Partial Cu occupancy in uranium copper dianti­monide, UCu_0.60(4)Sb₂

The title compound, UCu_0.60(4)Sb₂, crystallizes in the tetra­gonal space group P4/nmm. The U atom and one independent Sb atom have 4mm site symmetry, whereas the Cu atom and the other Sb atom have 2m site symmetry. Zigzag USb sheets stack perpendicular to the c axis. These sheets are separated by square-planar nets of Sb atoms and Cu atoms. The length of the a axis for UCu_xSb₂ is invariant to x, whereas there is a linear relationship between Cu occupancy and the length of the c axis (following Vegard's Law) that holds for x between 0 and 1. This is explained in terms of the crystal structure.

S1. Comment

UCu_0.60 (4)Sb₂ crystallizes with two formula units in the tetragonal space group P4/nmm. It possesses the HfCuSi₂ structure type (Andrukhiv et al., 1975). Zigzag U1Sb1 sheets stack perpendicular to the c axis (Fig. 1). These sheets are separated by square-planar nets of Sb2 atoms and Cu1 atoms, the repeating pattern being (a) Sb2 planar net, (b) U1Sb1 sheet, (c) Cu1 planar net and (d) U1Sb1 sheet [aligned antiparallel in the c direction to the (b) sheet]. The U1 and Sb1 atoms have 4mm site symmetry, whereas the Cu1 and Sb2 atoms have 42m site symmetry. The U1 atoms are surrounded by a square antiprism of Sb1 and Sb2 atoms. The geometry around the Sb1 atom is a square antiprism of Cu1 and U1 atoms. The Cu1 atoms are coordinated to four Sb1 atoms in a tetrahedral arrangement, and Sb2 atoms are coordinated to four U1 atoms, also in a tetrahedral arrangement.

Since the UMSb₂ compounds (M is a transition metal) were first reported [M = Ni, Cu (Kaczorowski, 1992); M = Fe, Ru, Co, Pd, Ag, Au (Kaczorowski et al., 1998)], they have received considerable attention, mainly because of their interesting magnetic properties, including Kondo behaviour (Kaczorowski et al., 1998; Bukowski et al., 2005). Large stoichiometric variations are frequently encountered in these UMSb₂ compounds, examples being UCo_0.46Sb₂ (Bukowski et al., 2004) and UNi_0.5Sb₂. Such variations are also common among rare-earth analogues (Wollesen et al., 1996). The compound UCu_0.60 (4)Sb₂ reported here is another stoichiometric variation in the UCu_xSb₂ system, for which the known compounds are UCu_0.44Sb₂ (Bobev et al., 2006), UCu_0.83Sb₂ (Bukowski et al., 2005) and UCuSb₂ (Kaczorowski et al., 1998). Reaction conditions and starting compositions are presumably the determining factors in the final Cu occupancy. This family of compounds obeys Vegard's Law (Vegard, 1921): the cell constant c increases linearly with Cu occupancy, as shown in Fig. 2, even though the present structures were determined at 100 and 120 K and the previous structures were determined at 298 K. This linear relationship holds at all Cu occupancies, including the `zero occupancy', i.e. USb₂. The structures of USb₂ and UCuSb₂ are indeed related (Fig. 3). In UCuSb₂, the voids between adjacent USb zigzag sheets are filled with Cu atoms, effectively pulling the sheets apart and preventing interlayer U—Sb bonding along the c axis. This simple geometric consideration explains why the c axis lengthens but the a axis remains unchanged when the Cu occupancy is increased.

S2. Experimental

USb₂ was obtained from the reaction of U powder [0.63 mmol, ORNL, prepared from turnings as described elsewhere (Haneveld & Jellinek, 1969)] and Sb (1.26 mmol, Aldrich, 99.5%) in a carbon-coated fused-silica tube. The tube was heated to 1273 K in 20 h, held there for 111 h, cooled to 773 K in 20 h, and then air-cooled to 293 K. Single crystals of uranium copper antimonide, UCu_0.60 (4)Sb₂, were obtained from the reaction of USb₂ (0.093 mmol) and CuO (0.093 mmol, Aldrich, 99.99%) in a carbon-coated fused-silica tube. The tube was heated to 773 K in 10 h, further heated to 973 K in 60 h, held there for 70 h, heated to 1173 K in 20 h, held there for 180 h, cooled to 773 K over a period of 100 h, and finally cooled to 293 K in 60 h. The product consisted mainly of UO₂ powder and elemental Sb, among which a few small black plates were found. Energy-dispersive X-ray analysis showed the presence of U, Cu, and Sb in these plates.

S3. Refinement

A numerical face-indexed absorption correction was performed using the program SADABS (Bruker, 2003). A correction was made for extinction. All atoms were given anisotropic displacement parameters. Data sets on the same crystal were collected at 100, 120, 200, and 298 K. The corresponding refined Cu occupancies were 0.634 (12), 0.600 (13), 0.608 (13) and 0.586 (12). We choose to report its value as 0.60 (4) and we report only the structure determinations at 100 and 120 K here. The structure was standardized by means of the program STRUCTURETIDY (Gelato & Parthé, 1987). The final difference electron densities show no significant residual peaks. The highest peaks are 1.24 and 0.07 Å from U, and the deepest holes are 1.29 and 0.89 Å from U, at 100 and 120 K, respectively.

Computing details

For both compounds, data collection: SMART (Bruker, 2003); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT (Bruker, 2003); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: CrystalMaker (Palmer, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. A view of the structure of UCu0.60 (4)Sb2, approximately along [010]. Displacement ellipsoids are shown at the 75% probability level.
	Fig. 2. The dependence of the length of the c axis on x in the known UCuxSb2 compounds.
	Fig. 3. Comparison of the structures of USb2 (left) and UCuSb2 (right).

(I_100K) uranium copper diantimonide

Crystal data

UCu0.60(4)Sb2	Dx = 9.943 Mg m^−3
Mr = 521.84	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P4/nmm	Cell parameters from 1655 reflections
Hall symbol: -P 4a 2a	θ = 4.4–28.5°
a = 4.320 (4) Å	µ = 65.20 mm^−1
c = 9.341 (9) Å	T = 100 K
V = 174.3 (3) Å^3	Plate, black
Z = 2	0.14 × 0.08 × 0.05 mm
F(000) = 424.80

Data collection

Bruker SMART 1000 CCD diffractometer	155 independent reflections
Radiation source: fine-focus sealed tube	155 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.075
ω scans	θmax = 28.1°, θmin = 2.2°
Absorption correction: numerical face-indexed (SADABS; Bruker, 2003)	h = −5→5
Tmin = 0.020, Tmax = 0.086	k = −5→5
1951 measured reflections	l = −12→12

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.024	w = 1/[σ^2(Fo^2) + (0.0306P)^2 + 1.6422P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.058	(Δ/σ)max < 0.001
S = 1.20	Δρmax = 1.32 e Å^−3
155 reflections	Δρmin = −3.32 e Å^−3
13 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0174 (16)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
U1	0.2500	0.2500	0.25716 (6)	0.0067 (3)
Sb1	0.2500	0.2500	0.65348 (12)	0.0087 (4)
Sb2	0.7500	0.2500	0.0000	0.0062 (4)
Cu1	0.7500	0.2500	0.5000	0.0080 (13)	0.634 (12)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
U1	0.0045 (4)	0.0045 (4)	0.0113 (5)	0.000	0.000	0.000
Sb1	0.0054 (4)	0.0054 (4)	0.0153 (7)	0.000	0.000	0.000
Sb2	0.0045 (5)	0.0045 (5)	0.0097 (7)	0.000	0.000	0.000
Cu1	0.0095 (15)	0.0095 (15)	0.0051 (18)	0.000	0.000	0.000

Geometric parameters (Å, º)

U1—Cu1^i	3.132 (2)	Sb1—U1^ii	3.167 (3)
U1—Cu1	3.132 (2)	Sb2—Sb2^viii	3.055 (3)
U1—Cu1^ii	3.132 (2)	Sb2—Sb2^vi	3.055 (3)
U1—Cu1^iii	3.132 (2)	Sb2—Sb2^vii	3.055 (3)
U1—Sb1^i	3.167 (3)	Sb2—Sb2^ix	3.055 (3)
U1—Sb1^iv	3.167 (3)	Sb2—U1^vi	3.231 (2)
U1—Sb1^v	3.167 (3)	Sb2—U1^x	3.231 (2)
U1—Sb1^ii	3.167 (3)	Sb2—U1^vii	3.231 (2)
U1—Sb2^iii	3.231 (2)	Cu1—Sb1^ii	2.593 (2)
U1—Sb2^vi	3.231 (2)	Cu1—Sb1^x	2.593 (2)
U1—Sb2	3.231 (2)	Cu1—Sb1^i	2.593 (2)
U1—Sb2^vii	3.231 (2)	Cu1—Cu1^xi	3.055 (3)
Sb1—Cu1^ii	2.593 (2)	Cu1—Cu1^ii	3.055 (3)
Sb1—Cu1^iii	2.593 (2)	Cu1—Cu1^i	3.055 (3)
Sb1—Cu1^i	2.593 (2)	Cu1—Cu1^xii	3.055 (3)
Sb1—Cu1	2.593 (2)	Cu1—U1^i	3.132 (2)
Sb1—U1^i	3.167 (3)	Cu1—U1^ii	3.132 (2)
Sb1—U1^iv	3.167 (3)	Cu1—U1^x	3.132 (2)
Sb1—U1^v	3.167 (3)
Cu1^i—U1—Cu1	58.37 (5)	U1^i—Sb1—U1	105.28 (3)
Cu1^i—U1—Cu1^ii	87.20 (8)	U1^iv—Sb1—U1	105.28 (3)
Cu1—U1—Cu1^ii	58.37 (5)	U1^v—Sb1—U1	105.28 (3)
Cu1^i—U1—Cu1^iii	58.37 (5)	U1^ii—Sb1—U1	105.28 (3)
Cu1—U1—Cu1^iii	87.20 (8)	Sb2^viii—Sb2—Sb2^vi	180.0
Cu1^ii—U1—Cu1^iii	58.37 (5)	Sb2^viii—Sb2—Sb2^vii	90.0
Cu1^i—U1—Sb1^i	48.603 (15)	Sb2^vi—Sb2—Sb2^vii	90.0
Cu1—U1—Sb1^i	48.603 (15)	Sb2^viii—Sb2—Sb2^ix	90.0
Cu1^ii—U1—Sb1^i	106.23 (5)	Sb2^vi—Sb2—Sb2^ix	90.0
Cu1^iii—U1—Sb1^i	106.23 (5)	Sb2^vii—Sb2—Sb2^ix	180.0
Cu1^i—U1—Sb1^iv	106.23 (5)	Sb2^viii—Sb2—U1^vi	118.22 (2)
Cu1—U1—Sb1^iv	106.23 (5)	Sb2^vi—Sb2—U1^vi	61.78 (2)
Cu1^ii—U1—Sb1^iv	48.603 (15)	Sb2^vii—Sb2—U1^vi	118.22 (2)
Cu1^iii—U1—Sb1^iv	48.603 (15)	Sb2^ix—Sb2—U1^vi	61.78 (2)
Sb1^i—U1—Sb1^iv	149.44 (6)	Sb2^viii—Sb2—U1^x	61.78 (2)
Cu1^i—U1—Sb1^v	48.603 (15)	Sb2^vi—Sb2—U1^x	118.22 (2)
Cu1—U1—Sb1^v	106.23 (5)	Sb2^vii—Sb2—U1^x	118.22 (2)
Cu1^ii—U1—Sb1^v	106.23 (5)	Sb2^ix—Sb2—U1^x	61.78 (2)
Cu1^iii—U1—Sb1^v	48.603 (15)	U1^vi—Sb2—U1^x	123.56 (5)
Sb1^i—U1—Sb1^v	86.016 (15)	Sb2^viii—Sb2—U1	118.22 (2)
Sb1^iv—U1—Sb1^v	86.016 (15)	Sb2^vi—Sb2—U1	61.78 (2)
Cu1^i—U1—Sb1^ii	106.23 (5)	Sb2^vii—Sb2—U1	61.78 (2)
Cu1—U1—Sb1^ii	48.603 (15)	Sb2^ix—Sb2—U1	118.22 (2)
Cu1^ii—U1—Sb1^ii	48.603 (15)	U1^vi—Sb2—U1	123.56 (5)
Cu1^iii—U1—Sb1^ii	106.23 (5)	U1^x—Sb2—U1	83.93 (8)
Sb1^i—U1—Sb1^ii	86.016 (15)	Sb2^viii—Sb2—U1^vii	61.78 (2)
Sb1^iv—U1—Sb1^ii	86.016 (15)	Sb2^vi—Sb2—U1^vii	118.22 (2)
Sb1^v—U1—Sb1^ii	149.44 (6)	Sb2^vii—Sb2—U1^vii	61.78 (2)
Cu1^i—U1—Sb2^iii	122.58 (5)	Sb2^ix—Sb2—U1^vii	118.22 (2)
Cu1—U1—Sb2^iii	178.364 (13)	U1^vi—Sb2—U1^vii	83.93 (8)
Cu1^ii—U1—Sb2^iii	122.58 (5)	U1^x—Sb2—U1^vii	123.56 (5)
Cu1^iii—U1—Sb2^iii	94.43 (8)	U1—Sb2—U1^vii	123.56 (5)
Sb1^i—U1—Sb2^iii	130.699 (18)	Sb1^ii—Cu1—Sb1^x	107.80 (4)
Sb1^iv—U1—Sb2^iii	74.92 (5)	Sb1^ii—Cu1—Sb1^i	112.86 (8)
Sb1^v—U1—Sb2^iii	74.92 (5)	Sb1^x—Cu1—Sb1^i	107.80 (4)
Sb1^ii—U1—Sb2^iii	130.699 (18)	Sb1^ii—Cu1—Sb1	107.80 (4)
Cu1^i—U1—Sb2^vi	178.364 (13)	Sb1^x—Cu1—Sb1	112.86 (8)
Cu1—U1—Sb2^vi	122.58 (5)	Sb1^i—Cu1—Sb1	107.80 (4)
Cu1^ii—U1—Sb2^vi	94.43 (8)	Sb1^ii—Cu1—Cu1^xi	126.10 (2)
Cu1^iii—U1—Sb2^vi	122.58 (5)	Sb1^x—Cu1—Cu1^xi	53.90 (2)
Sb1^i—U1—Sb2^vi	130.699 (18)	Sb1^i—Cu1—Cu1^xi	53.90 (2)
Sb1^iv—U1—Sb2^vi	74.92 (5)	Sb1—Cu1—Cu1^xi	126.10 (2)
Sb1^v—U1—Sb2^vi	130.699 (18)	Sb1^ii—Cu1—Cu1^ii	53.90 (2)
Sb1^ii—U1—Sb2^vi	74.92 (5)	Sb1^x—Cu1—Cu1^ii	126.10 (2)
Sb2^iii—U1—Sb2^vi	56.44 (5)	Sb1^i—Cu1—Cu1^ii	126.10 (2)
Cu1^i—U1—Sb2	122.58 (5)	Sb1—Cu1—Cu1^ii	53.90 (2)
Cu1—U1—Sb2	94.43 (8)	Cu1^xi—Cu1—Cu1^ii	180.0
Cu1^ii—U1—Sb2	122.58 (5)	Sb1^ii—Cu1—Cu1^i	126.10 (2)
Cu1^iii—U1—Sb2	178.364 (13)	Sb1^x—Cu1—Cu1^i	126.10 (2)
Sb1^i—U1—Sb2	74.92 (5)	Sb1^i—Cu1—Cu1^i	53.90 (2)
Sb1^iv—U1—Sb2	130.699 (18)	Sb1—Cu1—Cu1^i	53.90 (2)
Sb1^v—U1—Sb2	130.699 (18)	Cu1^xi—Cu1—Cu1^i	90.0
Sb1^ii—U1—Sb2	74.92 (5)	Cu1^ii—Cu1—Cu1^i	90.0
Sb2^iii—U1—Sb2	83.93 (8)	Sb1^ii—Cu1—Cu1^xii	53.90 (2)
Sb2^vi—U1—Sb2	56.44 (5)	Sb1^x—Cu1—Cu1^xii	53.90 (2)
Cu1^i—U1—Sb2^vii	94.43 (8)	Sb1^i—Cu1—Cu1^xii	126.10 (2)
Cu1—U1—Sb2^vii	122.58 (5)	Sb1—Cu1—Cu1^xii	126.10 (2)
Cu1^ii—U1—Sb2^vii	178.364 (13)	Cu1^xi—Cu1—Cu1^xii	90.0
Cu1^iii—U1—Sb2^vii	122.58 (5)	Cu1^ii—Cu1—Cu1^xii	90.0
Sb1^i—U1—Sb2^vii	74.92 (5)	Cu1^i—Cu1—Cu1^xii	180.0
Sb1^iv—U1—Sb2^vii	130.699 (18)	Sb1^ii—Cu1—U1^i	167.17 (2)
Sb1^v—U1—Sb2^vii	74.92 (5)	Sb1^x—Cu1—U1^i	66.39 (4)
Sb1^ii—U1—Sb2^vii	130.699 (18)	Sb1^i—Cu1—U1^i	79.97 (8)
Sb2^iii—U1—Sb2^vii	56.44 (5)	Sb1—Cu1—U1^i	66.39 (4)
Sb2^vi—U1—Sb2^vii	83.93 (8)	Cu1^xi—Cu1—U1^i	60.81 (2)
Sb2—U1—Sb2^vii	56.44 (5)	Cu1^ii—Cu1—U1^i	119.19 (2)
Cu1^ii—Sb1—Cu1^iii	72.20 (4)	Cu1^i—Cu1—U1^i	60.81 (2)
Cu1^ii—Sb1—Cu1^i	112.86 (8)	Cu1^xii—Cu1—U1^i	119.19 (2)
Cu1^iii—Sb1—Cu1^i	72.20 (4)	Sb1^ii—Cu1—U1	66.39 (4)
Cu1^ii—Sb1—Cu1	72.20 (4)	Sb1^x—Cu1—U1	167.17 (2)
Cu1^iii—Sb1—Cu1	112.86 (8)	Sb1^i—Cu1—U1	66.39 (4)
Cu1^i—Sb1—Cu1	72.20 (4)	Sb1—Cu1—U1	79.97 (8)
Cu1^ii—Sb1—U1^i	135.568 (16)	Cu1^xi—Cu1—U1	119.19 (2)
Cu1^iii—Sb1—U1^i	135.568 (16)	Cu1^ii—Cu1—U1	60.81 (2)
Cu1^i—Sb1—U1^i	65.00 (4)	Cu1^i—Cu1—U1	60.81 (2)
Cu1—Sb1—U1^i	65.00 (4)	Cu1^xii—Cu1—U1	119.19 (2)
Cu1^ii—Sb1—U1^iv	65.00 (4)	U1^i—Cu1—U1	121.63 (5)
Cu1^iii—Sb1—U1^iv	65.00 (4)	Sb1^ii—Cu1—U1^ii	79.97 (8)
Cu1^i—Sb1—U1^iv	135.568 (16)	Sb1^x—Cu1—U1^ii	66.39 (4)
Cu1—Sb1—U1^iv	135.568 (16)	Sb1^i—Cu1—U1^ii	167.17 (2)
U1^i—Sb1—U1^iv	149.44 (6)	Sb1—Cu1—U1^ii	66.39 (4)
Cu1^ii—Sb1—U1^v	135.568 (16)	Cu1^xi—Cu1—U1^ii	119.19 (2)
Cu1^iii—Sb1—U1^v	65.00 (4)	Cu1^ii—Cu1—U1^ii	60.81 (2)
Cu1^i—Sb1—U1^v	65.00 (4)	Cu1^i—Cu1—U1^ii	119.19 (2)
Cu1—Sb1—U1^v	135.568 (16)	Cu1^xii—Cu1—U1^ii	60.81 (2)
U1^i—Sb1—U1^v	86.016 (15)	U1^i—Cu1—U1^ii	87.20 (8)
U1^iv—Sb1—U1^v	86.016 (15)	U1—Cu1—U1^ii	121.63 (5)
Cu1^ii—Sb1—U1^ii	65.00 (4)	Sb1^ii—Cu1—U1^x	66.39 (4)
Cu1^iii—Sb1—U1^ii	135.568 (16)	Sb1^x—Cu1—U1^x	79.97 (8)
Cu1^i—Sb1—U1^ii	135.568 (16)	Sb1^i—Cu1—U1^x	66.39 (4)
Cu1—Sb1—U1^ii	65.00 (4)	Sb1—Cu1—U1^x	167.17 (2)
U1^i—Sb1—U1^ii	86.016 (15)	Cu1^xi—Cu1—U1^x	60.81 (2)
U1^iv—Sb1—U1^ii	86.016 (15)	Cu1^ii—Cu1—U1^x	119.19 (2)
U1^v—Sb1—U1^ii	149.43 (6)	Cu1^i—Cu1—U1^x	119.19 (2)
Cu1^ii—Sb1—U1	56.43 (4)	Cu1^xii—Cu1—U1^x	60.81 (2)
Cu1^iii—Sb1—U1	56.43 (4)	U1^i—Cu1—U1^x	121.63 (5)
Cu1^i—Sb1—U1	56.43 (4)	U1—Cu1—U1^x	87.20 (8)
Cu1—Sb1—U1	56.43 (4)	U1^ii—Cu1—U1^x	121.63 (5)

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1, −y, −z+1; (iii) x−1, y, z; (iv) −x, −y, −z+1; (v) −x, −y+1, −z+1; (vi) −x+1, −y, −z; (vii) −x+1, −y+1, −z; (viii) −x+2, −y+1, −z; (ix) −x+2, −y, −z; (x) x+1, y, z; (xi) −x+2, −y+1, −z+1; (xii) −x+2, −y, −z+1.

(I_120K) uranium copper diantimonide

Crystal data

UCu0.60(4)Sb2	Dx = 9.834 Mg m^−3
Mr = 519.65	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P4/nmm	Cell parameters from 1591 reflections
Hall symbol: -P 4a 2a	θ = 4.4–28.6°
a = 4.331 (4) Å	µ = 64.56 mm^−1
c = 9.355 (9) Å	T = 120 K
V = 175.5 (3) Å^3	Plate, black
Z = 2	0.14 × 0.08 × 0.05 mm
F(000) = 422.8

Data collection

Bruker SMART 1000 CCD diffractometer	160 independent reflections
Radiation source: fine-focus sealed tube	157 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.061
ω scans	θmax = 28.8°, θmin = 2.2°
Absorption correction: numerical face-indexed (SADABS; Bruker, 2003)	h = −5→5
Tmin = 0.016, Tmax = 0.086	k = −5→5
1966 measured reflections	l = −12→12

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.027	w = 1/[σ^2(Fo^2) + (0.0382P)^2 + 0.8954P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.066	(Δ/σ)max = 0.012
S = 1.32	Δρmax = 3.26 e Å^−3
160 reflections	Δρmin = −4.14 e Å^−3
13 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.021 (2)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
U1	0.2500	0.2500	0.25724 (6)	0.0069 (4)
Sb1	0.2500	0.2500	0.65345 (12)	0.0091 (4)
Sb2	0.7500	0.2500	0.0000	0.0063 (4)
Cu1	0.7500	0.2500	0.5000	0.0056 (14)	0.600 (13)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
U1	0.0056 (4)	0.0056 (4)	0.0096 (5)	0.000	0.000	0.000
Sb1	0.0064 (5)	0.0064 (5)	0.0144 (7)	0.000	0.000	0.000
Sb2	0.0057 (5)	0.0057 (5)	0.0074 (7)	0.000	0.000	0.000
Cu1	0.0073 (16)	0.0073 (16)	0.0021 (19)	0.000	0.000	0.000

Geometric parameters (Å, º)

U1—Cu1^i	3.138 (2)	Sb1—U1^iv	3.174 (3)
U1—Cu1	3.138 (2)	Sb1—U1^v	3.174 (3)
U1—Cu1^ii	3.138 (2)	Sb1—U1^ii	3.174 (3)
U1—Cu1^iii	3.138 (2)	Sb2—Sb2^viii	3.062 (3)
U1—Sb1^i	3.174 (3)	Sb2—Sb2^vi	3.062 (3)
U1—Sb1^iv	3.174 (3)	Sb2—Sb2^vii	3.062 (3)
U1—Sb1^v	3.174 (3)	Sb2—Sb2^ix	3.062 (3)
U1—Sb1^ii	3.174 (3)	Sb2—U1^vi	3.237 (2)
U1—Sb2^iii	3.237 (2)	Sb2—U1^x	3.237 (2)
U1—Sb2^vi	3.237 (2)	Sb2—U1^vii	3.237 (2)
U1—Sb2	3.237 (2)	Cu1—Sb1^ii	2.598 (2)
U1—Sb2^vii	3.237 (2)	Cu1—Sb1^x	2.598 (2)
Sb1—Cu1^ii	2.598 (2)	Cu1—Sb1^i	2.598 (2)
Sb1—Cu1^iii	2.598 (2)	Cu1—U1^i	3.138 (2)
Sb1—Cu1^i	2.598 (2)	Cu1—U1^x	3.138 (2)
Sb1—Cu1	2.598 (2)	Cu1—U1^ii	3.138 (2)
Sb1—U1^i	3.174 (3)
Cu1^i—U1—Cu1	58.41 (5)	Cu1—Sb1—U1^iv	135.563 (16)
Cu1^i—U1—Cu1^ii	87.28 (8)	U1^i—Sb1—U1^iv	149.48 (6)
Cu1—U1—Cu1^ii	58.41 (5)	Cu1^ii—Sb1—U1^v	135.563 (16)
Cu1^i—U1—Cu1^iii	58.41 (5)	Cu1^iii—Sb1—U1^v	64.97 (4)
Cu1—U1—Cu1^iii	87.28 (8)	Cu1^i—Sb1—U1^v	64.97 (4)
Cu1^ii—U1—Cu1^iii	58.41 (5)	Cu1—Sb1—U1^v	135.563 (16)
Cu1^i—U1—Sb1^i	48.605 (16)	U1^i—Sb1—U1^v	86.028 (15)
Cu1—U1—Sb1^i	48.605 (16)	U1^iv—Sb1—U1^v	86.028 (15)
Cu1^ii—U1—Sb1^i	106.28 (5)	Cu1^ii—Sb1—U1^ii	64.97 (4)
Cu1^iii—U1—Sb1^i	106.28 (5)	Cu1^iii—Sb1—U1^ii	135.563 (16)
Cu1^i—U1—Sb1^iv	106.28 (5)	Cu1^i—Sb1—U1^ii	135.563 (16)
Cu1—U1—Sb1^iv	106.28 (5)	Cu1—Sb1—U1^ii	64.97 (4)
Cu1^ii—U1—Sb1^iv	48.605 (16)	U1^i—Sb1—U1^ii	86.028 (15)
Cu1^iii—U1—Sb1^iv	48.605 (16)	U1^iv—Sb1—U1^ii	86.028 (15)
Sb1^i—U1—Sb1^iv	149.48 (6)	U1^v—Sb1—U1^ii	149.48 (6)
Cu1^i—U1—Sb1^v	48.605 (16)	Cu1^ii—Sb1—U1	56.46 (4)
Cu1—U1—Sb1^v	106.28 (5)	Cu1^iii—Sb1—U1	56.46 (4)
Cu1^ii—U1—Sb1^v	106.28 (5)	Cu1^i—Sb1—U1	56.46 (4)
Cu1^iii—U1—Sb1^v	48.605 (16)	Cu1—Sb1—U1	56.46 (4)
Sb1^i—U1—Sb1^v	86.028 (15)	U1^i—Sb1—U1	105.26 (3)
Sb1^iv—U1—Sb1^v	86.028 (15)	U1^iv—Sb1—U1	105.26 (3)
Cu1^i—U1—Sb1^ii	106.28 (5)	U1^v—Sb1—U1	105.26 (3)
Cu1—U1—Sb1^ii	48.605 (16)	U1^ii—Sb1—U1	105.26 (3)
Cu1^ii—U1—Sb1^ii	48.605 (16)	Sb2^viii—Sb2—Sb2^vi	180.0
Cu1^iii—U1—Sb1^ii	106.28 (5)	Sb2^viii—Sb2—Sb2^vii	90.0
Sb1^i—U1—Sb1^ii	86.028 (15)	Sb2^vi—Sb2—Sb2^vii	90.0
Sb1^iv—U1—Sb1^ii	86.028 (15)	Sb2^viii—Sb2—Sb2^ix	90.0
Sb1^v—U1—Sb1^ii	149.48 (6)	Sb2^vi—Sb2—Sb2^ix	90.0
Cu1^i—U1—Sb2^iii	122.55 (5)	Sb2^vii—Sb2—Sb2^ix	180.0
Cu1—U1—Sb2^iii	178.345 (14)	Sb2^viii—Sb2—U1^vi	118.23 (2)
Cu1^ii—U1—Sb2^iii	122.55 (5)	Sb2^vi—Sb2—U1^vi	61.77 (2)
Cu1^iii—U1—Sb2^iii	94.38 (8)	Sb2^vii—Sb2—U1^vi	118.23 (2)
Sb1^i—U1—Sb2^iii	130.689 (19)	Sb2^ix—Sb2—U1^vi	61.77 (2)
Sb1^iv—U1—Sb2^iii	74.89 (5)	Sb2^viii—Sb2—U1^x	61.77 (2)
Sb1^v—U1—Sb2^iii	74.89 (5)	Sb2^vi—Sb2—U1^x	118.23 (2)
Sb1^ii—U1—Sb2^iii	130.689 (19)	Sb2^vii—Sb2—U1^x	118.23 (2)
Cu1^i—U1—Sb2^vi	178.345 (14)	Sb2^ix—Sb2—U1^x	61.77 (2)
Cu1—U1—Sb2^vi	122.55 (5)	U1^vi—Sb2—U1^x	123.54 (5)
Cu1^ii—U1—Sb2^vi	94.38 (8)	Sb2^viii—Sb2—U1	118.23 (2)
Cu1^iii—U1—Sb2^vi	122.55 (5)	Sb2^vi—Sb2—U1	61.77 (2)
Sb1^i—U1—Sb2^vi	130.689 (19)	Sb2^vii—Sb2—U1	61.77 (2)
Sb1^iv—U1—Sb2^vi	74.89 (5)	Sb2^ix—Sb2—U1	118.23 (2)
Sb1^v—U1—Sb2^vi	130.689 (19)	U1^vi—Sb2—U1	123.54 (5)
Sb1^ii—U1—Sb2^vi	74.89 (5)	U1^x—Sb2—U1	83.96 (8)
Sb2^iii—U1—Sb2^vi	56.46 (5)	Sb2^viii—Sb2—U1^vii	61.77 (2)
Cu1^i—U1—Sb2	122.55 (5)	Sb2^vi—Sb2—U1^vii	118.23 (2)
Cu1—U1—Sb2	94.38 (8)	Sb2^vii—Sb2—U1^vii	61.77 (2)
Cu1^ii—U1—Sb2	122.55 (5)	Sb2^ix—Sb2—U1^vii	118.23 (2)
Cu1^iii—U1—Sb2	178.345 (14)	U1^vi—Sb2—U1^vii	83.96 (8)
Sb1^i—U1—Sb2	74.89 (5)	U1^x—Sb2—U1^vii	123.54 (5)
Sb1^iv—U1—Sb2	130.689 (19)	U1—Sb2—U1^vii	123.54 (5)
Sb1^v—U1—Sb2	130.689 (19)	Sb1^ii—Cu1—Sb1^x	107.78 (4)
Sb1^ii—U1—Sb2	74.89 (5)	Sb1^ii—Cu1—Sb1^i	112.92 (8)
Sb2^iii—U1—Sb2	83.96 (8)	Sb1^x—Cu1—Sb1^i	107.78 (4)
Sb2^vi—U1—Sb2	56.46 (5)	Sb1^ii—Cu1—Sb1	107.78 (4)
Cu1^i—U1—Sb2^vii	94.38 (8)	Sb1^x—Cu1—Sb1	112.92 (8)
Cu1—U1—Sb2^vii	122.55 (5)	Sb1^i—Cu1—Sb1	107.78 (4)
Cu1^ii—U1—Sb2^vii	178.345 (14)	Sb1^ii—Cu1—U1	66.43 (4)
Cu1^iii—U1—Sb2^vii	122.55 (5)	Sb1^x—Cu1—U1	167.18 (2)
Sb1^i—U1—Sb2^vii	74.89 (5)	Sb1^i—Cu1—U1	66.43 (4)
Sb1^iv—U1—Sb2^vii	130.689 (19)	Sb1—Cu1—U1	79.90 (8)
Sb1^v—U1—Sb2^vii	74.89 (5)	Sb1^ii—Cu1—U1^i	167.18 (2)
Sb1^ii—U1—Sb2^vii	130.689 (19)	Sb1^x—Cu1—U1^i	66.43 (4)
Sb2^iii—U1—Sb2^vii	56.46 (5)	Sb1^i—Cu1—U1^i	79.90 (8)
Sb2^vi—U1—Sb2^vii	83.96 (8)	Sb1—Cu1—U1^i	66.43 (4)
Sb2—U1—Sb2^vii	56.46 (5)	U1—Cu1—U1^i	121.59 (5)
Cu1^ii—Sb1—Cu1^iii	72.22 (4)	Sb1^ii—Cu1—U1^x	66.43 (4)
Cu1^ii—Sb1—Cu1^i	112.92 (8)	Sb1^x—Cu1—U1^x	79.90 (8)
Cu1^iii—Sb1—Cu1^i	72.22 (4)	Sb1^i—Cu1—U1^x	66.43 (4)
Cu1^ii—Sb1—Cu1	72.22 (4)	Sb1—Cu1—U1^x	167.18 (2)
Cu1^iii—Sb1—Cu1	112.92 (8)	U1—Cu1—U1^x	87.28 (8)
Cu1^i—Sb1—Cu1	72.22 (4)	U1^i—Cu1—U1^x	121.59 (5)
Cu1^ii—Sb1—U1^i	135.563 (16)	Sb1^ii—Cu1—U1^ii	79.90 (8)
Cu1^iii—Sb1—U1^i	135.563 (16)	Sb1^x—Cu1—U1^ii	66.43 (4)
Cu1^i—Sb1—U1^i	64.97 (4)	Sb1^i—Cu1—U1^ii	167.18 (2)
Cu1—Sb1—U1^i	64.97 (4)	Sb1—Cu1—U1^ii	66.43 (4)
Cu1^ii—Sb1—U1^iv	64.97 (4)	U1—Cu1—U1^ii	121.59 (5)
Cu1^iii—Sb1—U1^iv	64.97 (4)	U1^i—Cu1—U1^ii	87.28 (8)
Cu1^i—Sb1—U1^iv	135.563 (16)	U1^x—Cu1—U1^ii	121.59 (5)

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1, −y, −z+1; (iii) x−1, y, z; (iv) −x, −y, −z+1; (v) −x, −y+1, −z+1; (vi) −x+1, −y, −z; (vii) −x+1, −y+1, −z; (viii) −x+2, −y+1, −z; (ix) −x+2, −y, −z; (x) x+1, y, z.