metal-organic compounds
(C8H26N4)0.5[(UO2)2(SO4)3(H2O)]·2H2O, an organically templated uranyl sulfate with a novel layer type
aInorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, England, and bDepartment of Chemistry, Haverford College, 370 Lancaster Avenue, Haverford, PA 19041, USA
*Correspondence e-mail: dermot.ohare@chem.ox.ac.uk
The title compound, hemi[3,3′-(ethylenediiminio)dipropanaminium] aquatetraoxotri-μ-sulfato-diuranate(VI) dihydrate, (C8H26N4)0.5[(UO2)2(SO4)3(H2O)]·2H2O, contains infinite anionic [(UO2)2(H2O)(SO4)3]2− layers with [C8H26N4]4+ cations balancing charge and participating in extensive hydrogen bonding, along with uncoordinated water molecules. Each UVI centre is seven-coordinate with a pentagonal bipyramidal geometry, and each sulfate tetrahedron bridges three adjacent uranium centres.
Comment
The chemistry of open-framework metal phosphates is well known (Cheetham et al., 1999). Despite the depth of this investigation, little effort has been expended upon the analogous sulfate systems. Reports of organically templated metal sulfates have only appeared in the literature in recent years. Compounds incorporating Sc (Bull et al., 2002), V (Paul, Choudhury, Nagarajan & Rao, 2003; Khan et al., 1999), Cd (Paul et al., 2002b; Choudhury et al., 2001), Fe (Paul et al., 2002a; Paul et al., 2002; Paul, Choudhury & Rao, 2003), Zn (Morimoto & Lingafelter, 1970), Ce (Wang et al., 2002), La (Bataille & Louer, 2002; Xing, Shi et al., 2003; Xing, Liu et al., 2003) and U (Doran et al., 2002, 2003a,b,c,d; Norquist et al., 2002, 2003a,b; Norquist, Doran & O'Hare, 2003; Thomas et al., 2003; Stuart et al., 2003) are known. These compounds exhibit great structural diversity, with structures ranging from molecular anions to three-dimensional microporous materials. This report contains the synthesis and structure of an organically templated uranium(VI) sulfate, USO-25 (uranium sulfate from Oxford), (C8H26N4)0.5[(UO2)2(SO4)3(H2O)]·2H2O, (I).
Two independent U atoms are present in (I). Both U1 and U2 are seven-coordinate, in pentagonal bipyramidal geometries. Two short `uranyl' bonds to axial O atoms are observed for each uranium environment, with distances that range from 1.751 (5) to 1.764 (5) Å, close to the average reported value of 1.758 (3) Å (Burns et al., 1997). The O1—U1—O2 and O8—U2—O9 angles are close to 180°, with values of 177.8 (2) and 178.1 (2)°, respectively. Four of the five equatorial coordination sites around U1 are occupied by O atoms of sulfate groups, with U—O distances ranging between 2.359 (5) and 2.446 (5) Å. The last coordination site is occupied by a bound water molecule (O3); the U1—O3 distance is 2.421 (5) Å. The assignment of the bound water molecule was based upon hydrogen-bonding interactions. All five equatorial coordination sites around U2 are occupied by O atoms of sulfate groups, with U—O distances ranging from 2.332 (4) to 2.477 (5) Å. Three distinct sulfur sites are observed in (I): S1, S2 and S3 are all at the centre of [SO4] tetrahedra. Each sulfate group bridges three urananium centres and has one terminal O atom. The S—Ob (b = bridging) distances are 1.472 (5) and 1.504 (5) Å, while the S—Ot (t = terminal) distance are shorter, from 1.448 (5) to 1.456 (5) Å.
Layers are formed because each [SO4] tetrahedron bridges between three uranium centres (see Fig. 1). This layer topology was previously unknown in uranium chemistry, to the best of our knowledge. These layers propagate in the (101) plane and are separated by the template cations and water molecules (Fig. 2). The inter-layer species are involved in hydrogen bonding with the layer (Table 1).
Experimental
0.6356 g (1.50 × 10−3 mol) of UO2(CH3CO2)2·2H2O, 0.3403 g (3.47 × 10−3 mol) of H2SO4, 0.0863 g (4.95 × 10−4 mol) of N,N′-bis(3-aminopropyl)ethylenediamine and 1.009 g (5.60 × 10−2 mol) of water were placed into a 23 ml Teflon-lined autoclave. The autoclave was heated to 453 K for 24 h, after which it was slowly cooled to 297 K over an additional 24 h. The autoclave was opened in air and the products recovered by filtration.
Crystal data
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Refinement
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The CH and NH H atoms were positioned in idealized locations and refined by riding on their carrier atoms. The water H atoms were positioned geometrically to make plausible H⋯O hydrogen bonds, whilst maintaining the H—O—H bond angle of 109.5°. Atom H16, attached to O18, does not appear to form a hydrogen bond. Additionally, it makes close contacts (1.90 and 2.05 Å) with two CH H atoms, thus its location should be regarded as less certain. The constraint Uiso(H) = 1.2Ueq(carrier atom) was applied in all cases. The highest peak is at (0.7819, 0.7278, 0.0223) and the deepest hole is at (0.1111, 0.2500, 0.0000).
Data collection: COLLECT (Nonius, 1997); cell DENZO/SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO/SCALEPACK; program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: CRYSTALS (Watkin et al., 2003); molecular graphics: ATOMS (Dowty, 2000); software used to prepare material for publication: CRYSTALS.
Supporting information
https://doi.org/10.1107/S1600536804014941/hb6048sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536804014941/hb6048Isup2.hkl
Data collection: COLLECT (Nonius, 1997); cell
DENZO/SCALEPACK; data reduction: DENZO/SCALEPACK (Otwinowski & Minor, 1996); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: CRYSTALS (Watkin et al., 2003); molecular graphics: ATOMS (Dowty, 2000); software used to prepare material for publication: CRYSTALS.(C8H26N4)0.5[U2O4(SO4)3(H2O)]·2H2O | F(000) = 1764 |
Mr = 971.45 | Dx = 3.342 Mg m−3 |
Monoclinic, P21/n | Melting point: not measured K |
Hall symbol: -P 2yn | Mo Kα radiation, λ = 0.71073 Å |
a = 11.8400 (2) Å | Cell parameters from 3786 reflections |
b = 10.3190 (2) Å | θ = 5–27° |
c = 16.5919 (4) Å | µ = 17.18 mm−1 |
β = 107.7718 (9)° | T = 150 K |
V = 1930.41 (7) Å3 | Block, yellow |
Z = 4 | 0.16 × 0.10 × 0.06 mm |
Nonius KappaCCD diffractometer | 3523 reflections with I > 3σ(I) |
Graphite monochromator | Rint = 0.02 |
ω scans | θmax = 27.5°, θmin = 5.1° |
Absorption correction: multi-scan (DENZO/SCALEPACK; Otwinowski & Minor, 1996) | h = −15→15 |
Tmin = 0.14, Tmax = 0.36 | k = −11→13 |
7982 measured reflections | l = −21→21 |
4381 independent reflections |
Refinement on F2 | Hydrogen site location: inferred from neighbouring sites |
Least-squares matrix: full | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.025 | w = 1/[σ2(F*) + 4.55p] where p = 0.333max(Fo2,0) + 0.667Fc2 |
wR(F2) = 0.055 | (Δ/σ)max = 0.003 |
S = 0.98 | Δρmax = 1.17 e Å−3 |
3523 reflections | Δρmin = −1.42 e Å−3 |
272 parameters | Extinction correction: Larson (1970) |
0 restraints | Extinction coefficient: 36.0 (19) |
Primary atom site location: structure-invariant direct methods |
x | y | z | Uiso*/Ueq | ||
U1 | 0.899965 (19) | −0.25305 (2) | 1.046162 (14) | 0.0063 | |
U2 | 1.208537 (19) | −0.12659 (2) | 0.791265 (14) | 0.0053 | |
S1 | 0.97402 (14) | −0.05996 (15) | 0.8797 (1) | 0.0087 | |
S2 | 0.94243 (13) | −0.17531 (15) | 1.2753 (1) | 0.0062 | |
S3 | 0.86413 (14) | −0.54654 (15) | 1.1577 (1) | 0.0067 | |
O1 | 0.7487 (4) | −0.2166 (5) | 0.9979 (3) | 0.0139 | |
O2 | 1.0487 (4) | −0.2955 (5) | 1.0934 (3) | 0.0144 | |
O3 | 0.8856 (4) | −0.4190 (5) | 0.9403 (3) | 0.0153 | |
O4 | 0.9485 (6) | −0.1694 (5) | 0.9286 (3) | 0.0222 | |
O5 | 0.9365 (4) | −0.0267 (4) | 1.0639 (3) | 0.0109 | |
O6 | 0.8927 (4) | −0.2072 (5) | 1.1849 (3) | 0.0124 | |
O7 | 0.8197 (4) | −0.4523 (4) | 1.0870 (3) | 0.0103 | |
O8 | 1.2726 (4) | −0.0391 (4) | 0.8851 (3) | 0.0100 | |
O9 | 1.1486 (4) | −0.2178 (4) | 0.6983 (3) | 0.0097 | |
O10 | 1.0251 (4) | −0.1179 (5) | 0.8160 (3) | 0.0106 | |
O11 | 0.7982 (4) | −0.6714 (5) | 1.1297 (3) | 0.0104 | |
O12 | 0.8966 (4) | −0.2701 (4) | 1.3254 (3) | 0.0083 | |
O13 | 0.8387 (4) | −0.4984 (5) | 1.2343 (3) | 0.0099 | |
O14 | 0.9031 (4) | −0.0444 (5) | 1.2921 (3) | 0.0120 | |
O15 | 0.8668 (4) | 0.0109 (5) | 0.8371 (4) | 0.0193 | |
O16 | 1.0709 (4) | −0.1814 (5) | 1.3029 (3) | 0.0125 | |
O17 | 0.9912 (4) | −0.5679 (5) | 1.1768 (3) | 0.0121 | |
O18 | 1.2258 (5) | 0.2512 (6) | 1.2593 (4) | 0.0233 | |
O19 | 0.6861 (4) | −0.5560 (5) | 0.8608 (3) | 0.0137 | |
N1 | 0.5820 (5) | −0.6485 (5) | 0.9821 (4) | 0.0105 | |
N2 | 0.6353 (5) | −1.0486 (5) | 0.8344 (4) | 0.0107 | |
C1 | 0.4812 (5) | −0.5708 (6) | 0.9918 (4) | 0.0099 | |
C2 | 0.5497 (6) | −0.7894 (6) | 0.9652 (4) | 0.0094 | |
C3 | 0.6199 (6) | −0.8499 (7) | 0.9126 (5) | 0.0150 | |
C4 | 0.5886 (6) | −0.9918 (6) | 0.8998 (4) | 0.0109 | |
H1 | 0.8121 | −0.4689 | 0.9110 | 0.0177* | |
H2 | 0.9388 | −0.4167 | 0.9037 | 0.0177* | |
H3 | 0.7236 | −1.0394 | 0.8523 | 0.0146* | |
H4 | 0.6001 | −1.0021 | 0.7795 | 0.0146* | |
H5 | 0.6136 | −1.1424 | 0.8270 | 0.0146* | |
H6 | 0.6238 | −1.0389 | 0.9544 | 0.0147* | |
H7 | 0.5004 | −1.0015 | 0.8816 | 0.0147* | |
H8 | 0.7066 | −0.8405 | 0.9426 | 0.0211* | |
H9 | 0.6000 | −0.8057 | 0.8564 | 0.0211* | |
H10 | 0.5673 | −0.8366 | 1.0203 | 0.0127* | |
H11 | 0.4631 | −0.7964 | 0.9340 | 0.0127* | |
H12 | 0.6500 | −0.6417 | 1.0354 | 0.0146* | |
H13 | 0.6062 | −0.6129 | 0.9337 | 0.0146* | |
H14 | 0.4127 | −0.5771 | 0.9388 | 0.0130* | |
H15 | 0.4571 | −0.6051 | 1.0405 | 0.0130* | |
H16 | 1.2118 | 0.3229 | 1.2957 | 0.0295* | |
H17 | 1.2895 | 0.2774 | 1.2345 | 0.0295* | |
H18 | 0.6369 | −0.4908 | 0.8206 | 0.0151* | |
H19 | 0.6998 | −0.6331 | 0.8285 | 0.0151* |
U11 | U22 | U33 | U12 | U13 | U23 | |
U1 | 0.00751 (12) | 0.00534 (12) | 0.00694 (12) | −0.00040 (8) | 0.00337 (8) | 0.00045 (8) |
U2 | 0.00600 (11) | 0.00502 (11) | 0.00544 (11) | 0.00053 (8) | 0.00241 (8) | 0.00018 (8) |
S1 | 0.0117 (7) | 0.0060 (7) | 0.0111 (7) | −0.0021 (6) | 0.0076 (6) | −0.0013 (6) |
S2 | 0.0060 (6) | 0.0054 (7) | 0.0081 (7) | −0.0005 (5) | 0.0033 (5) | −0.0000 (5) |
S3 | 0.0086 (7) | 0.0049 (7) | 0.0083 (7) | −0.0016 (5) | 0.0052 (5) | 0.0002 (5) |
O1 | 0.016 (2) | 0.015 (2) | 0.012 (2) | −0.0003 (19) | 0.0065 (19) | −0.0007 (19) |
O2 | 0.014 (2) | 0.012 (2) | 0.020 (3) | −0.0034 (19) | 0.008 (2) | −0.003 (2) |
O3 | 0.016 (2) | 0.017 (3) | 0.017 (2) | −0.006 (2) | 0.012 (2) | −0.006 (2) |
O4 | 0.044 (3) | 0.013 (2) | 0.020 (3) | −0.007 (2) | 0.026 (3) | −0.004 (2) |
O5 | 0.019 (2) | 0.006 (2) | 0.012 (2) | −0.0053 (18) | 0.0122 (19) | −0.0038 (17) |
O6 | 0.019 (2) | 0.010 (2) | 0.010 (2) | −0.0019 (19) | 0.0071 (19) | −0.0033 (18) |
O7 | 0.014 (2) | 0.006 (2) | 0.011 (2) | −0.0009 (17) | 0.0035 (18) | 0.0029 (17) |
O8 | 0.012 (2) | 0.009 (2) | 0.011 (2) | 0.0027 (17) | 0.0060 (18) | −0.0005 (17) |
O9 | 0.013 (2) | 0.006 (2) | 0.011 (2) | 0.0003 (17) | 0.0040 (18) | 0.0001 (17) |
O10 | 0.009 (2) | 0.015 (2) | 0.008 (2) | 0.0005 (19) | 0.0031 (17) | −0.0027 (19) |
O11 | 0.014 (2) | 0.008 (2) | 0.009 (2) | −0.0020 (18) | 0.0028 (18) | 0.0012 (17) |
O12 | 0.009 (2) | 0.010 (2) | 0.0040 (19) | −0.0008 (17) | −0.0009 (16) | −0.0002 (17) |
O13 | 0.013 (2) | 0.008 (2) | 0.011 (2) | 0.0002 (19) | 0.0070 (17) | −0.0014 (18) |
O14 | 0.015 (2) | 0.013 (2) | 0.009 (2) | 0.0026 (19) | 0.0065 (18) | 0.0041 (18) |
O15 | 0.011 (2) | 0.015 (3) | 0.033 (3) | 0.006 (2) | 0.008 (2) | −0.000 (2) |
O16 | 0.009 (2) | 0.009 (2) | 0.019 (2) | −0.0008 (18) | 0.0040 (19) | 0.0005 (19) |
O17 | 0.009 (2) | 0.018 (2) | 0.011 (2) | −0.0006 (19) | 0.0044 (18) | −0.0033 (19) |
O18 | 0.021 (3) | 0.028 (3) | 0.021 (3) | −0.008 (2) | 0.008 (2) | 0.002 (2) |
O19 | 0.013 (2) | 0.008 (2) | 0.018 (2) | 0.0034 (19) | 0.0020 (19) | −0.0007 (19) |
N1 | 0.013 (3) | 0.006 (3) | 0.013 (3) | −0.001 (2) | 0.004 (2) | −0.001 (2) |
N2 | 0.010 (3) | 0.008 (2) | 0.015 (3) | −0.007 (2) | 0.003 (2) | −0.004 (2) |
C1 | 0.008 (3) | 0.010 (3) | 0.010 (3) | 0.001 (2) | 0.001 (2) | −0.004 (2) |
C2 | 0.012 (3) | 0.005 (3) | 0.011 (3) | 0.003 (2) | 0.003 (2) | −0.000 (2) |
C3 | 0.015 (3) | 0.015 (3) | 0.019 (3) | −0.005 (3) | 0.011 (3) | −0.002 (3) |
C4 | 0.009 (3) | 0.005 (3) | 0.018 (3) | −0.000 (2) | 0.003 (2) | 0.001 (3) |
U1—O1 | 1.764 (5) | N1—C1 | 1.487 (8) |
U1—O2 | 1.751 (5) | N1—C2 | 1.508 (8) |
U1—O3 | 2.421 (5) | N2—C4 | 1.482 (9) |
U1—O4 | 2.359 (5) | C1—C1iv | 1.528 (13) |
U1—O5 | 2.377 (4) | C2—C3 | 1.513 (9) |
U1—O6 | 2.377 (5) | C3—C4 | 1.509 (9) |
U1—O7 | 2.446 (5) | H1—O3 | 1.000 |
U2—O8 | 1.759 (5) | H2—O3 | 1.000 |
U2—O9 | 1.761 (5) | H3—N2 | 1.000 |
U2—O10 | 2.332 (4) | H4—N2 | 1.000 |
U2—O11i | 2.477 (5) | H5—N2 | 1.000 |
U2—O12ii | 2.376 (4) | H6—C4 | 1.000 |
U2—O13ii | 2.413 (5) | H7—C4 | 1.000 |
U2—O14iii | 2.379 (5) | H8—C3 | 1.000 |
S1—O4 | 1.475 (5) | H9—C3 | 1.000 |
S1—O5iii | 1.481 (5) | H10—C2 | 1.000 |
S1—O10 | 1.492 (5) | H11—C2 | 1.000 |
S1—O15 | 1.448 (5) | H12—N1 | 1.000 |
S2—O6 | 1.472 (5) | H13—N1 | 1.000 |
S2—O12 | 1.489 (5) | H14—C1 | 1.000 |
S2—O14 | 1.482 (5) | H15—C1 | 1.000 |
S2—O16 | 1.450 (5) | H16—O18 | 1.000 |
S3—O7 | 1.490 (5) | H17—O18 | 1.000 |
S3—O11 | 1.504 (5) | H18—O19 | 1.000 |
S3—O13 | 1.478 (5) | H19—O19 | 1.000 |
S3—O17 | 1.456 (5) | ||
O1—U1—O2 | 177.8 (2) | O12ii—U2—O13ii | 70.65 (16) |
O1—U1—O3 | 89.1 (2) | O12ii—U2—O14iii | 141.77 (16) |
O1—U1—O4 | 90.9 (2) | O13ii—U2—O14iii | 71.59 (16) |
O1—U1—O5 | 88.2 (2) | O4—S1—O5iii | 110.0 (3) |
O1—U1—O6 | 93.8 (2) | O4—S1—O10 | 106.2 (3) |
O1—U1—O7 | 83.0 (2) | O4—S1—O15 | 111.0 (3) |
O2—U1—O3 | 89.2 (2) | O5iii—S1—O10 | 108.8 (3) |
O2—U1—O4 | 89.8 (2) | O5iii—S1—O15 | 110.8 (3) |
O2—U1—O5 | 94.0 (2) | O10—S1—O15 | 110.0 (3) |
O2—U1—O6 | 86.8 (2) | O6—S2—O12 | 108.7 (3) |
O2—U1—O7 | 95.1 (2) | O6—S2—O14 | 110.1 (3) |
O3—U1—O4 | 68.89 (18) | O6—S2—O16 | 111.5 (3) |
O3—U1—O5 | 138.98 (16) | O12—S2—O14 | 107.8 (3) |
O3—U1—O6 | 145.88 (17) | O12—S2—O16 | 108.7 (3) |
O3—U1—O7 | 70.09 (16) | O14—S2—O16 | 109.8 (3) |
O4—U1—O5 | 70.25 (17) | O7—S3—O11 | 106.9 (3) |
O4—U1—O6 | 144.87 (18) | O7—S3—O13 | 110.0 (3) |
O4—U1—O7 | 138.60 (17) | O7—S3—O17 | 111.2 (3) |
O5—U1—O6 | 75.13 (16) | O11—S3—O13 | 109.4 (3) |
O5—U1—O7 | 149.63 (15) | O11—S3—O17 | 110.0 (3) |
O6—U1—O7 | 76.52 (16) | O13—S3—O17 | 109.4 (3) |
O8—U2—O9 | 178.1 (2) | U1—O4—S1 | 151.4 (3) |
O8—U2—O10 | 89.85 (18) | U1—O5—S1iii | 137.7 (3) |
O8—U2—O11i | 92.19 (18) | U1—O6—S2 | 155.5 (3) |
O8—U2—O12ii | 84.25 (18) | U1—O7—S3 | 133.9 (3) |
O8—U2—O13ii | 85.29 (19) | U2—O10—S1 | 137.8 (3) |
O8—U2—O14iii | 98.43 (19) | U2i—O11—S3 | 130.9 (3) |
O9—U2—O10 | 91.54 (19) | U2v—O12—S2 | 129.5 (2) |
O9—U2—O11i | 86.82 (18) | U2v—O13—S3 | 147.0 (3) |
O9—U2—O12ii | 93.85 (18) | U2iii—O14—S2 | 135.9 (3) |
O9—U2—O13ii | 94.44 (19) | C1—N1—C2 | 111.9 (5) |
O9—U2—O14iii | 83.30 (19) | N1—C1—C1iv | 109.6 (6) |
O10—U2—O11i | 75.94 (16) | N1—C2—C3 | 110.6 (5) |
O10—U2—O12ii | 146.19 (16) | C2—C3—C4 | 109.1 (6) |
O10—U2—O13ii | 142.10 (17) | N2—C4—C3 | 110.8 (5) |
O10—U2—O14iii | 72.02 (16) | H1—O3—H2 | 109.467 |
O11i—U2—O12ii | 71.08 (16) | H16—O18—H17 | 109.467 |
O11i—U2—O13ii | 141.71 (16) | H18—O19—H19 | 109.467 |
O11i—U2—O14iii | 146.10 (16) |
Symmetry codes: (i) −x+2, −y−1, −z+2; (ii) x+1/2, −y−1/2, z−1/2; (iii) −x+2, −y, −z+2; (iv) −x+1, −y−1, −z+2; (v) x−1/2, −y−1/2, z+1/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H1···O19 | 1.00 | 1.72 | 2.722 (7) | 180 |
O3—H2···O17i | 1.00 | 1.78 | 2.766 (7) | 168 |
O18—H17···O16vi | 1.00 | 1.98 | 2.977 (7) | 173 |
O19—H18···O16vii | 1.00 | 1.93 | 2.826 (7) | 148 |
O19—H19···O18vii | 1.00 | 1.77 | 2.757 (7) | 171 |
N1—H12···O11 | 1.00 | 1.99 | 2.963 (7) | 165 |
N1—H13···O19 | 1.00 | 1.85 | 2.827 (8) | 167 |
N2—H3···O15viii | 1.00 | 1.86 | 2.795 (7) | 154 |
N2—H4···O17ix | 1.00 | 1.94 | 2.910 (8) | 164 |
N2—H5···O16ix | 1.00 | 1.90 | 2.894 (7) | 175 |
Symmetry codes: (i) −x+2, −y−1, −z+2; (vi) −x+5/2, y+1/2, −z+5/2; (vii) x−1/2, −y−1/2, z−1/2; (viii) x, y−1, z; (ix) x−1/2, −y−3/2, z−1/2. |
Acknowledgements
The authors thank the EPSRC for support.
References
Altomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435. CrossRef Web of Science IUCr Journals Google Scholar
Bataille, T. & Louer, D. (2002). J. Mater. Chem. 12, 3487–3493. Web of Science CSD CrossRef CAS Google Scholar
Bull, I., Wheatley, P. S., Lightfoot, P., Morris, R. E., Sastre, E. & Wright, P. A. (2002). Chem. Commun. pp. 1180–1181. Web of Science CSD CrossRef Google Scholar
Burns, P. C., Ewing, R. C. & Hawthorne, F. C. (1997). Can. Mineral. 35, 1551–1570. CAS Google Scholar
Cheetham, A. K., Ferey, G. & Loiseau, T. (1999). Angew. Chem. Int. Ed. 38, 3269–3292. Web of Science CrossRef Google Scholar
Choudhury, A., Krishnamoorthy, J. & Rao, C. N. R. (2001). Chem. Commun. pp. 2610–2611. Web of Science CSD CrossRef Google Scholar
Doran, M. B., Norquist, A. J. & O'Hare, D. (2002). Chem. Commun. pp. 2946–2947. Web of Science CSD CrossRef Google Scholar
Doran, M. B., Norquist, A. J. & O'Hare, D. (2003a). Inorg. Chem. 42, 6989–6995. Web of Science CSD CrossRef PubMed CAS Google Scholar
Doran, M. B., Norquist, A. J. & O'Hare, D. (2003b). Acta Cryst. E59, m373–m375. Web of Science CSD CrossRef IUCr Journals Google Scholar
Doran, M. B., Norquist, A. J. & O'Hare, D. (2003c). Acta Cryst. E59, m762–m764. Web of Science CSD CrossRef IUCr Journals Google Scholar
Doran, M. B., Norquist, A. J. & O'Hare, D. (2003d). Acta Cryst. E59, m765–m767. Web of Science CSD CrossRef IUCr Journals Google Scholar
Dowty, E. (2000). ATOMS. Version 6.0. Shape Software, 521 Hidden Valley Road, Kingsport, TN 37663, USA. Google Scholar
Khan, M. I., Cevik, S. & Doedens, R. J. (1999). Inorg. Chim. Acta, 292, 112–116. Web of Science CrossRef CAS Google Scholar
Larson, A. C. (1970). Crystallographic Computing, edited by F. R. Ahmed, S. R. Hall & C. P. Huber, pp. 291–294. Copenhagen: Munksgaard. Google Scholar
Morimoto, C. N. & Lingafelter, E. C. (1970). Acta Cryst. B26, 335–341. CSD CrossRef IUCr Journals Web of Science Google Scholar
Nonius (1997). COLLECT. Nonius BV, Delft, The Netherlands. Google Scholar
Norquist, A. J., Doran, M. B. & O'Hare, D. (2003). Solid State Sci. 5, 1149–1158. Web of Science CSD CrossRef CAS Google Scholar
Norquist, A. J., Doran, M. B., Thomas, P. M. & O'Hare, D. (2003a). J. Chem. Soc. Dalton Trans. pp. 1168–1175. CrossRef Google Scholar
Norquist, A. J., Doran, M. B., Thomas, P. M. & O'Hare, D. (2003b). Inorg. Chem. 42, 5949–5953. Web of Science CSD CrossRef PubMed CAS Google Scholar
Norquist, A. J., Thomas, P. M., Doran, M. B. & O'Hare, D. (2002). Chem. Mater. 14, 5179–5184. Web of Science CSD CrossRef CAS Google Scholar
Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press. Google Scholar
Paul, G., Choudhury, A., Nagarajan, R. & Rao, C. N. R. (2003). Inorg. Chem. 42, 2004–2013. Web of Science CSD CrossRef PubMed CAS Google Scholar
Paul, G., Choudhury, A. & Rao, C. N. R. (2002a). Chem. Commun. pp. 1904–1905. Web of Science CSD CrossRef Google Scholar
Paul, G., Choudhury, A. & Rao, C. N. R. (2002b). J. Chem. Soc. Dalton Trans. 3859–3867. Google Scholar
Paul, G., Choudhury, A. & Rao, C. N. R. (2003). Chem. Mater. 15, 1174–1180. Web of Science CSD CrossRef CAS Google Scholar
Paul, G., Choudhury, A., Sampathkumaran, E. V. & Rao, C. N. R. (2002). Angew. Chem. Int. Ed. 41, 4297–4300. Web of Science CrossRef CAS Google Scholar
Stuart, C. L., Doran, M. B., Norquist, A. J. & O'Hare, D. (2003). Acta Cryst. E59, m446–m448. Web of Science CSD CrossRef IUCr Journals Google Scholar
Thomas, P. M., Norquist, A. J., Doran, M. B. & O'Hare, D. (2003). J. Mater. Chem. 13, 88–92. Web of Science CSD CrossRef CAS Google Scholar
Wang, D., Yu, R., Xu, Y., Feng, S., Xu, R., Kumada, N., Kinomura, N., Matumura, Y. & Takano, M. (2002). Chem. Lett. pp. 1120–1121. Web of Science CSD CrossRef Google Scholar
Watkin, D. J., Prout, C. K., Carruthers, J. R., Betteridge, P. W. & Cooper R. I. (2003). CRYSTALS. Issue 11. Chemical Crystallography Laboratory, Oxford, England. Google Scholar
Xing, Y., Liu, Y., Shi, Z., Meng, H. & Pang, W. (2003). J. Solid State Chem. 174, 381–385. Web of Science CSD CrossRef CAS Google Scholar
Xing, Y., Shi, Z., Li, G., Pang, W. (2003). Dalton Trans. pp. 940–943. Web of Science CSD CrossRef Google Scholar
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