Poly[triaqua-μ4-fumarato-cobalt(II)], [Co(C4H2O4)(H2O)3]n, (I), contains two symmetry-independent octahedrally coordinated Co2+ ions, both on inversion centers. One Co2+ ion is coordinated by two water molecules and four fumarate dianions, whereas the other Co2+ ion is surrounded by four water molecules and two fumarate dianions. Each fumarate dianion is bonded to three Co2+ ions, leading to a two-dimensional structure. The fumarate dianions are nonplanar; the angle between the planes of the two carboxylate groups is 54.9 (2)°. The cobalt(II) fumarate layers are connected by hydrogen bonding into a three-dimensional network. Compound (I) is not isostructural with calcium(II) fumarate trihydrate [Gupta et al. (1972). Acta Cryst. B28, 135–139]. In poly[μ4-fumarato-dimethanolcobalt(II)], [Co(C4H2O4)(CH4O)2]n, (II), the Co2+ ions are octahedrally coordinated by four fumarate dianions and two methanol molecules, leading to a three-dimensional structure. The fumarate group is planar. The Co2+ ions and the fumarate dianions both lie on inversion centers. Additionally, the one-dimensional structure of catena-poly[[[tetraaquacobalt(II)]-μ2-fumarato] monohydrate], {[Co(C4H2O4)(H2O)4]·H2O}n, (III), was redetermined at a higher resolution, and the space group C2/c was confirmed.
Supporting information
CCDC references: 749689; 749690; 749691
A methanol solution (50 ml) containing fumaric acid (0.93 g, 8 mmol) was heated
at 333 K for 1 h with stirring and then left to cool to room temperature.
After the addition of a methanol solution (50 ml) containing
Co(CH3COO)2.4H2O (1 g, 4 mmol), a magenta-coloured powder precipitated.
The precipitate was filtered off, washed with methanol and dried for 3 h at
323 K. The powder pattern of the precipitate and the calculated powder pattern
from the single-crystal structure of cobalt(II) fumarate methanol disolvate
were compared and proved to be congruent. Red crystals of the compounds
reported here were prepared by vapour diffusion, using water as solvent in all
three cases and acetone for (I), methanol for (II) and ethanol for (III) as
antisolvent. Crystals of (I) formed after four days, crystals of compound (II)
and (III) after one week.
The H atoms of the methyl group of (II) were constrained [C—H = 0.98 Å and
Uiso(H) = 1.5Ueq(C)]. All other H atoms in (I), (II) and
(III) were located in difference Fourier syntheses and were freely refined
[C—H = 0.93 (3) and 1.00 (3), 0.91 (2), and 0.928 (14) Å, respectively].
The crystal of (I) was twinned. The twin relations were htwin =
h, ktwin = -0.115h - k and ltwin =
-0.870h - l. The twin fraction refined to 0.241 (4).
For all compounds, data collection: SMART (Siemens, 1995); cell refinement: SMART (Siemens, 1995); data reduction: SAINT (Siemens, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).
(I) Poly[triaqua-µ
4-fumarato-cobalt(II)]
top
Crystal data top
[Co(C4H2O4)(H2O)3] | Z = 2 |
Mr = 227.03 | F(000) = 230 |
Triclinic, P1 | Dx = 1.985 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 6.8793 (17) Å | Cell parameters from 58 reflections |
b = 7.644 (2) Å | θ = 3–23° |
c = 8.026 (3) Å | µ = 2.26 mm−1 |
α = 101.51 (2)° | T = 167 K |
β = 112.03 (2)° | Rod, red |
γ = 92.82 (3)° | 0.52 × 0.20 × 0.14 mm |
V = 379.8 (2) Å3 | |
Data collection top
Siemens SMART 1K CCD diffractometer | 2411 independent reflections |
Radiation source: normal-focus sealed tube | 1660 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.044 |
ω scans | θmax = 31.5°, θmin = 2.8° |
Absorption correction: multi-scan (SADABS; Sheldrick, 2000) | h = −9→10 |
Tmin = 0.575, Tmax = 0.729 | k = −11→11 |
6668 measured reflections | l = −11→11 |
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: difference Fourier map |
wR(F2) = 0.091 | All H-atom parameters refined |
S = 1.00 | w = 1/[σ^2^(Fo^2^) + (0.04P)^2^] where P = (Fo^2^ + 2Fc^2^)/3 |
2411 reflections | (Δ/σ)max = 0.003 |
145 parameters | Δρmax = 1.07 e Å−3 |
0 restraints | Δρmin = −0.94 e Å−3 |
Crystal data top
[Co(C4H2O4)(H2O)3] | γ = 92.82 (3)° |
Mr = 227.03 | V = 379.8 (2) Å3 |
Triclinic, P1 | Z = 2 |
a = 6.8793 (17) Å | Mo Kα radiation |
b = 7.644 (2) Å | µ = 2.26 mm−1 |
c = 8.026 (3) Å | T = 167 K |
α = 101.51 (2)° | 0.52 × 0.20 × 0.14 mm |
β = 112.03 (2)° | |
Data collection top
Siemens SMART 1K CCD diffractometer | 2411 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2000) | 1660 reflections with I > 2σ(I) |
Tmin = 0.575, Tmax = 0.729 | Rint = 0.044 |
6668 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.038 | 0 restraints |
wR(F2) = 0.091 | All H-atom parameters refined |
S = 1.00 | Δρmax = 1.07 e Å−3 |
2411 reflections | Δρmin = −0.94 e Å−3 |
145 parameters | |
Special details top
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 F^2^ against ALL reflections. The weighted
R-factor wR and goodness of fit S are based on
F^2^, conventional R-factors R are based on F,
with F set to zero for negative F^2^. The threshold expression
of F^2^ > σ(F^2^) is used only for calculating
R-factors(gt) etc. and is not relevant to the choice of
reflections for refinement. R-factors based on F^2^ 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 | |
Co1 | 0.0000 | 0.5000 | 0.5000 | 0.00918 (13) | |
Co2 | 0.5000 | 1.0000 | 0.5000 | 0.01026 (14) | |
O1 | 0.2944 (3) | 0.6128 (3) | 0.5305 (2) | 0.0136 (4) | |
O2 | 0.5960 (3) | 0.7970 (3) | 0.6380 (2) | 0.0124 (4) | |
O3 | 0.7892 (3) | 0.3575 (3) | 1.0426 (2) | 0.0159 (4) | |
O4 | 0.8770 (3) | 0.6109 (3) | 1.2664 (2) | 0.0127 (4) | |
O5 | −0.0018 (3) | 0.2402 (3) | 0.3366 (3) | 0.0143 (4) | |
O6 | 0.2449 (3) | 0.8438 (3) | 0.2860 (3) | 0.0165 (4) | |
O7 | 0.2892 (4) | 1.0519 (3) | 0.6454 (3) | 0.0202 (5) | |
C1 | 0.4824 (4) | 0.6640 (4) | 0.6432 (3) | 0.0100 (5) | |
C2 | 0.5795 (4) | 0.5610 (4) | 0.7870 (4) | 0.0117 (5) | |
C3 | 0.7224 (4) | 0.6340 (4) | 0.9549 (4) | 0.0133 (5) | |
C4 | 0.8021 (4) | 0.5255 (4) | 1.0966 (3) | 0.0118 (5) | |
H2A | 0.524 (5) | 0.430 (5) | 0.736 (4) | 0.019 (8)* | |
H3A | 0.766 (4) | 0.758 (4) | 0.991 (4) | 0.017 (8)* | |
H5A | 0.109 (8) | 0.228 (6) | 0.330 (6) | 0.059 (15)* | |
H5B | −0.063 (6) | 0.259 (5) | 0.242 (5) | 0.029 (10)* | |
H6A | 0.242 (6) | 0.780 (6) | 0.182 (6) | 0.053 (13)* | |
H6B | 0.195 (7) | 0.767 (6) | 0.316 (6) | 0.059 (15)* | |
H7A | 0.253 (5) | 1.142 (6) | 0.669 (5) | 0.028 (11)* | |
H7B | 0.209 (6) | 0.977 (6) | 0.652 (5) | 0.045 (13)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Co1 | 0.0093 (3) | 0.0093 (3) | 0.0084 (2) | 0.0004 (2) | 0.00223 (19) | 0.0033 (2) |
Co2 | 0.0116 (3) | 0.0084 (3) | 0.0096 (2) | 0.0014 (2) | 0.00254 (19) | 0.0028 (2) |
O1 | 0.0072 (9) | 0.0178 (10) | 0.0151 (9) | −0.0005 (8) | 0.0029 (7) | 0.0056 (8) |
O2 | 0.0118 (9) | 0.0103 (10) | 0.0143 (9) | 0.0003 (7) | 0.0032 (7) | 0.0051 (8) |
O3 | 0.0213 (10) | 0.0124 (10) | 0.0115 (9) | 0.0036 (8) | 0.0036 (8) | 0.0031 (8) |
O4 | 0.0143 (9) | 0.0117 (10) | 0.0096 (9) | 0.0013 (8) | 0.0024 (7) | 0.0021 (8) |
O5 | 0.0143 (10) | 0.0166 (11) | 0.0128 (10) | 0.0048 (8) | 0.0046 (8) | 0.0058 (8) |
O6 | 0.0196 (10) | 0.0155 (11) | 0.0134 (10) | −0.0033 (8) | 0.0064 (8) | 0.0024 (9) |
O7 | 0.0244 (12) | 0.0162 (12) | 0.0269 (12) | 0.0067 (10) | 0.0162 (10) | 0.0071 (10) |
C1 | 0.0120 (12) | 0.0102 (13) | 0.0079 (11) | 0.0030 (10) | 0.0047 (10) | 0.0003 (10) |
C2 | 0.0118 (12) | 0.0105 (13) | 0.0145 (12) | 0.0031 (10) | 0.0062 (10) | 0.0043 (11) |
C3 | 0.0159 (13) | 0.0108 (13) | 0.0141 (13) | 0.0024 (11) | 0.0063 (11) | 0.0040 (11) |
C4 | 0.0076 (11) | 0.0155 (14) | 0.0124 (12) | 0.0007 (10) | 0.0038 (9) | 0.0036 (11) |
Geometric parameters (Å, º) top
Co1—O1 | 2.0686 (18) | O5—H5B | 0.76 (4) |
Co1—O4i | 2.1133 (18) | O6—H6A | 0.87 (5) |
Co1—O5 | 2.147 (2) | O6—H6B | 0.79 (5) |
Co2—O6 | 2.042 (2) | O7—H7A | 0.76 (4) |
Co2—O2 | 2.0755 (18) | O7—H7B | 0.80 (4) |
Co2—O7 | 2.183 (2) | C1—C2 | 1.495 (4) |
O1—C1 | 1.255 (3) | C2—C3 | 1.321 (4) |
O2—C1 | 1.269 (3) | C2—H2A | 1.00 (3) |
O3—C4 | 1.258 (3) | C3—C4 | 1.495 (4) |
O4—C4 | 1.278 (3) | C3—H3A | 0.93 (3) |
O5—H5A | 0.79 (5) | | |
| | | |
O1—Co1—O4i | 93.85 (7) | Co2—O7—H7A | 125 (3) |
O1—Co1—O5 | 96.99 (8) | Co2—O7—H7B | 125 (3) |
O4i—Co1—O5 | 86.93 (8) | H7A—O7—H7B | 107 (4) |
O6—Co2—O2 | 95.65 (8) | O1—C1—O2 | 122.9 (2) |
O6—Co2—O7 | 86.61 (9) | O1—C1—C2 | 118.8 (2) |
O2—Co2—O7 | 87.69 (8) | O2—C1—C2 | 118.3 (2) |
C1—O1—Co1 | 144.11 (17) | C3—C2—C1 | 124.3 (3) |
C1—O2—Co2 | 128.33 (16) | C3—C2—H2A | 125.5 (17) |
C4—O4—Co1ii | 126.91 (17) | C1—C2—H2A | 110.2 (17) |
Co1—O5—H5A | 112 (3) | C2—C3—C4 | 121.5 (3) |
Co1—O5—H5B | 97 (3) | C2—C3—H3A | 119.9 (17) |
H5A—O5—H5B | 100 (4) | C4—C3—H3A | 118.3 (18) |
Co2—O6—H6A | 127 (3) | O3—C4—O4 | 124.3 (2) |
Co2—O6—H6B | 112 (3) | O3—C4—C3 | 118.6 (2) |
H6A—O6—H6B | 98 (4) | O4—C4—C3 | 117.1 (2) |
| | | |
O4iii—Co1—O1—C1 | 159.3 (3) | Co2—O2—C1—O1 | 16.3 (4) |
O4i—Co1—O1—C1 | −20.7 (3) | Co2—O2—C1—C2 | −165.40 (16) |
O5—Co1—O1—C1 | −108.0 (3) | O1—C1—C2—C3 | −147.4 (3) |
O5iv—Co1—O1—C1 | 72.0 (3) | O2—C1—C2—C3 | 34.3 (4) |
O6—Co2—O2—C1 | −31.5 (2) | C1—C2—C3—C4 | 175.6 (2) |
O6v—Co2—O2—C1 | 148.5 (2) | Co1ii—O4—C4—O3 | 0.5 (4) |
O7—Co2—O2—C1 | 54.9 (2) | Co1ii—O4—C4—C3 | 179.58 (15) |
O7v—Co2—O2—C1 | −125.1 (2) | C2—C3—C4—O3 | 23.3 (4) |
Co1—O1—C1—O2 | −146.5 (2) | C2—C3—C4—O4 | −155.8 (3) |
Co1—O1—C1—C2 | 35.2 (4) | | |
Symmetry codes: (i) −x+1, −y+1, −z+2; (ii) x+1, y, z+1; (iii) x−1, y, z−1; (iv) −x, −y+1, −z+1; (v) −x+1, −y+2, −z+1. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O5—H5A···O2vi | 0.79 (6) | 1.97 (6) | 2.755 (3) | 170 (4) |
O5—H5B···O3iii | 0.76 (4) | 1.87 (4) | 2.620 (3) | 167 (4) |
O6—H6A···O3vi | 0.87 (4) | 1.83 (4) | 2.694 (3) | 175 (4) |
O6—H6B···O1 | 0.79 (5) | 2.20 (5) | 2.833 (3) | 138 (4) |
O6—H6B···O4iii | 0.79 (5) | 2.30 (5) | 2.957 (3) | 142 (4) |
O7—H7A···O4vii | 0.76 (4) | 2.18 (4) | 2.936 (4) | 175 (4) |
O7—H7B···O5iv | 0.80 (5) | 2.17 (5) | 2.971 (4) | 176 (4) |
Symmetry codes: (iii) x−1, y, z−1; (iv) −x, −y+1, −z+1; (vi) −x+1, −y+1, −z+1; (vii) −x+1, −y+2, −z+2. |
(II) poly[µ
4-fumarato-dimethanolcobalt(II)]
top
Crystal data top
[Co(C4H2O4)(CH4O)2] | F(000) = 484 |
Mr = 237.07 | Dx = 1.947 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 80 reflections |
a = 15.547 (4) Å | θ = 3–23° |
b = 7.020 (2) Å | µ = 2.12 mm−1 |
c = 8.2270 (13) Å | T = 165 K |
β = 115.73 (2)° | Prism, red |
V = 808.9 (4) Å3 | 0.40 × 0.26 × 0.24 mm |
Z = 4 | |
Data collection top
Siemens SMART 1K CCD diffractometer | 1611 independent reflections |
Radiation source: normal-focus sealed tube | 1402 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.025 |
ω scans | θmax = 34.2°, θmin = 2.9° |
Absorption correction: multi-scan (SADABS; Sheldrick, 2000) | h = −23→23 |
Tmin = 0.530, Tmax = 0.602 | k = −10→11 |
7132 measured reflections | l = −12→12 |
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)] = 0.023 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.061 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.01 | w = 1/[σ^2^(Fo^2^) + (0.03P)^2^ + 1.1P] where P = (Fo^2^ + 2Fc^2^)/3 |
1611 reflections | (Δ/σ)max < 0.001 |
70 parameters | Δρmax = 0.48 e Å−3 |
0 restraints | Δρmin = −0.64 e Å−3 |
Crystal data top
[Co(C4H2O4)(CH4O)2] | V = 808.9 (4) Å3 |
Mr = 237.07 | Z = 4 |
Monoclinic, C2/c | Mo Kα radiation |
a = 15.547 (4) Å | µ = 2.12 mm−1 |
b = 7.020 (2) Å | T = 165 K |
c = 8.2270 (13) Å | 0.40 × 0.26 × 0.24 mm |
β = 115.73 (2)° | |
Data collection top
Siemens SMART 1K CCD diffractometer | 1611 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2000) | 1402 reflections with I > 2σ(I) |
Tmin = 0.530, Tmax = 0.602 | Rint = 0.025 |
7132 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.023 | 0 restraints |
wR(F2) = 0.061 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.01 | Δρmax = 0.48 e Å−3 |
1611 reflections | Δρmin = −0.64 e Å−3 |
70 parameters | |
Special details top
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 F^2^ against ALL reflections. The weighted
R-factor wR and goodness of fit S are based on
F^2^, conventional R-factors R are based on F,
with F set to zero for negative F^2^. The threshold expression
of F^2^ > σ(F^2^) is used only for calculating
R-factors(gt) etc. and is not relevant to the choice of
reflections for refinement. R-factors based on F^2^ 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 | |
Co1 | 0.2500 | 0.2500 | 0.5000 | 0.00897 (6) | |
O1 | 0.36063 (6) | 0.15407 (13) | 0.74360 (11) | 0.01288 (16) | |
O2 | 0.29011 (6) | −0.06569 (13) | 0.84046 (12) | 0.01423 (17) | |
O3 | 0.16082 (6) | 0.04138 (14) | 0.51795 (12) | 0.01573 (17) | |
C1 | 0.36385 (7) | 0.02119 (16) | 0.84867 (14) | 0.01062 (18) | |
C2 | 0.45934 (8) | −0.04100 (17) | 0.99018 (15) | 0.01236 (19) | |
C3 | 0.11717 (17) | −0.1002 (3) | 0.3861 (2) | 0.0453 (5) | |
H3B | 0.0890 | −0.0414 | 0.2662 | 0.068* | |
H3C | 0.0671 | −0.1635 | 0.4082 | 0.068* | |
H3D | 0.1651 | −0.1942 | 0.3923 | 0.068* | |
H2A | 0.4577 (13) | −0.141 (3) | 1.059 (3) | 0.021 (4)* | |
H3A | 0.1913 (15) | −0.014 (3) | 0.617 (3) | 0.037 (6)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Co1 | 0.00782 (9) | 0.00962 (10) | 0.00845 (10) | 0.00060 (7) | 0.00259 (7) | 0.00051 (7) |
O1 | 0.0098 (3) | 0.0146 (4) | 0.0123 (3) | 0.0009 (3) | 0.0030 (3) | 0.0048 (3) |
O2 | 0.0095 (3) | 0.0177 (4) | 0.0137 (4) | −0.0027 (3) | 0.0034 (3) | 0.0040 (3) |
O3 | 0.0154 (4) | 0.0167 (4) | 0.0128 (4) | −0.0018 (3) | 0.0040 (3) | 0.0029 (3) |
C1 | 0.0093 (4) | 0.0118 (5) | 0.0101 (4) | 0.0008 (3) | 0.0035 (3) | 0.0005 (4) |
C2 | 0.0095 (4) | 0.0136 (5) | 0.0125 (4) | 0.0016 (4) | 0.0035 (3) | 0.0042 (4) |
C3 | 0.0638 (13) | 0.0432 (10) | 0.0247 (8) | −0.0354 (10) | 0.0153 (8) | −0.0086 (7) |
Geometric parameters (Å, º) top
Co1—O3 | 2.0656 (10) | O3—C3 | 1.409 (2) |
Co1—O3i | 2.0657 (10) | O3—H3A | 0.84 (2) |
Co1—O1i | 2.1060 (10) | C1—C2 | 1.4998 (16) |
Co1—O1 | 2.1060 (10) | C2—C2v | 1.334 (2) |
Co1—O2ii | 2.1204 (9) | C2—H2A | 0.91 (2) |
Co1—O2iii | 2.1205 (9) | C3—H3B | 0.9800 |
O1—C1 | 1.2579 (14) | C3—H3C | 0.9800 |
O2—C1 | 1.2742 (13) | C3—H3D | 0.9800 |
O2—Co1iv | 2.1204 (9) | | |
| | | |
O3—Co1—O3i | 180.00 (5) | C1—O2—Co1iv | 139.36 (8) |
O3—Co1—O1i | 89.91 (4) | C3—O3—Co1 | 123.99 (10) |
O3i—Co1—O1i | 90.09 (4) | C3—O3—H3A | 107.4 (16) |
O3—Co1—O1 | 90.09 (4) | Co1—O3—H3A | 106.6 (15) |
O3i—Co1—O1 | 89.91 (4) | O1—C1—O2 | 123.51 (10) |
O1i—Co1—O1 | 180.00 (5) | O1—C1—C2 | 118.68 (10) |
O3—Co1—O2ii | 90.08 (4) | O2—C1—C2 | 117.80 (10) |
O3i—Co1—O2ii | 89.92 (4) | C2v—C2—C1 | 122.37 (13) |
O1i—Co1—O2ii | 93.20 (4) | C2v—C2—H2A | 122.7 (11) |
O1—Co1—O2ii | 86.80 (4) | C1—C2—H2A | 114.9 (11) |
O3—Co1—O2iii | 89.92 (4) | O3—C3—H3B | 109.5 |
O3i—Co1—O2iii | 90.08 (4) | O3—C3—H3C | 109.5 |
O1i—Co1—O2iii | 86.80 (4) | H3B—C3—H3C | 109.5 |
O1—Co1—O2iii | 93.20 (4) | O3—C3—H3D | 109.5 |
O2ii—Co1—O2iii | 180.0 | H3B—C3—H3D | 109.5 |
C1—O1—Co1 | 131.57 (7) | H3C—C3—H3D | 109.5 |
| | | |
O3—Co1—O1—C1 | −0.17 (11) | O2iii—Co1—O3—C3 | −27.84 (15) |
O3i—Co1—O1—C1 | 179.83 (11) | Co1—O1—C1—O2 | −12.96 (18) |
O2ii—Co1—O1—C1 | 89.91 (11) | Co1—O1—C1—C2 | 166.26 (8) |
O2iii—Co1—O1—C1 | −90.09 (11) | Co1iv—O2—C1—O1 | −164.89 (9) |
O1i—Co1—O3—C3 | 58.97 (15) | Co1iv—O2—C1—C2 | 15.89 (18) |
O1—Co1—O3—C3 | −121.03 (15) | O1—C1—C2—C2v | 0.8 (2) |
O2ii—Co1—O3—C3 | 152.16 (15) | O2—C1—C2—C2v | −179.93 (15) |
Symmetry codes: (i) −x+1/2, −y+1/2, −z+1; (ii) −x+1/2, y+1/2, −z+3/2; (iii) x, −y, z−1/2; (iv) −x+1/2, y−1/2, −z+3/2; (v) −x+1, −y, −z+2. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3A···O2 | 0.84 (2) | 1.85 (2) | 2.6485 (15) | 159 (2) |
C2—H2A···O1vi | 0.91 (2) | 2.57 (2) | 3.1796 (18) | 125.4 (17) |
Symmetry code: (vi) x, −y, z+1/2. |
(III)
catena-poly[[[tetraaquacobalt(II)]-µ
2-fumarato] monohydrate]
top
Crystal data top
[Co(C4H2O4)(H2O)4]·H2O | F(000) = 540 |
Mr = 263.07 | Dx = 1.906 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 121 reflections |
a = 5.2561 (11) Å | θ = 3–23° |
b = 13.145 (2) Å | µ = 1.90 mm−1 |
c = 13.321 (3) Å | T = 166 K |
β = 95.188 (16)° | Block, red |
V = 916.6 (3) Å3 | 0.60 × 0.55 × 0.50 mm |
Z = 4 | |
Data collection top
Siemens SMART 1K CCD diffractometer | 1815 independent reflections |
Radiation source: normal-focus sealed tube | 1771 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.025 |
ω scans | θmax = 34.2°, θmin = 3.1° |
Absorption correction: multi-scan (SADABS; Sheldrick, 2000) | h = −8→8 |
Tmin = 0.301, Tmax = 0.386 | k = −20→19 |
8327 measured reflections | l = −20→20 |
Refinement top
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.018 | All H-atom parameters refined |
wR(F2) = 0.049 | w = 1/[σ^2^(Fo^2^) + (0.02P)^2^ + 0.6P] where P = (Fo^2^ + 2Fc^2^)/3 |
S = 1.04 | (Δ/σ)max = 0.002 |
1815 reflections | Δρmax = 0.56 e Å−3 |
90 parameters | Δρmin = −0.30 e Å−3 |
0 restraints | Extinction correction: SHELXL97, Fc^*^=kFc[1+0.001xFc^2^λ^3^/sin(2θ)]^-1/4^ |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0653 (17) |
Crystal data top
[Co(C4H2O4)(H2O)4]·H2O | V = 916.6 (3) Å3 |
Mr = 263.07 | Z = 4 |
Monoclinic, C2/c | Mo Kα radiation |
a = 5.2561 (11) Å | µ = 1.90 mm−1 |
b = 13.145 (2) Å | T = 166 K |
c = 13.321 (3) Å | 0.60 × 0.55 × 0.50 mm |
β = 95.188 (16)° | |
Data collection top
Siemens SMART 1K CCD diffractometer | 1815 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2000) | 1771 reflections with I > 2σ(I) |
Tmin = 0.301, Tmax = 0.386 | Rint = 0.025 |
8327 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.018 | 0 restraints |
wR(F2) = 0.049 | All H-atom parameters refined |
S = 1.04 | Δρmax = 0.56 e Å−3 |
1815 reflections | Δρmin = −0.30 e Å−3 |
90 parameters | |
Special details top
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 F^2^ against ALL reflections. The weighted
R-factor wR and goodness of fit S are based on
F^2^, conventional R-factors R are based on F,
with F set to zero for negative F^2^. The threshold expression
of F^2^ > σ(F^2^) is used only for calculating
R-factors(gt) etc. and is not relevant to the choice of
reflections for refinement. R-factors based on F^2^ 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 | |
Co1 | 0.5000 | 0.521354 (11) | 0.2500 | 0.00894 (6) | |
O1 | 0.66720 (12) | 0.41061 (5) | 0.34838 (5) | 0.01388 (12) | |
O2 | 0.38818 (12) | 0.37949 (5) | 0.46236 (5) | 0.01486 (12) | |
O3 | 0.79528 (13) | 0.52833 (5) | 0.15710 (5) | 0.01689 (13) | |
O4 | 0.29066 (12) | 0.63086 (5) | 0.15840 (5) | 0.01271 (11) | |
O5 | 1.0000 | 0.29869 (7) | 0.2500 | 0.01504 (16) | |
C1 | 0.59750 (15) | 0.36517 (6) | 0.42601 (6) | 0.01087 (13) | |
C2 | 0.78514 (15) | 0.28956 (6) | 0.47320 (6) | 0.01180 (13) | |
H2A | 0.957 (3) | 0.3007 (11) | 0.4652 (10) | 0.016 (3)* | |
H3A | 0.931 (3) | 0.5574 (13) | 0.1571 (13) | 0.030 (4)* | |
H3B | 0.789 (4) | 0.4818 (14) | 0.1186 (16) | 0.037 (5)* | |
H4A | 0.328 (3) | 0.6854 (14) | 0.1814 (13) | 0.032 (4)* | |
H4B | 0.344 (3) | 0.6293 (14) | 0.1005 (14) | 0.032 (4)* | |
H5A | 0.918 (3) | 0.3344 (12) | 0.2784 (12) | 0.022 (4)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Co1 | 0.00957 (8) | 0.00820 (8) | 0.00915 (8) | 0.000 | 0.00146 (5) | 0.000 |
O1 | 0.0155 (3) | 0.0131 (3) | 0.0138 (3) | 0.0038 (2) | 0.0057 (2) | 0.00536 (19) |
O2 | 0.0125 (3) | 0.0185 (3) | 0.0142 (3) | 0.0035 (2) | 0.0042 (2) | 0.0051 (2) |
O3 | 0.0134 (3) | 0.0202 (3) | 0.0180 (3) | −0.0057 (2) | 0.0063 (2) | −0.0072 (2) |
O4 | 0.0150 (3) | 0.0117 (3) | 0.0116 (3) | 0.0000 (2) | 0.0022 (2) | 0.00047 (19) |
O5 | 0.0194 (4) | 0.0104 (4) | 0.0165 (4) | 0.000 | 0.0080 (3) | 0.000 |
C1 | 0.0121 (3) | 0.0094 (3) | 0.0111 (3) | 0.0001 (2) | 0.0012 (2) | 0.0011 (2) |
C2 | 0.0115 (3) | 0.0117 (3) | 0.0123 (3) | 0.0013 (2) | 0.0014 (2) | 0.0025 (2) |
Geometric parameters (Å, º) top
Co1—O3 | 2.0727 (8) | O3—H3A | 0.810 (18) |
Co1—O3i | 2.0727 (8) | O3—H3B | 0.797 (19) |
Co1—O1 | 2.0978 (7) | O4—H4A | 0.797 (18) |
Co1—O1i | 2.0978 (7) | O4—H4B | 0.844 (18) |
Co1—O4 | 2.1281 (7) | O5—H5A | 0.761 (15) |
Co1—O4i | 2.1281 (7) | C1—C2 | 1.4978 (11) |
O1—C1 | 1.2763 (10) | C2—C2ii | 1.3326 (15) |
O2—C1 | 1.2557 (10) | C2—H2A | 0.928 (14) |
| | | |
O3—Co1—O3i | 174.93 (4) | O4—Co1—O4i | 94.87 (4) |
O3—Co1—O1 | 96.30 (3) | C1—O1—Co1 | 134.13 (5) |
O3i—Co1—O1 | 87.23 (3) | Co1—O3—H3A | 136.8 (12) |
O3—Co1—O1i | 87.23 (3) | Co1—O3—H3B | 111.2 (15) |
O3i—Co1—O1i | 96.30 (3) | H3A—O3—H3B | 110 (2) |
O1—Co1—O1i | 92.12 (4) | Co1—O4—H4A | 106.8 (13) |
O3—Co1—O4 | 90.23 (3) | Co1—O4—H4B | 108.1 (12) |
O3i—Co1—O4 | 86.34 (3) | H4A—O4—H4B | 106.4 (17) |
O1—Co1—O4 | 173.34 (2) | O2—C1—O1 | 124.61 (7) |
O1i—Co1—O4 | 86.88 (3) | O2—C1—C2 | 120.28 (7) |
O3—Co1—O4i | 86.34 (3) | O1—C1—C2 | 115.11 (7) |
O3i—Co1—O4i | 90.23 (3) | C2ii—C2—C1 | 122.61 (9) |
O1—Co1—O4i | 86.87 (3) | C2ii—C2—H2A | 120.2 (9) |
O1i—Co1—O4i | 173.34 (2) | C1—C2—H2A | 117.2 (9) |
| | | |
O3—Co1—O1—C1 | −179.12 (8) | Co1—O1—C1—O2 | 0.60 (13) |
O3i—Co1—O1—C1 | 4.53 (8) | Co1—O1—C1—C2 | 179.95 (5) |
O1i—Co1—O1—C1 | −91.67 (8) | O2—C1—C2—C2ii | 25.56 (14) |
O4i—Co1—O1—C1 | 94.91 (8) | O1—C1—C2—C2ii | −153.82 (10) |
Symmetry codes: (i) −x+1, y, −z+1/2; (ii) −x+3/2, −y+1/2, −z+1. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3A···O4iii | 0.809 (16) | 2.121 (16) | 2.9306 (11) | 178.8 (17) |
O3—H3B···O2i | 0.80 (2) | 1.91 (2) | 2.6481 (11) | 153 (2) |
O4—H4A···O5iv | 0.797 (18) | 1.929 (18) | 2.7062 (12) | 164.8 (17) |
O4—H4B···O2v | 0.844 (18) | 1.879 (18) | 2.7098 (11) | 167.6 (16) |
O5—H5A···O1 | 0.761 (16) | 1.958 (16) | 2.7122 (10) | 171.4 (17) |
C2—H2A···O2iii | 0.931 (16) | 2.495 (16) | 3.3982 (13) | 163.6 (12) |
Symmetry codes: (i) −x+1, y, −z+1/2; (iii) x+1, y, z; (iv) x−1/2, y+1/2, z; (v) x, −y+1, z−1/2. |
Experimental details
| (I) | (II) | (III) |
Crystal data |
Chemical formula | [Co(C4H2O4)(H2O)3] | [Co(C4H2O4)(CH4O)2] | [Co(C4H2O4)(H2O)4]·H2O |
Mr | 227.03 | 237.07 | 263.07 |
Crystal system, space group | Triclinic, P1 | Monoclinic, C2/c | Monoclinic, C2/c |
Temperature (K) | 167 | 165 | 166 |
a, b, c (Å) | 6.8793 (17), 7.644 (2), 8.026 (3) | 15.547 (4), 7.020 (2), 8.2270 (13) | 5.2561 (11), 13.145 (2), 13.321 (3) |
α, β, γ (°) | 101.51 (2), 112.03 (2), 92.82 (3) | 90, 115.73 (2), 90 | 90, 95.188 (16), 90 |
V (Å3) | 379.8 (2) | 808.9 (4) | 916.6 (3) |
Z | 2 | 4 | 4 |
Radiation type | Mo Kα | Mo Kα | Mo Kα |
µ (mm−1) | 2.26 | 2.12 | 1.90 |
Crystal size (mm) | 0.52 × 0.20 × 0.14 | 0.40 × 0.26 × 0.24 | 0.60 × 0.55 × 0.50 |
|
Data collection |
Diffractometer | Siemens SMART 1K CCD diffractometer | Siemens SMART 1K CCD diffractometer | Siemens SMART 1K CCD diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2000) | Multi-scan (SADABS; Sheldrick, 2000) | Multi-scan (SADABS; Sheldrick, 2000) |
Tmin, Tmax | 0.575, 0.729 | 0.530, 0.602 | 0.301, 0.386 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 6668, 2411, 1660 | 7132, 1611, 1402 | 8327, 1815, 1771 |
Rint | 0.044 | 0.025 | 0.025 |
(sin θ/λ)max (Å−1) | 0.735 | 0.790 | 0.790 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.038, 0.091, 1.00 | 0.023, 0.061, 1.01 | 0.018, 0.049, 1.04 |
No. of reflections | 2411 | 1611 | 1815 |
No. of parameters | 145 | 70 | 90 |
H-atom treatment | All H-atom parameters refined | H atoms treated by a mixture of independent and constrained refinement | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 1.07, −0.94 | 0.48, −0.64 | 0.56, −0.30 |
Hydrogen-bond geometry (Å, º) for (I) top
D—H···A | D—H | H···A | D···A | D—H···A |
O5—H5A···O2i | 0.79 (6) | 1.97 (6) | 2.755 (3) | 170 (4) |
O5—H5B···O3ii | 0.76 (4) | 1.87 (4) | 2.620 (3) | 167 (4) |
O6—H6A···O3i | 0.87 (4) | 1.83 (4) | 2.694 (3) | 175 (4) |
O6—H6B···O1 | 0.79 (5) | 2.20 (5) | 2.833 (3) | 138 (4) |
O6—H6B···O4ii | 0.79 (5) | 2.30 (5) | 2.957 (3) | 142 (4) |
O7—H7A···O4iii | 0.76 (4) | 2.18 (4) | 2.936 (4) | 175 (4) |
O7—H7B···O5iv | 0.80 (5) | 2.17 (5) | 2.971 (4) | 176 (4) |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x−1, y, z−1; (iii) −x+1, −y+2, −z+2; (iv) −x, −y+1, −z+1. |
Hydrogen-bond geometry (Å, º) for (II) top
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3A···O2 | 0.84 (2) | 1.85 (2) | 2.6485 (15) | 159 (2) |
C2—H2A···O1i | 0.91 (2) | 2.57 (2) | 3.1796 (18) | 125.4 (17) |
Symmetry code: (i) x, −y, z+1/2. |
Hydrogen-bond geometry (Å, º) for (III) top
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3A···O4i | 0.809 (16) | 2.121 (16) | 2.9306 (11) | 178.8 (17) |
O3—H3B···O2ii | 0.80 (2) | 1.91 (2) | 2.6481 (11) | 153 (2) |
O4—H4A···O5iii | 0.797 (18) | 1.929 (18) | 2.7062 (12) | 164.8 (17) |
O4—H4B···O2iv | 0.844 (18) | 1.879 (18) | 2.7098 (11) | 167.6 (16) |
O5—H5A···O1 | 0.761 (16) | 1.958 (16) | 2.7122 (10) | 171.4 (17) |
Symmetry codes: (i) x+1, y, z; (ii) −x+1, y, −z+1/2; (iii) x−1/2, y+1/2, z; (iv) x, −y+1, z−1/2. |
Site symmetries for cobalt(II) fumarate trihydrate, methanol disolvate,
pentahydrate and tetrahydrate top | trihydrate | methanol disolvate | pentahydrate | tetrahydrate |
space group | P1 | C2/c | C2/c | P21/c |
Z | 2 | 4 | 4 | 4 |
Co2+ | 1, 1(a) | 1 | 2 | 1 |
fumarate | 1 | 1 | 1 | 1 |
cobalt(II) fumarate-topology | 2D | 3D | 1D | 1D |
(a) two symmetry independant Co2+ ions |
Octahedral coordination of Co2+ ions was first observed by Werner (1893). To date, only two cobalt(II) fumarate complexes containing water molecules are known: cobalt(II) fumarate tetrahydrate [which is actually a tetraaquacobalt(II) fumarate (Konar et al., 2003; Zheng & Xie, 2004; Padmanabhan et al., 2008)] and cobalt(II) fumarate pentahydrate [which is actually a tetraaquacobalt(II) fumarate monohydrate (Gupta & Sinha, 1978; Konar et al., 2003; Marsh & Spek, 2001; Porollo et al., 1997)]. Compounds in which Co2+ ions [and other bivalent metal(II) ions] are bonded to saturated or unsaturated dicarboxylic acids, such as fumaric, maleic and succinic acid, have also been reported (e.g. Rao et al., 2004; Yaghi et al., 2003). In recent years, investigations of cobalt(II) fumarate phases containing additional organic ligands have been carried out (e.g. Chen et al., 2007; Konar et al., 2004; Liu et al., 2003; Ma et al., 2003; Manna et al., 2007; Zhang et al., 2004, 2005). Ligands included benzimidazole, o-phenanthroline, pyrazine, and pyridine and its derivatives. These compounds form chain structures, layers or three-dimensional frameworks. Saturated dicarboxylic acids tend to form coordination polymers with open three-dimensional frameworks. In contrast unsaturated dicarboxylic acids lead to metal(II) hydrate complexes with predominantly chain structures.
The cobalt(II) fumarate tetra- and pentahydrates built from the Co2+ ion and the fumarate dianion crystallize in one-dimensional polymeric chain structures (Gupta & Sinha, 1978; Konar et al., 2003; Marsh & Spek, 2001; Padmanabhan et al., 2008; Porollo et al., 1997; Zheng & Xie, 2004). These chains are connected into a three-dimensional network by hydrogen bonds between water molecules and carboxylate groups.
We have prepared a novel cobalt(II) fumarate trihydrate and a cobalt(II) fumarate methanol disolvate and have redetermined additionally the structure of cobalt(II) fumarate pentahydrate.
The trihydrate, (I), forms two-dimensional layers parallel to the 111 plane, as shown in Fig. 1. There are two symmetrically independent Co2+ ions, both on inversion centers. Atom Co1 is coordinated by two water molecules [Co1—O5 = 2.147 (2) Å] and four fumarate dianions [Co1—O1 = 2.0686 (18) Å and Co1—O4 = 2.1132 (18) Å], whereas atom Co2 is surrounded by four water molecules [Co2—O6 = 2.042 (2) Å and Co2—O7 = 2.183 (2) Å] and two fumarate dianions [Co2—O2 = 2.0755 (18) Å]. Both Co2+ ions are coordinated with a distorted octahedral geometry. Hence cobalt(II) fumarate trihydrate is actually a mixture of a tetracobalt(II) fumarate and a diaquacobalt(II) fumarate. The fumarate group has a trans conformation, with a C1—C2—C3—C4 torsion angle of 175.6 (2)°. The carboxylate groups are rotated out of the plane; the angles between the plane of the central butene group and the planes of the two carboxylate groups are 32.0 (2) and 23.0 (1)°. The fumarate dianions act as bridging ligands, linking the two symmetrically independant Co2+ ions to form layers parallel to the [111] plane. The layer is characterized by two different ring systems. There is a 14-membered ring, consisting of two Co1 atoms and two fumarate dianions, and a 22-membered ring, consisting of two Co1 atoms, two Co2 atoms and four fumarate dianions. The three independent water molecules act as donors for six different O—H···O hydrogen bonds (Table 1). Four of them connect the layers through an extensive hydrogen-bonding network to form a three-dimensional framework, as shown in Fig. 2. Within the layers the O6/H6B group is involved in a rather weak bifurcated hydrogen bond, while the O5/H5B group is involved in a rather strong hydrogen bond, as shown in Fig. 1. There is only one other report of the crystal structure of a metal(II) fumarate trihydrate, calcium(II) fumarate trihydrate (Gupta et al., 1972). Its coordination geometry, however, is not similar to that of (I). Its structure consists of an eightfold-coordinated Ca2+ ion surrounded by two independant and two symmetry-related water molecules and three symmetry-related fumarate dianions.
Cobalt(II) fumarate methanol disolvate, (II), belongs to the group of cobalt(II) fumarates containing an additional organic ligand. The octahedrally coordinated Co2+ ion is located on a crystallographic inversion center. Each Co2+ ion is bonded to O atoms of four symmetry-related fumarate groups [Co1—O1 = 2.1060 (10) Å and Co1—O2 = 2.1205 (9) Å] and two O atoms of two symmetry-related methanol groups [Co1—O3 = 2.0657 (10) Å], as shown in Fig. 3. The methanol OH group donates an intramolecular hydrogen bond to carboxylate atom O2 (Table 2). The fumarate group is planar (the mean deviation from the plane is only 0.002 Å) and has a crystallographic inversion center at the midpoint of the C═C double bond. The Co2+ ions and fumarate dianions form a three-dimensional framework, as shown in Fig. 4. The structure is characterized by a system of 14-membered rings, consisting of two Co2+ ions and two fumarate dianions. Larger 22-membered rings consisting of four Co2+ ions and four fumarate dianions result in channels along the c-axis direction. The methanol ligands are located in these channels. The structure of (II) is clearly different from the structures of many two-dimensional coordination polymers that have been reported in the past few decades. Thus the incorporation of a methanol ligand into cobalt(II) fumarate phases offers an interesting method for structural modification and the synthesis of further novel metal–organic framework structures.
There has been some confusion about the correct space group of the pentahydrate, (III). The structure was originally determined by Gupta & Sinha (1978) in space group C2/c. It was redetermined by Porollo et al. (1997) and refined in the noncentrosymmetric space group C2. Marsh & Spek (2001) showed that the coordinates of this structure could be transformed to C2/c. Two years later the structure of (III) was redetermined by Konar et al. (2003) and refined in the noncentrosymmetric space group Cc. The present redetermination of the compound confirms the space group C2/c. The low R value (0.018) for the refinement in C2/c shows that space groups C2 and Cc can be excluded. The Co2+ ion is located on a twofold axis and has an octahedral coordination. Two cis positions are occupied by two fumarate groups and the other positions are occupied by four water molecules. The Co2+ ions and fumarate dianions form one-dimensional zigzag chains along the c direction, as shown in Fig. 5. These chains are connected by O—H···O hydrogen bonds (Table 3) into a three-dimensional network, as shown in Fig. 6. There is a crystallographic inversion center at the midpoint of the C═C double bond of the fumarate group. The angle between the plane of the central butene group and the planes of the two carboxylate groups is 25.9 (1)°. A one-dimensional structure has also been observed in the crystal structure of cobalt(II) fumarate tetrahydrate (Konar et al., 2003). There the fumarate groups are in trans positions with respect to the Co2+ ions, resulting in almost linear chains.
The site symmetries of the cobalt and fumarate ions for all four compounds are given in Table 4. The compounds reported demonstrate all three of the types of framework (one-, two- and three-dimensional), that are possible for these structures.