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The structure of cronstedtite-1M was refined using a crystal from Eisleben (Saxony-Anhalt, Germany). The space group is Cm, a = 5.5033 (3), b = 9.5289 (6), c = 7.3328 (5) Å, β = 104.493 (7)°, composition (Fe2+2.461Fe3+0.539)(Si1.461Fe3+0.539)O5(OH)4, Z = 2. Despite diffusely streaked characteristic polytype reflections, the refinement converged to Robs = 0.0242 for 1117 independent reflections. Separate Robs values of 0.0183 and 0.0553 were obtained for 415 subfamily and 702 characteristic reflections, respectively. The structure is built of one edge-sharing octahedral (Oc) and one corner-sharing tetrahedral (Tet) sheet forming the 1:1 layer by sharing apical corners of the Tet sheet. Consecutive layers are shifted by a/3 of the hexagonal cell, the polytype belongs to the subfamily (Bailey's group) A. There are two octahedral sites M1 (at m), M2 (in a general position) both fully occupied by Fe. Since the M2 octahedron is larger than M1, the Oc sheet is meso-octahedral. The Tet sheet contains one tetrahedral position, T1, occupied by Si and Fe in the ratio 0.731:0.269 (9). The ring of tetrahedra is strongly ditrigonalized, α = +12.7°; Franzini type A. Of three H atoms localized, two are involved in hydrogen bonds, linking OH groups of the Oc sheet with basal O atoms of the Tet sheet. The basal O atoms (acceptors) of the Tet sheet are rotated close to OH groups (donors) of the Oc sheet of an adjacent layer in order to achieve reasonable lengths and geometries of hydrogen bonds. The structure is interpreted as an example of the order–disorder (OD) structure of more than one kind of layer with a very low degree of desymmetrization.
Supporting information
CCDC reference: 1024945
Crystal data, data collection and structure refinement details are summarized
in Table 1.
S2. Results and discussion
top
Data collection: CrysAlis PRO, Agilent Technologies,
Version 1.171.37.31 (release 14-01-2014 CrysAlis171 .NET)
(compiled Jan 14 2014,18:38:05); cell refinement: CrysAlis PRO, Agilent Technologies,
Version 1.171.37.31 (release 14-01-2014 CrysAlis171 .NET)
(compiled Jan 14 2014,18:38:05); data reduction: CrysAlis PRO, Agilent Technologies,
Version 1.171.37.31 (release 14-01-2014 CrysAlis171 .NET)
(compiled Jan 14 2014,18:38:05).
Crystal data top
Fe3.539H4O9Si1.461 | F(000) = 377 |
Mr = 386.7 | Dx = 3.448 Mg m−3 |
Monoclinic, Cm | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: C -2y | Cell parameters from 1042 reflections |
a = 5.5033 (3) Å | θ = 4.2–30.3° |
b = 9.5289 (5) Å | µ = 7.04 mm−1 |
c = 7.3328 (5) Å | T = 293 K |
β = 104.493 (6)° | Plate, black |
V = 372.30 (4) Å3 | 0.25 × 0.15 × 0.10 mm |
Z = 2 | |
Data collection top
Xcalibur, Atlas, Gemini ultra diffractometer | 1117 independent reflections |
Radiation source: X-ray tube | 999 reflections with I > 3σ(I) |
Graphite monochromator | Rint = 0.020 |
Detector resolution: 10.3784 pixels mm-1 | θmax = 30.9°, θmin = 2.9° |
ω scans | h = −7→7 |
Absorption correction: multi-scan CrysAlis PRO, Agilent Technologies,
Version 1.171.37.31 (release 14-01-2014 CrysAlis171 .NET)
(compiled Jan 14 2014,18:38:05)
Empirical absorption correction using spherical harmonics,
implemented in SCALE3 ABSPACK scaling algorithm.
Empirical absorption correction using spherical harmonics,
implemented in SCALE3 ABSPACK scaling algorithm. | k = −12→13 |
Tmin = 0.554, Tmax = 1 | l = −10→10 |
2993 measured reflections | |
Refinement top
Refinement on F | 14 constraints |
R[F2 > 2σ(F2)] = 0.024 | All H-atom parameters refined |
wR(F2) = 0.035 | Weighting scheme based on measured s.u.'s w = 1/(σ2(F) + 0.0001F2) |
S = 1.64 | (Δ/σ)max = 0.019 |
1117 reflections | Δρmax = 0.62 e Å−3 |
77 parameters | Δρmin = −0.37 e Å−3 |
3 restraints | Absolute structure: 533 of Friedel pairs used in the refinement |
Crystal data top
Fe3.539H4O9Si1.461 | V = 372.30 (4) Å3 |
Mr = 386.7 | Z = 2 |
Monoclinic, Cm | Mo Kα radiation |
a = 5.5033 (3) Å | µ = 7.04 mm−1 |
b = 9.5289 (5) Å | T = 293 K |
c = 7.3328 (5) Å | 0.25 × 0.15 × 0.10 mm |
β = 104.493 (6)° | |
Data collection top
Xcalibur, Atlas, Gemini ultra diffractometer | 1117 independent reflections |
Absorption correction: multi-scan CrysAlis PRO, Agilent Technologies,
Version 1.171.37.31 (release 14-01-2014 CrysAlis171 .NET)
(compiled Jan 14 2014,18:38:05)
Empirical absorption correction using spherical harmonics,
implemented in SCALE3 ABSPACK scaling algorithm.
Empirical absorption correction using spherical harmonics,
implemented in SCALE3 ABSPACK scaling algorithm. | 999 reflections with I > 3σ(I) |
Tmin = 0.554, Tmax = 1 | Rint = 0.020 |
2993 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.024 | 3 restraints |
wR(F2) = 0.035 | All H-atom parameters refined |
S = 1.64 | Δρmax = 0.62 e Å−3 |
1117 reflections | Δρmin = −0.37 e Å−3 |
77 parameters | Absolute structure: 533 of Friedel pairs used in the refinement |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | Occ. (<1) |
Fem1 | 0.25 | 0.5 | 0.6 | 0.0116 (3) | |
Fem2 | 0.2516 (2) | 0.16754 (7) | 0.59589 (16) | 0.01178 (17) | |
Sit1 | 0.4519 (2) | 0.16619 (8) | 0.19842 (17) | 0.0091 (3) | 0.731 (9) |
Fet1 | 0.4519 (2) | 0.16619 (8) | 0.19842 (17) | 0.0091 (3) | 0.269 (9) |
O1 | −0.0109 (11) | 0.5 | 0.1200 (7) | 0.0302 (19) | |
O2 | 0.1426 (8) | 0.2172 (4) | 0.1208 (5) | 0.0310 (13) | |
O4 | 0.5371 (7) | 0.1633 (3) | 0.4448 (5) | 0.0164 (11) | |
Oh1 | 0.5279 (10) | 0.5 | 0.4467 (7) | 0.0163 (16) | |
Oh2 | −0.0335 (11) | 0.5 | 0.7365 (7) | 0.0146 (17) | |
Oh3 | 0.4631 (8) | 0.3357 (3) | 0.7374 (5) | 0.0145 (11) | |
H1 | 0.493 (14) | 0.5 | 0.319 (3) | 0.0195* | |
H2 | 0.005 (14) | 0.5 | 0.863 (3) | 0.0175* | |
H3 | 0.507 (10) | 0.334 (5) | 0.863 (3) | 0.0174* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Fem1 | 0.0093 (4) | 0.0093 (4) | 0.0174 (5) | 0 | 0.0053 (4) | 0 |
Fem2 | 0.0091 (3) | 0.0085 (3) | 0.0187 (3) | −0.0001 (3) | 0.0053 (2) | 0.0001 (3) |
Sit1 | 0.0090 (4) | 0.0102 (4) | 0.0081 (5) | −0.0005 (11) | 0.0023 (3) | −0.0008 (9) |
Fet1 | 0.0090 (4) | 0.0102 (4) | 0.0081 (5) | −0.0005 (11) | 0.0023 (3) | −0.0008 (9) |
O1 | 0.033 (3) | 0.035 (3) | 0.023 (3) | 0 | 0.006 (2) | 0 |
O2 | 0.030 (2) | 0.036 (2) | 0.027 (2) | 0.0011 (19) | 0.0070 (18) | 0.0003 (18) |
O4 | 0.0156 (17) | 0.0170 (19) | 0.0171 (17) | −0.0008 (14) | 0.0046 (16) | −0.0008 (13) |
Oh1 | 0.016 (2) | 0.017 (3) | 0.016 (2) | 0 | 0.004 (2) | 0 |
Oh2 | 0.015 (2) | 0.014 (2) | 0.015 (3) | 0 | 0.006 (3) | 0 |
Oh3 | 0.0137 (17) | 0.0137 (18) | 0.016 (2) | −0.0013 (16) | 0.0034 (17) | 0.0003 (13) |
Geometric parameters (Å, º) top
Fem1—O4i | 2.103 (3) | Fem2—Oh3 | 2.096 (3) |
Fem1—O4ii | 2.103 (3) | Fem2—Oh3ii | 2.103 (5) |
Fem1—Oh1 | 2.112 (6) | Sit1—O1v | 1.714 (2) |
Fem1—Oh2 | 2.054 (6) | Sit1—O2 | 1.724 (4) |
Fem1—Oh3 | 2.061 (3) | Sit1—O2vi | 1.721 (5) |
Fem1—Oh3iii | 2.061 (3) | Sit1—O4 | 1.750 (4) |
Fem2—O4 | 2.137 (4) | Oh1—H1 | 0.91 (2) |
Fem2—O4ii | 2.136 (3) | Oh2—H2 | 0.90 (2) |
Fem2—Oh1iv | 2.142 (3) | Oh3—H3 | 0.89 (2) |
Fem2—Oh2v | 2.098 (3) | | |
| | | |
O4i—Fem1—O4ii | 95.47 (12) | O4—Fem2—Oh3 | 83.22 (15) |
O4i—Fem1—Oh1 | 95.26 (14) | O4—Fem2—Oh3ii | 177.50 (13) |
O4i—Fem1—Oh2 | 82.84 (14) | O4ii—Fem2—Oh1iv | 97.19 (13) |
O4i—Fem1—Oh3 | 176.58 (15) | O4ii—Fem2—Oh2v | 178.1 (2) |
O4i—Fem1—Oh3iii | 82.78 (13) | O4ii—Fem2—Oh3 | 81.15 (13) |
O4ii—Fem1—Oh1 | 95.26 (14) | O4ii—Fem2—Oh3ii | 83.08 (15) |
O4ii—Fem1—Oh2 | 82.84 (14) | Oh1iv—Fem2—Oh2v | 82.24 (14) |
O4ii—Fem1—Oh3 | 82.78 (13) | Oh1iv—Fem2—Oh3 | 178.33 (14) |
O4ii—Fem1—Oh3iii | 176.58 (15) | Oh1iv—Fem2—Oh3ii | 80.35 (18) |
Oh1—Fem1—Oh2 | 177.16 (17) | Oh2v—Fem2—Oh3 | 99.42 (14) |
Oh1—Fem1—Oh3 | 82.01 (14) | Oh2v—Fem2—Oh3ii | 98.5 (2) |
Oh1—Fem1—Oh3iii | 82.01 (14) | Oh3—Fem2—Oh3ii | 99.28 (16) |
Oh2—Fem1—Oh3 | 99.81 (15) | O1v—Sit1—O2 | 109.9 (2) |
Oh2—Fem1—Oh3iii | 99.81 (15) | O1v—Sit1—O2vi | 110.6 (3) |
Oh3—Fem1—Oh3iii | 98.81 (13) | O1v—Sit1—O4 | 107.9 (2) |
O4—Fem2—O4ii | 97.36 (15) | O2—Sit1—O2vi | 110.0 (2) |
O4—Fem2—Oh1iv | 97.15 (18) | O2—Sit1—O4 | 109.4 (2) |
O4—Fem2—Oh2v | 80.98 (19) | O2vi—Sit1—O4 | 108.90 (18) |
Symmetry codes: (i) x−1/2, y+1/2, z; (ii) x−1/2, −y+1/2, z; (iii) x, −y+1, z; (iv) x−1/2, y−1/2, z; (v) x+1/2, y−1/2, z; (vi) x+1/2, −y+1/2, z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
Oh2—H2···O1vii | 0.90 (2) | 1.91 (3) | 2.784 (7) | 164 (7) |
Oh3—H3···O2viii | 0.89 (2) | 1.91 (2) | 2.782 (5) | 165 (5) |
Symmetry codes: (vii) x, y, z+1; (viii) x+1/2, −y+1/2, z+1. |
Experimental details
Crystal data |
Chemical formula | Fe3.539H4O9Si1.461 |
Mr | 386.7 |
Crystal system, space group | Monoclinic, Cm |
Temperature (K) | 293 |
a, b, c (Å) | 5.5033 (3), 9.5289 (5), 7.3328 (5) |
β (°) | 104.493 (6) |
V (Å3) | 372.30 (4) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 7.04 |
Crystal size (mm) | 0.25 × 0.15 × 0.10 |
|
Data collection |
Diffractometer | Xcalibur, Atlas, Gemini ultra diffractometer |
Absorption correction | Multi-scan CrysAlis PRO, Agilent Technologies,
Version 1.171.37.31 (release 14-01-2014 CrysAlis171 .NET)
(compiled Jan 14 2014,18:38:05)
Empirical absorption correction using spherical harmonics,
implemented in SCALE3 ABSPACK scaling algorithm.
Empirical absorption correction using spherical harmonics,
implemented in SCALE3 ABSPACK scaling algorithm. |
Tmin, Tmax | 0.554, 1 |
No. of measured, independent and observed [I > 3σ(I)] reflections | 2993, 1117, 999 |
Rint | 0.020 |
(sin θ/λ)max (Å−1) | 0.723 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.024, 0.035, 1.64 |
No. of reflections | 1117 |
No. of parameters | 77 |
No. of restraints | 3 |
H-atom treatment | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 0.62, −0.37 |
Absolute structure | 533 of Friedel pairs used in the refinement |
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