Hexaaqua­dibromidoeuropium(III) bromide, [EuBr₂(H₂O)₆]Br

Abstract

The title compound crystallizes with the GdCl₃·6H₂O structure type, exhibiting discrete [EuBr₂(H₂O)₆]⁺ cations as the main building blocks, linked with isolated bromide anions via H⋯Br hydrogen bonds to form a complex framework. The Eu atom and one Br atom each lie on a twofold rotation axis.

Related literature

For related literature, see: Bärnighausen et al. (1965 ▶); Bell & Smith (1990 ▶); Burns & Peterson (1971 ▶); Demyanets et al. (1974 ▶); Duhlev et al. (1988 ▶); Graeber et al. (1966 ▶); Habenschuss & Spedding (1980 ▶); Junk et al. (1999 ▶); Kolitsch (2006 ▶); Marezio et al. (1961 ▶); Reuter et al. (1994 ▶); Tegenfeldt et al. (1979 ▶); Wickleder & Meyer (1995 ▶).

Experimental

Crystal data

• [EuBr₂(H₂O)₆]Br

• M _r = 499.79

• Monoclinic,

• a = 8.1672 (7) Å

• b = 6.7538 (4) Å

• c = 12.5451 (10) Å

• β = 127.077 (5)°

• V = 552.08 (8) ų

• Z = 2

• Mo Kα radiation

• μ = 16.52 mm⁻¹

• T = 293 (2) K

• 0.25 × 0.24 × 0.18 mm

Data collection

• Stoe IPDSII diffractometer

• Absorption correction: numerical [X-RED (Stoe & Cie, 2001 ▶) and X-SHAPE (Stoe & Cie, 1999 ▶)] T _min = 0.065, T _max = 0.155

• 10921 measured reflections

• 1613 independent reflections

• 1397 reflections with I > 2s(I)

• R _int = 0.067

Refinement

• R[F ² > 2σ(F ²)] = 0.028

• wR(F ²) = 0.049

• S = 1.11

• 1613 reflections

• 72 parameters

• All H-atom parameters refined

• Δρ_max = 1.14 e Å⁻³

• Δρ_min = −1.10 e Å⁻³

Data collection: X-AREA (Stoe & Cie, 2006 ▶); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DRAWXTL (Finger et al., 2007 ▶); software used to prepare material for publication: PLATON (Spek, 2003 ▶).

Supplementary Material

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected geometric parameters (Å, °).

Eu1—Br1	2.9449 (5)
Eu1—O1	2.424 (3)
Eu1—O2	2.422 (3)
Eu1—O3	2.388 (3)

Br1—Eu1—O1	146.89 (8)
Br1—Eu1—O1i	76.21 (9)
Br1—Eu1—O2	77.33 (8)
Br1—Eu1—O2i	78.22 (8)
Br1—Eu1—O3	107.21 (9)
Br1—Eu1—O3i	143.18 (8)
Br1—Eu1—Br1i	84.41 (2)
O1—Eu1—O1i	132.3 (2)
O2—Eu1—O2i	146.8 (2)
O3—Eu1—O3i	84.5 (2)
O1—Eu1—O2	72.6 (1)
O1—Eu1—O2i	122.0 (1)
O1—Eu1—O3	75.8 (1)
O1—Eu1—O3i	69.3 (1)
O2—Eu1—O3	70.9 (1)
O2—Eu1—O3i	138.6 (1)

Symmetry code: (i) .

Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H11⋯Br2ii	0.83 (2)	2.53 (8)	3.343 (4)	168 (6)
O1—H12⋯Br1iii	0.83 (2)	2.52 (13)	3.333 (4)	165 (6)
O2—H21⋯Br1iv	0.82 (2)	2.49 (10)	3.307 (4)	172 (6)
O2—H22⋯Br2v	0.83 (2)	2.63 (11)	3.417 (4)	161 (6)
O3—H31⋯Br1vi	0.83 (2)	2.46 (8)	3.288 (4)	173 (6)
O3—H32⋯Br2	0.83 (2)	2.52 (11)	3.328 (5)	163 (6)

Symmetry codes: (ii) ; (iii) ; (iv) ; (v) ; (vi) .

supplementary crystallographic information

Comment

[EuBr₂(H₂O)₆]Br crystallizes in the monoclinic space group P2/c (No. 13) and is isotypic with the GdCl₃^.6H₂O structure type (Marezio et al., 1961), like many chloride hexahydrates MCl₃^.6H₂O with M = Y (Bell & Smith, 1990), Ce (Reuter et al., 1994), Nd (Habenschuss & Spedding, 1980), Sm - Tm (Graeber et al., 1966), Am, Bk (Burns & Peterson, 1971), and two bromide hexahydrates MBr₃^.6H₂O (M = Pr, Dy, Junk et al., 1999).

The Eu atoms in [EuBr₂(H₂O)₆]Br are coordinated by six water molecules and two bromine atoms forming a distorted square antiprism (Fig. 1). Hydrogen bonds H—Br connect the [EuBr₂(H₂O)₆]⁺ cations with the Br^- counter-anions to a network. The bromine atom Br1 belonging to the cationic complex is surrounded by four, the isolated bromine atom Br2 by six hydrogen bonds (Fig. 2). A view of the unit cell of [EuBr₂(H₂O)₆]Br is given in Fig. 3.

The H—Br distances (2.46–2.63 Å) are in good agreement with those in other bromide hydrates (e.g. 2.38–2.54 Å in [Sc(H₂O)₅(OH)]Br₂, Kolitsch, 2006; 2.32–2.80 Å in [Ca(H₂O)₆]₂[CdBr₆], Duhlev et al., 1988; 2.40–2.83 A in NaBr^.2H₂O, Tegenfeldt et al., 1979). The Eu^III—O distances in [EuBr₂(H₂O)₆]Br range from 2.39 to 2.42 Å and thus are very similar to those in EuCl₃^.3H₂O (2.39–2.40 Å, Reuter et al., 1994), EuCl₃^.6H₂O (2.39–2.43 Å, Graeber et al., 1966), or EuCl(OH)₂ (2.35–2.44 Å, Demyanets et al., 1974). The same holds for the Eu^III—Br distances in [EuBr₂(H₂O)₆]Br (2.94 Å) which lie between those in Na₃EuBr₆ (2.83 Å, Wickleder & Meyer, 1995) and those in EuOBr (3.19 Å, Bärnighausen et al., 1965).

Experimental

Colourless single crystals of [EuBr₂(H₂O)₆]Br were obtained by recrystallizing the commercially available product ("EuBr₃^.X H₂O", Alfa Aesar, 99.99%) under argon from degassed aqueous HBr solution by slow cooling of a solution saturated at ca 60 °C to room temperature.

Refinement

The positions of all hydrogen atoms were identified from the difference Fourier map, close to their ideal positions. Their refinement was performed applying a DFIX command (Sheldrick, 2008), restricting the O—H bond lengths to 0.82 ± 0.02 Å.

Figures

Fig. 1.

View of the cationic [Eu(H2O)6Br2]+ unit in [Eu(H2O)6Br2]Br, with displacement ellipsoids drawn at the 90% propability level. H atoms are shown as black spheres of arbitrary radii. [Symmetry code: (i) -x, y, 1/2 - z.]

Fig. 2.

View of the H—Br contacts in [Eu(H2O)6Br(2)2]Br(1), left: four hydrogen bonds link Br1 to water molecules, right: six hydrogen bonds link Br2 to water molecules. All displacement ellipsoids are drawn at the 90% propability level. [Symmetry codes: (i) -x, y, 1/2 - z; (ii) -x, -y, -z; (iii) x, -y, 1/2 + z.]

Fig. 3.

View along (010) on the crystal structure of [Eu(H2O)6Br2]Br. Small black spheres represent H atoms, large black spheres represent Eu atoms, grey spheres represent Br atoms, light grey spheres represent O atoms. Grey polyhedra represent the coordination of H atoms around Br atoms.

Crystal data

[EuBr2(H2O)6]Br	F000 = 456
Mr = 499.79	Dx = 3.006 Mg m−3
Monoclinic, P2/c	Mo Kα radiation λ = 0.71073 Å
Hall symbol: -P 2yc	Cell parameters from 10367 reflections
a = 8.1672 (7) Å	θ = 3.0–32.1º
b = 6.7538 (4) Å	µ = 16.52 mm−1
c = 12.5451 (10) Å	T = 293 (2) K
β = 127.077 (5)º	Irregular polyhedron, clear colourless
V = 552.08 (8) Å3	0.25 × 0.24 × 0.18 mm
Z = 2

Data collection

Stoe IPDSII diffractometer	1613 independent reflections
Radiation source: fine-focus sealed tube	1397 reflections with I > 2s(I)
Monochromator: graphite	Rint = 0.067
T = 293(2) K	θmax = 30.0º
ω scans (in two runs with φ1 = 0° and φ2 = 90°)	θmin = 3.0º
Absorption correction: numerical[X-RED (Stoe & Cie, 2001) and X-SHAPE (Stoe & Cie, 1999)]	h = −11→11
Tmin = 0.065, Tmax = 0.155	k = −9→9
10921 measured reflections	l = −17→17

Refinement

Refinement on F2	Hydrogen site location: difference Fourier map
Least-squares matrix: full	All H-atom parameters refined
R[F2 > 2σ(F2)] = 0.028	w = 1/[σ2(Fo2) + (0.0169P)2] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.049	(Δ/σ)max < 0.001
S = 1.11	Δρmax = 1.14 e Å−3
1613 reflections	Δρmin = −1.10 e Å−3
72 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0409 (10)
Secondary atom site location: difference Fourier map

Special details

Experimental. The title compoud is a commercially available chemical (Alfa Aesar) and was recrystallized under argon from degassed aqueous HBr solution. A suitable single-crystal was sealed with mother liquor in a thin-walled glass capillary.

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 (Ų)

	x	y	z	Uiso*/Ueq
Eu1	0.50000	0.16454 (4)	0.25000	0.0170 (1)
Br1	0.70613 (6)	−0.15845 (7)	0.44669 (4)	0.0295 (1)
Br2	0.00000	0.63151 (9)	0.25000	0.0318 (2)
O1	0.1772 (5)	0.3097 (5)	0.0676 (3)	0.0320 (7)
O2	0.2413 (5)	0.0620 (5)	0.2757 (4)	0.0313 (7)
O3	0.4434 (5)	0.4262 (5)	0.3524 (4)	0.0335 (7)
H11	0.148 (11)	0.336 (10)	−0.006 (4)	0.06 (2)*
H12	0.072 (9)	0.258 (14)	0.050 (10)	0.10 (3)*
H21	0.253 (12)	0.098 (11)	0.342 (5)	0.07 (2)*
H22	0.183 (11)	−0.046 (6)	0.253 (9)	0.09 (3)*
H31	0.518 (10)	0.526 (7)	0.376 (8)	0.08 (2)*
H32	0.321 (5)	0.456 (12)	0.315 (8)	0.09 (3)*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Eu1	0.0168 (1)	0.0180 (1)	0.0172 (1)	0.000	0.0109 (1)	0.000
Br1	0.0295 (2)	0.0293 (2)	0.0266 (3)	0.0027 (2)	0.0152 (2)	0.0066 (2)
Br2	0.0294 (3)	0.0360 (3)	0.0327 (4)	0.000	0.0202 (3)	0.000
O1	0.0233 (13)	0.0385 (17)	0.0256 (18)	0.0036 (12)	0.0102 (13)	0.0084 (14)
O2	0.0316 (15)	0.0367 (17)	0.0355 (19)	−0.0076 (13)	0.0254 (15)	−0.0055 (14)
O3	0.0308 (15)	0.0302 (15)	0.042 (2)	−0.0035 (13)	0.0229 (16)	−0.0106 (14)

Geometric parameters (Å, °)

Eu1—Br1	2.9449 (5)	Eu1—O3i	2.388 (3)
Eu1—Br1i	2.9449 (5)	O1—H11	0.82 (2)
Eu1—O1	2.424 (3)	O1—H12	0.83 (2)
Eu1—O1i	2.424 (3)	O2—H21	0.82 (2)
Eu1—O2	2.422 (3)	O2—H22	0.82 (2)
Eu1—O2i	2.422 (3)	O3—H31	0.83 (2)
Eu1—O3	2.388 (3)	O3—H32	0.83 (2)
Br1—Eu1—O1	146.89 (8)	O1—Eu1—O2	72.6 (1)
Br1i—Eu1—O1i	146.89 (8)	O1i—Eu1—O2i	72.6 (1)
Br1—Eu1—O1i	76.21 (9)	O1—Eu1—O2i	122.0 (1)
Br1i—Eu1—O1	76.21 (9)	O1i—Eu1—O2	122.0 (1)
Br1—Eu1—O2	77.33 (8)	O1—Eu1—O3	75.8 (1)
Br1i—Eu1—O2i	77.33 (8)	O1i—Eu1—O3i	75.8 (1)
Br1—Eu1—O2i	78.22 (8)	O1—Eu1—O3i	69.3 (1)
Br1i—Eu1—O2	78.22 (8)	O1i—Eu1—O3	69.3 (1)
Br1—Eu1—O3	107.21 (9)	O2—Eu1—O3	70.9 (1)
Br1i—Eu1—O3i	107.21 (9)	O2i—Eu1—O3i	70.9 (1)
Br1—Eu1—O3i	143.18 (8)	O2—Eu1—O3i	138.6 (1)
Br1i—Eu1—O3	143.18 (8)	O2i—Eu1—O3	138.6 (1)
Br1—Eu1—Br1i	84.41 (2)	H11—O1—H12	104 (8)
O1—Eu1—O1i	132.3 (2)	H21—O2—H22	107 (8)
O2—Eu1—O2i	146.8 (2)	H31—O3—H32	112 (8)
O3—Eu1—O3i	84.5 (2)

Symmetry codes: (i) −x+1, y, −z+1/2.

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H11···Br2ii	0.83 (2)	2.53 (8)	3.343 (4)	168 (6)
O1—H12···Br1iii	0.83 (2)	2.52 (13)	3.333 (4)	165 (6)
O2—H21···Br1iv	0.82 (2)	2.49 (10)	3.307 (4)	172 (6)
O2—H22···Br2v	0.83 (2)	2.63 (11)	3.417 (4)	161 (6)
O3—H31···Br1vi	0.83 (2)	2.46 (8)	3.288 (4)	173 (6)
O3—H32···Br2	0.83 (2)	2.52 (11)	3.328 (5)	163 (6)

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