Cs2UPd3Se6

Oh, G.N.; Ibers, J.A.

doi:10.1107/S1600536810053924

inorganic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 67| Part 2| February 2011| Page i9

doi:10.1107/S1600536810053924

Open

access

Cs₂UPd₃Se₆

George N. Oh ^a and James A. Ibers ^a ^*

^aDepartment of Chemistry, Northwestern University, 2145 Sheridan Rd., Evanston, IL 60208-3113, USA
^*Correspondence e-mail: ibers@chem.northwestern.edu

(Received 8 December 2010; accepted 22 December 2010; online 12 January 2011)

Dicaesium uranium(IV) tripalladium(II) hexaselenide, Cs₂UPd₃Se₆, crystallizes in the space group Fmmm in the Ba₂NaCu₃O₆ structure type. The asymmetric unit comprises the following atoms with site symmetries as shown: U1 (mm2), Cs1 (222), Cs2 (m2m), Pd1 (.m.), Pd2 (2mm), Se1 (m..), and Se2 (1). This layered structure contains six edge-sharing square-planar [PdSe₄] units that form a hexagon. These, in turn, edge-share with [USe₆] trigonal–prismatic units, forming an extended layer parallel to (010). The layers are stacked along [010]. They are staggered, and are separated by the Cs atoms. The Cs atoms are either coordinated in a square antiprism of Se atoms or are ten-coordinate, with one square face and the opposite face hexagonal.

Related literature

Ba₂NaCu₃O₆ was reported by Tams & Müller-Buschbaum (1992 ). For related structures, see: Daoudi & Noël (1989 ); Bronger et al. (1991 ); Yao & Ibers (2008 ); Huang et al. (2001 ); Klepp et al. (1996 ). For synthetic details, see: Bugaris & Ibers (2008 ); Haneveld & Jellinek (1969 ). For computational details, see: Gelato & Parthé (1987 ); Le Page (1988 ).

Experimental

Crystal data

Cs₂UPd₃Se₆
M_r = 1296.81
Orthorhombic, F m m m
a = 10.1034 (5) Å
b = 15.5046 (8) Å
c = 17.5503 (8) Å
V = 2749.2 (2) Å³
Z = 8
Mo Kα radiation
μ = 36.67 mm⁻¹
T = 100 K
0.21 × 0.17 × 0.01 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: numerical (face indexed using SADABS; Sheldrick, 2008b ) T_min = 0.049, T_max = 0.689
8099 measured reflections
963 independent reflections
921 reflections with I > 2σ(I)
R_int = 0.035

Refinement

R[F² > 2σ(F²)] = 0.019
wR(F²) = 0.055
S = 1.46
963 reflections
38 parameters
Δρ_max = 1.34 e Å⁻³
Δρ_min = −2.21 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008a ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008a); molecular graphics: CrystalMaker (Palmer, 2009 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810053924/wm2437sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536810053924/wm2437Isup2.hkl

checkCIF report

Comment top

As part of continuing efforts to synthesize new uranium chalcogenide compounds, Cs₂UPd₃Se₆ was synthesized. It crystallizes in the orthorhombic space group Fmmm in the Ba₂NaCu₃O₆ structure type (Tams & Müller-Buschbaum, 1992). The asymmetric unit comprises the following atoms with site symmetries as shown: U1 (mm2); Cs1 (222); Cs2 (m2m); Pd1 (.m.); Pd2 (2mm); Se1 (m..); and Se2 (1) (Fig. 1). This layered structure (Fig. 2) contains six edge-sharing square-planar [PdSe₄] units that form a hexagon. These, in turn, edge-share with [USe₆] trigonal-prism units to form an extended layer parallel to (010). The layers are stacked along [010] and are separated by Cs atoms. The Cs atoms are either coordinated in a square antiprism of Se atoms or are ten-coordinate, with one square face and the opposite face hexagonal (Fig. 3).

The shortest Se–Se distance is 3.3344 (9) Å, far longer than a single bond. Thus, formal oxidation states may be assigned as follows: Cs: +1; U: +4; Pd: +2; Se: -2. Pd²⁺ typically has a square-planar coordination. In contrast, trigonal-prismatic coordination is unusual for U⁴⁺, though it is known, for example in Ba₄Cr₂US₉ (Yao & Ibers, 2008).

U–Se distances are 2.8353 (5) Å and 2.8704 (7) Å, similar to those in other compounds containing six-coordinate U⁴⁺ atoms, such as in CsUCuSe₃ (Huang et al., 2001), where the U–Se distances range from 2.8265 (6) Å to 2.8611 (8) Å. Pd–Se distances are typical for square-planar Pd²⁺ atoms, ranging from 2.4516 (5) Å to 2.4736 (6) Å, similar to those of 2.453 (6) Å to 2.456 (7) Å in Cs₂Pd₃Se₄ (Bronger et al., 1991) and those of 2.476 (1) Å and 2.479 (1) Å found in UPdSe₃ (Daoudi & Noël, 1989). The Cs1–Se distances, which are 3.4653 (5) Å and 3.4682 (5) Å, are shorter than are typical for eight-coordinate Cs. Typical are those in CsUCuSe₃ which range from 3.5825 (16) Å to 3.8246 (11) Å. On the other hand, the ten-coordinate Cs2—Se distances are typical. They range from 3.7847 (7) Å to 3.9511 (7) Å, to be compared to 3.660 (3) Å to 3.961 (7) Å in CsFe₂Se₃ (Klepp et al., 1996).

Related literature top

Ba₂NaCu₃O₆ was reported by Tams & Müller-Buschbaum (1992). For related structures, see: Daoudi & Noël (1989); Bronger et al. (1991); Yao & Ibers (2008); Huang et al. (2001); Klepp et al. (1996). For synthetic details, see: Bugaris & Ibers (2008); Haneveld & Jellinek (1969). For computational details, see: Gelato & Parthé (1987); Le Page (1988).

Experimental top

Black hexagonal plates of Cs₂UPd₃Se₆ were synthesized by the combination of U (0.063 mmol), Pd (Johnson Matthey 99.94%, 0.063 mmol), Se (Cerac 99.999%, 0.253 mmol), and 125 mg CsCl (Aldrich 99.9%, 0.743 mmol) as a flux. U filings (Oak Ridge National Laboratory) were powdered by hydridization and subsequent decomposition under heat and vacuum (Bugaris & Ibers, 2008), in a modification of a previous literature method (Haneveld & Jellinek, 1969). The mixture was loaded into a carbon-coated fused-silica tube in an Ar filled glove box and then sealed under 10 ^-4 Torr vacuum. The reaction was heated to 1273 K in 48 h, held there for 6 h, cooled to 1223 K in 12 h, held there for 24 h, then cooled to 298 K at 3.2 K/h.

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008a); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008a); molecular graphics: CrystalMaker (Palmer, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008a).

Figures top

	Fig. 1. : Asymmetric unit of Cs₂UPd₃Se₆ (95% probability ellipsoids).
	Fig. 2. : Structure of Cs₂UPd₃Se₆viewed down the b-axis (left) and the c-axis (right).
	Fig. 3. : Coordination environment of atom Cs2.

Dicaesium uranium(IV) tripalladium(II) hexaselenide top

Crystal data top

Cs₂UPd₃Se₆	F(000) = 4352
M_r = 1296.81	D_x = 6.266 Mg m⁻³
Orthorhombic, Fmmm	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -F 2 2	Cell parameters from 5598 reflections
a = 10.1034 (5) Å	θ = 2.3–28.2°
b = 15.5046 (8) Å	µ = 36.67 mm⁻¹
c = 17.5503 (8) Å	T = 100 K
V = 2749.2 (2) Å³	Hexagonal plate, black
Z = 8	0.21 × 0.17 × 0.01 mm

Data collection top

Bruker APEXII CCD diffractometer	963 independent reflections
Radiation source: fine-focus sealed tube	921 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.035
ω scans	θ_max = 28.6°, θ_min = 2.3°
Absorption correction: numerical (face indexed using SADABS; Sheldrick, 2008b)	h = −13→13
T_min = 0.049, T_max = 0.689	k = −20→20
8099 measured reflections	l = −23→23

Refinement top

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)] = 0.019	[1.00000 + 0.00000exp(0.00(sinθ/λ)²)]/ [σ²(F_o²) + 0.0000 + 0.0000*P + (0.0241P)² + 0.0000sinθ/λ] where P = 1.00000F_o² + 0.00000F_c²
wR(F²) = 0.055	(Δ/σ)_max < 0.001
S = 1.46	Δρ_max = 1.34 e Å⁻³
963 reflections	Δρ_min = −2.21 e Å⁻³
38 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008a), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.000083 (9)

Crystal data top

Cs₂UPd₃Se₆	V = 2749.2 (2) Å³
M_r = 1296.81	Z = 8
Orthorhombic, Fmmm	Mo Kα radiation
a = 10.1034 (5) Å	µ = 36.67 mm⁻¹
b = 15.5046 (8) Å	T = 100 K
c = 17.5503 (8) Å	0.21 × 0.17 × 0.01 mm

Data collection top

Bruker APEXII CCD diffractometer	963 independent reflections
Absorption correction: numerical (face indexed using SADABS; Sheldrick, 2008b)	921 reflections with I > 2σ(I)
T_min = 0.049, T_max = 0.689	R_int = 0.035
8099 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.019	38 parameters
wR(F²) = 0.055	0 restraints
S = 1.46	Δρ_max = 1.34 e Å⁻³
963 reflections	Δρ_min = −2.21 e Å⁻³

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
U1	0.0000	0.0000	0.166826 (18)	0.00859 (12)
Cs1	0.2500	0.2500	0.2500	0.00986 (14)
Cs2	0.0000	0.30128 (4)	0.0000	0.01609 (16)
Pd1	0.33694 (4)	0.0000	0.15828 (3)	0.00866 (14)
Pd2	0.17351 (6)	0.0000	0.0000	0.00843 (16)
Se1	0.0000	0.10753 (4)	0.29996 (3)	0.00912 (15)
Se2	0.19159 (4)	0.11000 (3)	0.09981 (2)	0.00908 (13)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
U1	0.00523 (18)	0.0108 (2)	0.00978 (19)	0.000	0.000	0.000
Cs1	0.0078 (2)	0.0105 (3)	0.0113 (3)	0.000	0.000	0.000
Cs2	0.0104 (3)	0.0233 (4)	0.0146 (3)	0.000	0.000	0.000
Pd1	0.0049 (2)	0.0109 (3)	0.0102 (3)	0.000	−0.00063 (15)	0.000
Pd2	0.0067 (3)	0.0106 (4)	0.0080 (3)	0.000	0.000	0.000
Se1	0.0058 (3)	0.0107 (3)	0.0109 (3)	0.000	0.000	0.0004 (2)
Se2	0.0065 (2)	0.0105 (3)	0.0103 (2)	−0.00038 (17)	−0.00027 (15)	−0.00014 (16)

Geometric parameters (Å, º) top

U1—Se2	2.8353 (5)	Cs2—Se2^xvi	3.8301 (5)
U1—Se2ⁱ	2.8353 (5)	Cs2—Se2	3.9511 (7)
U1—Se2ⁱⁱ	2.8353 (5)	Cs2—Se2^xvii	3.9511 (7)
U1—Se2ⁱⁱⁱ	2.8353 (5)	Cs2—Se2ⁱⁱ	3.9511 (7)
U1—Se1ⁱ	2.8704 (7)	Cs2—Se2^xviii	3.9511 (7)
U1—Se1	2.8704 (7)	Cs2—Pd1^ix	4.4635 (6)
U1—Pd1ⁱ	3.4076 (4)	Cs2—Pd1^xix	4.4635 (6)
U1—Pd1	3.4076 (4)	Pd1—Se1^xi	2.4557 (6)
U1—Pd2^iv	3.4125 (4)	Pd1—Se1^v	2.4557 (6)
U1—Pd2	3.4125 (4)	Pd1—Se2ⁱⁱⁱ	2.4736 (6)
U1—Pd1^v	3.4836 (6)	Pd1—Se2	2.4736 (6)
U1—Pd1^vi	3.4836 (6)	Pd1—Pd2	3.2316 (6)
Cs1—Se2^vii	3.4653 (5)	Pd1—U1^v	3.4836 (6)
Cs1—Se2^viii	3.4653 (5)	Pd1—Cs1^v	4.2880 (3)
Cs1—Se2^ix	3.4653 (5)	Pd1—Cs2^xx	4.4636 (6)
Cs1—Se2	3.4653 (5)	Pd1—Cs2^xv	4.4636 (6)
Cs1—Se1	3.4682 (5)	Pd2—Se2	2.4516 (5)
Cs1—Se1^ix	3.4682 (5)	Pd2—Se2^xxi	2.4516 (5)
Cs1—Se1^x	3.4682 (5)	Pd2—Se2ⁱⁱⁱ	2.4516 (5)
Cs1—Se1^xi	3.4682 (5)	Pd2—Se2^xviii	2.4516 (5)
Cs1—Pd1	4.2880 (3)	Pd2—Pd1^xviii	3.2316 (6)
Cs1—Pd1^xii	4.2881 (3)	Pd2—U1^iv	3.4125 (4)
Cs1—Pd1^v	4.2881 (3)	Pd2—Cs2^xv	4.5137 (6)
Cs1—Pd1^ix	4.2881 (3)	Pd2—Cs2^xx	4.5137 (6)
Cs2—Se1^x	3.7847 (7)	Se1—Pd1^vi	2.4557 (6)
Cs2—Se1^xiii	3.7847 (7)	Se1—Pd1^v	2.4557 (6)
Cs2—Se2^ix	3.8301 (5)	Se1—Cs1^x	3.4682 (5)
Cs2—Se2^xiv	3.8301 (5)	Se1—Cs2^x	3.7847 (7)
Cs2—Se2^xv	3.8301 (5)	Se2—Cs2^xv	3.8301 (5)

Se2—U1—Se2ⁱ	130.98 (2)	Se2^xv—Cs2—Se2ⁱⁱ	150.563 (16)
Se2—U1—Se2ⁱⁱ	86.111 (19)	Se2^xvi—Cs2—Se2ⁱⁱ	70.624 (13)
Se2ⁱ—U1—Se2ⁱⁱ	73.96 (2)	Se2—Cs2—Se2ⁱⁱ	58.670 (15)
Se2—U1—Se2ⁱⁱⁱ	73.96 (2)	Se2^xvii—Cs2—Se2ⁱⁱ	52.634 (14)
Se2ⁱ—U1—Se2ⁱⁱⁱ	86.111 (19)	Se1^x—Cs2—Se2^xviii	133.761 (13)
Se2ⁱⁱ—U1—Se2ⁱⁱⁱ	130.98 (2)	Se1^xiii—Cs2—Se2^xviii	82.482 (12)
Se2—U1—Se1ⁱ	133.399 (11)	Se2^ix—Cs2—Se2^xviii	94.230 (11)
Se2ⁱ—U1—Se1ⁱ	89.330 (14)	Se2^xiv—Cs2—Se2^xviii	117.735 (13)
Se2ⁱⁱ—U1—Se1ⁱ	133.398 (11)	Se2^xv—Cs2—Se2^xviii	70.624 (13)
Se2ⁱⁱⁱ—U1—Se1ⁱ	89.330 (14)	Se2^xvi—Cs2—Se2^xviii	150.563 (16)
Se2—U1—Se1	89.331 (14)	Se2—Cs2—Se2^xviii	52.633 (14)
Se2ⁱ—U1—Se1	133.398 (11)	Se2^xvii—Cs2—Se2^xviii	58.670 (15)
Se2ⁱⁱ—U1—Se1	89.330 (14)	Se2ⁱⁱ—Cs2—Se2^xviii	82.711 (18)
Se2ⁱⁱⁱ—U1—Se1	133.398 (11)	Se1^x—Cs2—Pd1^ix	33.369 (10)
Se1ⁱ—U1—Se1	71.02 (3)	Se1^xiii—Cs2—Pd1^ix	108.628 (18)
Se2—U1—Pd1ⁱ	131.589 (12)	Se2^ix—Cs2—Pd1^ix	33.614 (9)
Se2ⁱ—U1—Pd1ⁱ	45.548 (10)	Se2^xiv—Cs2—Pd1^ix	109.694 (16)
Se2ⁱⁱ—U1—Pd1ⁱ	45.548 (10)	Se2^xv—Cs2—Pd1^ix	74.720 (12)
Se2ⁱⁱⁱ—U1—Pd1ⁱ	131.589 (12)	Se2^xvi—Cs2—Pd1^ix	76.571 (12)
Se1ⁱ—U1—Pd1ⁱ	92.053 (8)	Se2—Cs2—Pd1^ix	93.521 (9)
Se1—U1—Pd1ⁱ	92.053 (8)	Se2^xvii—Cs2—Pd1^ix	167.125 (9)
Se2—U1—Pd1	45.549 (10)	Se2ⁱⁱ—Cs2—Pd1^ix	115.027 (9)
Se2ⁱ—U1—Pd1	131.590 (12)	Se2^xviii—Cs2—Pd1^ix	127.822 (8)
Se2ⁱⁱ—U1—Pd1	131.590 (12)	Se1^x—Cs2—Pd1^xix	33.369 (10)
Se2ⁱⁱⁱ—U1—Pd1	45.549 (10)	Se1^xiii—Cs2—Pd1^xix	108.628 (18)
Se1ⁱ—U1—Pd1	92.053 (8)	Se2^ix—Cs2—Pd1^xix	76.571 (12)
Se1—U1—Pd1	92.052 (8)	Se2^xiv—Cs2—Pd1^xix	74.720 (12)
Pd1ⁱ—U1—Pd1	174.96 (2)	Se2^xv—Cs2—Pd1^xix	109.694 (16)
Se2—U1—Pd2^iv	89.701 (13)	Se2^xvi—Cs2—Pd1^xix	33.614 (9)
Se2ⁱ—U1—Pd2^iv	45.040 (11)	Se2—Cs2—Pd1^xix	115.028 (9)
Se2ⁱⁱ—U1—Pd2^iv	45.040 (11)	Se2^xvii—Cs2—Pd1^xix	127.822 (8)
Se2ⁱⁱⁱ—U1—Pd2^iv	89.702 (13)	Se2ⁱⁱ—Cs2—Pd1^xix	93.520 (9)
Se1ⁱ—U1—Pd2^iv	134.300 (11)	Se2^xviii—Cs2—Pd1^xix	167.125 (9)
Se1—U1—Pd2^iv	134.300 (11)	Pd1^ix—Cs2—Pd1^xix	43.318 (11)
Pd1ⁱ—U1—Pd2^iv	56.567 (13)	Se1^xi—Pd1—Se1^v	85.52 (3)
Pd1—U1—Pd2^iv	118.389 (14)	Se1^xi—Pd1—Se2ⁱⁱⁱ	171.97 (3)
Se2—U1—Pd2	45.038 (11)	Se1^v—Pd1—Se2ⁱⁱⁱ	93.095 (17)
Se2ⁱ—U1—Pd2	89.702 (13)	Se1^xi—Pd1—Se2	93.096 (18)
Se2ⁱⁱ—U1—Pd2	89.702 (13)	Se1^v—Pd1—Se2	171.96 (3)
Se2ⁱⁱⁱ—U1—Pd2	45.040 (11)	Se2ⁱⁱⁱ—Pd1—Se2	87.18 (3)
Se1ⁱ—U1—Pd2	134.300 (11)	Se1^xi—Pd1—Pd2	126.819 (19)
Se1—U1—Pd2	134.300 (11)	Se1^v—Pd1—Pd2	126.82 (2)
Pd1ⁱ—U1—Pd2	118.388 (14)	Se2ⁱⁱⁱ—Pd1—Pd2	48.701 (14)
Pd1—U1—Pd2	56.568 (13)	Se2—Pd1—Pd2	48.699 (14)
Pd2^iv—U1—Pd2	61.821 (18)	Se1^xi—Pd1—U1	131.077 (15)
Se2—U1—Pd1^v	92.446 (11)	Se1^v—Pd1—U1	131.077 (15)
Se2ⁱ—U1—Pd1^v	133.501 (12)	Se2ⁱⁱⁱ—Pd1—U1	54.909 (13)
Se2ⁱⁱ—U1—Pd1^v	133.501 (12)	Se2—Pd1—U1	54.909 (13)
Se2ⁱⁱⁱ—U1—Pd1^v	92.445 (11)	Pd2—Pd1—U1	61.793 (13)
Se1ⁱ—U1—Pd1^v	44.171 (11)	Se1^xi—Pd1—U1^v	54.538 (17)
Se1—U1—Pd1^v	44.172 (11)	Se1^v—Pd1—U1^v	54.538 (17)
Pd1ⁱ—U1—Pd1^v	120.746 (11)	Se2ⁱⁱⁱ—Pd1—U1^v	130.265 (15)
Pd1—U1—Pd1^v	64.299 (14)	Se2—Pd1—U1^v	130.266 (15)
Pd2^iv—U1—Pd1^v	177.312 (13)	Pd2—Pd1—U1^v	177.495 (17)
Pd2—U1—Pd1^v	120.866 (11)	U1—Pd1—U1^v	115.701 (14)
Se2—U1—Pd1^vi	133.502 (12)	Se1^xi—Pd1—Cs1	53.965 (11)
Se2ⁱ—U1—Pd1^vi	92.445 (11)	Se1^v—Pd1—Cs1	129.73 (2)
Se2ⁱⁱ—U1—Pd1^vi	92.445 (11)	Se2ⁱⁱⁱ—Pd1—Cs1	131.100 (17)
Se2ⁱⁱⁱ—U1—Pd1^vi	133.501 (12)	Se2—Pd1—Cs1	53.905 (11)
Se1ⁱ—U1—Pd1^vi	44.171 (11)	Pd2—Pd1—Cs1	102.592 (7)
Se1—U1—Pd1^vi	44.172 (11)	U1—Pd1—Cs1	77.222 (7)
Pd1ⁱ—U1—Pd1^vi	64.300 (14)	U1^v—Pd1—Cs1	76.474 (7)
Pd1—U1—Pd1^vi	120.745 (11)	Se1^xi—Pd1—Cs1^v	129.73 (2)
Pd2^iv—U1—Pd1^vi	120.866 (11)	Se1^v—Pd1—Cs1^v	53.965 (11)
Pd2—U1—Pd1^vi	177.312 (13)	Se2ⁱⁱⁱ—Pd1—Cs1^v	53.904 (11)
Pd1^v—U1—Pd1^vi	56.446 (15)	Se2—Pd1—Cs1^v	131.099 (17)
Se2^vii—Cs1—Se2^viii	80.953 (16)	Pd2—Pd1—Cs1^v	102.592 (7)
Se2^vii—Cs1—Se2^ix	102.430 (16)	U1—Pd1—Cs1^v	77.222 (7)
Se2^viii—Cs1—Se2^ix	160.389 (13)	U1^v—Pd1—Cs1^v	76.475 (7)
Se2^vii—Cs1—Se2	160.389 (13)	Cs1—Pd1—Cs1^v	129.363 (12)
Se2^viii—Cs1—Se2	102.430 (16)	Se1^xi—Pd1—Cs2^xx	114.000 (17)
Se2^ix—Cs1—Se2	80.953 (16)	Se1^v—Pd1—Cs2^xx	57.960 (16)
Se2^vii—Cs1—Se1	94.738 (13)	Se2ⁱⁱⁱ—Pd1—Cs2^xx	59.002 (13)
Se2^viii—Cs1—Se1	62.144 (11)	Se2—Pd1—Cs2^xx	115.901 (19)
Se2^ix—Cs1—Se1	135.669 (11)	Pd2—Pd1—Cs2^xx	69.734 (10)
Se2—Cs1—Se1	70.690 (13)	U1—Pd1—Cs2^xx	113.335 (9)
Se2^vii—Cs1—Se1^ix	62.143 (11)	U1^v—Pd1—Cs2^xx	111.952 (8)
Se2^viii—Cs1—Se1^ix	94.738 (13)	Cs1—Pd1—Cs2^xx	158.937 (12)
Se2^ix—Cs1—Se1^ix	70.691 (13)	Cs1^v—Pd1—Cs2^xx	71.656 (7)
Se2—Cs1—Se1^ix	135.670 (11)	Se1^xi—Pd1—Cs2^xv	57.960 (16)
Se1—Cs1—Se1^ix	150.71 (2)	Se1^v—Pd1—Cs2^xv	114.000 (17)
Se2^vii—Cs1—Se1^x	70.691 (13)	Se2ⁱⁱⁱ—Pd1—Cs2^xv	115.903 (19)
Se2^viii—Cs1—Se1^x	135.670 (11)	Se2—Pd1—Cs2^xv	59.003 (13)
Se2^ix—Cs1—Se1^x	62.143 (11)	Pd2—Pd1—Cs2^xv	69.734 (10)
Se2—Cs1—Se1^x	94.738 (13)	U1—Pd1—Cs2^xv	113.335 (9)
Se1—Cs1—Se1^x	86.513 (16)	U1^v—Pd1—Cs2^xv	111.952 (8)
Se1^ix—Cs1—Se1^x	100.875 (18)	Cs1—Pd1—Cs2^xv	71.656 (7)
Se2^vii—Cs1—Se1^xi	135.670 (11)	Cs1^v—Pd1—Cs2^xv	158.937 (12)
Se2^viii—Cs1—Se1^xi	70.691 (13)	Cs2^xx—Pd1—Cs2^xv	87.301 (15)
Se2^ix—Cs1—Se1^xi	94.738 (13)	Se2—Pd2—Se2^xxi	171.45 (3)
Se2—Cs1—Se1^xi	62.144 (11)	Se2—Pd2—Se2ⁱⁱⁱ	88.16 (2)
Se1—Cs1—Se1^xi	100.876 (18)	Se2^xxi—Pd2—Se2ⁱⁱⁱ	91.20 (2)
Se1^ix—Cs1—Se1^xi	86.514 (16)	Se2—Pd2—Se2^xviii	91.20 (2)
Se1^x—Cs1—Se1^xi	150.71 (2)	Se2^xxi—Pd2—Se2^xviii	88.16 (2)
Se2^vii—Cs1—Pd1	152.457 (10)	Se2ⁱⁱⁱ—Pd2—Se2^xviii	171.45 (3)
Se2^viii—Cs1—Pd1	71.604 (10)	Se2—Pd2—Pd1^xviii	125.177 (18)
Se2^ix—Cs1—Pd1	104.229 (10)	Se2^xxi—Pd2—Pd1^xviii	49.289 (12)
Se2—Cs1—Pd1	35.226 (10)	Se2ⁱⁱⁱ—Pd2—Pd1^xviii	125.176 (18)
Se1—Cs1—Pd1	70.632 (11)	Se2^xviii—Pd2—Pd1^xviii	49.289 (12)
Se1^ix—Cs1—Pd1	121.430 (10)	Se2—Pd2—Pd1	49.289 (12)
Se1^x—Cs1—Pd1	129.052 (12)	Se2^xxi—Pd2—Pd1	125.177 (18)
Se1^xi—Cs1—Pd1	34.930 (10)	Se2ⁱⁱⁱ—Pd2—Pd1	49.289 (12)
Se2^vii—Cs1—Pd1^xii	35.225 (10)	Se2^xviii—Pd2—Pd1	125.177 (18)
Se2^viii—Cs1—Pd1^xii	104.228 (10)	Pd1^xviii—Pd2—Pd1	118.54 (2)
Se2^ix—Cs1—Pd1^xii	71.605 (10)	Se2—Pd2—U1^iv	130.638 (16)
Se2—Cs1—Pd1^xii	152.458 (10)	Se2^xxi—Pd2—U1^iv	54.919 (11)
Se1—Cs1—Pd1^xii	129.051 (12)	Se2ⁱⁱⁱ—Pd2—U1^iv	130.639 (16)
Se1^ix—Cs1—Pd1^xii	34.930 (10)	Se2^xviii—Pd2—U1^iv	54.919 (11)
Se1^x—Cs1—Pd1^xii	70.633 (11)	Pd1^xviii—Pd2—U1^iv	61.640 (9)
Se1^xi—Cs1—Pd1^xii	121.430 (10)	Pd1—Pd2—U1^iv	179.818 (19)
Pd1—Cs1—Pd1^xii	156.358 (11)	Se2—Pd2—U1	54.919 (11)
Se2^vii—Cs1—Pd1^v	104.228 (10)	Se2^xxi—Pd2—U1	130.639 (16)
Se2^viii—Cs1—Pd1^v	35.225 (10)	Se2ⁱⁱⁱ—Pd2—U1	54.919 (11)
Se2^ix—Cs1—Pd1^v	152.458 (10)	Se2^xviii—Pd2—U1	130.639 (16)
Se2—Cs1—Pd1^v	71.605 (10)	Pd1^xviii—Pd2—U1	179.818 (19)
Se1—Cs1—Pd1^v	34.931 (10)	Pd1—Pd2—U1	61.639 (9)
Se1^ix—Cs1—Pd1^v	129.051 (12)	U1^iv—Pd2—U1	118.178 (18)
Se1^x—Cs1—Pd1^v	121.430 (10)	Se2—Pd2—Cs2^xv	58.042 (13)
Se1^xi—Cs1—Pd1^v	70.632 (11)	Se2^xxi—Pd2—Cs2^xv	114.859 (18)
Pd1—Cs1—Pd1^v	50.637 (12)	Se2ⁱⁱⁱ—Pd2—Cs2^xv	114.859 (18)
Pd1^xii—Cs1—Pd1^v	135.902 (12)	Se2^xviii—Pd2—Cs2^xv	58.041 (13)
Se2^vii—Cs1—Pd1^ix	71.605 (10)	Pd1^xviii—Pd2—Cs2^xv	68.073 (10)
Se2^viii—Cs1—Pd1^ix	152.458 (10)	Pd1—Pd2—Cs2^xv	68.073 (10)
Se2^ix—Cs1—Pd1^ix	35.225 (10)	U1^iv—Pd2—Cs2^xv	112.050 (5)
Se2—Cs1—Pd1^ix	104.228 (10)	U1—Pd2—Cs2^xv	112.050 (5)
Se1—Cs1—Pd1^ix	121.430 (10)	Se2—Pd2—Cs2^xx	114.860 (18)
Se1^ix—Cs1—Pd1^ix	70.632 (11)	Se2^xxi—Pd2—Cs2^xx	58.041 (13)
Se1^x—Cs1—Pd1^ix	34.930 (10)	Se2ⁱⁱⁱ—Pd2—Cs2^xx	58.041 (13)
Se1^xi—Cs1—Pd1^ix	129.051 (12)	Se2^xviii—Pd2—Cs2^xx	114.859 (18)
Pd1—Cs1—Pd1^ix	135.903 (12)	Pd1^xviii—Pd2—Cs2^xx	68.073 (10)
Pd1^xii—Cs1—Pd1^ix	50.638 (12)	Pd1—Pd2—Cs2^xx	68.073 (10)
Pd1^v—Cs1—Pd1^ix	156.358 (11)	U1^iv—Pd2—Cs2^xx	112.050 (5)
Se1^x—Cs2—Se1^xiii	136.13 (3)	U1—Pd2—Cs2^xx	112.050 (5)
Se1^x—Cs2—Se2^ix	56.056 (8)	Cs2^xv—Pd2—Cs2^xx	86.091 (16)
Se1^xiii—Cs2—Se2^ix	106.862 (13)	Pd1^vi—Se1—Pd1^v	84.26 (3)
Se1^x—Cs2—Se2^xiv	106.862 (13)	Pd1^vi—Se1—U1	81.29 (2)
Se1^xiii—Cs2—Se2^xiv	56.056 (8)	Pd1^v—Se1—U1	81.29 (2)
Se2^ix—Cs2—Se2^xiv	137.91 (2)	Pd1^vi—Se1—Cs1	175.16 (2)
Se1^x—Cs2—Se2^xv	106.862 (13)	Pd1^v—Se1—Cs1	91.105 (9)
Se1^xiii—Cs2—Se2^xv	56.056 (8)	U1—Se1—Cs1	99.446 (14)
Se2^ix—Cs2—Se2^xv	54.431 (13)	Pd1^vi—Se1—Cs1^x	91.105 (9)
Se2^xiv—Cs2—Se2^xv	108.889 (16)	Pd1^v—Se1—Cs1^x	175.16 (2)
Se1^x—Cs2—Se2^xvi	56.056 (8)	U1—Se1—Cs1^x	99.446 (14)
Se1^xiii—Cs2—Se2^xvi	106.862 (13)	Cs1—Se1—Cs1^x	93.487 (16)
Se2^ix—Cs2—Se2^xvi	108.889 (16)	Pd1^vi—Se1—Cs2^x	88.67 (2)
Se2^xiv—Cs2—Se2^xvi	54.431 (13)	Pd1^v—Se1—Cs2^x	88.67 (2)
Se2^xv—Cs2—Se2^xvi	137.91 (2)	U1—Se1—Cs2^x	166.43 (3)
Se1^x—Cs2—Se2	82.483 (12)	Cs1—Se1—Cs2^x	89.806 (14)
Se1^xiii—Cs2—Se2	133.760 (13)	Cs1^x—Se1—Cs2^x	89.806 (14)
Se2^ix—Cs2—Se2	70.625 (13)	Pd2—Se2—Pd1	82.01 (2)
Se2^xiv—Cs2—Se2	150.562 (16)	Pd2—Se2—U1	80.043 (17)
Se2^xv—Cs2—Se2	94.230 (11)	Pd1—Se2—U1	79.542 (17)
Se2^xvi—Cs2—Se2	117.736 (13)	Pd2—Se2—Cs1	172.72 (2)
Se1^x—Cs2—Se2^xvii	133.761 (13)	Pd1—Se2—Cs1	90.869 (15)
Se1^xiii—Cs2—Se2^xvii	82.482 (12)	U1—Se2—Cs1	100.224 (13)
Se2^ix—Cs2—Se2^xvii	150.563 (16)	Pd2—Se2—Cs2^xv	89.066 (18)
Se2^xiv—Cs2—Se2^xvii	70.624 (13)	Pd1—Se2—Cs2^xv	87.383 (16)
Se2^xv—Cs2—Se2^xvii	117.735 (13)	U1—Se2—Cs2^xv	163.979 (19)
Se2^xvi—Cs2—Se2^xvii	94.230 (11)	Cs1—Se2—Cs2^xv	89.104 (12)
Se2—Cs2—Se2^xvii	82.710 (18)	Pd2—Se2—Cs2	99.726 (15)
Se1^x—Cs2—Se2ⁱⁱ	82.482 (12)	Pd1—Se2—Cs2	172.903 (19)
Se1^xiii—Cs2—Se2ⁱⁱ	133.761 (13)	U1—Se2—Cs2	107.516 (12)
Se2^ix—Cs2—Se2ⁱⁱ	117.735 (13)	Cs1—Se2—Cs2	87.161 (12)
Se2^xiv—Cs2—Se2ⁱⁱ	94.229 (11)	Cs2^xv—Se2—Cs2	85.771 (11)

Symmetry codes: (i) −x, −y, z; (ii) −x, y, z; (iii) x, −y, z; (iv) −x, −y, −z; (v) −x+1/2, −y, −z+1/2; (vi) x−1/2, y, −z+1/2; (vii) x, −y+1/2, −z+1/2; (viii) −x+1/2, y, −z+1/2; (ix) −x+1/2, −y+1/2, z; (x) −x, −y+1/2, −z+1/2; (xi) x+1/2, y, −z+1/2; (xii) x, y+1/2, −z+1/2; (xiii) −x, −y+1/2, z−1/2; (xiv) x−1/2, −y+1/2, −z; (xv) −x+1/2, −y+1/2, −z; (xvi) x−1/2, −y+1/2, z; (xvii) −x, y, −z; (xviii) x, y, −z; (xix) x−1/2, y+1/2, z; (xx) x+1/2, y−1/2, z; (xxi) x, −y, −z.

Experimental details

Crystal data
Chemical formula	Cs₂UPd₃Se₆
M_r	1296.81
Crystal system, space group	Orthorhombic, Fmmm
Temperature (K)	100
a, b, c (Å)	10.1034 (5), 15.5046 (8), 17.5503 (8)
V (Å³)	2749.2 (2)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	36.67
Crystal size (mm)	0.21 × 0.17 × 0.01

Data collection
Diffractometer	Bruker APEXII CCD diffractometer
Absorption correction	Numerical (face indexed using SADABS; Sheldrick, 2008b)
T_min, T_max	0.049, 0.689
No. of measured, independent and observed [I > 2σ(I)] reflections	8099, 963, 921
R_int	0.035
(sin θ/λ)_max (Å⁻¹)	0.673

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.019, 0.055, 1.46
No. of reflections	963
No. of parameters	38
Δρ_max, Δρ_min (e Å⁻³)	1.34, −2.21

Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXS97 (Sheldrick, 2008a), SHELXL97 (Sheldrick, 2008a), CrystalMaker (Palmer, 2009).

Acknowledgements

The research was kindly supported by the US Department of Energy, Basic Energy Sciences, Chemical Sciences, Biosciences, and Geosciences Division and Divison of Materials Science and Engineering grant ER-15522. Use was made of the IMSERC X-ray Facility at Northwestern University, supported by the International Institute of Nanotechnology (IIN).

References

Bronger, W., Rennau, R. & Schmitz, D. (1991). Z. Anorg. Allg. Chem. 597, 27–32. CrossRef CAS Web of Science Google Scholar
Bruker (2009). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Bugaris, D. E. & Ibers, J. A. (2008). Acta Cryst. E64, i55–i56. Web of Science CrossRef IUCr Journals Google Scholar
Daoudi, A. & Noël, H. (1989). J. Less-Common Met. 153, 293–298. CrossRef CAS Google Scholar
Gelato, L. M. & Parthé, E. (1987). J. Appl. Cryst. 20, 139–143. CrossRef Web of Science IUCr Journals Google Scholar
Haneveld, A. J. K. & Jellinek, F. (1969). J. Less-Common Met. 18, 123–129. CrossRef CAS Google Scholar
Huang, F. Q., Mitchell, K. & Ibers, J. A. (2001). Inorg. Chem. 40, 5123–5126. Web of Science CrossRef PubMed CAS Google Scholar
Klepp, K. O., Sparlinek, W. & Boller, H. (1996). J. Alloys Compd, 238, 1–5. CrossRef CAS Web of Science Google Scholar
Le Page, Y. (1988). J. Appl. Cryst. 21, 983–984. CrossRef Web of Science IUCr Journals Google Scholar
Palmer, D. (2009). CrystalMaker. CrystalMaker Software Ltd, Oxford, England. Google Scholar
Sheldrick, G. M. (2008a). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2008b). SADABS. University of Göttingen, Germany. Google Scholar
Tams, G. & Müller-Buschbaum, H. (1992). Z. Anorg. Allg. Chem. 617, 19–22. CrossRef CAS Web of Science Google Scholar
Yao, J. & Ibers, J. A. (2008). Z. Anorg. Allg. Chem. 634, 1645–1647. Web of Science CrossRef CAS Google Scholar