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The crystal structure of calcium chloride rhenate(VII) dihydrate, CaCl(ReO
4)·2H
2O, investigated at 85 K, consists of calcium cations, chloride anions, rhenate(VII) anions and water molecules. In the nearly tetrahedral rhenate(VII) anion, all constituent atoms lie on special positions of
m2
m (Re) and
m (O) site symmetries. The Cl
− anion and water O atom lie on special positions of
m2
m and 2 site symmetries, respectively. The Ca
2+ ion, also on a special position (
m2
m), is eight-coordinated in a distorted square-antiprismatic coordination mode. The crystal has a layered structure stabilized by Ca—O coordination bonds and O—H
Cl hydrogen bonds.
Supporting information
The title compound was obtained in the reaction of calcium chloride with
rhenic(VII) acid in aqueous solution. The crystals were obtained in the form
of colourless, transparent blocks. A crystal suitable for X-ray analysis was
cut from a larger crystal.
The water H atom was located in a difference Fourier map and refined
isotropically. The highest peaks in the difference Fourier map are near atom
Re1 (the peak of 3.33 e Å-3 at 0.56 Å from Re1 and the peak of 1.83 e Å-3 at 0.61 Å from Re1).
Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell refinement: CrysAlis RED (Oxford Diffraction, 2006); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Bruker, 1998); software used to prepare material for publication: SHELXL97.
Calcium chloride rhenate(VII) dihydrate
top
Crystal data top
CaCl(ReO4)·2H2O | F(000) = 656 |
Mr = 361.76 | Dx = 3.641 Mg m−3 |
Orthorhombic, Cmcm | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2c 2 | Cell parameters from 7496 reflections |
a = 7.009 (2) Å | θ = 2–35° |
b = 14.148 (4) Å | µ = 19.5 mm−1 |
c = 6.656 (2) Å | T = 85 K |
V = 660.0 (3) Å3 | Blocks, colourless |
Z = 4 | 0.09 × 0.08 × 0.05 mm |
Data collection top
Kuma KM-4 CCD diffractometer | 985 independent reflections |
Radiation source: sealed tube | 935 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.065 |
ω & ϕ scans | θmax = 37.5°, θmin = 5.2° |
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2006) | h = −11→12 |
Tmin = 0.265, Tmax = 0.423 | k = −24→22 |
8292 measured reflections | l = −11→11 |
Refinement top
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.016 | All H-atom parameters refined |
wR(F2) = 0.037 | w = 1/[σ2(Fo2) + (0.0203P)2 + 0.5702P] where P = (Fo2 + 2Fc2)/3 |
S = 1.09 | (Δ/σ)max = 0.001 |
985 reflections | Δρmax = 3.32 e Å−3 |
35 parameters | Δρmin = −2.60 e Å−3 |
0 restraints | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0091 (3) |
Crystal data top
CaCl(ReO4)·2H2O | V = 660.0 (3) Å3 |
Mr = 361.76 | Z = 4 |
Orthorhombic, Cmcm | Mo Kα radiation |
a = 7.009 (2) Å | µ = 19.5 mm−1 |
b = 14.148 (4) Å | T = 85 K |
c = 6.656 (2) Å | 0.09 × 0.08 × 0.05 mm |
Data collection top
Kuma KM-4 CCD diffractometer | 985 independent reflections |
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2006) | 935 reflections with I > 2σ(I) |
Tmin = 0.265, Tmax = 0.423 | Rint = 0.065 |
8292 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.016 | 0 restraints |
wR(F2) = 0.037 | All H-atom parameters refined |
S = 1.09 | Δρmax = 3.32 e Å−3 |
985 reflections | Δρmin = −2.60 e Å−3 |
35 parameters | |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Re1 | 0 | 0.242666 (9) | 0.75 | 0.00391 (5) | |
Ca1 | 0 | 0.41009 (5) | 0.25 | 0.00467 (11) | |
Cl1 | 0.5 | 0.38338 (6) | 0.75 | 0.00865 (14) | |
O1 | 0.2028 (3) | 0.5 | 0.5 | 0.0074 (3) | |
O2 | 0 | 0.31571 (14) | 0.5423 (3) | 0.0113 (4) | |
O3 | 0.1996 (3) | 0.17157 (14) | 0.75 | 0.0099 (4) | |
H1 | 0.264 (4) | 0.462 (3) | 0.539 (5) | 0.021 (9)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Re1 | 0.00337 (7) | 0.00457 (7) | 0.00379 (7) | 0 | 0 | 0 |
Ca1 | 0.0044 (3) | 0.0055 (2) | 0.0041 (3) | 0 | 0 | 0 |
Cl1 | 0.0075 (3) | 0.0093 (3) | 0.0091 (4) | 0 | 0 | 0 |
O1 | 0.0073 (8) | 0.0067 (7) | 0.0082 (8) | 0 | 0 | −0.0003 (6) |
O2 | 0.0154 (10) | 0.0096 (8) | 0.0087 (8) | 0 | 0 | 0.0037 (6) |
O3 | 0.0058 (8) | 0.0097 (8) | 0.0144 (9) | 0.0030 (6) | 0 | 0 |
Geometric parameters (Å, º) top
Re1—O2 | 1.726 (2) | Ca1—O3i | 2.401 (2) |
Re1—O3 | 1.723 (2) | Ca1—Ca1ii | 4.189 (2) |
Ca1—O1 | 2.531 (2) | O1—H1 | 0.74 (3) |
Ca1—O2 | 2.359 (2) | | |
| | | |
O3—Re1—O2 | 110.45 (5) | O1—Ca1—O1ii | 68.33 (9) |
O2—Ca1—O2iii | 111.07 (11) | O1—Ca1—O1iii | 82.20 (6) |
O3i—Ca1—O3iv | 122.48 (10) | O2—Ca1—O3i | 74.20 (4) |
O1—Ca1—O1v | 119.67 (5) | | |
Symmetry codes: (i) x−1/2, −y+1/2, z−1/2; (ii) −x, −y+1, −z+1; (iii) x, y, −z+1/2; (iv) −x+1/2, −y+1/2, −z+1; (v) −x, −y+1, z−1/2. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···Cl1 | 0.74 (3) | 2.44 (3) | 3.135 (2) | 159 (4) |
Experimental details
Crystal data |
Chemical formula | CaCl(ReO4)·2H2O |
Mr | 361.76 |
Crystal system, space group | Orthorhombic, Cmcm |
Temperature (K) | 85 |
a, b, c (Å) | 7.009 (2), 14.148 (4), 6.656 (2) |
V (Å3) | 660.0 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 19.5 |
Crystal size (mm) | 0.09 × 0.08 × 0.05 |
|
Data collection |
Diffractometer | Kuma KM-4 CCD diffractometer |
Absorption correction | Analytical (CrysAlis RED; Oxford Diffraction, 2006) |
Tmin, Tmax | 0.265, 0.423 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 8292, 985, 935 |
Rint | 0.065 |
(sin θ/λ)max (Å−1) | 0.857 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.016, 0.037, 1.09 |
No. of reflections | 985 |
No. of parameters | 35 |
H-atom treatment | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 3.32, −2.60 |
Selected geometric parameters (Å, º) topRe1—O2 | 1.726 (2) | Ca1—O2 | 2.359 (2) |
Re1—O3 | 1.723 (2) | Ca1—O3i | 2.401 (2) |
Ca1—O1 | 2.531 (2) | Ca1—Ca1ii | 4.189 (2) |
| | | |
O3—Re1—O2 | 110.45 (5) | O1—Ca1—O1ii | 68.33 (9) |
O2—Ca1—O2iii | 111.07 (11) | O1—Ca1—O1iii | 82.20 (6) |
O3i—Ca1—O3iv | 122.48 (10) | O2—Ca1—O3i | 74.20 (4) |
O1—Ca1—O1v | 119.67 (5) | | |
Symmetry codes: (i) x−1/2, −y+1/2, z−1/2; (ii) −x, −y+1, −z+1; (iii) x, y, −z+1/2; (iv) −x+1/2, −y+1/2, −z+1; (v) −x, −y+1, z−1/2. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···Cl1 | 0.74 (3) | 2.44 (3) | 3.135 (2) | 159 (4) |
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Currently all rhenate(VII) salts of the metals of the first and second main groups of the periodic table are known except for beryllium rhenate(VII) (e.g. Krebs & Hasse, 1982; Todorov & Macicek, 1995). Most of these compounds have been investigated as easy-to-prepare crystalline hydrates. The other properties explored include thermal decomposition patterns monitored by thermogravimetric measurements [e.g. lithium rhenate(VII) monohydrate; Abakumov et al., 2001]. Calcium chloride rhenate(VII) dihydrate was obtained in an effort to crystallize a new calcium rhenate(VII) hydrate as a result of the reaction between calcium chloride and rhenic(VII) acid in aqueous solution. Previously reported data on calcium rhenate(VII) include three crystal structure determinations of the dihydrate salt (Matveeva et al., 1980; Picard et al., 1988; Baur & Kassner, 1992).
The title crystal structure consists of calcium cations, chloride anions, rhenate(VII) anions and water molecules of crystallization.
Atom Re1 lies on a special position of m2m site symmetry and the rhenate(VII) O atoms (O2 and O3) occupy special positions of m site symmetry. The rhenate(VII) anion has a slightly distorted tetrahedral geometry, as shown by the O—Re—O bond angles, which deviate slightly from the ideal tetrahedral values (Table 1). The Re—O bond lengths are equal and in good agreement with values observed for similar compounds [e.g. Sr(ReO4)2·2H2O (Todorov et al., 1996), Ba(ReO4)2·H2O (Todorov & Macicek, 1995) and LiReO4·H2O (Abakumov et al. 2001)].
The chloride anion and water atom O1 lie on special positions of m2m and 2 site symmetries, respectively.
The calcium ion lies on a special position of m2m symmetry and is eight-coordinated in a distorted square-antiprismatic mode (Fig. 1). The four ligands forming the square basal plane are water molecules [Ca—O = 2.531 (2) Å; Table 1]. The other basal plane is formed by four O atoms from four different rhenate(VII) anions [Ca—O = 2.359 (2) and 2.401 (2) Å; see Fig. 1 for the relevant symmetry operations]. The two basal planes are parallel. The central Ca2+ ion deviates by 1.245 (2) and 1.272 (2) Å from the two basal planes formed by the water and rhenate(VII) ligands, respectively. There are no chloride anions within the Ca2+ coordination sphere. This coordination pattern of the Ca2+ ion is comparable to that reported for calcium rhenate(VII) dihydrate (Baur & Kassner, 1992); however, in that crystal structure the Ca2+ ion does not lie on a special position and the distortion of the coordination polyhedron is greater than in the case of the title compound.
The packing (Fig. 2) comprises layers consisting of Ca2+ cations and chloride anions alternating with rhenate(VII) anion layers perpendicular to [010]. Neighbouring layers are joined by Ca—O coordination bonds. Within each Ca2+ cation–chloride anion layer, cation and anion columns can be distinguished (Fig. 3). Each Cl- anion participates in four O—H···Cl hydrogen bonds where four symmetry-related water molecules act as donors (Fig. 3). Thus R42(8) structural motifs are formed (Etter et al., 1990). Each such motif consists of the following atoms: Cl1, H1, O1, H1(x, -y + 1, -z + 1), Cl1(-x + 1, -y + 1, z - 1/2), H1(-x + 1, -y + 1, -z + 1), O1(-x + 1, -y + 1, -z + 1) and H1(-x + 1, y, z).