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Crystals of dihydroxysamarium chloride were synthesized hydro­thermally at 473 K. The orthorhombic structure was determined by single-crystal X-ray diffraction analysis. [beta]-­Sm(OH)2Cl exhibits a lamellar structure built up from the stacking of neutral slabs; all the atoms lie on crystallographic mirror planes. The structure is stabilized by strong hydrogen bonds between the OH groups and the Cl ions of adjacent layers.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270101016882/os1144sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270101016882/os1144Isup2.hkl
Contains datablock I

Comment top

Research into field of compounds with microporous frameworks has been dramatically enhanced by use of a hydrothermal technique (Cheetham et al., 1999). Inside this large family of compounds, the hybrids whose structures are built up from the iono-covalent association of inorganic and organic moieties show great porosity with, for example, metallocarboxylates (Li et al., 1999) or metallophosphonates (Riou et al., 2000).

In our work with metallosulfonates with open-structures, we have obtained a by-product which corresponds to a new polymorph of bis(hydroxyl)samarium chloride denoted β-Sm(OH)2Cl to distinguish from the already reported form (Klevtsova et al., 1969). β-Sm(OH)2Cl is a bidimensional structure built up from the stacking along [100] of neutral layers (noted A on Fig. 1a) in strict alternation with their equivalent (noted B) from an n-mirror glide. Inside the layers, each Sm atom is eight-coordinated, with six Sm—O distances in the range 2.383 (5)–2.452 (4) Å and two longer Sm···Cl distances of 2.930 (2) Å (Table 1). The edge-connections of these polyhedra form corrugated layers (Fig. 1 b) whose mean plane is parallel to (100).

The stabilization of the structure is ensured via hydrogen bonds between the protons of the OH groups and the Cl ions from an adjacent layer. It is worth noting that two successive layers along [100] are arranged in such a way that the OH groups from one layer and the Cl ions of the other are face to face (Fig. 1a) resulting in short Cl···O distances (<3.5 Å) implying strong hydrogen bonds which stabilize the structure (Table 2). In a first examination, the structure of the previously reported variety of Sm(OH)2Cl (Klevtsova et al., 1969) looks very different from the title compound (I) since it exhibits a three-dimensional framework with a larger density (4.991 versus 4.892 g cm-3). Nevertheless, some correlations between the two structure types are observed. The coordination around Sm is similar with six Sm—O distances in the range 2.36 (2)–2.46 (1) Å and two longer Sm···Cl distances [3.176 (5) and 2.936 (5)]. Furthermore, the framework (Fig. 2) is built up from the connection via the OH groups of layers almost identical to the B layers drawn on Fig. 1a. In fact, just the relative location of the Cl ions in the Sm(OH)6Cl2 polyhedra differs. In (I) they are all located on the outer edges of the corrugated planes (Fig. 1 b) and point alternatively on each side of the layers whereas they constitute the internal edge-sharing of the similar planes in the other form. This difference prohibits any phase transition between the two forms without a complete rearrangement of the structure.

Experimental top

The title compound (I) was prepared from a mixture of samarium trichloride hexahydrate, ethylsulfonic acid and deionized water in the molar ratio 1:2:300. The initial pH was adjusted to 8 by adding dropwise a concentrated NaOH solution. The resulting mixture was sealed in a teflon-lined autoclave (Parr) then heated for two days at 473 K under autogenous pressure. After cooling to room temperature, the pH was measured to 4 (?? what was added, or had the ph changed to 4??), the solid was separated from the solution by filtration, washed with water and dried in air. β-Sm(OH)2Cl was obtained pure in the form of ??colorless?? rhombic platelets. Attempts to synthesize β-Sm(OH)2Cl without ethylsulfonic acid have failed leading to a mixture of the two varieties of Sm(OH)2Cl. A suitable single-crystal for X-ray diffraction study was choosen by optical microscopy and glued on a glass fiber.

The data set is complete to 98.2% at θ=28.96°. The OH groups were defined both from electroneutrality and bond-valence calculations (O'Keeffe et al., 1992).

H atoms were refined with constraints on the O—H distances.

Computing details top

Data collection: SMART (Bruker, 199?); cell refinement: SMART (Bruker, 199?); data reduction: SMART (Bruker, 199?); program(s) used to solve structure: SHELXTL (Sheldrick, 1994); program(s) used to refine structure: SHELXTL (Sheldrick, 1994); molecular graphics: DIAMOND (Brandenburg, 1996); software used to prepare material for publication: SHELXTL (Sheldrick, 1994).

Figures top
[Figure 1] Fig. 1. (a) β-Sm(OH)2Cl, projection along [010] showing the bidimensional feature of the structure (black and white circles for Cl and O atoms, respectively, small circles for H atoms) and (b) the perspective view of one corrugated plane of β-Sm(OH)2Cl.
[Figure 2] Fig. 2. Sm(OH)2Cl (Klevtsova et al., 1969), projection along [010] showing the three-dimensional feature of the structure (black and white circles for Cl and OH groups respectively).
(I) top
Crystal data top
H2ClO2SmDx = 4.892 Mg m3
Mr = 219.5Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, PnmaCell parameters from 1259 reflections
a = 12.6014 (14) Åθ = 3.2–29.9°
b = 3.7706 (4) ŵ = 20.32 mm1
c = 6.2740 (7) ÅT = 296 K
V = 298.11 (6) Å3Rhombohedral, light yellow
Z = 40.04 × 0.04 × 0.04 mm
F(000) = 388
Data collection top
CCD area-detector
diffractometer
454 independent reflections
Radiation source: fine-focus sealed tube347 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.028
ω scansθmax = 29.9°, θmin = 3.2°
Absorption correction: semi-empirical (using intensity measurements)
SADABS (Sheldrick, 1996)
h = 1517
Tmin = 0.497, Tmax = 0.497k = 45
1935 measured reflectionsl = 38
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.025Only H-atom coordinates refined
wR(F2) = 0.060 w = 1/[σ2(Fo2) + (0.0325P)2]
where P = (Fo2 + 2Fc2)/3
S = 1.12(Δ/σ)max < 0.001
454 reflectionsΔρmax = 1.13 e Å3
30 parametersΔρmin = 1.11 e Å3
2 restraintsExtinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0034 (8)
Crystal data top
H2ClO2SmV = 298.11 (6) Å3
Mr = 219.5Z = 4
Orthorhombic, PnmaMo Kα radiation
a = 12.6014 (14) ŵ = 20.32 mm1
b = 3.7706 (4) ÅT = 296 K
c = 6.2740 (7) Å0.04 × 0.04 × 0.04 mm
Data collection top
CCD area-detector
diffractometer
454 independent reflections
Absorption correction: semi-empirical (using intensity measurements)
SADABS (Sheldrick, 1996)
347 reflections with I > 2σ(I)
Tmin = 0.497, Tmax = 0.497Rint = 0.028
1935 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0252 restraints
wR(F2) = 0.060Only H-atom coordinates refined
S = 1.12Δρmax = 1.13 e Å3
454 reflectionsΔρmin = 1.11 e Å3
30 parameters
Special details top

Experimental. 'Blessing (1995). Acta Cryst. A51, 33–38'

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*/Ueq
Sm0.06096 (3)0.75000.24830 (6)0.00993 (19)
Cl0.21914 (14)1.25000.4122 (3)0.0171 (4)
O10.0813 (4)0.25000.0018 (9)0.0121 (10)
O20.0437 (3)0.25000.3660 (8)0.0118 (11)
H10.146 (3)0.25000.057 (13)0.020*
H20.108 (3)0.25000.311 (14)0.020*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Sm0.0126 (2)0.0068 (3)0.0104 (2)0.0000.00185 (14)0.000
Cl0.0143 (7)0.0155 (8)0.0217 (9)0.0000.0024 (8)0.000
O10.008 (2)0.014 (3)0.014 (2)0.0000.0010 (19)0.000
O20.011 (2)0.015 (3)0.009 (3)0.0000.0005 (19)0.000
Geometric parameters (Å, º) top
Sm—O1i2.383 (5)Sm—Smi3.9525 (7)
Sm—O22.416 (3)Sm—Smv3.9525 (7)
Sm—O2ii2.416 (3)Cl—Smii2.9301 (15)
Sm—O2iii2.430 (5)O1—Smi2.383 (5)
Sm—O12.452 (4)O1—Smiv2.452 (4)
Sm—O1ii2.452 (4)O1—H10.90 (2)
Sm—Cl2.9301 (15)O2—Smiv2.416 (3)
Sm—Cliv2.9301 (15)O2—Smiii2.430 (5)
Sm—Smiv3.7706 (4)O2—H20.89 (2)
Sm—Smii3.7706 (4)
O1i—Sm—O277.92 (13)O1—Sm—Smii140.26 (10)
O1i—Sm—O2ii77.92 (13)O1ii—Sm—Smii39.74 (10)
O2—Sm—O2ii102.57 (17)Cl—Sm—Smii49.95 (2)
O1i—Sm—O2iii126.05 (17)Cliv—Sm—Smii130.05 (2)
O2—Sm—O2iii69.31 (14)Smiv—Sm—Smii180.00 (2)
O2ii—Sm—O2iii69.31 (14)O1i—Sm—Smi35.74 (7)
O1i—Sm—O170.32 (13)O2—Sm—Smi69.92 (12)
O2—Sm—O169.51 (14)O2ii—Sm—Smi113.64 (11)
O2ii—Sm—O1148.19 (15)O2iii—Sm—Smi138.61 (7)
O2iii—Sm—O1129.61 (10)O1—Sm—Smi34.58 (11)
O1i—Sm—O1ii70.32 (13)O1ii—Sm—Smi84.85 (11)
O2—Sm—O1ii148.19 (15)Cl—Sm—Smi148.00 (4)
O2ii—Sm—O1ii69.51 (14)Cliv—Sm—Smi103.55 (3)
O2iii—Sm—O1ii129.61 (10)Smiv—Sm—Smi61.511 (6)
O1—Sm—O1ii100.5 (2)Smii—Sm—Smi118.489 (6)
O1i—Sm—Cl138.00 (5)O1i—Sm—Smv35.74 (7)
O2—Sm—Cl139.99 (13)O2—Sm—Smv113.64 (11)
O2ii—Sm—Cl76.23 (10)O2ii—Sm—Smv69.92 (12)
O2iii—Sm—Cl73.22 (9)O2iii—Sm—Smv138.61 (7)
O1—Sm—Cl130.16 (11)O1—Sm—Smv84.85 (11)
O1ii—Sm—Cl69.85 (11)O1ii—Sm—Smv34.58 (11)
O1i—Sm—Cliv138.00 (5)Cl—Sm—Smv103.55 (3)
O2—Sm—Cliv76.23 (10)Cliv—Sm—Smv148.00 (4)
O2ii—Sm—Cliv139.99 (13)Smiv—Sm—Smv118.489 (6)
O2iii—Sm—Cliv73.22 (9)Smii—Sm—Smv61.511 (6)
O1—Sm—Cliv69.85 (11)Smi—Sm—Smv56.978 (12)
O1ii—Sm—Cliv130.16 (11)Sm—Cl—Smii80.09 (5)
Cl—Sm—Cliv80.09 (5)Smi—O1—Sm109.68 (13)
O1i—Sm—Smiv90.0Smi—O1—Smiv109.68 (13)
O2—Sm—Smiv38.72 (8)Sm—O1—Smiv100.5 (2)
O2ii—Sm—Smiv141.28 (8)Smi—O1—H1115 (6)
O2iii—Sm—Smiv90.0Sm—O1—H1111 (3)
O1—Sm—Smiv39.74 (10)Smiv—O1—H1111 (3)
O1ii—Sm—Smiv140.26 (10)Sm—O2—Smiv102.57 (17)
Cl—Sm—Smiv130.05 (2)Sm—O2—Smiii110.69 (14)
Cliv—Sm—Smiv49.95 (2)Smiv—O2—Smiii110.69 (14)
O1i—Sm—Smii90.0Sm—O2—H2112 (3)
O2—Sm—Smii141.28 (8)Smiv—O2—H2112 (3)
O2ii—Sm—Smii38.72 (8)Smiii—O2—H2108 (6)
O2iii—Sm—Smii90.0
Symmetry codes: (i) x, y+1, z; (ii) x, y+1, z; (iii) x, y+1, z+1; (iv) x, y1, z; (v) x, y+2, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···Clvi0.90 (2)2.54 (2)3.193 (4)130 (2)
O2—H2···Clvii0.89 (2)2.58 (3)3.461 (5)170 (8)
Symmetry codes: (vi) x+1/2, y+1, z1/2; (vii) x1/2, y1, z+1/2.

Experimental details

Crystal data
Chemical formulaH2ClO2Sm
Mr219.5
Crystal system, space groupOrthorhombic, Pnma
Temperature (K)296
a, b, c (Å)12.6014 (14), 3.7706 (4), 6.2740 (7)
V3)298.11 (6)
Z4
Radiation typeMo Kα
µ (mm1)20.32
Crystal size (mm)0.04 × 0.04 × 0.04
Data collection
DiffractometerCCD area-detector
diffractometer
Absorption correctionSemi-empirical (using intensity measurements)
SADABS (Sheldrick, 1996)
Tmin, Tmax0.497, 0.497
No. of measured, independent and
observed [I > 2σ(I)] reflections
1935, 454, 347
Rint0.028
(sin θ/λ)max1)0.702
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.025, 0.060, 1.12
No. of reflections454
No. of parameters30
No. of restraints2
H-atom treatmentOnly H-atom coordinates refined
Δρmax, Δρmin (e Å3)1.13, 1.11

Computer programs: SMART (Bruker, 199?), SHELXTL (Sheldrick, 1994), DIAMOND (Brandenburg, 1996).

Selected bond lengths (Å) top
Sm—O1i2.383 (5)Sm—O12.452 (4)
Sm—O22.416 (3)Sm—O1ii2.452 (4)
Sm—O2ii2.416 (3)Sm—Cl2.9301 (15)
Sm—O2iii2.430 (5)Sm—Cliv2.9301 (15)
Symmetry codes: (i) x, y+1, z; (ii) x, y+1, z; (iii) x, y+1, z+1; (iv) x, y1, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···Clv0.90 (2)2.54 (2)3.193 (4)129.7 (18)
O2—H2···Clvi0.89 (2)2.58 (3)3.461 (5)170 (8)
Symmetry codes: (v) x+1/2, y+1, z1/2; (vi) x1/2, y1, z+1/2.
 

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