCOHP = 0.0037 Ry cell-1) (Fig. 4d).

Related literature top

For related literature, see: Andersen (1975); Andersen & Jepsen (1984); Andersen et al. (1985, 1986); Arnfelt & Westgren (1935); Audier et al. (1988); Ball & Lloyd (1985); von Barth & Hedin (1972); Dubost et al. (1986); Farrugia (1999); Guryan et al. (1988); Knowles & Stobbs (1988); Konno et al. (2002); Pavlyuk & Bodak (1992); Pavlyuk et al. (2008a,b); Pavlyuk et al. (1995a,b,c,d); Schneider & von Heimendahl (1973); Simon et al. (1976); Van Smaalen, Meetsma, de Boer & Bronsveld (1990); Villars (1997); Zachwieja (1995).

Experimental top

The samples from the Li50Cu25Al25–Li35Cu35Al30 compositional range were prepared from the following reactants: lithium (rod, 99.9 at.%), copper (ingots, 99.999 at.%) and aluminium (ingots, 99.999 at.%). Appropriate amounts were mixed according to the aimed stoichiometry of the product and placed into tantalum crucibles in the glove-box under an argon atmosphere. These crucibles were sealed by arc melting under a dry argon atmosphere. The reaction between the metals was carried out in an induction furnace at 1373 K. After 15 min, the samples were rapidly cooled to room temperature by removing the crucibles from the furnace into ambient conditions. The reaction product was powdered in an agate mortar, filled into a capillary of 0.3 mm diameter and sealed for X-ray diffraction (XRD) on a Stoe Stadi P (Mo Kα1 radiation) in Debye–Scherrer mode (2θ from 3 to 59° in 2θ steps of 0.02°, linear position-sensitive detector with 6° aperture). A laminar-like single crystal, exhibiting metallic lustre, was isolated from the alloy by mechanical fragmentation. A single crystal was protected from air during X-ray data collection in a sealed thin-walled glass capillary (Hilgenberg, No. 10).

Refinement top

The analysis of systematic extinctions yielded the space group R3m and was confirmed by the following structure refinement. Also a statistical test of the distribution of the E values using the program E-STATS in the WinGX system (Farrugia, 1999) suggested that the structure is centrosymmetric. The structure was solved after the analytical absorption correction. In the first stage of the refinement, the positions of Cu and Al atoms were obtained correctly by direct methods. The remaining Li atoms were located in subsequent difference Fourier syntheses. Initial refinement of atomic parameters showed that the 18h and 3a positions were occupied by statistical mixtures of Al and Cu atoms. Moreover, the 18h position is more occupied by Cu atoms, while on site 3a, the aluminium content is predominant. In this structure, Al atoms fully occupy only one 6c site. The other two crystallographic 6c sites are occupied by Li atoms.

In the final refinement cycles, all atoms were successfully refined with anisotropic (Li atoms with isotropic) displacement parameters. The atomic coordinates were standardized using the STRUCTURE TIDY program (Gelato & Parthé, 1987).

Computing details top

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).

Figures top
[Figure 1] Fig. 1. The clinographic projection of the Li12Cu12.60Al14.37 unit-cell contents and the coordination polyhedra of atoms.
[Figure 2] Fig. 2. The relationship between MgZn2, MgNi2, W6Fe7, Cs6K7, Li12Cu13Al14 (Li12Cu12.60Al14.37), Li8Cu12+xAl6-x and K4Au7Ge2 structures.
[Figure 3] Fig. 3. (a) The electron localization function (ELF) mapping and (b) isosurfaces of the electron localization function around the atoms for Li12Cu13Al14.
[Figure 4] Fig. 4. (a) Total and partial DOS and (bd)–COHP curves for Li12Cu13Al14 from TB-LMTO-ASA calculations.
dodecalithium dodecacopper tetradecaaluminium top
Crystal data top
Li12Cu12.60Al14.37Dx = 3.640 Mg m3
Mr = 1271.71Mo Kα radiation, λ = 0.71073 Å
Trigonal, R3mCell parameters from 863 reflections
Hall symbol: -R 3 2"θ = 4.4–26.3°
a = 4.9301 (8) ŵ = 11.82 mm1
c = 27.561 (6) ÅT = 293 K
V = 580.2 (3) Å3Plate, metallic dark grey
Z = 10.16 × 0.09 × 0.03 mm
F(000) = 588.6
Data collection top
Oxford Diffraction Xcalibur3 CCD
182 independent reflections
Radiation source: fine-focus sealed tube173 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.072
Detector resolution: 0 pixels mm-1θmax = 26.3°, θmin = 4.4°
ω scansh = 46
Absorption correction: analytical
(CrysAlis RED; Oxford Diffraction, 2005)
k = 56
Tmin = 0.291, Tmax = 0.698l = 3333
863 measured reflections
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullPrimary atom site location: structure-invariant direct methods
R[F2 > 2σ(F2)] = 0.056Secondary atom site location: difference Fourier map
wR(F2) = 0.158 w = 1/[σ2(Fo2) + (0.1061P)2 + 0.4112P]
where P = (Fo2 + 2Fc2)/3
S = 1.25(Δ/σ)max = 0.001
182 reflectionsΔρmax = 1.67 e Å3
19 parametersΔρmin = 1.71 e Å3
Crystal data top
Li12Cu12.60Al14.37Z = 1
Mr = 1271.71Mo Kα radiation
Trigonal, R3mµ = 11.82 mm1
a = 4.9301 (8) ÅT = 293 K
c = 27.561 (6) Å0.16 × 0.09 × 0.03 mm
V = 580.2 (3) Å3
Data collection top
Oxford Diffraction Xcalibur3 CCD
182 independent reflections
Absorption correction: analytical
(CrysAlis RED; Oxford Diffraction, 2005)
173 reflections with I > 2σ(I)
Tmin = 0.291, Tmax = 0.698Rint = 0.072
863 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.05619 parameters
wR(F2) = 0.1580 restraints
S = 1.25Δρmax = 1.67 e Å3
182 reflectionsΔρmin = 1.71 e Å3
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Cu10.49970 (9)0.50030 (9)0.41177 (3)0.0181 (8)0.678 (13)
Al10.49970 (9)0.50030 (9)0.41177 (3)0.0181 (8)0.32
Cu20.00000.00000.00000.0212 (16)0.132 (13)
Al20.00000.00000.00000.0212 (16)0.87
Al30.00000.00000.45141 (10)0.0177 (13)
Li10.00000.00000.1649 (10)0.037 (6)*
Li20.00000.00000.3524 (7)0.025 (4)*
Atomic displacement parameters (Å2) top
Cu10.0135 (9)0.0135 (9)0.0284 (11)0.0077 (5)0.00089 (18)0.00089 (18)
Al10.0135 (9)0.0135 (9)0.0284 (11)0.0077 (5)0.00089 (18)0.00089 (18)
Cu20.023 (2)0.023 (2)0.018 (2)0.0113 (10)0.0000.000
Al20.023 (2)0.023 (2)0.018 (2)0.0113 (10)0.0000.000
Al30.0176 (16)0.0176 (16)0.0177 (19)0.0088 (8)0.0000.000
Geometric parameters (Å, º) top
Cu1—Al1i2.4606 (13)Al3—Cu1xv2.6963 (13)
Cu1—Cu1i2.4606 (13)Al3—Al1xvi2.6963 (13)
Cu1—Al1ii2.4606 (13)Al3—Cu1xvi2.6963 (13)
Cu1—Cu1ii2.4606 (13)Al3—Cu1i2.6963 (13)
Cu1—Cu1iii2.4695 (13)Al3—Al1i2.6963 (13)
Cu1—Al1iii2.4695 (13)Al3—Al1iii2.6963 (13)
Cu1—Al1iv2.4695 (13)Li1—Al1vii2.78 (2)
Cu1—Cu1iv2.4695 (13)Li1—Cu1vii2.78 (2)
Cu1—Al2v2.5896 (10)Li1—Al1xi2.78 (2)
Cu1—Cu2v2.5896 (10)Li1—Cu1xi2.78 (2)
Cu1—Al3vi2.6963 (13)Li1—Al1ix2.78 (2)
Cu1—Al32.6963 (13)Li1—Cu1ix2.78 (2)
Cu2—Al1vii2.5896 (10)Li1—Li1viii2.848 (2)
Cu2—Cu1vii2.5896 (10)Li1—Li1xvii2.8480 (19)
Cu2—Al1viii2.5896 (10)Li1—Li1xviii2.848 (2)
Cu2—Cu1viii2.5896 (10)Li1—Cu1xix2.86 (2)
Cu2—Al1ix2.5897 (10)Li1—Al1xix2.86 (2)
Cu2—Cu1ix2.5897 (10)Li1—Cu1xx2.86 (2)
Cu2—Al1x2.5897 (10)Li2—Al2xxi2.894 (4)
Cu2—Cu1x2.5897 (10)Li2—Cu2xxi2.894 (4)
Cu2—Cu1xi2.5897 (10)Li2—Al2v2.894 (4)
Cu2—Al1xi2.5897 (10)Li2—Cu2v2.894 (4)
Cu2—Cu1xii2.5897 (10)Li2—Al2xxii2.894 (4)
Cu2—Al1xii2.5897 (10)Li2—Cu2xxii2.894 (4)
Al3—Al3xiii2.678 (6)Li2—Al1i2.959 (11)
Al3—Al1xiv2.6963 (13)Li2—Cu1i2.959 (11)
Al3—Cu1xiv2.6963 (13)Li2—Cu1iii2.959 (11)
Al3—Al1xv2.6963 (13)
Al1i—Cu1—Cu1i0.00 (4)Al1xiv—Al3—Cu1132.19 (12)
Al1i—Cu1—Al1ii60.000 (1)Cu1xiv—Al3—Cu1132.19 (12)
Cu1i—Cu1—Al1ii60.000 (1)Al1xv—Al3—Cu1104.70 (7)
Al1i—Cu1—Cu1ii60.000 (1)Cu1xv—Al3—Cu1104.70 (7)
Cu1i—Cu1—Cu1ii60.000 (1)Al1xvi—Al3—Cu1104.70 (7)
Al1ii—Cu1—Cu1ii0.00 (5)Cu1xvi—Al3—Cu1104.70 (7)
Al1i—Cu1—Cu1iii120.0Al3xiii—Al3—Cu1i113.90 (6)
Cu1i—Cu1—Cu1iii120.0Al1xiv—Al3—Cu1i104.70 (7)
Al1ii—Cu1—Cu1iii180.00 (9)Cu1xiv—Al3—Cu1i104.70 (7)
Cu1ii—Cu1—Cu1iii180.00 (9)Al1xv—Al3—Cu1i54.51 (4)
Al1i—Cu1—Al1iii120.0Cu1xv—Al3—Cu1i54.51 (4)
Cu1i—Cu1—Al1iii120.0Al1xvi—Al3—Cu1i132.19 (12)
Al1ii—Cu1—Al1iii180.00 (9)Cu1xvi—Al3—Cu1i132.19 (12)
Cu1ii—Cu1—Al1iii180.00 (9)Cu1—Al3—Cu1i54.30 (4)
Cu1iii—Cu1—Al1iii0.00 (4)Al3xiii—Al3—Al1i113.90 (6)
Al1i—Cu1—Al1iv180.00 (9)Al1xiv—Al3—Al1i104.70 (7)
Cu1i—Cu1—Al1iv180.00 (9)Cu1xiv—Al3—Al1i104.70 (7)
Al1ii—Cu1—Al1iv120.000 (1)Al1xv—Al3—Al1i54.51 (4)
Cu1ii—Cu1—Al1iv120.000 (1)Cu1xv—Al3—Al1i54.51 (4)
Cu1iii—Cu1—Al1iv60.0Al1xvi—Al3—Al1i132.19 (12)
Al1iii—Cu1—Al1iv60.0Cu1xvi—Al3—Al1i132.19 (12)
Al1i—Cu1—Cu1iv180.00 (9)Cu1—Al3—Al1i54.30 (4)
Cu1i—Cu1—Cu1iv180.00 (9)Cu1i—Al3—Al1i0.00 (5)
Al1ii—Cu1—Cu1iv120.000 (1)Al3xiii—Al3—Al1iii113.90 (6)
Cu1ii—Cu1—Cu1iv120.000 (1)Al1xiv—Al3—Al1iii104.70 (7)
Cu1iii—Cu1—Cu1iv60.0Cu1xiv—Al3—Al1iii104.70 (7)
Al1iii—Cu1—Cu1iv60.0Al1xv—Al3—Al1iii132.19 (12)
Al1iv—Cu1—Cu1iv0.00 (5)Cu1xv—Al3—Al1iii132.19 (12)
Al1i—Cu1—Al2v118.476 (16)Al1xvi—Al3—Al1iii54.30 (4)
Cu1i—Cu1—Al2v118.476 (16)Cu1xvi—Al3—Al1iii54.30 (4)
Al1ii—Cu1—Al2v118.476 (16)Cu1—Al3—Al1iii54.51 (4)
Cu1ii—Cu1—Al2v118.476 (16)Cu1i—Al3—Al1iii104.70 (7)
Cu1iii—Cu1—Al2v61.524 (15)Al1i—Al3—Al1iii104.70 (7)
Al1iii—Cu1—Al2v61.524 (15)Al1vii—Li1—Cu1vii0.00 (2)
Al1iv—Cu1—Al2v61.524 (15)Al1vii—Li1—Al1xi52.8 (5)
Cu1iv—Cu1—Al2v61.524 (15)Cu1vii—Li1—Al1xi52.8 (5)
Al1i—Cu1—Cu2v118.476 (16)Al1vii—Li1—Cu1xi52.8 (5)
Cu1i—Cu1—Cu2v118.476 (16)Cu1vii—Li1—Cu1xi52.8 (5)
Al1ii—Cu1—Cu2v118.476 (16)Al1xi—Li1—Cu1xi0.00 (5)
Cu1ii—Cu1—Cu2v118.476 (16)Al1vii—Li1—Al1ix52.8 (5)
Cu1iii—Cu1—Cu2v61.524 (15)Cu1vii—Li1—Al1ix52.8 (5)
Al1iii—Cu1—Cu2v61.524 (15)Al1xi—Li1—Al1ix52.8 (5)
Al1iv—Cu1—Cu2v61.524 (15)Cu1xi—Li1—Al1ix52.8 (5)
Cu1iv—Cu1—Cu2v61.524 (15)Al1vii—Li1—Cu1ix52.8 (5)
Al2v—Cu1—Cu2v0.0Cu1vii—Li1—Cu1ix52.8 (5)
Al1i—Cu1—Al3vi117.25 (2)Al1xi—Li1—Cu1ix52.8 (5)
Cu1i—Cu1—Al3vi117.25 (2)Cu1xi—Li1—Cu1ix52.8 (5)
Al1ii—Cu1—Al3vi62.85 (2)Al1ix—Li1—Cu1ix0.00 (3)
Cu1ii—Cu1—Al3vi62.85 (2)Al1vii—Li1—Li1viii106.6 (11)
Cu1iii—Cu1—Al3vi117.15 (2)Cu1vii—Li1—Li1viii106.6 (11)
Al1iii—Cu1—Al3vi117.15 (2)Al1xi—Li1—Li1viii106.6 (11)
Al1iv—Cu1—Al3vi62.75 (2)Cu1xi—Li1—Li1viii106.6 (11)
Cu1iv—Cu1—Al3vi62.75 (2)Al1ix—Li1—Li1viii61.0 (8)
Al2v—Cu1—Al3vi109.74 (5)Cu1ix—Li1—Li1viii61.0 (8)
Cu2v—Cu1—Al3vi109.74 (5)Al1vii—Li1—Li1xvii106.6 (11)
Al1i—Cu1—Al362.85 (2)Cu1vii—Li1—Li1xvii106.6 (11)
Cu1i—Cu1—Al362.85 (2)Al1xi—Li1—Li1xvii61.0 (8)
Al1ii—Cu1—Al3117.25 (2)Cu1xi—Li1—Li1xvii61.0 (8)
Cu1ii—Cu1—Al3117.25 (2)Al1ix—Li1—Li1xvii106.6 (11)
Cu1iii—Cu1—Al362.75 (2)Cu1ix—Li1—Li1xvii106.6 (11)
Al1iii—Cu1—Al362.75 (2)Li1viii—Li1—Li1xvii119.89 (13)
Al1iv—Cu1—Al3117.15 (2)Al1vii—Li1—Li1xviii61.0 (8)
Cu1iv—Cu1—Al3117.15 (2)Cu1vii—Li1—Li1xviii61.0 (8)
Al2v—Cu1—Al3109.74 (5)Al1xi—Li1—Li1xviii106.6 (11)
Cu2v—Cu1—Al3109.74 (5)Cu1xi—Li1—Li1xviii106.6 (11)
Al3vi—Cu1—Al3132.19 (12)Al1ix—Li1—Li1xviii106.6 (11)
Al1vii—Cu2—Cu1vii0.00 (3)Cu1ix—Li1—Li1xviii106.6 (11)
Al1vii—Cu2—Al1viii180.00 (3)Li1viii—Li1—Li1xviii119.89 (13)
Cu1vii—Cu2—Al1viii180.00 (3)Li1xvii—Li1—Li1xviii119.89 (13)
Al1vii—Cu2—Cu1viii180.00 (3)Al1vii—Li1—Cu1xix119.30 (3)
Cu1vii—Cu2—Cu1viii180.00 (3)Cu1vii—Li1—Cu1xix119.30 (3)
Al1viii—Cu2—Cu1viii0.00 (3)Al1xi—Li1—Cu1xix150.72 (3)
Al1vii—Cu2—Al1ix56.95 (3)Cu1xi—Li1—Cu1xix150.72 (3)
Cu1vii—Cu2—Al1ix56.95 (3)Al1ix—Li1—Cu1xix150.72 (3)
Al1viii—Cu2—Al1ix123.05 (3)Cu1ix—Li1—Cu1xix150.72 (3)
Cu1viii—Cu2—Al1ix123.05 (3)Li1viii—Li1—Cu1xix102.7 (11)
Al1vii—Cu2—Cu1ix56.95 (3)Li1xvii—Li1—Cu1xix102.7 (11)
Cu1vii—Cu2—Cu1ix56.95 (3)Li1xviii—Li1—Cu1xix58.3 (8)
Al1viii—Cu2—Cu1ix123.05 (3)Al1vii—Li1—Al1xix119.30 (3)
Cu1viii—Cu2—Cu1ix123.05 (3)Cu1vii—Li1—Al1xix119.30 (3)
Al1ix—Cu2—Cu1ix0.00 (3)Al1xi—Li1—Al1xix150.72 (3)
Al1vii—Cu2—Al1x123.05 (3)Cu1xi—Li1—Al1xix150.72 (3)
Cu1vii—Cu2—Al1x123.05 (3)Al1ix—Li1—Al1xix150.72 (3)
Al1viii—Cu2—Al1x56.95 (3)Cu1ix—Li1—Al1xix150.72 (3)
Cu1viii—Cu2—Al1x56.95 (3)Li1viii—Li1—Al1xix102.7 (11)
Al1ix—Cu2—Al1x180.00 (3)Li1xvii—Li1—Al1xix102.7 (11)
Cu1ix—Cu2—Al1x180.00 (3)Li1xviii—Li1—Al1xix58.3 (8)
Al1vii—Cu2—Cu1x123.05 (3)Cu1xix—Li1—Al1xix0.00 (2)
Cu1vii—Cu2—Cu1x123.05 (3)Al1vii—Li1—Cu1xx150.72 (3)
Al1viii—Cu2—Cu1x56.95 (3)Cu1vii—Li1—Cu1xx150.72 (3)
Cu1viii—Cu2—Cu1x56.95 (3)Al1xi—Li1—Cu1xx150.72 (3)
Al1ix—Cu2—Cu1x180.00 (3)Cu1xi—Li1—Cu1xx150.72 (3)
Cu1ix—Cu2—Cu1x180.00 (3)Al1ix—Li1—Cu1xx119.30 (3)
Al1x—Cu2—Cu1x0.00 (2)Cu1ix—Li1—Cu1xx119.30 (3)
Al1vii—Cu2—Cu1xi56.95 (3)Li1viii—Li1—Cu1xx58.3 (8)
Cu1vii—Cu2—Cu1xi56.95 (3)Li1xvii—Li1—Cu1xx102.7 (11)
Al1viii—Cu2—Cu1xi123.05 (3)Li1xviii—Li1—Cu1xx102.7 (11)
Cu1viii—Cu2—Cu1xi123.05 (3)Cu1xix—Li1—Cu1xx51.0 (5)
Al1ix—Cu2—Cu1xi56.95 (3)Al1xix—Li1—Cu1xx51.0 (5)
Cu1ix—Cu2—Cu1xi56.95 (3)Al3—Li2—Al2xxi100.4 (4)
Al1x—Cu2—Cu1xi123.05 (3)Al3—Li2—Cu2xxi100.4 (4)
Cu1x—Cu2—Cu1xi123.05 (3)Al2xxi—Li2—Cu2xxi0.0
Al1vii—Cu2—Al1xi56.95 (3)Al3—Li2—Al2v100.4 (4)
Cu1vii—Cu2—Al1xi56.95 (3)Al2xxi—Li2—Al2v116.8 (2)
Al1viii—Cu2—Al1xi123.05 (3)Cu2xxi—Li2—Al2v116.8 (2)
Cu1viii—Cu2—Al1xi123.05 (3)Al3—Li2—Cu2v100.4 (4)
Al1ix—Cu2—Al1xi56.95 (3)Al2xxi—Li2—Cu2v116.8 (2)
Cu1ix—Cu2—Al1xi56.95 (3)Cu2xxi—Li2—Cu2v116.8 (2)
Al1x—Cu2—Al1xi123.05 (3)Al2v—Li2—Cu2v0.0
Cu1x—Cu2—Al1xi123.05 (3)Al3—Li2—Al2xxii100.4 (4)
Cu1xi—Cu2—Al1xi0.00 (6)Al2xxi—Li2—Al2xxii116.8 (2)
Al1vii—Cu2—Cu1xii123.05 (3)Cu2xxi—Li2—Al2xxii116.8 (2)
Cu1vii—Cu2—Cu1xii123.05 (3)Al2v—Li2—Al2xxii116.8 (2)
Al1viii—Cu2—Cu1xii56.95 (3)Cu2v—Li2—Al2xxii116.8 (2)
Cu1viii—Cu2—Cu1xii56.95 (3)Al3—Li2—Cu2xxii100.4 (4)
Al1ix—Cu2—Cu1xii123.05 (3)Al2xxi—Li2—Cu2xxii116.8 (2)
Cu1ix—Cu2—Cu1xii123.05 (3)Cu2xxi—Li2—Cu2xxii116.8 (2)
Al1x—Cu2—Cu1xii56.95 (3)Al2v—Li2—Cu2xxii116.8 (2)
Cu1x—Cu2—Cu1xii56.95 (3)Cu2v—Li2—Cu2xxii116.8 (2)
Cu1xi—Cu2—Cu1xii180.00 (6)Al2xxii—Li2—Cu2xxii0.0
Al1xi—Cu2—Cu1xii180.00 (6)Al3—Li2—Cu156.4 (3)
Al1vii—Cu2—Al1xii123.05 (3)Al2xxi—Li2—Cu1144.1 (4)
Cu1vii—Cu2—Al1xii123.05 (3)Cu2xxi—Li2—Cu1144.1 (4)
Al1viii—Cu2—Al1xii56.95 (3)Al2v—Li2—Cu152.50 (8)
Cu1viii—Cu2—Al1xii56.95 (3)Cu2v—Li2—Cu152.50 (8)
Al1ix—Cu2—Al1xii123.05 (3)Al2xxii—Li2—Cu195.71 (16)
Cu1ix—Cu2—Al1xii123.05 (3)Cu2xxii—Li2—Cu195.71 (16)
Al1x—Cu2—Al1xii56.95 (3)Al3—Li2—Al1i56.4 (3)
Cu1x—Cu2—Al1xii56.95 (3)Al2xxi—Li2—Al1i144.1 (4)
Cu1xi—Cu2—Al1xii180.00 (6)Cu2xxi—Li2—Al1i144.1 (4)
Al1xi—Cu2—Al1xii180.00 (6)Al2v—Li2—Al1i95.71 (16)
Cu1xii—Cu2—Al1xii0.00 (4)Cu2v—Li2—Al1i95.71 (16)
Al3xiii—Al3—Al1xiv113.90 (6)Al2xxii—Li2—Al1i52.50 (8)
Al3xiii—Al3—Cu1xiv113.90 (6)Cu2xxii—Li2—Al1i52.50 (8)
Al1xiv—Al3—Cu1xiv0.0Cu1—Li2—Al1i49.14 (19)
Al3xiii—Al3—Al1xv113.90 (6)Al3—Li2—Cu1i56.4 (3)
Al1xiv—Al3—Al1xv54.30 (4)Al2xxi—Li2—Cu1i144.1 (4)
Cu1xiv—Al3—Al1xv54.30 (4)Cu2xxi—Li2—Cu1i144.1 (4)
Al3xiii—Al3—Cu1xv113.90 (6)Al2v—Li2—Cu1i95.71 (16)
Al1xiv—Al3—Cu1xv54.30 (4)Cu2v—Li2—Cu1i95.71 (16)
Cu1xiv—Al3—Cu1xv54.30 (4)Al2xxii—Li2—Cu1i52.50 (8)
Al1xv—Al3—Cu1xv0.00 (4)Cu2xxii—Li2—Cu1i52.50 (8)
Al3xiii—Al3—Al1xvi113.90 (6)Cu1—Li2—Cu1i49.14 (19)
Al1xiv—Al3—Al1xvi54.51 (4)Al1i—Li2—Cu1i0.00 (4)
Cu1xiv—Al3—Al1xvi54.51 (4)Al3—Li2—Cu1iii56.4 (3)
Al1xv—Al3—Al1xvi104.70 (7)Al2xxi—Li2—Cu1iii95.71 (16)
Cu1xv—Al3—Al1xvi104.70 (7)Cu2xxi—Li2—Cu1iii95.71 (16)
Al3xiii—Al3—Cu1xvi113.90 (6)Al2v—Li2—Cu1iii52.50 (8)
Al1xiv—Al3—Cu1xvi54.51 (4)Cu2v—Li2—Cu1iii52.50 (8)
Cu1xiv—Al3—Cu1xvi54.51 (4)Al2xxii—Li2—Cu1iii144.1 (4)
Al1xv—Al3—Cu1xvi104.70 (7)Cu2xxii—Li2—Cu1iii144.1 (4)
Cu1xv—Al3—Cu1xvi104.70 (7)Cu1—Li2—Cu1iii49.3 (2)
Al1xvi—Al3—Cu1xvi0.00 (4)Al1i—Li2—Cu1iii92.3 (4)
Al3xiii—Al3—Cu1113.90 (6)Cu1i—Li2—Cu1iii92.3 (4)
Symmetry codes: (i) x+y, x+1, z; (ii) y+1, xy+1, z; (iii) y+1, xy, z; (iv) x+y+1, x+1, z; (v) x+2/3, y+1/3, z+1/3; (vi) x+1, y+1, z; (vii) x2/3, y1/3, z1/3; (viii) x+2/3, y+1/3, z+1/3; (ix) x+y+1/3, x+2/3, z1/3; (x) xy1/3, x2/3, z+1/3; (xi) y+1/3, xy1/3, z1/3; (xii) y1/3, x+y+1/3, z+1/3; (xiii) x, y, z+1; (xiv) x1, y1, z; (xv) y, xy, z; (xvi) x+y, x, z; (xvii) x1/3, y2/3, z+1/3; (xviii) x1/3, y+1/3, z+1/3; (xix) x+1/3, y+2/3, z+2/3; (xx) xy+1/3, x1/3, z+2/3; (xxi) x1/3, y2/3, z+1/3; (xxii) x1/3, y+1/3, z+1/3.

Experimental details

Crystal data
Chemical formulaLi12Cu12.60Al14.37
Crystal system, space groupTrigonal, R3m
Temperature (K)293
a, c (Å)4.9301 (8), 27.561 (6)
V3)580.2 (3)
Radiation typeMo Kα
µ (mm1)11.82
Crystal size (mm)0.16 × 0.09 × 0.03
Data collection
DiffractometerOxford Diffraction Xcalibur3 CCD
Absorption correctionAnalytical
(CrysAlis RED; Oxford Diffraction, 2005)
Tmin, Tmax0.291, 0.698
No. of measured, independent and
observed [I > 2σ(I)] reflections
863, 182, 173
(sin θ/λ)max1)0.624
R[F2 > 2σ(F2)], wR(F2), S 0.056, 0.158, 1.25
No. of reflections182
No. of parameters19
Δρmax, Δρmin (e Å3)1.67, 1.71

Computer programs: CrysAlis CCD (Oxford Diffraction, 2004), CrysAlis RED (Oxford Diffraction, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 1999).


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