Poly[tetraaqua-μ4-squarato-di-μ3-squarato-disam­arium(III)]

Akkari, H.; Bouacida, S.; Bénard-Rocherullé, P.; Merazig, H.; Roisnel, T.

doi:10.1107/S160053680803674X

Poly[tetraaqua-μ₄-squarato-di-μ₃-squarato-disamarium(III)]

H. Akkari, S. Bouacida, P. Bénard-Rocherullé, H. Merazig and T. Roisnel

The structure of the title compound, [Sm₂(C₄O₄)₃(H₂O)₄]_n, consists of infinite-chain structural units, built from edge-sharing samarium SmO₇(H₂O)₂ polyhedra and linked via bis-monodendate squarate (sq1) groups. The chains extend along [100] in a zigzag mode and are interconnected by bis-chelating squarate (sq2) ligands into layers parallel to (101). Interlayer hydrogen bonds strengthen the cohesion of the three-dimensional network. The samarium cation is coordinated by four O atoms from sq1 units and three O atoms from sq2 units, in addition to two water O atoms. The best representation of the samarium SmO₇(H₂O)₂ polyhedron is distorted tricapped trigonal-prismatic. The sq1 ligand has one metal-free O atom and relates three Sm atoms in a bis-monodentate and chelation fashion, the second squarate, sq2, is strictly centrosymmetric and acts as a bis-chelating ligand.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S160053680803674X/dn2395sup1.cif Contains datablocks global, I
	Structure factor file (CIF format) https://doi.org/10.1107/S160053680803674X/dn2395Isup2.hkl Contains datablock I

CCDC reference: 712315

checkCIF report

Key indicators

Single-crystal X-ray study
T = 296 K
Mean (C-C) = 0.004 Å
R factor = 0.023
wR factor = 0.058
Data-to-parameter ratio = 15.8

checkCIF/PLATON results

No syntax errors found



Alert level C
            Value of measurement temperature given =   296.000
            Value of melting point given =     0.000
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Sm1    --  O3_a    ..       5.35 su
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Sm1    --  O4_a    ..       6.10 su
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Sm1    --  O5_e    ..       7.02 su
PLAT041_ALERT_1_C Calc. and Rep. SumFormula Strings    Differ ....          ?
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT045_ALERT_1_C Calculated and Reported Z Differ by ............       2.00 Ratio

Alert level G
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          6
PLAT180_ALERT_4_G Check Cell Rounding: # of Values Ending with 0 =          3
PLAT720_ALERT_4_G Number of Unusual/Non-Standard Labels ..........          4

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   6 ALERT level C = Check and explain
   3 ALERT level G = General alerts; check

   3 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

Comment top

A family of weakly hydrated lanthanide(III) squarates, [Ln(H₂O)₂]₂ (C₄O₄)₃ (Ln= La, Ce, Pr, Nd, Sm, Eu) was synthesized hydrothermally (Trombe et al., 1988; Trombe et al., 1990) starting from heating hydrated lanthanide(III) squarates (Petit et al., 1990) in water inside a closed vessel. Unit-cell parameters of the whole compounds were determined from X-ray powder patterns. However, only crystal structure of cerium compound was determined using single-crystal X-ray techniques. Accordingly, much effort was given to experimental conditions in order to obtain single-crystals of the other lanthanides. Unfortunately, up to now no other single-crystal of lanthanide(III) squarate tetrahydrates could be obtained. Therefore herein we report on crystal structure of Di(samarium(III)diaqua) trisquarate, [Sm(H₂O)₂]₂(C₄O₄)₃ (I).

The compound (I) was synthesized during one of our attempts to create novel lanthanide(III) squarates. However, only [Sm(H₂O)₂]₂(C₄O₄)₃ separated from solution and a view of the molecular structure is given in Fig. 1. Trombe et al. reported the structure of cerium(III) squarate tetrahydrate (Trombe et al., 1988; Trombe et al., 1990). The samarium analog is isostructural, the compound crystallizing with similar unit-cell dimensions. Its molecular structure displays a layered structure based on infinite chains structural units, built from edge sharing distorted tricapped trigonal prism polyhedra SmO₇(H₂O)₂ (Fig. 2). These polyhedra are connected via regular squarate sq1 groups along [100] in zigzag mode and interconnected by bis-chelating squarate anions sq2 into layers parallel to (101) plan (Fig. 2). Hydrogen bonds strengthen the structure (table 1, Fig. 2). The two crystallographically independent squarate anions present a case of chelation. One (sq1) has no imposed symmetry. One of its oxygen atoms, namely O2, is not bound to any samarium atom. The oxygen atoms O3 and O4 chelate one samarium atom. The atom O4 binds also another samarium atom while the atom O3 binds only one samarium atom. Thus, the squarate sq1 ligand relates three metal centers. The second symmetric squarate sq2 ligand chelates on both side one samarium atom, and one more Sm atom is also bounded to the oxygen atom O5 of each bite , so that four metal centers are related.

Related literature top

For lanthanide squarates see Trombe et al. (1988, 1990); Petit et al. (1990).

Experimental top

For convenience, 3,4-dihydroxy-3-cyclobutene-1,2-dione (H₂C₄O₄) is named squaric acid hereafter. Pale yellow single crystals of the title compound were hydrothermally synthesized during an attempt to synthesize open frameworks of lanthanide squarates. A mixture of samarium chloride, SmCl₃.6H₂O, and squaric acid in molar ratio 2/3/704 were dissolved in 10 ml distilled water while stirring. The resulting mixture (pH = 2) was transferred into was transferred into a Teflon-lined acid digestion bomb (Parr) and heated at 150 °C for two days under autogenous pressure. Then the autoclave was cooled to room temperature by turning off the power. The pH after treatment remains unchanged. Products were filtered off, washed with distilled water and dried at room temperature. Crystals with cubic morphology were selected for single-crystal diffraction after checking under a polarizing microscope and identifying by X-ray powder diffraction.

Computing details top

Data collection: COLLECT (Nonius, 1998); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR2002 (Burla et al., 2003); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia,1997) and DIAMOND (Brandenburg & Berndt,2001); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top

	Fig. 1. View of the molecular geometry of the title compound with the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented as small spheres of arbitrary radii. [Symmetry codes: (i) x-1, y, z; (ii) -x, -y+1, -z+1]
	Fig. 2. A diagram of the layered crystal packing in the unit cell of (I). Hydrogen bonds are shown as green dashed lines.

Poly[tetraaqua-µ₄-squarato-di-µ₃-squarato-disamarium(III)] top

Crystal data top

[Sm₂(C₄O₄)₃(H₂O)₄]	F(000) = 664
M_r = 708.88	D_x = 2.929 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 5454 reflections
a = 7.0824 (1) Å	θ = 2.6–42.1°
b = 16.7725 (3) Å	µ = 7.33 mm⁻¹
c = 6.9066 (1) Å	T = 296 K
β = 101.585 (1)°	Cube, yellow
V = 803.72 (2) Å³	0.15 × 0.14 × 0.14 mm
Z = 2

Data collection top

Nonius KappaCCD diffractometer	2199 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.029
Graphite monochromator	θ_max = 30.0°, θ_min = 2.9°
ϕ scans, and ω scans with κ offsets	h = −9→9
3906 measured reflections	k = −23→22
2340 independent reflections	l = −9→9

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)] = 0.023	Hydrogen site location: difference Fourier map
wR(F²) = 0.058	H atoms treated by a mixture of independent and constrained refinement
S = 1.08	w = 1/[σ²(F_o²) + (0.103P)² + 0.3358P] where P = (F_o² + 2F_c²)/3
2340 reflections	(Δ/σ)_max = 0.002
148 parameters	Δρ_max = 1.54 e Å⁻³
6 restraints	Δρ_min = −1.96 e Å⁻³

Crystal data top

[Sm₂(C₄O₄)₃(H₂O)₄]	V = 803.72 (2) Å³
M_r = 708.88	Z = 2
Monoclinic, P2₁/c	Mo Kα radiation
a = 7.0824 (1) Å	µ = 7.33 mm⁻¹
b = 16.7725 (3) Å	T = 296 K
c = 6.9066 (1) Å	0.15 × 0.14 × 0.14 mm
β = 101.585 (1)°

Data collection top

Nonius KappaCCD diffractometer	2199 reflections with I > 2σ(I)
3906 measured reflections	R_int = 0.029
2340 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.023	6 restraints
wR(F²) = 0.058	H atoms treated by a mixture of independent and constrained refinement
S = 1.08	Δρ_max = 1.54 e Å⁻³
2340 reflections	Δρ_min = −1.96 e Å⁻³
148 parameters

Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

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

	x	y	z	U_iso*/U_eq
Sm1	−0.26067 (2)	0.42004 (1)	0.48851 (2)	0.0098 (1)
O1	0.0020 (3)	0.34943 (13)	0.6725 (3)	0.0183 (6)
O1W	−0.1467 (3)	0.32226 (14)	0.2658 (4)	0.0255 (7)
O2	0.2263 (3)	0.18597 (13)	0.6602 (3)	0.0207 (6)
O2W	−0.4770 (3)	0.41711 (14)	0.1649 (3)	0.0208 (6)
O3	0.5958 (3)	0.29019 (13)	0.5489 (3)	0.0183 (6)
O4	0.3785 (3)	0.44362 (12)	0.5380 (3)	0.0154 (5)
O5	−0.0375 (3)	0.48117 (13)	0.3160 (3)	0.0183 (6)
O6	−0.2690 (3)	0.43098 (13)	0.8510 (3)	0.0166 (6)
C1	0.1656 (3)	0.33329 (16)	0.6427 (4)	0.0129 (7)
C2	0.2704 (4)	0.25667 (17)	0.6407 (4)	0.0134 (7)
C3	0.4325 (4)	0.30194 (16)	0.5902 (4)	0.0134 (7)
C4	0.3272 (4)	0.37486 (16)	0.5872 (4)	0.0127 (7)
C5	−0.0241 (4)	0.48952 (17)	0.1381 (4)	0.0135 (7)
C6	−0.1238 (4)	0.46752 (17)	0.9388 (4)	0.0135 (7)
H2W2	−0.587 (5)	0.385 (3)	0.161 (7)	0.0500*
H1W1	−0.025 (3)	0.315 (3)	0.241 (7)	0.0500*
H1W2	−0.422 (7)	0.411 (3)	0.053 (5)	0.0500*
H2W1	−0.233 (5)	0.285 (2)	0.196 (7)	0.0500*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Sm1	0.0083 (1)	0.0107 (1)	0.0115 (1)	0.0004 (1)	0.0045 (1)	0.0009 (1)
O1	0.0085 (8)	0.0229 (11)	0.0246 (11)	0.0029 (7)	0.0059 (7)	0.0039 (9)
O1W	0.0188 (10)	0.0266 (12)	0.0334 (13)	−0.0030 (9)	0.0111 (9)	−0.0144 (10)
O2	0.0163 (9)	0.0158 (10)	0.0320 (12)	0.0001 (8)	0.0094 (9)	0.0051 (9)
O2W	0.0163 (10)	0.0300 (12)	0.0162 (10)	−0.0024 (8)	0.0033 (8)	−0.0031 (8)
O3	0.0103 (8)	0.0179 (10)	0.0293 (11)	0.0016 (7)	0.0100 (8)	0.0042 (8)
O4	0.0128 (9)	0.0122 (9)	0.0221 (10)	−0.0009 (7)	0.0057 (7)	0.0031 (8)
O5	0.0218 (10)	0.0253 (11)	0.0093 (9)	−0.0052 (8)	0.0069 (7)	−0.0004 (8)
O6	0.0117 (9)	0.0258 (11)	0.0127 (10)	−0.0063 (8)	0.0034 (7)	−0.0032 (8)
C1	0.0094 (10)	0.0133 (12)	0.0164 (12)	0.0022 (9)	0.0034 (9)	0.0018 (10)
C2	0.0116 (11)	0.0165 (12)	0.0130 (12)	0.0002 (9)	0.0046 (9)	0.0044 (10)
C3	0.0101 (10)	0.0147 (12)	0.0158 (12)	0.0014 (9)	0.0037 (9)	0.0020 (10)
C4	0.0102 (10)	0.0137 (12)	0.0143 (12)	0.0001 (9)	0.0030 (9)	0.0014 (9)
C5	0.0130 (11)	0.0180 (13)	0.0099 (11)	−0.0019 (9)	0.0034 (9)	−0.0008 (9)
C6	0.0126 (11)	0.0176 (12)	0.0107 (11)	−0.0007 (9)	0.0033 (9)	0.0003 (10)

Geometric parameters (Å, º) top

Sm1—O1	2.351 (2)	O5—C5	1.259 (3)
Sm1—O1W	2.491 (2)	O6—C6	1.245 (4)
Sm1—O2W	2.443 (2)	O1W—H2W1	0.94 (4)
Sm1—O5	2.393 (2)	O1W—H1W1	0.92 (2)
Sm1—O6	2.523 (2)	O2W—H2W2	0.94 (4)
Sm1—O3ⁱ	2.474 (2)	O2W—H1W2	0.94 (4)
Sm1—O4ⁱ	2.675 (2)	C1—C2	1.486 (4)
Sm1—O4ⁱⁱ	2.429 (2)	C1—C4	1.456 (4)
Sm1—O5ⁱⁱ	2.808 (2)	C2—C3	1.476 (4)
O1—C1	1.247 (3)	C3—C4	1.431 (4)
O2—C2	1.241 (4)	C5—C6ⁱⁱⁱ	1.463 (4)
O3—C3	1.261 (4)	C5—C6ⁱⁱ	1.457 (4)
O4—C4	1.276 (3)

Sm1···Sm1^iv	4.3507 (2)	O6···O1	2.833 (3)
Sm1···O2W^iv	4.293 (2)	O6···O5ⁱⁱ	3.036 (3)
Sm1···O2^v	4.266 (2)	O6···C3ⁱ	3.297 (3)
Sm1···H2W1^vi	3.72 (4)	O6···C6^xii	3.335 (4)
O1···O1W	2.832 (3)	O6···O4ⁱ	2.964 (3)
O1···O2	3.178 (3)	O6···C5ⁱⁱ	2.456 (4)
O1···O3ⁱ	3.001 (3)	O6···O2W^xiii	2.865 (3)
O1···O6	2.833 (3)	O6···O2W^iv	3.108 (3)
O1···C6	2.959 (4)	O6···O3ⁱ	3.169 (3)
O1···O5ⁱⁱ	2.852 (3)	O1···H2W1^vi	2.83 (3)
O1···C5ⁱⁱ	2.992 (4)	O1···H1W1^vi	2.81 (5)
O1···O1W^vi	3.176 (3)	O1W···H1W2	2.65 (5)
O1W···C5	3.116 (4)	O2···H2W2^viii	1.78 (4)
O1W···C6ⁱⁱⁱ	3.348 (4)	O2···H1W1^vi	1.97 (3)
O1W···O1	2.832 (3)	O2W···H2W1	2.79 (3)
O1W···O2W	2.799 (3)	O3···H2W1^viii	1.90 (4)
O1W···O3ⁱ	2.978 (3)	O4···H2W2^ix	2.84 (5)
O1W···O5	2.778 (3)	O5···H1W1	2.84 (5)
O1W···C1	3.064 (4)	O6···H1W2^xiii	1.96 (4)
O1W···O1^vii	3.176 (3)	C1···C5ⁱⁱ	3.569 (4)
O1W···O2^vii	2.882 (3)	C2···C2^vi	3.461 (4)
O1W···O3^v	2.834 (3)	C2···O3^vi	3.357 (3)
O2···O1W^vi	2.882 (3)	C2···O2^vii	3.409 (3)
O2···O2W^viii	2.716 (3)	C2···O2W^viii	3.407 (4)
O2···C3^vi	3.042 (3)	C2···C3^vi	3.239 (4)
O2···O1	3.178 (3)	C2···C2^vii	3.461 (4)
O2···Sm1^viii	4.266 (2)	C3···O2^vii	3.042 (3)
O2···C4^vi	3.066 (3)	C3···C2^vii	3.239 (4)
O2···C2^vi	3.409 (3)	C4···O2^vii	3.066 (3)
O2W···O6ⁱⁱⁱ	2.865 (3)	C5···C5^xi	2.035 (4)
O2W···O2^v	2.716 (3)	C5···O5^xi	3.289 (3)
O2W···C2^v	3.407 (4)	C5···C1ⁱⁱ	3.569 (4)
O2W···Sm1^iv	4.293 (2)	C6···C6^xii	2.093 (4)
O2W···O4ⁱⁱ	3.095 (3)	C6···O2W^xiii	3.314 (4)
O2W···O1W	2.799 (3)	C6···O6^xii	3.335 (4)
O2W···O4ⁱ	2.991 (3)	C6···O1W^xiii	3.348 (4)
O2W···C6^iv	3.382 (4)	C6···O2W^iv	3.382 (4)
O2W···C6ⁱⁱⁱ	3.314 (4)	C1···H1W1^vi	2.97 (4)
O2W···O6^iv	3.108 (3)	C1···H1W1	2.85 (5)
O3···C2^vii	3.357 (3)	C2···H2W2^viii	2.58 (5)
O3···O6^ix	3.169 (3)	C2···H1W1^vi	2.62 (3)
O3···O1^ix	3.001 (3)	C3···H2W1^viii	2.75 (4)
O3···O4	2.992 (3)	C5···H1W2	3.06 (5)
O3···O1W^ix	2.978 (3)	C5···H1W1	3.01 (5)
O3···O1W^viii	2.834 (3)	C6···H1W2^xiii	2.58 (5)
O4···O5ⁱⁱ	3.069 (3)	H2W2···O2^v	1.78 (4)
O4···O3	2.992 (3)	H2W2···C2^v	2.58 (5)
O4···O5	3.101 (3)	H1W1···C1	2.85 (5)
O4···O6^ix	2.964 (3)	H1W1···C5	3.01 (5)
O4···O2W^ix	2.991 (3)	H1W1···O1^vii	2.81 (5)
O4···O4^x	2.679 (3)	H1W1···O2^vii	1.97 (3)
O4···O2Wⁱⁱ	3.095 (3)	H1W1···C1^vii	2.97 (5)
O5···O6ⁱⁱ	3.036 (3)	H1W1···C2^vii	2.62 (3)
O5···C4ⁱⁱ	3.322 (4)	H1W2···O6ⁱⁱⁱ	1.96 (4)
O5···O5ⁱⁱ	2.569 (3)	H1W2···C5	3.06 (5)
O5···O1ⁱⁱ	2.852 (3)	H1W2···C6ⁱⁱⁱ	2.58 (5)
O5···C5^xi	3.289 (3)	H1W2···H2W1	2.59 (6)
O5···C4	3.379 (4)	H2W1···H1W2	2.59 (6)
O5···O4ⁱⁱ	3.069 (3)	H2W1···Sm1^vii	3.72 (4)
O5···C1ⁱⁱ	3.270 (3)	H2W1···O1^vii	2.83 (3)
O5···O1W	2.778 (3)	H2W1···O3^v	1.90 (4)
O5···O4	3.101 (3)	H2W1···C3^v	2.75 (4)
O6···C4ⁱ	3.208 (4)

O1—Sm1—O1W	71.51 (8)	O4ⁱⁱ—Sm1—O5ⁱⁱ	72.21 (7)
O1—Sm1—O2W	140.08 (7)	Sm1—O1—C1	132.91 (18)
O1—Sm1—O5	87.41 (7)	Sm1^ix—O3—C3	109.09 (17)
O1—Sm1—O6	70.97 (7)	Sm1^ix—O4—C4	103.35 (17)
O1—Sm1—O3ⁱ	76.87 (7)	Sm1ⁱⁱ—O4—C4	139.42 (19)
O1—Sm1—O4ⁱ	132.68 (7)	Sm1^ix—O4—Sm1ⁱⁱ	116.89 (8)
O1—Sm1—O4ⁱⁱ	137.53 (7)	Sm1—O5—C5	136.09 (19)
O1—Sm1—O5ⁱⁱ	66.44 (7)	Sm1—O5—Sm1ⁱⁱ	121.45 (8)
O1W—Sm1—O2W	69.11 (8)	Sm1ⁱⁱ—O5—C5	101.94 (17)
O1W—Sm1—O5	69.29 (7)	Sm1—O6—C6	109.72 (18)
O1W—Sm1—O6	137.37 (8)	Sm1—O1W—H1W1	129 (3)
O1W—Sm1—O3ⁱ	73.72 (7)	Sm1—O1W—H2W1	120 (2)
O1W—Sm1—O4ⁱ	127.78 (7)	H1W1—O1W—H2W1	111 (4)
O1W—Sm1—O4ⁱⁱ	136.25 (8)	Sm1—O2W—H1W2	118 (3)
O1W—Sm1—O5ⁱⁱ	112.32 (7)	H2W2—O2W—H1W2	113 (4)
O2W—Sm1—O5	84.76 (7)	Sm1—O2W—H2W2	114 (3)
O2W—Sm1—O6	140.71 (7)	C2—C1—C4	89.5 (2)
O2W—Sm1—O3ⁱ	86.17 (7)	O1—C1—C2	132.2 (2)
O2W—Sm1—O4ⁱ	71.35 (7)	O1—C1—C4	138.2 (3)
O2W—Sm1—O4ⁱⁱ	78.88 (7)	O2—C2—C3	137.9 (3)
O2W—Sm1—O5ⁱⁱ	136.44 (7)	C1—C2—C3	88.3 (2)
O5—Sm1—O6	127.76 (7)	O2—C2—C1	133.5 (3)
O3ⁱ—Sm1—O5	142.75 (7)	C2—C3—C4	90.9 (2)
O4ⁱ—Sm1—O5	138.06 (7)	O3—C3—C2	140.0 (3)
O4ⁱⁱ—Sm1—O5	79.07 (7)	O3—C3—C4	129.0 (3)
O5—Sm1—O5ⁱⁱ	58.56 (7)	O4—C4—C3	127.0 (3)
O3ⁱ—Sm1—O6	78.72 (7)	O4—C4—C1	141.7 (3)
O4ⁱ—Sm1—O6	69.46 (7)	C1—C4—C3	91.3 (2)
O4ⁱⁱ—Sm1—O6	86.00 (7)	O5—C5—C6ⁱⁱ	127.7 (3)
O5ⁱⁱ—Sm1—O6	69.21 (6)	O5—C5—C6ⁱⁱⁱ	140.7 (3)
O3ⁱ—Sm1—O4ⁱ	70.92 (7)	C6ⁱⁱⁱ—C5—C6ⁱⁱ	91.6 (2)
O3ⁱ—Sm1—O4ⁱⁱ	134.03 (7)	C5^xiii—C6—C5ⁱⁱ	88.4 (2)
O3ⁱ—Sm1—O5ⁱⁱ	137.16 (6)	O6—C6—C5^xiii	141.1 (3)
O4ⁱ—Sm1—O4ⁱⁱ	63.11 (7)	O6—C6—C5ⁱⁱ	130.5 (3)
O4ⁱ—Sm1—O5ⁱⁱ	119.80 (6)

O1W—Sm1—O1—C1	49.0 (2)	O5—Sm1—O4ⁱⁱ—C4ⁱⁱ	−10.5 (3)
O2W—Sm1—O1—C1	58.6 (3)	O6—Sm1—O4ⁱⁱ—C4ⁱⁱ	119.2 (3)
O5—Sm1—O1—C1	−20.1 (3)	O1—Sm1—O5ⁱⁱ—Sm1ⁱⁱ	102.06 (11)
O6—Sm1—O1—C1	−151.7 (3)	O1—Sm1—O5ⁱⁱ—C5ⁱⁱ	−70.85 (18)
O3ⁱ—Sm1—O1—C1	125.9 (3)	O1W—Sm1—O5ⁱⁱ—Sm1ⁱⁱ	45.64 (12)
O4ⁱ—Sm1—O1—C1	173.7 (2)	O1W—Sm1—O5ⁱⁱ—C5ⁱⁱ	−127.27 (18)
O4ⁱⁱ—Sm1—O1—C1	−90.8 (3)	O2W—Sm1—O5ⁱⁱ—Sm1ⁱⁱ	−37.02 (15)
O5ⁱⁱ—Sm1—O1—C1	−76.7 (3)	O2W—Sm1—O5ⁱⁱ—C5ⁱⁱ	150.07 (17)
O1—Sm1—O5—C5	126.2 (3)	O5—Sm1—O5ⁱⁱ—Sm1ⁱⁱ	0.00 (10)
O1—Sm1—O5—Sm1ⁱⁱ	−63.81 (10)	O5—Sm1—O5ⁱⁱ—C5ⁱⁱ	−172.9 (2)
O1W—Sm1—O5—C5	55.0 (3)	O6—Sm1—O5ⁱⁱ—Sm1ⁱⁱ	179.65 (12)
O1W—Sm1—O5—Sm1ⁱⁱ	−135.00 (12)	O6—Sm1—O5ⁱⁱ—C5ⁱⁱ	6.74 (17)
O2W—Sm1—O5—C5	−14.6 (3)	Sm1—O1—C1—C4	50.2 (5)
O2W—Sm1—O5—Sm1ⁱⁱ	155.38 (10)	Sm1—O1—C1—C2	−125.6 (3)
O6—Sm1—O5—C5	−170.4 (3)	Sm1^ix—O3—C3—C4	5.9 (4)
O6—Sm1—O5—Sm1ⁱⁱ	−0.42 (14)	Sm1^ix—O3—C3—C2	179.9 (3)
O3ⁱ—Sm1—O5—C5	62.0 (3)	Sm1^ix—O4—C4—C3	−6.7 (3)
O3ⁱ—Sm1—O5—Sm1ⁱⁱ	−128.01 (10)	Sm1ⁱⁱ—O4—C4—C1	6.3 (6)
O4ⁱ—Sm1—O5—C5	−69.0 (3)	Sm1^ix—O4—C4—C1	178.9 (3)
O4ⁱ—Sm1—O5—Sm1ⁱⁱ	101.01 (11)	Sm1ⁱⁱ—O4—C4—C3	−179.2 (2)
O4ⁱⁱ—Sm1—O5—C5	−94.3 (3)	Sm1—O5—C5—C6ⁱⁱⁱ	−2.1 (6)
O4ⁱⁱ—Sm1—O5—Sm1ⁱⁱ	75.72 (10)	Sm1—O5—C5—C6ⁱⁱ	177.5 (2)
O5ⁱⁱ—Sm1—O5—C5	−170.0 (3)	Sm1ⁱⁱ—O5—C5—C6ⁱⁱ	6.2 (3)
O5ⁱⁱ—Sm1—O5—Sm1ⁱⁱ	−0.02 (12)	Sm1ⁱⁱ—O5—C5—C6ⁱⁱⁱ	−173.4 (4)
O1—Sm1—O6—C6	63.89 (19)	Sm1—O6—C6—C5^xiii	−172.7 (3)
O1W—Sm1—O6—C6	93.4 (2)	Sm1—O6—C6—C5ⁱⁱ	8.8 (4)
O2W—Sm1—O6—C6	−146.84 (18)	O1—C1—C2—C3	178.7 (3)
O5—Sm1—O6—C6	−7.0 (2)	C4—C1—C2—O2	−174.0 (3)
O3ⁱ—Sm1—O6—C6	143.7 (2)	O1—C1—C2—O2	3.2 (5)
O4ⁱ—Sm1—O6—C6	−142.6 (2)	O1—C1—C4—O4	−2.9 (7)
O4ⁱⁱ—Sm1—O6—C6	−79.85 (19)	O1—C1—C4—C3	−178.5 (3)
O5ⁱⁱ—Sm1—O6—C6	−7.37 (18)	C2—C1—C4—O4	174.0 (4)
O1—Sm1—O3ⁱ—C3ⁱ	138.84 (19)	C2—C1—C4—C3	−1.6 (2)
O1W—Sm1—O3ⁱ—C3ⁱ	−146.90 (19)	C4—C1—C2—C3	1.5 (2)
O2W—Sm1—O3ⁱ—C3ⁱ	−77.56 (18)	O2—C2—C3—C4	173.6 (4)
O5—Sm1—O3ⁱ—C3ⁱ	−153.71 (17)	C1—C2—C3—O3	−176.9 (4)
O6—Sm1—O3ⁱ—C3ⁱ	65.99 (18)	O2—C2—C3—O3	−1.7 (6)
O1—Sm1—O4ⁱ—C4ⁱ	−43.5 (2)	C1—C2—C3—C4	−1.6 (2)
O1W—Sm1—O4ⁱ—C4ⁱ	56.25 (19)	O3—C3—C4—C1	177.7 (3)
O2W—Sm1—O4ⁱ—C4ⁱ	98.70 (17)	C2—C3—C4—O4	−175.0 (3)
O5—Sm1—O4ⁱ—C4ⁱ	157.38 (16)	O3—C3—C4—O4	1.2 (5)
O6—Sm1—O4ⁱ—C4ⁱ	−78.46 (17)	C2—C3—C4—C1	1.6 (2)
O1—Sm1—O4ⁱⁱ—C4ⁱⁱ	63.3 (3)	O5—C5—C6ⁱⁱⁱ—O6ⁱⁱⁱ	0.9 (7)
O1W—Sm1—O4ⁱⁱ—C4ⁱⁱ	−54.2 (3)	O5—C5—C6ⁱⁱ—O6ⁱⁱ	1.2 (5)
O2W—Sm1—O4ⁱⁱ—C4ⁱⁱ	−97.3 (3)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2W—H2W2···O2^v	0.94 (4)	1.78 (4)	2.716 (3)	173 (4)
O1W—H1W1···O2^vii	0.92 (2)	1.97 (3)	2.882 (3)	171 (4)
O2W—H1W2···O6ⁱⁱⁱ	0.94 (4)	1.96 (4)	2.865 (3)	162 (4)
O1W—H2W1···O3^v	0.94 (4)	1.90 (4)	2.834 (3)	179 (5)

Symmetry codes: (iii) x, y, z−1; (v) x−1, −y+1/2, z−1/2; (vii) x, −y+1/2, z−1/2.

Experimental details

Crystal data
Chemical formula	[Sm₂(C₄O₄)₃(H₂O)₄]
M_r	708.88
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	296
a, b, c (Å)	7.0824 (1), 16.7725 (3), 6.9066 (1)
β (°)	101.585 (1)
V (Å³)	803.72 (2)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	7.33
Crystal size (mm)	0.15 × 0.14 × 0.14

Data collection
Diffractometer	Nonius KappaCCD diffractometer
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	3906, 2340, 2199
R_int	0.029
(sin θ/λ)_max (Å⁻¹)	0.703

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.023, 0.058, 1.08
No. of reflections	2340
No. of parameters	148
No. of restraints	6
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	1.54, −1.96

Computer programs: COLLECT (Nonius, 1998), DENZO and SCALEPACK (Otwinowski & Minor, 1997), SIR2002 (Burla et al., 2003), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia,1997) and DIAMOND (Brandenburg & Berndt,2001), WinGX (Farrugia, 1999).