Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270103014586/iz1030sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270103014586/iz1030Isup2.hkl | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270103014586/iz1030IIsup3.hkl |
Cs[Si3O6(OH)] was prepared from tetramethoxysilane (1.477 g), caesium hydroxide (1.512 g), tetraethylammonium hydroxide (TEAOH, 0.326 g) and distilled water (6 ml), giving an SiO2/Cs2O/TEAOH/H2O gel composition of 1:0.26:0.08:40. Rb[Si2O4(OH)] was prepared from colloidal silica (Aldrich AS40, 0.627 g), rubidium hydroxide (2.086 g) and distilled water (9 ml), giving an SiO2/Rb2O/H2O gel composition of 1:1.95:120. Both reactions were carried out in Parr acid digestion bombs with 23 ml poly(tetrafluoroethylene) liners. All gels were prepared, mixed and aged for 1 h in the Teflon liners, which were generally half filled. Both reactions were carried out at 493 K for a period of 5 d.
For both compounds, data collection: SMART (Bruker, 2000); cell refinement: SMART; data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).
Cs[Si3O6(OH)] | Dx = 3.052 Mg m−3 |
Mr = 330.19 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, P212121 | Cell parameters from 192 reflections |
a = 4.9163 (9) Å | θ = 5–25° |
b = 10.340 (2) Å | µ = 5.64 mm−1 |
c = 14.136 (3) Å | T = 293 K |
V = 718.6 (2) Å3 | Prism, colorless |
Z = 4 | 0.22 × 0.04 × 0.02 mm |
F(000) = 616 |
Bruker AXS four-circle diffractometer | 1517 reflections with I > 2σ(I) |
Bruker SMART 1000 CCD scans | Rint = 0.052 |
Absorption correction: multi-scan (Blessing, 1995; Sheldrick, 2001) | θmax = 28.2°, θmin = 2.4° |
Tmin = 0.370, Tmax = 0.896 | h = −6→6 |
5183 measured reflections | k = −12→13 |
1670 independent reflections | l = −18→18 |
Refinement on F2 | w = 1/[σ2(Fo2) + (0.0433P)2 + 0.0545P] where P = (Fo2 + 2Fc2)/3 |
Least-squares matrix: full | (Δ/σ)max = 0.001 |
R[F2 > 2σ(F2)] = 0.033 | Δρmax = 0.74 e Å−3 |
wR(F2) = 0.082 | Δρmin = −0.75 e Å−3 |
S = 0.93 | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
1670 reflections | Extinction coefficient: 0.0221 (12) |
101 parameters | Absolute structure: Flack (1983), 650 Friedel pairs |
0 restraints | Absolute structure parameter: 0.00 (3) |
H-atom parameters not refined |
Cs[Si3O6(OH)] | V = 718.6 (2) Å3 |
Mr = 330.19 | Z = 4 |
Orthorhombic, P212121 | Mo Kα radiation |
a = 4.9163 (9) Å | µ = 5.64 mm−1 |
b = 10.340 (2) Å | T = 293 K |
c = 14.136 (3) Å | 0.22 × 0.04 × 0.02 mm |
Bruker AXS four-circle diffractometer | 1670 independent reflections |
Absorption correction: multi-scan (Blessing, 1995; Sheldrick, 2001) | 1517 reflections with I > 2σ(I) |
Tmin = 0.370, Tmax = 0.896 | Rint = 0.052 |
5183 measured reflections |
R[F2 > 2σ(F2)] = 0.033 | H-atom parameters not refined |
wR(F2) = 0.082 | Δρmax = 0.74 e Å−3 |
S = 0.93 | Δρmin = −0.75 e Å−3 |
1670 reflections | Absolute structure: Flack (1983), 650 Friedel pairs |
101 parameters | Absolute structure parameter: 0.00 (3) |
0 restraints |
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. Structure determination. Single crystal X–ray diffraction experiments were carried out on a 4–circle Bruker 1 K Smart–CCD diffractometer. X–rays were generated at 50 kV and 30 mA using normal–focus X–ray tube with Mo as the target metal (Mo K-alpha, L= 0.71073 A). Each crystal was collected at room temperature with a phi and omega scans using 0.3 degree rotations/frame. A total of 1650 frames were collected for each crystal spanning one hemisphere of reciprocal space out to 0.75 A. Data were integrated using SAINT (Bruker, 2000), and empirical absorption corrections were preformed in the program SADABS (Sheldrick, 2000). Structures were solved in SHELXS (Sheldrick, 1990) using direct methods, and successive refinements were preformed in SHELXL–97 by difference Fourier synthesis (Sheldrick, 1993). All least–squares refinements were carried out against |F2|. |
x | y | z | Uiso*/Ueq | ||
Cs1 | 0.96911 (8) | 0.41523 (3) | 0.74709 (3) | 0.02941 (16) | |
Si1 | 0.9820 (3) | 0.58294 (12) | 1.00897 (9) | 0.0116 (3) | |
Si2 | 0.4790 (3) | 0.64876 (12) | 0.89281 (10) | 0.0117 (3) | |
Si3 | 0.8928 (3) | 0.29464 (14) | 1.05627 (11) | 0.0127 (3) | |
O1 | 0.4019 (9) | 0.6159 (4) | 0.7884 (3) | 0.0214 (9) | |
O2 | 0.7923 (8) | 0.6101 (4) | 0.9180 (3) | 0.0201 (9) | |
O3 | 0.5859 (7) | 0.2505 (4) | 1.0302 (3) | 0.0186 (8) | |
O4 | 0.8974 (8) | 0.4519 (4) | 1.0617 (3) | 0.0181 (9) | |
O5 | 0.4456 (9) | 0.8035 (4) | 0.9144 (3) | 0.0212 (9) | |
O6 | 0.2907 (7) | 0.5751 (4) | 0.9716 (3) | 0.0181 (8) | |
O7 | 0.9768 (9) | 0.2370 (4) | 1.1570 (3) | 0.0216 (8) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cs1 | 0.0292 (2) | 0.0325 (2) | 0.0266 (2) | −0.00522 (15) | −0.00434 (19) | −0.00456 (18) |
Si1 | 0.0127 (6) | 0.0123 (5) | 0.0098 (6) | 0.0002 (6) | 0.0024 (5) | 0.0009 (5) |
Si2 | 0.0137 (6) | 0.0137 (6) | 0.0076 (6) | 0.0004 (6) | 0.0015 (6) | −0.0001 (5) |
Si3 | 0.0131 (7) | 0.0136 (7) | 0.0113 (7) | −0.0005 (5) | −0.0013 (5) | 0.0002 (6) |
O1 | 0.028 (2) | 0.025 (2) | 0.0104 (18) | −0.0058 (16) | −0.0007 (17) | −0.0011 (16) |
O2 | 0.0118 (17) | 0.034 (2) | 0.015 (2) | 0.0006 (16) | 0.0019 (15) | 0.0023 (18) |
O3 | 0.0144 (17) | 0.0242 (19) | 0.017 (2) | −0.0029 (15) | −0.0015 (15) | −0.0018 (16) |
O4 | 0.023 (2) | 0.0144 (18) | 0.017 (2) | 0.0000 (14) | 0.0034 (17) | 0.0012 (15) |
O5 | 0.028 (2) | 0.0187 (17) | 0.017 (2) | 0.0018 (18) | −0.0046 (19) | −0.0024 (16) |
O6 | 0.0146 (17) | 0.027 (2) | 0.012 (2) | 0.0033 (16) | 0.0033 (15) | 0.0034 (18) |
O7 | 0.029 (2) | 0.0204 (18) | 0.0151 (18) | 0.0012 (19) | −0.0067 (19) | 0.0025 (15) |
Cs1—O1i | 3.029 (4) | Si2—O6 | 1.636 (4) |
Cs1—O7ii | 3.190 (4) | Si2—O5 | 1.637 (4) |
Cs1—O7iii | 3.247 (4) | Si2—Cs1ix | 4.0443 (15) |
Cs1—O2 | 3.264 (4) | Si2—Cs1x | 4.0445 (15) |
Cs1—O5iv | 3.271 (4) | Si3—O7 | 1.598 (4) |
Cs1—O4v | 3.465 (4) | Si3—O3iii | 1.616 (4) |
Cs1—O1 | 3.525 (4) | Si3—O3 | 1.619 (4) |
Cs1—O1iv | 3.627 (4) | Si3—O4 | 1.628 (4) |
Cs1—O3iii | 3.630 (4) | Si3—Cs1ii | 4.0958 (16) |
Cs1—Si2 | 3.9849 (15) | O1—Cs1x | 3.029 (4) |
Cs1—Si1v | 4.0312 (15) | O1—Cs1ix | 3.627 (4) |
Cs1—Si2iv | 4.0443 (15) | O3—Si3ii | 1.616 (4) |
Si1—O4 | 1.601 (4) | O3—Cs1ii | 3.630 (4) |
Si1—O5vi | 1.608 (4) | O4—Cs1vii | 3.465 (4) |
Si1—O6i | 1.609 (4) | O5—Si1xi | 1.608 (4) |
Si1—O2 | 1.613 (4) | O5—Cs1ix | 3.271 (4) |
Si1—Cs1vii | 4.0312 (15) | O6—Si1x | 1.609 (4) |
Si1—Cs1viii | 4.3142 (16) | O7—Cs1iii | 3.190 (4) |
Si2—O1 | 1.562 (4) | O7—Cs1ii | 3.247 (4) |
Si2—O2 | 1.631 (4) | ||
O1i—Cs1—O7ii | 142.11 (10) | O5vi—Si1—O2 | 110.2 (2) |
O1i—Cs1—O7iii | 73.25 (11) | O6i—Si1—O2 | 107.0 (2) |
O7ii—Cs1—O7iii | 99.59 (10) | O4—Si1—Cs1vii | 58.17 (14) |
O1i—Cs1—O2 | 67.76 (11) | O5vi—Si1—Cs1vii | 51.14 (15) |
O7ii—Cs1—O2 | 77.75 (10) | O6i—Si1—Cs1vii | 142.51 (16) |
O7iii—Cs1—O2 | 101.23 (10) | O2—Si1—Cs1vii | 110.27 (15) |
O1i—Cs1—O5iv | 144.51 (11) | O4—Si1—Cs1 | 93.34 (15) |
O7ii—Cs1—O5iv | 69.47 (10) | O5vi—Si1—Cs1 | 156.68 (16) |
O7iii—Cs1—O5iv | 126.82 (10) | O6i—Si1—Cs1 | 72.28 (15) |
O2—Cs1—O5iv | 124.65 (10) | O2—Si1—Cs1 | 48.95 (15) |
O1i—Cs1—O4v | 103.85 (10) | Cs1vii—Si1—Cs1 | 138.55 (4) |
O7ii—Cs1—O4v | 97.04 (10) | O4—Si1—Cs1viii | 78.65 (16) |
O7iii—Cs1—O4v | 155.21 (10) | O5vi—Si1—Cs1viii | 62.64 (16) |
O2—Cs1—O4v | 100.18 (10) | O6i—Si1—Cs1viii | 70.53 (15) |
O5iv—Cs1—O4v | 44.61 (9) | O2—Si1—Cs1viii | 169.35 (16) |
O1i—Cs1—O1 | 96.92 (11) | Cs1vii—Si1—Cs1viii | 72.10 (3) |
O7ii—Cs1—O1 | 67.65 (9) | Cs1—Si1—Cs1viii | 135.89 (3) |
O7iii—Cs1—O1 | 145.52 (9) | O1—Si2—O2 | 112.5 (2) |
O2—Cs1—O1 | 45.84 (9) | O1—Si2—O6 | 113.9 (2) |
O5iv—Cs1—O1 | 80.23 (10) | O2—Si2—O6 | 105.7 (2) |
O4v—Cs1—O1 | 58.68 (10) | O1—Si2—O5 | 111.3 (2) |
O1i—Cs1—O1iv | 164.68 (9) | O2—Si2—O5 | 107.1 (2) |
O7ii—Cs1—O1iv | 41.94 (9) | O6—Si2—O5 | 105.8 (2) |
O7iii—Cs1—O1iv | 91.76 (9) | O1—Si2—Cs1 | 61.73 (17) |
O2—Cs1—O1iv | 119.67 (10) | O2—Si2—Cs1 | 52.66 (15) |
O5iv—Cs1—O1iv | 44.67 (9) | O6—Si2—Cs1 | 114.30 (15) |
O4v—Cs1—O1iv | 88.41 (9) | O5—Si2—Cs1 | 138.51 (17) |
O1—Cs1—O1iv | 97.32 (4) | O1—Si2—Cs1ix | 63.48 (16) |
O1i—Cs1—O3iii | 92.59 (10) | O2—Si2—Cs1ix | 142.04 (16) |
O7ii—Cs1—O3iii | 61.21 (9) | O6—Si2—Cs1ix | 110.00 (15) |
O7iii—Cs1—O3iii | 44.56 (9) | O5—Si2—Cs1ix | 50.98 (15) |
O2—Cs1—O3iii | 72.03 (10) | Cs1—Si2—Cs1ix | 119.30 (4) |
O5iv—Cs1—O3iii | 122.48 (10) | O1—Si2—Cs1x | 40.39 (15) |
O4v—Cs1—O3iii | 157.75 (9) | O2—Si2—Cs1x | 123.40 (16) |
O1—Cs1—O3iii | 105.04 (9) | O6—Si2—Cs1x | 73.61 (15) |
O1iv—Cs1—O3iii | 78.27 (9) | O5—Si2—Cs1x | 128.03 (16) |
O1i—Cs1—Si2 | 84.84 (9) | Cs1—Si2—Cs1x | 75.51 (3) |
O7ii—Cs1—Si2 | 67.69 (7) | Cs1ix—Si2—Cs1x | 79.63 (3) |
O7iii—Cs1—Si2 | 122.85 (7) | O7—Si3—O3iii | 114.5 (2) |
O2—Cs1—Si2 | 23.40 (7) | O7—Si3—O3 | 109.8 (2) |
O5iv—Cs1—Si2 | 101.41 (8) | O3iii—Si3—O3 | 107.08 (12) |
O4v—Cs1—Si2 | 80.58 (7) | O7—Si3—O4 | 109.1 (2) |
O1—Cs1—Si2 | 22.97 (7) | O3iii—Si3—O4 | 108.4 (2) |
O1iv—Cs1—Si2 | 106.52 (7) | O3—Si3—O4 | 107.8 (2) |
O3iii—Cs1—Si2 | 86.18 (6) | O7—Si3—Cs1ii | 47.85 (16) |
O1i—Cs1—Si1v | 122.96 (8) | O3iii—Si3—Cs1ii | 131.22 (15) |
O7ii—Cs1—Si1v | 86.55 (8) | O3—Si3—Cs1ii | 62.04 (15) |
O7iii—Cs1—Si1v | 140.70 (7) | O4—Si3—Cs1ii | 120.29 (16) |
O2—Cs1—Si1v | 117.95 (7) | Si2—O1—Cs1x | 120.1 (2) |
O5iv—Cs1—Si1v | 22.51 (7) | Si2—O1—Cs1 | 95.30 (19) |
O4v—Cs1—Si1v | 23.12 (6) | Cs1x—O1—Cs1 | 96.92 (11) |
O1—Cs1—Si1v | 72.55 (7) | Si2—O1—Cs1ix | 93.86 (17) |
O1iv—Cs1—Si1v | 67.17 (7) | Cs1x—O1—Cs1ix | 101.81 (12) |
O3iii—Cs1—Si1v | 144.44 (6) | Cs1—O1—Cs1ix | 151.33 (13) |
Si2—Cs1—Si1v | 95.52 (3) | Si1—O2—Si2 | 139.8 (3) |
O1i—Cs1—Si2iv | 160.67 (8) | Si1—O2—Cs1 | 109.17 (18) |
O7ii—Cs1—Si2iv | 57.21 (7) | Si2—O2—Cs1 | 103.94 (19) |
O7iii—Cs1—Si2iv | 107.02 (7) | Si3ii—O3—Si3 | 143.2 (3) |
O2—Cs1—Si2iv | 129.60 (7) | Si3ii—O3—Cs1ii | 115.26 (17) |
O5iv—Cs1—Si2iv | 22.88 (7) | Si3—O3—Cs1ii | 94.76 (17) |
O4v—Cs1—Si2iv | 67.47 (7) | Si1—O4—Si3 | 145.8 (3) |
O1—Cs1—Si2iv | 92.93 (7) | Si1—O4—Cs1vii | 98.71 (17) |
O1iv—Cs1—Si2iv | 22.66 (7) | Si3—O4—Cs1vii | 115.11 (19) |
O3iii—Cs1—Si2iv | 100.88 (7) | Si1xi—O5—Si2 | 145.9 (3) |
Si2—Cs1—Si2iv | 109.65 (2) | Si1xi—O5—Cs1ix | 106.36 (18) |
Si1v—Cs1—Si2iv | 45.18 (3) | Si2—O5—Cs1ix | 106.14 (18) |
O4—Si1—O5vi | 106.0 (2) | Si1x—O6—Si2 | 137.2 (3) |
O4—Si1—O6i | 110.8 (2) | Si3—O7—Cs1iii | 139.4 (2) |
O5vi—Si1—O6i | 111.3 (2) | Si3—O7—Cs1ii | 110.8 (2) |
O4—Si1—O2 | 111.6 (2) | Cs1iii—O7—Cs1ii | 99.59 (10) |
Symmetry codes: (i) x+1, y, z; (ii) x−1/2, −y+1/2, −z+2; (iii) x+1/2, −y+1/2, −z+2; (iv) −x+1, y−1/2, −z+3/2; (v) −x+3/2, −y+1, z−1/2; (vi) x+1/2, −y+3/2, −z+2; (vii) −x+3/2, −y+1, z+1/2; (viii) −x+5/2, −y+1, z+1/2; (ix) −x+1, y+1/2, −z+3/2; (x) x−1, y, z; (xi) x−1/2, −y+3/2, −z+2. |
Rb[Si2O4(OH)] | Dx = 2.9 Mg m−3 |
Mr = 222.66 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, Pcmn | Cell parameters from 89 reflections |
a = 4.8147 (13) Å | θ = 5–25° |
b = 8.267 (2) Å | µ = 10.10 mm−1 |
c = 12.814 (3) Å | T = 293 K |
V = 510.0 (2) Å3 | Hexagonal, colorless |
Z = 4 | 0.11 × 0.04 × 0.01 mm |
F(000) = 424 |
Bruker AXS four-circle diffractometer | 559 reflections with I > 2σ(I) |
Bruker SMART 1000 CCD scans | Rint = 0.045 |
Absorption correction: multi-scan (Blessing, 1995; Sheldrick, 2001) | θmax = 28.2°, θmin = 3.2° |
Tmin = 0.403, Tmax = 0.906 | h = −6→6 |
3401 measured reflections | k = −10→10 |
647 independent reflections | l = −16→17 |
Refinement on F2 | 0 restraints |
Least-squares matrix: full | H-atom parameters not refined |
R[F2 > 2σ(F2)] = 0.027 | w = 1/[σ2(Fo2) + (0.0477P)2 + 0.2002P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.080 | (Δ/σ)max < 0.001 |
S = 1.09 | Δρmax = 0.59 e Å−3 |
647 reflections | Δρmin = −0.68 e Å−3 |
40 parameters |
Rb[Si2O4(OH)] | V = 510.0 (2) Å3 |
Mr = 222.66 | Z = 4 |
Orthorhombic, Pcmn | Mo Kα radiation |
a = 4.8147 (13) Å | µ = 10.10 mm−1 |
b = 8.267 (2) Å | T = 293 K |
c = 12.814 (3) Å | 0.11 × 0.04 × 0.01 mm |
Bruker AXS four-circle diffractometer | 647 independent reflections |
Absorption correction: multi-scan (Blessing, 1995; Sheldrick, 2001) | 559 reflections with I > 2σ(I) |
Tmin = 0.403, Tmax = 0.906 | Rint = 0.045 |
3401 measured reflections |
R[F2 > 2σ(F2)] = 0.027 | 0 restraints |
wR(F2) = 0.080 | H-atom parameters not refined |
S = 1.09 | Δρmax = 0.59 e Å−3 |
647 reflections | Δρmin = −0.68 e Å−3 |
40 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
Rb1 | 0.53159 (9) | 0.75 | 0.46487 (4) | 0.0253 (2) | |
Si1 | 0.50817 (14) | 0.56212 (10) | 0.18906 (7) | 0.0113 (2) | |
O1 | 0.2322 (4) | 0.4563 (3) | 0.21655 (16) | 0.0164 (5) | |
O2 | 0.6363 (4) | 0.5071 (3) | 0.08027 (18) | 0.0216 (5) | |
O3 | 0.4072 (7) | 0.75 | 0.1898 (3) | 0.0233 (7) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Rb1 | 0.0288 (3) | 0.0205 (3) | 0.0265 (3) | 0 | −0.00795 (17) | 0 |
Si1 | 0.0099 (4) | 0.0122 (4) | 0.0118 (5) | −0.0004 (2) | −0.0002 (3) | 0.0001 (3) |
O1 | 0.0145 (10) | 0.0183 (10) | 0.0164 (12) | −0.0040 (7) | 0.0024 (8) | −0.0024 (8) |
O2 | 0.0179 (10) | 0.0337 (13) | 0.0131 (12) | 0.0006 (9) | 0.0033 (9) | −0.0031 (9) |
O3 | 0.0206 (15) | 0.0139 (15) | 0.036 (2) | 0 | −0.0096 (14) | 0 |
Rb1—O2i | 2.911 (2) | Si1—O3 | 1.6275 (13) |
Rb1—O2ii | 2.911 (2) | Si1—O1v | 1.628 (2) |
Rb1—O2iii | 2.962 (2) | Si1—O1 | 1.629 (2) |
Rb1—O2iv | 2.962 (2) | Si1—Rb1ix | 3.9465 (11) |
Rb1—O1v | 3.041 (2) | Si1—Rb1x | 3.9766 (10) |
Rb1—O1vi | 3.041 (2) | Si1—Rb1xi | 4.1109 (10) |
Rb1—O3vii | 3.573 (3) | O1—Si1i | 1.628 (2) |
Rb1—O3 | 3.576 (4) | O1—Rb1x | 3.041 (2) |
Rb1—Si1 | 3.8622 (12) | O2—Rb1xi | 2.911 (2) |
Rb1—Si1viii | 3.8622 (12) | O2—Rb1ix | 2.962 (2) |
Rb1—Si1iii | 3.9465 (11) | O3—Si1viii | 1.6275 (13) |
Rb1—Si1iv | 3.9465 (11) | O3—Rb1xii | 3.573 (3) |
Si1—O2 | 1.591 (2) | ||
O2i—Rb1—O2ii | 93.79 (9) | Si1—Rb1—Si1iii | 147.223 (18) |
O2i—Rb1—O2iii | 161.26 (3) | Si1viii—Rb1—Si1iii | 121.62 (2) |
O2ii—Rb1—O2iii | 87.55 (6) | O2i—Rb1—Si1iv | 102.97 (5) |
O2i—Rb1—O2iv | 87.55 (6) | O2ii—Rb1—Si1iv | 143.04 (5) |
O2ii—Rb1—O2iv | 161.26 (3) | O2iii—Rb1—Si1iv | 66.44 (5) |
O2iii—Rb1—O2iv | 85.34 (9) | O2iv—Rb1—Si1iv | 21.06 (4) |
O2i—Rb1—O1v | 69.28 (6) | O1v—Rb1—Si1iv | 99.06 (4) |
O2ii—Rb1—O1v | 117.73 (6) | O1vi—Rb1—Si1iv | 126.80 (4) |
O2iii—Rb1—O1v | 126.18 (6) | O3vii—Rb1—Si1iv | 75.22 (6) |
O2iv—Rb1—O1v | 80.21 (6) | O3—Rb1—Si1iv | 144.26 (4) |
O2i—Rb1—O1vi | 117.73 (6) | Si1—Rb1—Si1iv | 121.62 (2) |
O2ii—Rb1—O1vi | 69.28 (6) | Si1viii—Rb1—Si1iv | 147.223 (18) |
O2iii—Rb1—O1vi | 80.21 (6) | Si1iii—Rb1—Si1iv | 46.35 (3) |
O2iv—Rb1—O1vi | 126.18 (6) | O2—Si1—O3 | 113.17 (16) |
O1v—Rb1—O1vi | 68.25 (8) | O2—Si1—O1v | 111.57 (12) |
O2i—Rb1—O3vii | 76.92 (6) | O3—Si1—O1v | 106.45 (14) |
O2ii—Rb1—O3vii | 76.92 (6) | O2—Si1—O1 | 110.63 (11) |
O2iii—Rb1—O3vii | 85.22 (6) | O3—Si1—O1 | 105.51 (14) |
O2iv—Rb1—O3vii | 85.22 (6) | O1v—Si1—O1 | 109.23 (7) |
O1v—Rb1—O3vii | 143.55 (5) | O2—Si1—Rb1 | 154.90 (9) |
O1vi—Rb1—O3vii | 143.55 (5) | O3—Si1—Rb1 | 67.65 (13) |
O2i—Rb1—O3 | 72.22 (6) | O1v—Si1—Rb1 | 48.57 (8) |
O2ii—Rb1—O3 | 72.22 (6) | O1—Si1—Rb1 | 92.39 (8) |
O2iii—Rb1—O3 | 125.63 (5) | O2—Si1—Rb1ix | 42.00 (9) |
O2iv—Rb1—O3 | 125.63 (5) | O3—Si1—Rb1ix | 78.24 (13) |
O1v—Rb1—O3 | 45.53 (5) | O1v—Si1—Rb1ix | 101.87 (8) |
O1vi—Rb1—O3 | 45.53 (5) | O1—Si1—Rb1ix | 145.75 (8) |
O3vii—Rb1—O3 | 134.11 (3) | Rb1—Si1—Rb1ix | 119.43 (2) |
O2i—Rb1—Si1 | 60.36 (5) | O2—Si1—Rb1x | 66.64 (8) |
O2ii—Rb1—Si1 | 95.32 (5) | O3—Si1—Rb1x | 116.72 (11) |
O2iii—Rb1—Si1 | 138.17 (5) | O1v—Si1—Rb1x | 133.64 (9) |
O2iv—Rb1—Si1 | 101.53 (5) | O1—Si1—Rb1x | 44.64 (8) |
O1v—Rb1—Si1 | 23.66 (4) | Rb1—Si1—Rb1x | 137.03 (2) |
O1vi—Rb1—Si1 | 62.31 (4) | Rb1ix—Si1—Rb1x | 102.61 (3) |
O3vii—Rb1—Si1 | 136.12 (5) | O2—Si1—Rb1xi | 33.12 (8) |
O3—Rb1—Si1 | 24.90 (2) | O3—Si1—Rb1xi | 141.70 (13) |
O2i—Rb1—Si1viii | 95.32 (5) | O1v—Si1—Rb1xi | 83.77 (8) |
O2ii—Rb1—Si1viii | 60.36 (5) | O1—Si1—Rb1xi | 105.48 (8) |
O2iii—Rb1—Si1viii | 101.53 (5) | Rb1—Si1—Rb1xi | 132.35 (2) |
O2iv—Rb1—Si1viii | 138.17 (5) | Rb1ix—Si1—Rb1xi | 63.485 (19) |
O1v—Rb1—Si1viii | 62.31 (4) | Rb1x—Si1—Rb1xi | 73.05 (2) |
O1vi—Rb1—Si1viii | 23.66 (4) | Si1i—O1—Si1 | 138.71 (14) |
O3vii—Rb1—Si1viii | 136.12 (5) | Si1i—O1—Rb1x | 107.76 (10) |
O3—Rb1—Si1viii | 24.90 (2) | Si1—O1—Rb1x | 113.25 (10) |
Si1—Rb1—Si1viii | 47.43 (3) | Si1—O2—Rb1xi | 129.51 (12) |
O2i—Rb1—Si1iii | 143.04 (5) | Si1—O2—Rb1ix | 116.94 (11) |
O2ii—Rb1—Si1iii | 102.97 (5) | Rb1xi—O2—Rb1ix | 92.45 (6) |
O2iii—Rb1—Si1iii | 21.06 (4) | Si1viii—O3—Si1 | 145.2 (2) |
O2iv—Rb1—Si1iii | 66.44 (5) | Si1viii—O3—Rb1xii | 99.91 (12) |
O1v—Rb1—Si1iii | 126.80 (4) | Si1—O3—Rb1xii | 99.91 (12) |
O1vi—Rb1—Si1iii | 99.06 (4) | Si1viii—O3—Rb1 | 87.45 (12) |
O3vii—Rb1—Si1iii | 75.22 (6) | Si1—O3—Rb1 | 87.45 (12) |
O3—Rb1—Si1iii | 144.26 (4) | Rb1xii—O3—Rb1 | 153.40 (11) |
Symmetry codes: (i) x−1/2, −y+1, −z+1/2; (ii) x−1/2, y+1/2, −z+1/2; (iii) −x+3/2, −y+3/2, z+1/2; (iv) −x+3/2, y, z+1/2; (v) x+1/2, −y+1, −z+1/2; (vi) x+1/2, y+1/2, −z+1/2; (vii) −x+1/2, −y+3/2, z+1/2; (viii) x, −y+3/2, z; (ix) −x+3/2, −y+3/2, z−1/2; (x) x−1/2, y−1/2, −z+1/2; (xi) x+1/2, y−1/2, −z+1/2; (xii) −x+1/2, −y+3/2, z−1/2. |
Experimental details
(I) | (II) | |
Crystal data | ||
Chemical formula | Cs[Si3O6(OH)] | Rb[Si2O4(OH)] |
Mr | 330.19 | 222.66 |
Crystal system, space group | Orthorhombic, P212121 | Orthorhombic, Pcmn |
Temperature (K) | 293 | 293 |
a, b, c (Å) | 4.9163 (9), 10.340 (2), 14.136 (3) | 4.8147 (13), 8.267 (2), 12.814 (3) |
V (Å3) | 718.6 (2) | 510.0 (2) |
Z | 4 | 4 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 5.64 | 10.10 |
Crystal size (mm) | 0.22 × 0.04 × 0.02 | 0.11 × 0.04 × 0.01 |
Data collection | ||
Diffractometer | Bruker AXS four-circle diffractometer | Bruker AXS four-circle diffractometer |
Absorption correction | Multi-scan (Blessing, 1995; Sheldrick, 2001) | Multi-scan (Blessing, 1995; Sheldrick, 2001) |
Tmin, Tmax | 0.370, 0.896 | 0.403, 0.906 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5183, 1670, 1517 | 3401, 647, 559 |
Rint | 0.052 | 0.045 |
(sin θ/λ)max (Å−1) | 0.666 | 0.664 |
Refinement | ||
R[F2 > 2σ(F2)], wR(F2), S | 0.033, 0.082, 0.93 | 0.027, 0.080, 1.09 |
No. of reflections | 1670 | 647 |
No. of parameters | 101 | 40 |
H-atom treatment | H-atom parameters not refined | H-atom parameters not refined |
Δρmax, Δρmin (e Å−3) | 0.74, −0.75 | 0.59, −0.68 |
Absolute structure | Flack (1983), 650 Friedel pairs | ? |
Absolute structure parameter | 0.00 (3) | ? |
Computer programs: SMART (Bruker, 2000), SMART, SAINT (Bruker, 2000), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).
During our search for novel mixed-geometry (octahedral/tetrahedral metal oxide) open frameworks, we discovered two phyllosilicate by-products, and we subsequently altered the synthesis conditions in order to isolate these layered silicates. Both title compounds exhibit novel phyllosilicate structures. The rubidium compound is the only known high-mass alkali described by a six-membered ring silica sheet – a characteristic reported as belonging to low-mass alkali phyllosilicates (Dejong et al., 1994). Likewise, the caesium compound exhibits novel four- and six-ring sheets, in which the six-membered rings adopt boat conformations. A structural study of these layered compounds may lead to a better understanding of the hydrothermal synthesis of octahedral/tetrahedral open frameworks, since a large number of reported mixed-geometry metal oxide frameworks exhibit alternating layers of silica sheets and octahedral metal oxide sheets (Ananias et al., 2001; Rocha et al., 1998). Furthermore, these structures have potential applications in ion-exchange and chemisorption processes (Da Fonseca et al., 2000; Lagadic et al., 2001; Pagnoux et al.. 1991). Preliminary experiments for Rb[Si2O4(OH)] are promising in this context.
Fig. 1 illustrates the sandwich structure of the Cs phyllosilicate, clearly showing the Cs atoms residing between the silica sheets. The Cs atom is coordinated to nine neighboring O atoms, with Cs—O distances in the range 3.02–3.62 Å. Two dangling O atoms propagate into the interlayer space, of which one must be protonated for the electroneutrality of the structure. No H atom could be located in the difference Fourier map because of the large electron density associated with the Cs atom. However, the Si3—O7 bond length of 1.600 (4) Å agrees with the value reported for an Si—OH bond length in tetrahedral silicates with three bridging O atoms (Nyfeler & Armbruster, 1998). Fig. 2 illustrates the four- and six-membered ring topology of the silica sheet, which is unique to phyllosilicates.
Fig. 3 illustrates the typical sandwich structure of a phyllosilicate for the Rb compound. The Rb atom occupies the interlayer space and is eightfold coordinated to neighboring O atoms, with Rb—O distances in the range 2.91–3.57 Å. Again, no H atoms could be located in the difference Fourier maps, although the presence of H atoms is required for the electroneutrality of the structure. The Si1—O2 bond length of 1.591 (2) Å is slightly shorter than that reported for a typical Si—OH bond length in this bonding situation, reflecting the fact that the O atom only requires protonation to fractional occupancy of 0.5 (Nyfeler & Armbruster, 1998). Fig. 4 depicts the corrugated six-membered ring topology of the silica sheet, which is very similar to the topology of δ–Na2Si2O5 (Kahlenberg et al., 1999). This compound is the first example of a high-mass alkali phyllosilicate with such a topology, and this result may raise new questions concerning the molecular modeling of disilicate glasses from phyllosilicate structures (Nyfeler & Armbruster, 1998).