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Yttrium tricopper dialuminium, YCu3Al2, is isostructural with hexagonal CaCu5, in which each Cu atom at the 3g(½,0,½) position in space group P6/mmm (No. 191) is partially replaced by an Al atom. The hydrogen-uptake properties are usually enhanced in other AB5 structures by aluminium substitution. YCu5 does not show any hydrogen absorption, and the goal of the present work is to investigate whether aluminium substitution could expand the metal-atom lattice enough to provide better interstitial positions for hydrogen storage. However, no enthalpy change was observed up to 773 K under 3 MPa static H2 pressure by differential thermal analysis (DTA) for the title compound. The compound does not show any significant hydrogen absorption/desorption in the pressure-composition isotherms (P-C-T diagrams) in the temperature range 298-673 K under 3.3 MPa H2 pressure.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270101010009/br1341sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270101010009/br1341Isup2.hkl
Contains datablock I

Comment top

Previous investigations have shown that the light rare-earth elements, and incidentally also some heavy rare-earth elements, form a hexagonal compound of the AB5 system (CaCu5 type) as reported in the literature (Dwight, 1961; Wernick & Geller, 1959; Haszko, 1960). The stoichiometric composition of these hexagonal phases does not seem well established as some rare-earth elements have the CaCu5 structure in compounds of composition RCu4 as well as RCu5 (Gschneidner, 1961).

Studies of the intermetallic AB5 system (CaCu5 type) has shown that several properties, e.g. the hydrogen-absorption properties of the phases, can be easily varied over a wide range by the partial replacement of A or B atoms by other metals (Lanker et al., 1982; Van Vucht, Kuijpers & Bruning, 1970). Relatively large differences in the metallic radii of the A and B metals favors the stability of the AB5 phases, making them so-called `line compounds' in their binary-phase diagrams. This stability may be essential in order to obtain a homogeneous composition of the intermetallic compound.

Pure RCu5 is not stable and crystallizes in the BaAl4 type structure. It is noted that aluminium substitution stabilizes the hexagonal CaCu5 type structure for RCu4Al compounds (R = La—Sm; Takeshita et al., 1978).

The investigation of the present compound is part of a larger project aimed at finding alternative intermetallic AB5 compounds for hydrogen absorption, based on both elements lighter than lanthanides (for example, R = Y) and cheap elements (for example, substitution of a B atom in RB5-type structures by Cu and Al).

Both YCu5 and YNi5 did not show any hydrogen uptake and it was therefore of interest to study the influence of metal-atom replacement in YCu5 (Wernick & Geller, 1959; Buschow & Goot, 1971) by aluminium as the atomic radius of Al (1.432 Å) is larger than that of Cu (1.278 Å; Teatum et al., 1960), thus expanding the metal-atom lattice and possibly also providing interstitial positions for hydrogen.

The YCu5 structure (Wernick & Geller, 1959) is built from alternate layers of the CaCu5 type, viz. each Y is surrounded by six Cu atoms in one plane (at 2.88 Å) and by two more sets of six Cu atoms in adjacent planes (at 3.23 Å).

The same planes exist in YCu3Al2 but at slightly different distances (Fig. 1). The average nearest-neighbour Cu1—Cu2 distances are increased compared with those of YCu5 (2.49 and 2.51 Å; Wernick & Geller, 1959). The (Cu—Cu) distances in the present compound are close to those of a normal close-packed Cu atom with coordination number (CN) 12 (average nearest-neighbor distance = 2.56 Å; Wernick & Geller, 1959).

This compound does not show any hydrogen absorption/desorption in the pressure-composition isotherms (P—C—T diagrams) in the temperature range 298–673 K under 3.3 MPa H2 pressure using an automated Sieverts-type apparatus. No enthalpy change was observed up to 773 K in 3 MPa static hydrogen pressure by differential thermal analysis (DTA) for the present compound. No disproportion of the alloy was observed by XRD after DTA and P—C—T.

Experimental top

The purity of the starting materials was 99.99% for Cu and Al, and 99.9% for Y. A pressed tablet of a mixture of suitable weight% ratio of finely powdered starting materials was sintered at 773 K in 0.6 MPa Ar gas for 1 h, followed by higher temperature annealing at 1023 K for 1 h, with subsequent rapid cooling to room temperature. The sample was crushed and reheated directly to 1023 K under the same conditions as above, followed by cooling (at 20 K min-1 to 673 K) and then rapid cooling to room temperature. Upon optical microscopic examination, the alloy exhibited regular metallic hexagons. Some of the crystallites were isolated and crushed to powder form for identification by Guinier–Hägg X-ray powder diffraction. The atomic composition was verified by EDX analysis with a Jeol 820 scanning electron microscope equipped with a LINK elemental analysis system.

Refinement top

The highest peak in the residual density map, 1.86 e/Å3 at (0, 0, 0.1241), is 0.51 Å from the Y-position. The absorption correction was carried out with XABS2 (Parkin et al., 1995) using reflection data from the whole sphere.

Computing details top

Data collection: DIF4 (Stoe & Cie, 1988); cell refinement: DIF4; data reduction: REDU4 (Stoe & Cie, 1988); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Bergerhoff, 1996).

Figures top
[Figure 1] Fig. 1. Stereoview of the unit-cell contents with ellipsoids plotted at the 90% probability level. Position M is a mixed position of Cu2 (31%) and Al2 (69%).
Yttrium tricopper dialuminium top
Crystal data top
YCu3Al2Dx = 5.747 Mg m3
Mr = 332.03Mo Kα radiation, λ = 0.71073 Å
Hexagonal, P6/mmmCell parameters from 50 reflections
a = 5.172 (3) Åθ = 18–22°
c = 4.141 (2) ŵ = 31.38 mm1
V = 95.93 (9) Å3T = 293 K
Z = 1Metallic prism, grey
F(000) = 1510.29 × 0.07 × 0.06 mm
Data collection top
Stoe AED2
diffractometer
182 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.099
Graphite monochromatorθmax = 44.9°, θmin = 4.6°
θ–2θ scansh = 1010
Absorption correction: multi-scan
(XABS2; Parkin et al., 1995)
k = 1010
Tmin = 0.062, Tmax = 0.152l = 87
2818 measured reflections4 standard reflections every 120 min
196 independent reflections intensity decay: <1%
Refinement top
Refinement on F20 restraints
Least-squares matrix: full w = 1/[σ2(Fo2) + (0.020P)2]
where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.021(Δ/σ)max < 0.001
wR(F2) = 0.055Δρmax = 1.86 e Å3
S = 1.38Δρmin = 2.21 e Å3
196 reflectionsExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
10 parametersExtinction coefficient: 0.167 (16)
Crystal data top
YCu3Al2Z = 1
Mr = 332.03Mo Kα radiation
Hexagonal, P6/mmmµ = 31.38 mm1
a = 5.172 (3) ÅT = 293 K
c = 4.141 (2) Å0.29 × 0.07 × 0.06 mm
V = 95.93 (9) Å3
Data collection top
Stoe AED2
diffractometer
182 reflections with I > 2σ(I)
Absorption correction: multi-scan
(XABS2; Parkin et al., 1995)
Rint = 0.099
Tmin = 0.062, Tmax = 0.1524 standard reflections every 120 min
2818 measured reflections intensity decay: <1%
196 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.02110 parameters
wR(F2) = 0.0550 restraints
S = 1.38Δρmax = 1.86 e Å3
196 reflectionsΔρmin = 2.21 e Å3
Special details top

Experimental. This residual peak is most probably due to errors in the low-angle reflections. Two refinements using reflection data with 2θ > 40° and one with 2θ > 60° did not give any high residual peaks. The high internal R value is most probably an effect of the slightly irregular crystal shape together with a very high absorption coefficient. Heavily absorbing crystals give contributions to the reflection intensities proportional to the respective surface areas exposed to the X-ray beam. The internal R values calculated from the data with 2θ > 40° and the data with 2θ > 60° were not significantly improved. At present, our absorption-correction programs work on the principle of correcting the intensities of the reflections transmitted through the crystal. Attempts to use the observed shape of the crystal and analytical corrections with the use of this shape failed.

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)
Y0000.00351 (14)
Cu10.33330.666700.00484 (14)
Cu20.500.50.00551 (15)0.314 (4)
Al20.500.50.00551 (15)0.69
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Y0.00227 (16)0.00227 (16)0.0060 (2)0.00114 (8)0.0000.000
Cu10.00593 (17)0.00593 (17)0.00265 (19)0.00297 (8)0.0000.000
Cu20.0088 (2)0.0015 (2)0.0038 (2)0.00076 (11)0.0000.000
Al20.0088 (2)0.0015 (2)0.0038 (2)0.00076 (11)0.0000.000
Geometric parameters (Å, º) top
Y—Cu1i2.9861 (17)Cu2—Cu1xiii2.5527 (10)
Y—Cu1ii2.9861 (17)Cu2—Cu1ii2.5527 (10)
Y—Cu1iii2.9861 (17)Cu2—Cu1iii2.5527 (10)
Y—Cu12.9861 (17)Cu2—Cu1xiv2.5527 (10)
Y—Cu1iv2.9861 (17)Cu2—Al2xv2.5860 (15)
Y—Cu1v2.9861 (17)Cu2—Al2xvi2.5860 (15)
Y—Al2vi3.3128 (13)Cu2—Cu2xv2.5860 (15)
Y—Al2vii3.3128 (13)Cu2—Cu2xvi2.5860 (15)
Y—Cu2vi3.3128 (13)Cu2—Al2vi2.5860 (15)
Y—Cu2vii3.3128 (13)Cu2—Al2xvii2.5860 (15)
Y—Cu23.3128 (13)Cu2—Cu2vi2.5860 (15)
Y—Al23.3128 (13)Cu2—Cu2xvii2.5860 (15)
Cu1—Al2viii2.5527 (10)Al2—Cu1xiii2.5527 (10)
Cu1—Al2ix2.5527 (10)Al2—Cu1ii2.5527 (10)
Cu1—Cu2viii2.5527 (10)Al2—Cu1iii2.5527 (10)
Cu1—Cu2ix2.5527 (10)Al2—Cu1xiv2.5527 (10)
Cu1—Al2x2.5527 (10)Al2—Al2xv2.5860 (15)
Cu1—Al2xi2.5527 (10)Al2—Al2xvi2.5860 (15)
Cu1—Cu2x2.5527 (10)Al2—Cu2xv2.5860 (15)
Cu1—Cu2xi2.5527 (10)Al2—Cu2xvi2.5860 (15)
Cu1—Al2vi2.5527 (10)Al2—Al2vi2.5860 (15)
Cu1—Al2xii2.5527 (10)Al2—Al2xvii2.5860 (15)
Cu1—Cu2vi2.5527 (10)Al2—Cu2vi2.5860 (15)
Cu1—Cu2xii2.5527 (10)Al2—Cu2xvii2.5860 (15)
Cu1i—Y—Cu1ii180.0Cu1xiii—Cu2—Cu1ii180.0
Cu1i—Y—Cu1iii120.0Cu1xiii—Cu2—Cu1iii108.41 (4)
Cu1ii—Y—Cu1iii60.0Cu1ii—Cu2—Cu1iii71.59 (4)
Cu1i—Y—Cu160.0Cu1xiii—Cu2—Cu1xiv71.59 (4)
Cu1ii—Y—Cu1120.0Cu1ii—Cu2—Cu1xiv108.41 (4)
Cu1iii—Y—Cu160.0Cu1iii—Cu2—Cu1xiv180.0
Cu1i—Y—Cu1iv60.0Cu1xiii—Cu2—Al2xv59.567 (17)
Cu1ii—Y—Cu1iv120.0Cu1ii—Cu2—Al2xv120.433 (17)
Cu1iii—Y—Cu1iv180.0Cu1iii—Cu2—Al2xv59.567 (17)
Cu1—Y—Cu1iv120.0Cu1xiv—Cu2—Al2xv120.433 (17)
Cu1i—Y—Cu1v120.0Cu1xiii—Cu2—Al2xvi120.433 (17)
Cu1ii—Y—Cu1v60.0Cu1ii—Cu2—Al2xvi59.567 (17)
Cu1iii—Y—Cu1v120.0Cu1iii—Cu2—Al2xvi120.433 (17)
Cu1—Y—Cu1v180.0Cu1xiv—Cu2—Al2xvi59.567 (17)
Cu1iv—Y—Cu1v60.0Al2xv—Cu2—Al2xvi180.0
Cu1i—Y—Al2vi90.0Cu1xiii—Cu2—Cu2xv59.567 (17)
Cu1ii—Y—Al2vi90.0Cu1ii—Cu2—Cu2xv120.433 (17)
Cu1iii—Y—Al2vi47.465 (15)Cu1iii—Cu2—Cu2xv59.567 (17)
Cu1—Y—Al2vi47.465 (15)Cu1xiv—Cu2—Cu2xv120.433 (17)
Cu1iv—Y—Al2vi132.535 (16)Al2xv—Cu2—Cu2xv0.0
Cu1v—Y—Al2vi132.535 (15)Al2xvi—Cu2—Cu2xv180.0
Cu1i—Y—Al2vii90.0Cu1xiii—Cu2—Cu2xvi120.433 (17)
Cu1ii—Y—Al2vii90.0Cu1ii—Cu2—Cu2xvi59.567 (17)
Cu1iii—Y—Al2vii132.535 (16)Cu1iii—Cu2—Cu2xvi120.433 (17)
Cu1—Y—Al2vii132.535 (15)Cu1xiv—Cu2—Cu2xvi59.567 (17)
Cu1iv—Y—Al2vii47.465 (15)Al2xv—Cu2—Cu2xvi180.0
Cu1v—Y—Al2vii47.465 (15)Al2xvi—Cu2—Cu2xvi0.0
Al2vi—Y—Al2vii180.0Cu2xv—Cu2—Cu2xvi180.0
Cu1i—Y—Cu2vi90.0Cu1xiii—Cu2—Al2vi59.567 (17)
Cu1ii—Y—Cu2vi90.0Cu1ii—Cu2—Al2vi120.433 (17)
Cu1iii—Y—Cu2vi47.465 (15)Cu1iii—Cu2—Al2vi59.567 (17)
Cu1—Y—Cu2vi47.465 (15)Cu1xiv—Cu2—Al2vi120.433 (17)
Cu1iv—Y—Cu2vi132.535 (16)Al2xv—Cu2—Al2vi60.0
Cu1v—Y—Cu2vi132.535 (15)Al2xvi—Cu2—Al2vi120.0
Al2vi—Y—Cu2vi0.0Cu2xv—Cu2—Al2vi60.0
Al2vii—Y—Cu2vi180.0Cu2xvi—Cu2—Al2vi120.0
Cu1i—Y—Cu2vii90.0Cu1xiii—Cu2—Al2xvii120.433 (17)
Cu1ii—Y—Cu2vii90.0Cu1ii—Cu2—Al2xvii59.567 (17)
Cu1iii—Y—Cu2vii132.535 (16)Cu1iii—Cu2—Al2xvii120.433 (17)
Cu1—Y—Cu2vii132.535 (15)Cu1xiv—Cu2—Al2xvii59.567 (17)
Cu1iv—Y—Cu2vii47.465 (15)Al2xv—Cu2—Al2xvii120.0
Cu1v—Y—Cu2vii47.465 (15)Al2xvi—Cu2—Al2xvii60.0
Al2vi—Y—Cu2vii180.0Cu2xv—Cu2—Al2xvii120.0
Al2vii—Y—Cu2vii0.0Cu2xvi—Cu2—Al2xvii60.0
Cu2vi—Y—Cu2vii180.0Al2vi—Cu2—Al2xvii180.0
Cu1i—Y—Cu2132.535 (16)Cu1xiii—Cu2—Cu2vi59.567 (17)
Cu1ii—Y—Cu247.465 (16)Cu1ii—Cu2—Cu2vi120.433 (17)
Cu1iii—Y—Cu247.465 (16)Cu1iii—Cu2—Cu2vi59.567 (17)
Cu1—Y—Cu290.0Cu1xiv—Cu2—Cu2vi120.433 (17)
Cu1iv—Y—Cu2132.535 (16)Al2xv—Cu2—Cu2vi60.0
Cu1v—Y—Cu290.0Al2xvi—Cu2—Cu2vi120.0
Al2vi—Y—Cu245.947 (14)Cu2xv—Cu2—Cu2vi60.0
Al2vii—Y—Cu2134.053 (14)Cu2xvi—Cu2—Cu2vi120.0
Cu2vi—Y—Cu245.947 (14)Al2vi—Cu2—Cu2vi0.0
Cu2vii—Y—Cu2134.053 (14)Al2xvii—Cu2—Cu2vi180.0
Cu1i—Y—Al2132.535 (16)Cu1xiii—Cu2—Cu2xvii120.433 (17)
Cu1ii—Y—Al247.465 (16)Cu1ii—Cu2—Cu2xvii59.567 (17)
Cu1iii—Y—Al247.465 (16)Cu1iii—Cu2—Cu2xvii120.433 (17)
Cu1—Y—Al290.0Cu1xiv—Cu2—Cu2xvii59.567 (17)
Cu1iv—Y—Al2132.535 (16)Al2xv—Cu2—Cu2xvii120.0
Cu1v—Y—Al290.0Al2xvi—Cu2—Cu2xvii60.0
Al2vi—Y—Al245.947 (14)Cu2xv—Cu2—Cu2xvii120.0
Al2vii—Y—Al2134.053 (14)Cu2xvi—Cu2—Cu2xvii60.0
Cu2vi—Y—Al245.947 (14)Al2vi—Cu2—Cu2xvii180.0
Cu2vii—Y—Al2134.053 (14)Al2xvii—Cu2—Cu2xvii0.0
Cu2—Y—Al20.0Cu2vi—Cu2—Cu2xvii180.0
Al2viii—Cu1—Al2ix145.991 (18)Cu1xiii—Al2—Cu1ii180.0
Al2viii—Cu1—Cu2viii0.0Cu1xiii—Al2—Cu1iii108.41 (4)
Al2ix—Cu1—Cu2viii145.991 (18)Cu1ii—Al2—Cu1iii71.59 (4)
Al2viii—Cu1—Cu2ix145.991 (18)Cu1xiii—Al2—Cu1xiv71.59 (4)
Al2ix—Cu1—Cu2ix0.0Cu1ii—Al2—Cu1xiv108.41 (4)
Cu2viii—Cu1—Cu2ix145.991 (18)Cu1iii—Al2—Cu1xiv180.0
Al2viii—Cu1—Al2x108.41 (4)Cu1xiii—Al2—Al2xv59.567 (17)
Al2ix—Cu1—Al2x60.87 (3)Cu1ii—Al2—Al2xv120.433 (17)
Cu2viii—Cu1—Al2x108.41 (4)Cu1iii—Al2—Al2xv59.567 (17)
Cu2ix—Cu1—Al2x60.87 (3)Cu1xiv—Al2—Al2xv120.433 (17)
Al2viii—Cu1—Al2xi60.87 (3)Cu1xiii—Al2—Al2xvi120.433 (17)
Al2ix—Cu1—Al2xi108.41 (4)Cu1ii—Al2—Al2xvi59.567 (17)
Cu2viii—Cu1—Al2xi60.87 (3)Cu1iii—Al2—Al2xvi120.433 (17)
Cu2ix—Cu1—Al2xi108.41 (4)Cu1xiv—Al2—Al2xvi59.567 (17)
Al2x—Cu1—Al2xi145.991 (18)Al2xv—Al2—Al2xvi180.0
Al2viii—Cu1—Cu2x108.41 (4)Cu1xiii—Al2—Cu2xv59.567 (17)
Al2ix—Cu1—Cu2x60.87 (3)Cu1ii—Al2—Cu2xv120.433 (17)
Cu2viii—Cu1—Cu2x108.41 (4)Cu1iii—Al2—Cu2xv59.567 (17)
Cu2ix—Cu1—Cu2x60.87 (3)Cu1xiv—Al2—Cu2xv120.433 (17)
Al2x—Cu1—Cu2x0.0Al2xv—Al2—Cu2xv0.0
Al2xi—Cu1—Cu2x145.991 (18)Al2xvi—Al2—Cu2xv180.0
Al2viii—Cu1—Cu2xi60.87 (3)Cu1xiii—Al2—Cu2xvi120.433 (17)
Al2ix—Cu1—Cu2xi108.41 (4)Cu1ii—Al2—Cu2xvi59.567 (17)
Cu2viii—Cu1—Cu2xi60.87 (3)Cu1iii—Al2—Cu2xvi120.433 (17)
Cu2ix—Cu1—Cu2xi108.41 (4)Cu1xiv—Al2—Cu2xvi59.567 (17)
Al2x—Cu1—Cu2xi145.991 (18)Al2xv—Al2—Cu2xvi180.0
Al2xi—Cu1—Cu2xi0.0Al2xvi—Al2—Cu2xvi0.0
Cu2x—Cu1—Cu2xi145.991 (18)Cu2xv—Al2—Cu2xvi180.0
Al2viii—Cu1—Al2vi145.991 (17)Cu1xiii—Al2—Al2vi59.567 (17)
Al2ix—Cu1—Al2vi60.87 (3)Cu1ii—Al2—Al2vi120.433 (17)
Cu2viii—Cu1—Al2vi145.991 (17)Cu1iii—Al2—Al2vi59.567 (17)
Cu2ix—Cu1—Al2vi60.87 (3)Cu1xiv—Al2—Al2vi120.433 (17)
Al2x—Cu1—Al2vi60.87 (3)Al2xv—Al2—Al2vi60.0
Al2xi—Cu1—Al2vi145.991 (18)Al2xvi—Al2—Al2vi120.0
Cu2x—Cu1—Al2vi60.87 (3)Cu2xv—Al2—Al2vi60.0
Cu2xi—Cu1—Al2vi145.991 (18)Cu2xvi—Al2—Al2vi120.0
Al2viii—Cu1—Al2xii60.87 (3)Cu1xiii—Al2—Al2xvii120.433 (17)
Al2ix—Cu1—Al2xii145.991 (17)Cu1ii—Al2—Al2xvii59.567 (17)
Cu2viii—Cu1—Al2xii60.87 (3)Cu1iii—Al2—Al2xvii120.433 (17)
Cu2ix—Cu1—Al2xii145.991 (17)Cu1xiv—Al2—Al2xvii59.567 (17)
Al2x—Cu1—Al2xii145.991 (17)Al2xv—Al2—Al2xvii120.0
Al2xi—Cu1—Al2xii60.87 (3)Al2xvi—Al2—Al2xvii60.0
Cu2x—Cu1—Al2xii145.991 (17)Cu2xv—Al2—Al2xvii120.0
Cu2xi—Cu1—Al2xii60.87 (3)Cu2xvi—Al2—Al2xvii60.0
Al2vi—Cu1—Al2xii108.41 (4)Al2vi—Al2—Al2xvii180.0
Al2viii—Cu1—Cu2vi145.991 (17)Cu1xiii—Al2—Cu2vi59.567 (17)
Al2ix—Cu1—Cu2vi60.87 (3)Cu1ii—Al2—Cu2vi120.433 (17)
Cu2viii—Cu1—Cu2vi145.991 (17)Cu1iii—Al2—Cu2vi59.567 (17)
Cu2ix—Cu1—Cu2vi60.87 (3)Cu1xiv—Al2—Cu2vi120.433 (17)
Al2x—Cu1—Cu2vi60.87 (3)Al2xv—Al2—Cu2vi60.0
Al2xi—Cu1—Cu2vi145.991 (18)Al2xvi—Al2—Cu2vi120.0
Cu2x—Cu1—Cu2vi60.87 (3)Cu2xv—Al2—Cu2vi60.0
Cu2xi—Cu1—Cu2vi145.991 (18)Cu2xvi—Al2—Cu2vi120.0
Al2vi—Cu1—Cu2vi0.0Al2vi—Al2—Cu2vi0.0
Al2xii—Cu1—Cu2vi108.41 (4)Al2xvii—Al2—Cu2vi180.0
Al2viii—Cu1—Cu2xii60.87 (3)Cu1xiii—Al2—Cu2xvii120.433 (17)
Al2ix—Cu1—Cu2xii145.991 (17)Cu1ii—Al2—Cu2xvii59.567 (17)
Cu2viii—Cu1—Cu2xii60.87 (3)Cu1iii—Al2—Cu2xvii120.433 (17)
Cu2ix—Cu1—Cu2xii145.991 (17)Cu1xiv—Al2—Cu2xvii59.567 (17)
Al2x—Cu1—Cu2xii145.991 (17)Al2xv—Al2—Cu2xvii120.0
Al2xi—Cu1—Cu2xii60.87 (3)Al2xvi—Al2—Cu2xvii60.0
Cu2x—Cu1—Cu2xii145.991 (17)Cu2xv—Al2—Cu2xvii120.0
Cu2xi—Cu1—Cu2xii60.87 (3)Cu2xvi—Al2—Cu2xvii60.0
Al2vi—Cu1—Cu2xii108.41 (4)Al2vi—Al2—Cu2xvii180.0
Al2xii—Cu1—Cu2xii0.0Al2xvii—Al2—Cu2xvii0.0
Cu2vi—Cu1—Cu2xii108.41 (4)Cu2vi—Al2—Cu2xvii180.0
Symmetry codes: (i) x, y+1, z; (ii) x, y1, z; (iii) x+1, y+1, z; (iv) x1, y1, z; (v) x, y, z; (vi) x+y+1, x+1, z; (vii) x+y, x, z1; (viii) y, xy, z1; (ix) x, y+1, z; (x) y, xy, z; (xi) x, y+1, z1; (xii) x+y+1, x+1, z1; (xiii) x+1, y+1, z+1; (xiv) x, y1, z+1; (xv) y+1, xy, z; (xvi) y, xy1, z; (xvii) x+y+1, x, z.

Experimental details

Crystal data
Chemical formulaYCu3Al2
Mr332.03
Crystal system, space groupHexagonal, P6/mmm
Temperature (K)293
a, c (Å)5.172 (3), 4.141 (2)
V3)95.93 (9)
Z1
Radiation typeMo Kα
µ (mm1)31.38
Crystal size (mm)0.29 × 0.07 × 0.06
Data collection
DiffractometerStoe AED2
diffractometer
Absorption correctionMulti-scan
(XABS2; Parkin et al., 1995)
Tmin, Tmax0.062, 0.152
No. of measured, independent and
observed [I > 2σ(I)] reflections
2818, 196, 182
Rint0.099
(sin θ/λ)max1)0.993
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.021, 0.055, 1.38
No. of reflections196
No. of parameters10
Δρmax, Δρmin (e Å3)1.86, 2.21

Computer programs: DIF4 (Stoe & Cie, 1988), DIF4, REDU4 (Stoe & Cie, 1988), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), DIAMOND (Bergerhoff, 1996).

Selected bond lengths (Å) top
Y—Cu12.9861 (17)Cu1—Cu2i2.5527 (10)
Y—Cu23.3128 (13)Cu2—Cu2ii2.5860 (15)
Symmetry codes: (i) y, xy, z; (ii) y+1, xy, z.
 

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