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The structures of the two novel title compounds, Rb2[CrCl5(H2O)], (I), and Cs2[CrCl5(H2O)], (II), have been determined by single-crystal X-ray diffraction. Compounds (I) and (II) crystallize with Pnma and Cmcm symmetry, respectively. In (I), the Cr, three Cl and water O atom lie on a mirror plane; in (II), the Cs, Cr, O and one of the Cl atoms are at sites with m2m symmetry. The chromate anions are in a pseudo-cubic environment of eight Rb+ cations in (I) and in a pseudo-octahedral environment of six Cs+ cations in (II). The structural arrangement correlates with the ranion/rcation radius ratio.
Supporting information
The title compounds were synthezed according to the method of Palmer (1954). Stoichiometric proportions of ACl salts (A = Rb and Cs) and hexavalent CrO3 were dissolved in 12 M hydrochloric acid (6.0 ml). Ethanol (1.5 ml) was added in small portions. When the exothermal reaction was over, a saturated solution of ACl salt was added. The solution was first evaporated over a flame and, when crystals started to appear, the solution was evaporated over a boiling-water bath. The violet–red products were left to cool in a desiccator over silica gel and were then washed with ethanol. The resulting mixture was dried in an evacuated desiccator over sulfuric acid. Red–violet single crystals were obtained of a size suitable for single-crystal diffraction analysis.
The H-atom position in (I) was located from a Fourier difference map and was refined isotropically without any constraint. The highest peak of residual electron density for (II) is located at (0.0580, −0.0025, 1/4), 0.43 Å from the O atom, and does not correspond to the missing H atom. An attempt to use the H-atom coordinates determined by Greedan et al. (1980) for Cs2[FeCl5(H2O)] led to an unreasonable result.
For both compounds, data collection: SMART (Siemens, 1995); cell refinement: SAINT (Siemens, 1995); data reduction: SAINT and SADABS (Sheldrick, 2002); program(s) used to solve structure: SHELXTL (Bruker, 2001); program(s) used to refine structure: SHELXTL; molecular graphics: DIAMOND (Brandenburg, 2000); software used to prepare material for publication: SHELXTL.
(I) Rubidium aquapentachlorochromate(III)
top
Crystal data top
Rb2[CrCl5(H2O)] | F(000) = 772 |
Mr = 418.21 | Dx = 2.915 Mg m−3 |
Orthorhombic, Pnma | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ac 2n | Cell parameters from 7643 reflections |
a = 13.7558 (2) Å | θ = 2.4–32.9° |
b = 9.7484 (1) Å | µ = 12.68 mm−1 |
c = 7.1074 (1) Å | T = 168 K |
V = 953.08 (2) Å3 | Rhombic octahedron, red–violet |
Z = 4 | 0.10 × 0.06 × 0.03 mm |
Data collection top
Siemens SMART 1K CCD area-detector diffractometer | 1825 independent reflections |
Radiation source: fine-focus sealed tube | 1465 reflections with I > 2σI |
Graphite monochromator | Rint = 0.049 |
ω scans | θmax = 32.9°, θmin = 3.0° |
Absorption correction: multi-scan (SADABS; Sheldrick, 2002) | h = −20→20 |
Tmin = 0.364, Tmax = 0.702 | k = −14→14 |
14988 measured reflections | l = −10→10 |
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)] = 0.038 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.110 | All H-atom parameters refined |
S = 1.04 | w = 1/[σ2(Fo2) + (0.0689P)2 + 0.3749P] where P = (Fo2 + 2Fc2)/3 |
1825 reflections | (Δ/σ)max < 0.001 |
53 parameters | Δρmax = 0.97 e Å−3 |
0 restraints | Δρmin = −1.87 e Å−3 |
Crystal data top
Rb2[CrCl5(H2O)] | V = 953.08 (2) Å3 |
Mr = 418.21 | Z = 4 |
Orthorhombic, Pnma | Mo Kα radiation |
a = 13.7558 (2) Å | µ = 12.68 mm−1 |
b = 9.7484 (1) Å | T = 168 K |
c = 7.1074 (1) Å | 0.10 × 0.06 × 0.03 mm |
Data collection top
Siemens SMART 1K CCD area-detector diffractometer | 1825 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2002) | 1465 reflections with I > 2σI |
Tmin = 0.364, Tmax = 0.702 | Rint = 0.049 |
14988 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.038 | 0 restraints |
wR(F2) = 0.110 | All H-atom parameters refined |
S = 1.04 | Δρmax = 0.97 e Å−3 |
1825 reflections | Δρmin = −1.87 e Å−3 |
53 parameters | |
Special details top
Experimental. Data were collected at low temperature using a Siemens SMART CCD diffractometer equiped with a LT-2 device. A full sphere of reciprocal space was scanned by 0.3° steps in ω with a crystal–to–detector distance of 3.97 cm, 15 s per frame. A preliminary orientation matrix was obtained from the first 100 frames using SMART (Siemens, 1995). The collected frames were integrated using the preliminary orientation matrix which was updated every 100 frames. Final cell parameters were obtained by refinement of the position of 5499 reflections with I>10σ(I) after integration of all frames using SAINT (Siemens, 1995). |
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 | x | y | z | Uiso*/Ueq | |
Rb | 0.14484 (3) | −0.00050 (3) | 0.15441 (5) | 0.02097 (12) | |
Cr | 0.11050 (5) | 0.2500 | −0.31095 (10) | 0.01251 (16) | |
Cl1 | 0.21642 (9) | 0.2500 | −0.56749 (16) | 0.0231 (2) | |
Cl2 | 0.00625 (8) | 0.2500 | −0.04719 (18) | 0.0209 (2) | |
Cl3 | 0.24324 (7) | 0.2500 | −0.10841 (15) | 0.0159 (2) | |
Cl4 | 0.10392 (7) | 0.00856 (7) | −0.31936 (13) | 0.01887 (18) | |
O | −0.0063 (3) | 0.2500 | −0.4867 (6) | 0.0263 (9) | |
H | −0.025 (3) | 0.186 (4) | −0.531 (6) | 0.032 (13)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Rb | 0.02048 (19) | 0.0187 (2) | 0.0237 (2) | −0.00088 (11) | −0.00335 (12) | 0.00270 (12) |
Cr | 0.0129 (3) | 0.0097 (3) | 0.0149 (3) | 0.000 | −0.0029 (2) | 0.000 |
Cl1 | 0.0312 (6) | 0.0228 (5) | 0.0152 (5) | 0.000 | 0.0029 (4) | 0.000 |
Cl2 | 0.0167 (5) | 0.0183 (5) | 0.0278 (6) | 0.000 | 0.0043 (4) | 0.000 |
Cl3 | 0.0152 (5) | 0.0156 (5) | 0.0171 (4) | 0.000 | −0.0039 (4) | 0.000 |
Cl4 | 0.0208 (4) | 0.0109 (3) | 0.0250 (4) | −0.0002 (3) | −0.0058 (3) | −0.0018 (3) |
O | 0.030 (2) | 0.0133 (17) | 0.036 (2) | 0.000 | −0.0210 (18) | 0.000 |
Geometric parameters (Å, º) top
Rb—Cl2i | 3.2887 (8) | Cr—Rbiv | 4.1384 (7) |
Rb—Cl1ii | 3.2924 (9) | Cr—Rbv | 4.1597 (7) |
Rb—Cl3iii | 3.3358 (8) | Cr—Rbvi | 4.1597 (7) |
Rb—Cl3 | 3.3593 (8) | Cl2—Rbi | 3.2887 (8) |
Rb—Cl2 | 3.4133 (9) | Cl2—Rbvii | 3.2887 (8) |
Rb—Cl4 | 3.4151 (9) | Cl2—Rbiv | 3.4133 (9) |
Rb—Cl4iii | 3.4619 (11) | Cl3—Rbv | 3.3358 (8) |
Rb—Cl1iii | 3.4707 (10) | Cl3—Rbvi | 3.3358 (8) |
Rb—Cl4i | 3.6180 (11) | Cl3—Rbiv | 3.3594 (8) |
Rb—Cl4ii | 3.7833 (10) | Cl4—Rbv | 3.4620 (11) |
Rb—Cr | 4.1384 (7) | Cl4—Rbi | 3.6179 (11) |
Rb—Criii | 4.1596 (7) | Cl4—Rbviii | 3.7832 (10) |
Cr—O | 2.035 (4) | Cl1—Rbviii | 3.2924 (9) |
Cr—Cl3 | 2.3251 (12) | Cl1—Rbix | 3.2924 (9) |
Cr—Cl1 | 2.3340 (13) | Cl1—Rbv | 3.4707 (10) |
Cr—Cl4iv | 2.3561 (7) | Cl1—Rbvi | 3.4707 (10) |
Cr—Cl4 | 2.3561 (7) | O—H | 0.75 (4) |
Cr—Cl2 | 2.3603 (14) | | |
| | | |
Cl2i—Rb—Cl1ii | 151.24 (3) | O—Cr—Cl2 | 90.45 (13) |
Cl2i—Rb—Cl3iii | 82.50 (2) | Cl3—Cr—Cl2 | 89.17 (5) |
Cl1ii—Rb—Cl3iii | 95.70 (2) | Cl1—Cr—Cl2 | 178.79 (5) |
Cl2i—Rb—Cl3 | 131.56 (3) | Cl4iv—Cr—Cl2 | 89.82 (3) |
Cl1ii—Rb—Cl3 | 70.98 (2) | Cl4—Cr—Cl2 | 89.82 (3) |
Cl3iii—Rb—Cl3 | 128.685 (12) | O—Cr—Rb | 125.50 (9) |
Cl2i—Rb—Cl2 | 94.524 (10) | Cl3—Cr—Rb | 54.24 (2) |
Cl1ii—Rb—Cl2 | 83.59 (2) | Cl1—Cr—Rb | 123.58 (3) |
Cl3iii—Rb—Cl2 | 172.54 (3) | Cl4iv—Cr—Rb | 127.89 (3) |
Cl3—Rb—Cl2 | 58.10 (2) | Cl4—Cr—Rb | 55.61 (2) |
Cl2i—Rb—Cl4 | 71.73 (3) | Cl2—Cr—Rb | 55.57 (2) |
Cl1ii—Rb—Cl4 | 128.46 (2) | O—Cr—Rbiv | 125.49 (9) |
Cl3iii—Rb—Cl4 | 126.38 (2) | Cl3—Cr—Rbiv | 54.24 (2) |
Cl3—Rb—Cl4 | 59.95 (2) | Cl1—Cr—Rbiv | 123.58 (3) |
Cl2—Rb—Cl4 | 58.37 (2) | Cl4iv—Cr—Rbiv | 55.61 (2) |
Cl2i—Rb—Cl4iii | 128.80 (2) | Cl4—Cr—Rbiv | 127.89 (3) |
Cl1ii—Rb—Cl4iii | 71.70 (3) | Cl2—Cr—Rbiv | 55.57 (2) |
Cl3iii—Rb—Cl4iii | 59.70 (2) | Rb—Cr—Rbiv | 72.327 (15) |
Cl3—Rb—Cl4iii | 69.16 (2) | O—Cr—Rbv | 127.04 (8) |
Cl2—Rb—Cl4iii | 126.61 (2) | Cl3—Cr—Rbv | 53.22 (2) |
Cl4—Rb—Cl4iii | 102.60 (2) | Cl1—Cr—Rbv | 56.54 (3) |
Cl2i—Rb—Cl1iii | 73.97 (3) | Cl4iv—Cr—Rbv | 127.86 (3) |
Cl1ii—Rb—Cl1iii | 128.913 (13) | Cl4—Cr—Rbv | 56.32 (3) |
Cl3iii—Rb—Cl1iii | 57.65 (2) | Cl2—Cr—Rbv | 122.59 (3) |
Cl3—Rb—Cl1iii | 92.01 (2) | Rb—Cr—Rbv | 67.042 (10) |
Cl2—Rb—Cl1iii | 128.15 (3) | Rbiv—Cr—Rbv | 107.458 (16) |
Cl4—Rb—Cl1iii | 70.17 (2) | O—Cr—Rbvi | 127.04 (8) |
Cl4iii—Rb—Cl1iii | 57.29 (2) | Cl3—Cr—Rbvi | 53.22 (2) |
Cl2i—Rb—Cl4i | 57.41 (2) | Cl1—Cr—Rbvi | 56.54 (3) |
Cl1ii—Rb—Cl4i | 96.00 (3) | Cl4iv—Cr—Rbvi | 56.32 (3) |
Cl3iii—Rb—Cl4i | 104.89 (2) | Cl4—Cr—Rbvi | 127.86 (3) |
Cl3—Rb—Cl4i | 125.25 (2) | Cl2—Cr—Rbvi | 122.59 (3) |
Cl2—Rb—Cl4i | 67.87 (2) | Rb—Cr—Rbvi | 107.458 (16) |
Cl4—Rb—Cl4i | 99.45 (2) | Rbiv—Cr—Rbvi | 67.043 (10) |
Cl4iii—Rb—Cl4i | 157.856 (12) | Rbv—Cr—Rbvi | 71.565 (14) |
Cl1iii—Rb—Cl4i | 130.70 (2) | Cr—Cl2—Rbi | 101.53 (3) |
Cl2i—Rb—Cl4ii | 98.76 (3) | Cr—Cl2—Rbvii | 101.53 (3) |
Cl1ii—Rb—Cl4ii | 55.50 (2) | Rbi—Cl2—Rbvii | 95.39 (3) |
Cl3iii—Rb—Cl4ii | 65.55 (2) | Cr—Cl2—Rbiv | 89.66 (3) |
Cl3—Rb—Cl4ii | 126.35 (2) | Rbi—Cl2—Rbiv | 168.33 (4) |
Cl2—Rb—Cl4ii | 108.37 (2) | Rbvii—Cl2—Rbiv | 85.475 (10) |
Cl4—Rb—Cl4ii | 161.74 (3) | Cr—Cl2—Rb | 89.66 (3) |
Cl4iii—Rb—Cl4ii | 95.50 (2) | Rbi—Cl2—Rb | 85.476 (10) |
Cl1iii—Rb—Cl4ii | 123.19 (2) | Rbvii—Cl2—Rb | 168.33 (4) |
Cl4i—Rb—Cl4ii | 62.58 (2) | Rbiv—Cl2—Rb | 91.36 (3) |
Cl2i—Rb—Cr | 100.32 (2) | Cr—Cl3—Rbv | 92.84 (3) |
Cl1ii—Rb—Cr | 94.373 (17) | Cr—Cl3—Rbvi | 92.84 (3) |
Cl3iii—Rb—Cr | 152.47 (2) | Rbv—Cl3—Rbvi | 93.63 (3) |
Cl3—Rb—Cr | 34.167 (19) | Cr—Cl3—Rb | 91.60 (3) |
Cl2—Rb—Cr | 34.77 (2) | Rbv—Cl3—Rb | 86.385 (6) |
Cl4—Rb—Cr | 34.703 (14) | Rbvi—Cl3—Rb | 175.55 (4) |
Cl4iii—Rb—Cr | 99.809 (18) | Cr—Cl3—Rbiv | 91.60 (3) |
Cl1iii—Rb—Cr | 96.49 (2) | Rbv—Cl3—Rbiv | 175.56 (4) |
Cl4i—Rb—Cr | 99.431 (19) | Rbvi—Cl3—Rbiv | 86.386 (6) |
Cl4ii—Rb—Cr | 139.407 (16) | Rb—Cl3—Rbiv | 93.26 (3) |
Cl2i—Rb—Criii | 95.311 (17) | Cr—Cl4—Rb | 89.69 (3) |
Cl1ii—Rb—Criii | 98.99 (2) | Cr—Cl4—Rbv | 89.18 (3) |
Cl3iii—Rb—Criii | 33.94 (2) | Rb—Cl4—Rbv | 83.57 (2) |
Cl3—Rb—Criii | 97.582 (19) | Cr—Cl4—Rbi | 92.86 (3) |
Cl2—Rb—Criii | 153.51 (2) | Rb—Cl4—Rbi | 80.55 (2) |
Cl4—Rb—Criii | 101.936 (19) | Rbv—Cl4—Rbi | 163.97 (3) |
Cl4iii—Rb—Criii | 34.497 (14) | Cr—Cl4—Rbviii | 92.45 (3) |
Cl1iii—Rb—Criii | 34.13 (2) | Rb—Cl4—Rbviii | 161.74 (3) |
Cl4i—Rb—Criii | 137.167 (17) | Rbv—Cl4—Rbviii | 78.33 (2) |
Cl4ii—Rb—Criii | 94.331 (17) | Rbi—Cl4—Rbviii | 117.42 (2) |
Cr—Rb—Criii | 118.990 (16) | Cr—Cl1—Rbviii | 106.40 (3) |
O—Cr—Cl3 | 179.61 (13) | Cr—Cl1—Rbix | 106.40 (3) |
O—Cr—Cl1 | 90.76 (13) | Rbviii—Cl1—Rbix | 95.76 (3) |
Cl3—Cr—Cl1 | 89.63 (5) | Cr—Cl1—Rbv | 89.33 (3) |
O—Cr—Cl4iv | 87.37 (3) | Rbviii—Cl1—Rbv | 85.269 (9) |
Cl3—Cr—Cl4iv | 92.63 (3) | Rbix—Cl1—Rbv | 163.15 (4) |
Cl1—Cr—Cl4iv | 90.24 (3) | Cr—Cl1—Rbvi | 89.33 (3) |
O—Cr—Cl4 | 87.37 (3) | Rbviii—Cl1—Rbvi | 163.15 (4) |
Cl3—Cr—Cl4 | 92.63 (3) | Rbix—Cl1—Rbvi | 85.268 (8) |
Cl1—Cr—Cl4 | 90.24 (3) | Rbv—Cl1—Rbvi | 88.98 (3) |
Cl4iv—Cr—Cl4 | 174.72 (6) | Cr—O—H | 123 (3) |
Symmetry codes: (i) −x, −y, −z; (ii) x, y, z+1; (iii) −x+1/2, −y, z+1/2; (iv) x, −y+1/2, z; (v) −x+1/2, −y, z−1/2; (vi) −x+1/2, y+1/2, z−1/2; (vii) −x, y+1/2, −z; (viii) x, y, z−1; (ix) x, −y+1/2, z−1. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O—H···Cl4x | 0.75 (4) | 2.43 (4) | 3.171 (2) | 174 (5) |
Symmetry code: (x) −x, −y, −z−1. |
(II) Caesium aquapentachlorochromate(III)
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Crystal data top
Cs2[CrCl5(H2O)] | F(000) = 916 |
Mr = 513.09 | Dx = 3.377 Mg m−3 |
Orthorhombic, Cmcm | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2c 2 | Cell parameters from 3038 reflections |
a = 7.3868 (3) Å | θ = 2.4–32.9° |
b = 17.1107 (7) Å | µ = 9.50 mm−1 |
c = 7.9848 (4) Å | T = 173 K |
V = 1009.23 (8) Å3 | Rhombic octahedron, red–violet |
Z = 4 | 0.02 × 0.02 × 0.02 mm |
Data collection top
Siemens SMART 1K CCD area-detector diffractometer | 883 independent reflections |
Radiation source: fine-focus sealed tube | 686 reflections with I > 2σI |
Graphite monochromator | Rint = 0.078 |
ω scans | θmax = 30.5°, θmin = 2.4° |
Absorption correction: multi-scan (SADABS; Sheldrick, 2002) | h = −10→10 |
Tmin = 0.833, Tmax = 0.871 | k = −24→24 |
7414 measured reflections | l = −11→11 |
Refinement top
Refinement on F2 | 0 restraints |
Least-squares matrix: full | Primary atom site location: structure-invariant direct methods |
R[F2 > 2σ(F2)] = 0.050 | Secondary atom site location: difference Fourier map |
wR(F2) = 0.151 | w = 1/[σ2(Fo2) + (0.1P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.04 | (Δ/σ)max < 0.001 |
883 reflections | Δρmax = 2.88 e Å−3 |
28 parameters | Δρmin = −1.40 e Å−3 |
Crystal data top
Cs2[CrCl5(H2O)] | V = 1009.23 (8) Å3 |
Mr = 513.09 | Z = 4 |
Orthorhombic, Cmcm | Mo Kα radiation |
a = 7.3868 (3) Å | µ = 9.50 mm−1 |
b = 17.1107 (7) Å | T = 173 K |
c = 7.9848 (4) Å | 0.02 × 0.02 × 0.02 mm |
Data collection top
Siemens SMART 1K CCD area-detector diffractometer | 883 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2002) | 686 reflections with I > 2σI |
Tmin = 0.833, Tmax = 0.871 | Rint = 0.078 |
7414 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.050 | 28 parameters |
wR(F2) = 0.151 | 0 restraints |
S = 1.04 | Δρmax = 2.88 e Å−3 |
883 reflections | Δρmin = −1.40 e Å−3 |
Special details top
Experimental. The data were collected at low temperature using a Siemens SMART CCD diffractometer equiped with a LT-2 device. A full sphere of reciprocal space was scanned by 0.3° steps in ω with a crystal-to-detector distance of 3.97 cm, 15 s per frame. A preliminary orientation matrix was obtained from the first 100 frames using SMART (Siemens, 1995). The collected frames were integrated using the preliminary orientation matrix which was updated every 100 frames. Final cell parameters were obtained by refinement of the position of 5499 reflections with I>10σ(I) after integration of all frames using SAINT (Siemens, 1995). |
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 | x | y | z | Uiso*/Ueq | |
Cs1 | 0.0000 | 0.46927 (6) | 0.2500 | 0.0201 (3) | |
Cs2 | 0.0000 | 0.24580 (5) | −0.2500 | 0.0201 (3) | |
Cr | 0.5000 | 0.61615 (12) | 0.2500 | 0.0093 (4) | |
Cl1 | 0.7222 (3) | 0.61091 (11) | 0.4586 (3) | 0.0213 (4) | |
Cl2 | 0.5000 | 0.7510 (2) | 0.2500 | 0.0169 (7) | |
O | 0.5000 | 0.4955 (5) | 0.2500 | 0.0087 (18)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Cs1 | 0.0278 (6) | 0.0191 (5) | 0.0134 (5) | 0.000 | 0.000 | 0.000 |
Cs2 | 0.0195 (5) | 0.0125 (4) | 0.0283 (6) | 0.000 | 0.000 | 0.000 |
Cr | 0.0108 (11) | 0.0084 (9) | 0.0088 (9) | 0.000 | 0.000 | 0.000 |
Cl1 | 0.0220 (10) | 0.0195 (8) | 0.0224 (9) | 0.0045 (7) | −0.0112 (7) | −0.0027 (7) |
Cl2 | 0.0165 (17) | 0.0101 (13) | 0.024 (2) | 0.000 | 0.000 | 0.000 |
Geometric parameters (Å, º) top
Cs1—Cl1i | 3.392 (2) | Cs2—Cl2xiv | 3.9934 (2) |
Cs1—Cl1ii | 3.392 (2) | Cr—O | 2.064 (10) |
Cs1—Cl1iii | 3.392 (2) | Cr—Cl2 | 2.308 (4) |
Cs1—Cl1iv | 3.392 (2) | Cr—Cl1 | 2.340 (2) |
Cs1—Cl1v | 3.586 (2) | Cr—Cl1vi | 2.340 (2) |
Cs1—Cl1vi | 3.586 (2) | Cr—Cl1v | 2.340 (2) |
Cs1—Cl1vii | 3.586 (2) | Cr—Cl1xviii | 2.340 (2) |
Cs1—Cl1viii | 3.586 (2) | Cr—Cs1 | 4.4674 (13) |
Cs1—Cl2ix | 3.734 (4) | Cr—Cs1xix | 4.4674 (13) |
Cs1—Cs1x | 4.1286 (5) | Cr—Cs2xi | 4.3841 (12) |
Cs2—Cl1iv | 3.605 (2) | Cr—Cs2xvii | 4.3841 (12) |
Cs2—Cl1xi | 3.605 (2) | Cl1—Cs1ii | 3.392 (2) |
Cs2—Cl1xii | 3.605 (2) | Cl1—Cs1xix | 3.586 (2) |
Cs2—Cl1i | 3.605 (2) | Cl1—Cs2xi | 3.605 (2) |
Cs2—Cl1xiii | 3.665 (2) | Cl1—Cs2xx | 3.666 (2) |
Cs2—Cl1xiv | 3.665 (2) | Cl2—Cs2xi | 3.6938 (2) |
Cs2—Cl1xv | 3.665 (2) | Cl2—Cs2xvii | 3.6938 (2) |
Cs2—Cl1xvi | 3.665 (2) | Cl2—Cs1xxi | 3.734 (4) |
Cs2—Cl2xi | 3.6938 (2) | Cl2—Cs2xx | 3.9934 (2) |
Cs2—Cl2xvii | 3.6938 (2) | Cl2—Cs2xxi | 3.9934 (2) |
Cs2—Cl2ix | 3.9934 (2) | O—Cs1xix | 3.7206 (11) |
| | | |
Cl1i—Cs1—Cl1ii | 132.29 (7) | Cl1iv—Cs2—Cl2xi | 54.61 (5) |
Cl1i—Cs1—Cl1iii | 86.62 (7) | Cl1xi—Cs2—Cl2xi | 54.61 (5) |
Cl1ii—Cs1—Cl1iii | 74.44 (8) | Cl1xii—Cs2—Cl2xi | 123.99 (6) |
Cl1i—Cs1—Cl1iv | 74.44 (8) | Cl1i—Cs2—Cl2xi | 123.99 (6) |
Cl1ii—Cs1—Cl1iv | 86.62 (7) | Cl1xiii—Cs2—Cl2xi | 117.20 (5) |
Cl1iii—Cs1—Cl1iv | 132.29 (7) | Cl1xiv—Cs2—Cl2xi | 63.99 (5) |
Cl1i—Cs1—Cl1v | 159.74 (5) | Cl1xv—Cs2—Cl2xi | 117.20 (5) |
Cl1ii—Cs1—Cl1v | 66.96 (6) | Cl1xvi—Cs2—Cl2xi | 63.99 (5) |
Cl1iii—Cs1—Cl1v | 107.51 (4) | Cl1iv—Cs2—Cl2xvii | 123.99 (6) |
Cl1iv—Cs1—Cl1v | 104.23 (6) | Cl1xi—Cs2—Cl2xvii | 123.99 (6) |
Cl1i—Cs1—Cl1vi | 107.51 (4) | Cl1xii—Cs2—Cl2xvii | 54.61 (5) |
Cl1ii—Cs1—Cl1vi | 104.23 (6) | Cl1i—Cs2—Cl2xvii | 54.61 (5) |
Cl1iii—Cs1—Cl1vi | 159.74 (5) | Cl1xiii—Cs2—Cl2xvii | 63.99 (5) |
Cl1iv—Cs1—Cl1vi | 66.96 (6) | Cl1xiv—Cs2—Cl2xvii | 117.20 (5) |
Cl1v—Cs1—Cl1vi | 55.36 (7) | Cl1xv—Cs2—Cl2xvii | 63.99 (5) |
Cl1i—Cs1—Cl1vii | 66.96 (6) | Cl1xvi—Cs2—Cl2xvii | 117.20 (5) |
Cl1ii—Cs1—Cl1vii | 159.74 (5) | Cl2xi—Cs2—Cl2xvii | 178.31 (11) |
Cl1iii—Cs1—Cl1vii | 104.23 (6) | Cl1iv—Cs2—Cl2ix | 61.50 (5) |
Cl1iv—Cs1—Cl1vii | 107.51 (4) | Cl1xi—Cs2—Cl2ix | 116.53 (5) |
Cl1v—Cs1—Cl1vii | 94.96 (7) | Cl1xii—Cs2—Cl2ix | 116.53 (5) |
Cl1vi—Cs1—Cl1vii | 69.81 (7) | Cl1i—Cs2—Cl2ix | 61.50 (5) |
Cl1i—Cs1—Cl1viii | 104.23 (6) | Cl1xiii—Cs2—Cl2ix | 130.44 (6) |
Cl1ii—Cs1—Cl1viii | 107.51 (4) | Cl1xiv—Cs2—Cl2ix | 130.44 (6) |
Cl1iii—Cs1—Cl1viii | 66.96 (6) | Cl1xv—Cs2—Cl2ix | 51.64 (5) |
Cl1iv—Cs1—Cl1viii | 159.74 (5) | Cl1xvi—Cs2—Cl2ix | 51.64 (5) |
Cl1v—Cs1—Cl1viii | 69.81 (7) | Cl2xi—Cs2—Cl2ix | 89.981 (1) |
Cl1vi—Cs1—Cl1viii | 94.96 (7) | Cl2xvii—Cs2—Cl2ix | 89.981 (1) |
Cl1vii—Cs1—Cl1viii | 55.36 (7) | Cl1iv—Cs2—Cl2xiv | 116.53 (5) |
Cl1i—Cs1—O | 130.49 (8) | Cl1xi—Cs2—Cl2xiv | 61.50 (5) |
Cl1ii—Cs1—O | 56.52 (9) | Cl1xii—Cs2—Cl2xiv | 61.50 (5) |
Cl1iii—Cs1—O | 130.49 (8) | Cl1i—Cs2—Cl2xiv | 116.53 (5) |
Cl1iv—Cs1—O | 56.52 (9) | Cl1xiii—Cs2—Cl2xiv | 51.64 (5) |
Cl1v—Cs1—O | 49.48 (12) | Cl1xiv—Cs2—Cl2xiv | 51.64 (5) |
Cl1vi—Cs1—O | 49.48 (12) | Cl1xv—Cs2—Cl2xiv | 130.44 (6) |
Cl1vii—Cs1—O | 119.10 (13) | Cl1xvi—Cs2—Cl2xiv | 130.44 (6) |
Cl1viii—Cs1—O | 119.10 (13) | Cl2xi—Cs2—Cl2xiv | 89.981 (1) |
Cl1i—Cs1—Oviii | 56.52 (9) | Cl2xvii—Cs2—Cl2xiv | 89.981 (1) |
Cl1ii—Cs1—Oviii | 130.49 (8) | Cl2ix—Cs2—Cl2xiv | 177.44 (11) |
Cl1iii—Cs1—Oviii | 56.52 (9) | O—Cr—Cl2 | 180.000 (1) |
Cl1iv—Cs1—Oviii | 130.49 (8) | O—Cr—Cl1 | 87.80 (7) |
Cl1v—Cs1—Oviii | 119.10 (13) | Cl2—Cr—Cl1 | 92.20 (7) |
Cl1vi—Cs1—Oviii | 119.10 (13) | O—Cr—Cl1vi | 87.80 (7) |
Cl1vii—Cs1—Oviii | 49.48 (12) | Cl2—Cr—Cl1vi | 92.20 (7) |
Cl1viii—Cs1—Oviii | 49.48 (12) | Cl1—Cr—Cl1vi | 175.61 (13) |
O—Cs1—Oviii | 166.1 (3) | O—Cr—Cl1v | 87.80 (7) |
Cl1i—Cs1—Cl2ix | 66.14 (4) | Cl2—Cr—Cl1v | 92.20 (7) |
Cl1ii—Cs1—Cl2ix | 66.14 (4) | Cl1—Cr—Cl1v | 89.08 (11) |
Cl1iii—Cs1—Cl2ix | 66.14 (4) | Cl1vi—Cr—Cl1v | 90.75 (11) |
Cl1iv—Cs1—Cl2ix | 66.14 (4) | O—Cr—Cl1xviii | 87.80 (7) |
Cl1v—Cs1—Cl2ix | 132.52 (4) | Cl2—Cr—Cl1xviii | 92.20 (7) |
Cl1vi—Cs1—Cl2ix | 132.52 (4) | Cl1—Cr—Cl1xviii | 90.75 (11) |
Cl1vii—Cs1—Cl2ix | 132.52 (4) | Cl1vi—Cr—Cl1xviii | 89.08 (11) |
Cl1viii—Cs1—Cl2ix | 132.52 (4) | Cl1v—Cr—Cl1xviii | 175.61 (13) |
O—Cs1—Cl2ix | 96.94 (14) | O—Cr—Cs2xi | 122.60 (2) |
Oviii—Cs1—Cl2ix | 96.94 (14) | Cl2—Cr—Cs2xi | 57.40 (2) |
Cl1i—Cs1—Cs1x | 140.03 (4) | Cl1—Cr—Cs2xi | 55.23 (6) |
Cl1ii—Cs1—Cs1x | 55.92 (4) | Cl1vi—Cr—Cs2xi | 127.70 (6) |
Cl1iii—Cs1—Cs1x | 55.92 (4) | Cl1v—Cr—Cs2xi | 127.70 (6) |
Cl1iv—Cs1—Cs1x | 140.03 (4) | Cl1xviii—Cr—Cs2xi | 55.23 (6) |
Cl1v—Cs1—Cs1x | 51.59 (4) | O—Cr—Cs2xvii | 122.60 (2) |
Cl1vi—Cs1—Cs1x | 106.08 (4) | Cl2—Cr—Cs2xvii | 57.40 (2) |
Cl1vii—Cs1—Cs1x | 106.08 (4) | Cl1—Cr—Cs2xvii | 127.70 (6) |
Cl1viii—Cs1—Cs1x | 51.59 (4) | Cl1vi—Cr—Cs2xvii | 55.23 (6) |
O—Cs1—Cs1x | 88.24 (4) | Cl1v—Cr—Cs2xvii | 55.23 (6) |
Oviii—Cs1—Cs1x | 88.24 (4) | Cl1xviii—Cr—Cs2xvii | 127.70 (6) |
Cl2ix—Cs1—Cs1x | 104.76 (3) | Cs2xi—Cr—Cs2xvii | 114.80 (5) |
Cl1iv—Cs2—Cl1xi | 55.04 (6) | Cr—Cl1—Cs1ii | 158.12 (9) |
Cl1iv—Cs2—Cl1xii | 94.30 (7) | Cr—Cl1—Cs1xix | 95.55 (7) |
Cl1xi—Cs2—Cl1xii | 69.39 (6) | Cs1ii—Cl1—Cs1xix | 72.49 (4) |
Cl1iv—Cs2—Cl1i | 69.39 (6) | Cr—Cl1—Cs2xi | 92.54 (7) |
Cl1xi—Cs2—Cl1i | 94.30 (7) | Cs1ii—Cl1—Cs2xi | 104.34 (6) |
Cl1xii—Cs2—Cl1i | 55.04 (6) | Cs1xix—Cl1—Cs2xi | 85.37 (5) |
Cl1iv—Cs2—Cl1xiii | 167.54 (6) | Cr—Cl1—Cs2xx | 96.52 (7) |
Cl1xi—Cs2—Cl1xiii | 112.95 (3) | Cs1ii—Cl1—Cs2xx | 95.17 (5) |
Cl1xii—Cs2—Cl1xiii | 83.11 (4) | Cs1xix—Cl1—Cs2xx | 167.61 (6) |
Cl1i—Cs2—Cl1xiii | 117.82 (3) | Cs2xi—Cl1—Cs2xx | 96.89 (4) |
Cl1iv—Cs2—Cl1xiv | 117.82 (3) | Cr—Cl2—Cs2xi | 90.84 (5) |
Cl1xi—Cs2—Cl1xiv | 83.11 (4) | Cr—Cl2—Cs2xvii | 90.84 (5) |
Cl1xii—Cs2—Cl1xiv | 112.95 (3) | Cs2xi—Cl2—Cs2xvii | 178.31 (11) |
Cl1i—Cs2—Cl1xiv | 167.54 (6) | Cr—Cl2—Cs1xxi | 180.0 |
Cl1xiii—Cs2—Cl1xiv | 53.21 (7) | Cs2xi—Cl2—Cs1xxi | 89.16 (5) |
Cl1iv—Cs2—Cl1xv | 112.95 (3) | Cs2xvii—Cl2—Cs1xxi | 89.16 (5) |
Cl1xi—Cs2—Cl1xv | 167.54 (6) | Cr—Cl2—Cs2xx | 88.72 (5) |
Cl1xii—Cs2—Cl1xv | 117.82 (3) | Cs2xi—Cl2—Cs2xx | 90.019 (1) |
Cl1i—Cs2—Cl1xv | 83.11 (4) | Cs2xvii—Cl2—Cs2xx | 90.019 (1) |
Cl1xiii—Cs2—Cl1xv | 78.81 (6) | Cs1xxi—Cl2—Cs2xx | 91.28 (5) |
Cl1xiv—Cs2—Cl1xv | 101.95 (7) | Cr—Cl2—Cs2xxi | 88.72 (5) |
Cl1iv—Cs2—Cl1xvi | 83.11 (4) | Cs2xi—Cl2—Cs2xxi | 90.019 (1) |
Cl1xi—Cs2—Cl1xvi | 117.82 (3) | Cs2xvii—Cl2—Cs2xxi | 90.019 (1) |
Cl1xii—Cs2—Cl1xvi | 167.54 (6) | Cs1xxi—Cl2—Cs2xxi | 91.28 (5) |
Cl1i—Cs2—Cl1xvi | 112.95 (3) | Cs2xx—Cl2—Cs2xxi | 177.44 (11) |
Cl1xiii—Cs2—Cl1xvi | 101.95 (7) | Cr—O—Cs1xix | 96.94 (14) |
Cl1xiv—Cs2—Cl1xvi | 78.81 (6) | Cr—O—Cs1 | 96.94 (14) |
Cl1xv—Cs2—Cl1xvi | 53.21 (7) | Cs1xix—O—Cs1 | 166.1 (3) |
Symmetry codes: (i) x−1, −y+1, z−1/2; (ii) −x+1, −y+1, −z+1; (iii) x−1, −y+1, −z+1; (iv) −x+1, −y+1, z−1/2; (v) −x+1, y, z; (vi) −x+1, y, −z+1/2; (vii) x−1, y, −z+1/2; (viii) x−1, y, z; (ix) x−1/2, y−1/2, z; (x) −x, −y+1, −z+1; (xi) −x+1, −y+1, −z; (xii) x−1, −y+1, −z; (xiii) −x+1/2, y−1/2, z−1; (xiv) x−1/2, y−1/2, z−1; (xv) −x+1/2, y−1/2, −z+1/2; (xvi) x−1/2, y−1/2, −z+1/2; (xvii) −x, −y+1, −z; (xviii) x, y, −z+1/2; (xix) x+1, y, z; (xx) x+1/2, y+1/2, z+1; (xxi) x+1/2, y+1/2, z. |
Experimental details
| (I) | (II) |
Crystal data |
Chemical formula | Rb2[CrCl5(H2O)] | Cs2[CrCl5(H2O)] |
Mr | 418.21 | 513.09 |
Crystal system, space group | Orthorhombic, Pnma | Orthorhombic, Cmcm |
Temperature (K) | 168 | 173 |
a, b, c (Å) | 13.7558 (2), 9.7484 (1), 7.1074 (1) | 7.3868 (3), 17.1107 (7), 7.9848 (4) |
V (Å3) | 953.08 (2) | 1009.23 (8) |
Z | 4 | 4 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 12.68 | 9.50 |
Crystal size (mm) | 0.10 × 0.06 × 0.03 | 0.02 × 0.02 × 0.02 |
|
Data collection |
Diffractometer | Siemens SMART 1K CCD area-detector diffractometer | Siemens SMART 1K CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2002) | Multi-scan (SADABS; Sheldrick, 2002) |
Tmin, Tmax | 0.364, 0.702 | 0.833, 0.871 |
No. of measured, independent and observed (I > 2σI) reflections | 14988, 1825, 1465 | 7414, 883, 686 |
Rint | 0.049 | 0.078 |
(sin θ/λ)max (Å−1) | 0.765 | 0.715 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.038, 0.110, 1.04 | 0.050, 0.151, 1.04 |
No. of reflections | 1825 | 883 |
No. of parameters | 53 | 28 |
H-atom treatment | All H-atom parameters refined | ? |
Δρmax, Δρmin (e Å−3) | 0.97, −1.87 | 2.88, −1.40 |
Selected bond lengths (Å) for (I) topRb—Cl2i | 3.2887 (8) | Rb—Cl4i | 3.6180 (11) |
Rb—Cl1ii | 3.2924 (9) | Rb—Cl4ii | 3.7833 (10) |
Rb—Cl3iii | 3.3358 (8) | Cr—O | 2.035 (4) |
Rb—Cl3 | 3.3593 (8) | Cr—Cl3 | 2.3251 (12) |
Rb—Cl2 | 3.4133 (9) | Cr—Cl1 | 2.3340 (13) |
Rb—Cl4 | 3.4151 (9) | Cr—Cl4iv | 2.3561 (7) |
Rb—Cl4iii | 3.4619 (11) | Cr—Cl2 | 2.3603 (14) |
Rb—Cl1iii | 3.4707 (10) | O—H | 0.75 (4) |
Symmetry codes: (i) −x, −y, −z; (ii) x, y, z+1; (iii) −x+1/2, −y, z+1/2; (iv) x, −y+1/2, z. |
Hydrogen-bond geometry (Å, º) for (I) top
D—H···A | D—H | H···A | D···A | D—H···A |
O—H···Cl4v | 0.75 (4) | 2.43 (4) | 3.171 (2) | 174 (5) |
Symmetry code: (v) −x, −y, −z−1. |
Correlation between space group symmetry and the ranion/rcation ratio. topCompound | Space group | ranion/rcation* |
Rb2[TlCl5(H2O)]5 | Pnma | 1.649 |
Rb2[InCl5(H2O)]3 | Pnma | 1.649 |
Rb2[FeCl5(H2O)]2 | Pnma | 1.574 |
Rb2[CrCl5(H2O)]1 | Pnma | 1.550 |
Cs2[TlCl5(H2O)]5 | Pnma | 1.345 |
Cs2[InCl5(H2O)]3 | Pnma | 1.308 |
Cs2[FeCl5(H2O)]6 | Cmcm | 1.239 |
Cs2[RuCl5(H2O)]8 | Cmcm | 1.226 |
Cs2[IrCl5(H2O)]4 | Cmcm | 1.224 |
Cs2[RhCl5(H2O)]7 | Cmcm | 1.218 |
Cs2[CrCl5(H2O)]1 | Cmcm | 1.217 |
(1) This work (2) O'Connor et al. (1979) (3) Solans et al. (1988) (4) Coll et al. (1987) (5) Vasil'ev et al. (1994) (6) Greedan et al. (1980) (7) Thomas & Stanko (1973) (8) Hopkins et al. (1966) (*) Cation radii for eigt-fold coordination from Shannon (1976) |
Selected bond lengths (Å) for (II) topCs1—Cl1i | 3.392 (2) | Cs2—Cl2vi | 3.6938 (2) |
Cs1—Cl1ii | 3.586 (2) | Cs2—Cl2iii | 3.9934 (2) |
Cs1—Cl2iii | 3.734 (4) | Cr—O | 2.064 (10) |
Cs2—Cl1iv | 3.605 (2) | Cr—Cl2 | 2.308 (4) |
Cs2—Cl1v | 3.665 (2) | Cr—Cl1 | 2.340 (2) |
Symmetry codes: (i) x−1, −y+1, z−1/2; (ii) −x+1, y, z; (iii) x−1/2, y−1/2, z; (iv) −x+1, −y+1, z−1/2; (v) −x+1/2, y−1/2, z−1; (vi) −x+1, −y+1, −z. |
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Octahedral chromium(III) complexes have attracted increasing interest in the past decade, following the discovery of their catalytic properties. One application for these complexes is in homogeneous catalysis, where CO and CO2 are converted into organic compounds, such as methanol, at ambient conditions. The conversion into methanol may be of particular importance because it provides a possible way to reduce greenhouse gas emissions (Ogura & Yoshida, 1987). Substitution reactions of ligands are slow in chromium(III) complexes, a fact that corresponds to their considerable stability. Compounds containing the aquapentachlorochromate(III) complex anion, [CrCl5(H2O)]2−, have been described previously (Ogura & Yoshida, 1987) but have not been structurally characterized.
Two novel compounds were synthesized using the Palmer (1954) method and were identified as Rb2[CrCl5(H2O)], (I), and Cs2[CrCl5(H2O)], (II), by single-crystal diffraction. Both structures consist of layers of chromate complexes connected by O—H···Cl hydrogen bonds, as determined directly for (I) (Fig. 1 and Table 3). The position of the H atom could not be determined in (II). Nevertheless, by analogy with the structure of Cs2[FeCl5(H2O)] (Greedan et al., 1980), the short O···Cl distances of 3.380 (5) Å suggest the existence of bifurcated hydrogen bonds in (II) (Fig. 2).
The chromate anions in (I) and (II) occur in different environments; eight Rb+ cations form a pseudo-cubic environment in (I), whereas six Cs+ cations form a pseudo-octahedral environment in (II) (Figs. 3 and 4). Coll et al. (1987) proposed that the ranion/rcation ratio in alkali aquapentachlorometallates determines the structural type. In the present work, the anionic radius is defined by the average octahedral <M—X> distance (X = Cl and O). The correlation between the ionic radius ratio and the structure type is shown in Table 2 for aquapentachlorometallates(III) including Rb2[MCl5(H2O)] (M = Cr, Fe, In and Tl) and Cs2[MCl5(H2O)] (M = Cr, Fe, In, Ir, Rh, Ru and Tl). It is apparent that smaller radius ratios (1.21–1.24) correspond to the Cmcm structure, while larger radius ratios (1.30–1.65) correspond to the Pnma structure.