inorganic compounds
The triclinic form of dipotassium cobalt(II) bis(dihydrogendiphosphate) dihydrate
aLaboratory of Mineral Solid and Analytical Chemistry (LCSMA), Department of Chemistry, Faculty of Sciences, University Mohamed I, PO Box 717, 60000 Oujda, Morocco, and bInstitute of Physics of the ASCR, v.v.i., Na Slovance 2, 182 21 Praha 8, Czech Republic
*Correspondence e-mail: b.elbali@fso.ump.ma
In the title compound, K2Co(H2P2O7)2·2H2O, the octahedrally coordinated Co2+ ion lies on an inversion centre. Two bidentate dihydrogendiphosphate anions form the equatorial plane of the [CoO6] octahedron which is completed by two water molecules in axial positions. This results in isolated {Co(H2O)2[H2P2O7]2}4− entities linked into a three-dimensional network through K—O bonds and O—H⋯O hydrogen-bonding interactions involving the dihydrogendiphosphate anions and water molecules. The dihydrogendiphosphate anion, (H2P2O7)2−, is bent and shows an almost eclipsed conformation.
Related literature
The triclinic title compound is isotypic with K2Ni(H2P2O7)2·2H2O (Tahiri et al., 2004) and K2Zn(H2P2O7)2·2H2O (Tahiri et al., 2003). For orthorhombic forms of crystals of this formula type, see: Tahiri et al. (2002); Essehli et al. (2005).
Experimental
Crystal data
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Data collection
Refinement
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Data collection: CrysAlis CCD (Oxford Diffraction, 2004); cell CrysAlis RED (Oxford Diffraction, 2004); data reduction: CrysAlis RED; program(s) used to solve structure: SIR2002 (Burla et al., 2003); program(s) used to refine structure: JANA2006 (Petříček et al., 2006); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: JANA2006.
Supporting information
10.1107/S1600536811016345/wm2482sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536811016345/wm2482Isup2.hkl
To prepare the present crystals we used the same procedure as described in detail in (Tahiri et al., 2002). Solutions of CoCl2.4H2O (10 ml, 10 mmol) and K4P2O7 (10 ml, 20 mmol) were mixed in a beaker. The mixture was stirred for six hours and then allowed to stand for two weeks at room temperature. At the end of this period, large prismatic pink crystals have deposited, which were filtered-off and washed with a water-ethanol solution (20:80).
All hydrogen atoms were found in difference Fourier maps and their coordinates were refined independently. The isotropic atomic displacement parameters of hydrogen atoms were treated with 1.2×Ueq of the respective parent O atom.
Data collection: CrysAlis CCD (Oxford Diffraction, 2004); cell
CrysAlis RED (Oxford Diffraction, 2004); data reduction: CrysAlis RED (Oxford Diffraction, 2004); program(s) used to solve structure: SIR2002 (Burla et al., 2003); program(s) used to refine structure: JANA2006 (Petříček et al., 2006); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: JANA2006 (Petříček et al., 2006).Fig. 1. : The main coordination polyhedra in the title compound, shown as an ellipsoid plot with anisotropic displacement parameters drawn at the 50% probability level. [Symmetry codes: (i) 1 - x, 1 - y, 1 - z; (ii) 1 - x, -y, 1 - z; (iii) x, y, 1 + z; (iv) 2 - x, -y, 1 - z]. | |
Fig. 2. : Projection of the structure along the b-axis. H-bonds are displayed as dashed lines. |
K2Co(H2P2O7)2·2H2O | Z = 1 |
Mr = 525.1 | F(000) = 261 |
Triclinic, P1 | Dx = 2.412 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71069 Å |
a = 6.8737 (14) Å | Cell parameters from 4546 reflections |
b = 7.3565 (11) Å | θ = 3.1–26.6° |
c = 7.6141 (14) Å | µ = 2.29 mm−1 |
α = 80.740 (14)° | T = 292 K |
β = 72.397 (17)° | Prism, pink |
γ = 83.484 (14)° | 0.16 × 0.11 × 0.03 mm |
V = 361.35 (12) Å3 |
Oxford Diffraction Xcalibur diffractometer with a Sapphire 2 CCD detector | 1489 independent reflections |
Radiation source: Mo X-ray tube | 1013 reflections with I > 3σ(I) |
Graphite monochromator | Rint = 0.054 |
Detector resolution: 8.3438 pixels mm-1 | θmax = 26.6°, θmin = 3.1° |
Rotation method data acquisition using ω scans | h = −8→8 |
Absorption correction: analytical based on the crystal shape (CrysAlis RED; Oxford Diffraction, 2004) | k = −9→9 |
Tmin = 0.648, Tmax = 0.838 | l = −9→9 |
4546 measured reflections |
Refinement on F2 | 4 constraints |
R[F2 > 2σ(F2)] = 0.038 | Only H-atom coordinates refined |
wR(F2) = 0.090 | Weighting scheme based on measured s.u.'s w = 1/[σ2(I) + 0.0016I2] |
S = 1.17 | (Δ/σ)max = 0.044 |
1489 reflections | Δρmax = 0.47 e Å−3 |
118 parameters | Δρmin = −0.45 e Å−3 |
0 restraints |
K2Co(H2P2O7)2·2H2O | γ = 83.484 (14)° |
Mr = 525.1 | V = 361.35 (12) Å3 |
Triclinic, P1 | Z = 1 |
a = 6.8737 (14) Å | Mo Kα radiation |
b = 7.3565 (11) Å | µ = 2.29 mm−1 |
c = 7.6141 (14) Å | T = 292 K |
α = 80.740 (14)° | 0.16 × 0.11 × 0.03 mm |
β = 72.397 (17)° |
Oxford Diffraction Xcalibur diffractometer with a Sapphire 2 CCD detector | 1489 independent reflections |
Absorption correction: analytical based on the crystal shape (CrysAlis RED; Oxford Diffraction, 2004) | 1013 reflections with I > 3σ(I) |
Tmin = 0.648, Tmax = 0.838 | Rint = 0.054 |
4546 measured reflections |
R[F2 > 2σ(F2)] = 0.038 | 0 restraints |
wR(F2) = 0.090 | Only H-atom coordinates refined |
S = 1.17 | Δρmax = 0.47 e Å−3 |
1489 reflections | Δρmin = −0.45 e Å−3 |
118 parameters |
Refinement. The hydrogen atoms were localized from the difference Fourier map. Their coordinates were refined independently. The isotropic temperature parameters of hydrogen atoms were calculated as 1.2*Ueq of the parent atom. |
x | y | z | Uiso*/Ueq | ||
K1 | 0.89288 (17) | 0.26574 (14) | 0.70307 (15) | 0.0365 (4) | |
Co1 | 0.5 | 0.5 | 0.5 | 0.0172 (3) | |
P1 | 0.32488 (16) | 0.27153 (14) | 0.24623 (14) | 0.0181 (4) | |
P2 | 0.75153 (16) | 0.18965 (14) | 0.24070 (14) | 0.0177 (4) | |
O1 | 0.5649 (4) | 0.2309 (4) | 0.1518 (4) | 0.0242 (11) | |
O2 | 0.2951 (4) | 0.3930 (4) | 0.3932 (4) | 0.0213 (10) | |
O3 | 0.2401 (4) | 0.3486 (4) | 0.0882 (4) | 0.0241 (10) | |
O4 | 0.2372 (5) | 0.0812 (4) | 0.3353 (4) | 0.0263 (11) | |
H1 | 0.252 (7) | 0.045 (6) | 0.437 (6) | 0.0316* | |
O5 | 0.7435 (4) | 0.3267 (4) | 0.3681 (4) | 0.0231 (10) | |
O6 | 0.9309 (4) | 0.2143 (4) | 0.0601 (4) | 0.0258 (11) | |
H2 | 1.011 (7) | 0.252 (7) | 0.083 (7) | 0.0309* | |
O7 | 0.7467 (5) | −0.0072 (4) | 0.3310 (4) | 0.0283 (11) | |
O8 | 0.5496 (5) | 0.7064 (4) | 0.2702 (4) | 0.0274 (12) | |
H3 | 0.602 (8) | 0.692 (7) | 0.176 (7) | 0.0329* | |
H4 | 0.606 (7) | 0.790 (7) | 0.280 (7) | 0.0329* |
U11 | U22 | U33 | U12 | U13 | U23 | |
K1 | 0.0433 (6) | 0.0353 (6) | 0.0362 (6) | 0.0096 (5) | −0.0215 (5) | −0.0093 (5) |
Co1 | 0.0201 (4) | 0.0177 (4) | 0.0175 (4) | 0.0005 (3) | −0.0093 (3) | −0.0069 (3) |
P1 | 0.0183 (5) | 0.0215 (6) | 0.0184 (5) | −0.0008 (4) | −0.0095 (4) | −0.0062 (4) |
P2 | 0.0193 (5) | 0.0204 (6) | 0.0166 (5) | 0.0009 (4) | −0.0084 (4) | −0.0068 (4) |
O1 | 0.0183 (15) | 0.0363 (18) | 0.0229 (15) | 0.0048 (12) | −0.0110 (12) | −0.0128 (13) |
O2 | 0.0212 (15) | 0.0236 (15) | 0.0238 (15) | −0.0009 (12) | −0.0095 (12) | −0.0110 (12) |
O3 | 0.0222 (16) | 0.0337 (17) | 0.0198 (15) | −0.0011 (13) | −0.0130 (13) | −0.0008 (13) |
O4 | 0.0359 (18) | 0.0235 (16) | 0.0238 (17) | −0.0081 (13) | −0.0143 (15) | −0.0005 (13) |
O5 | 0.0225 (16) | 0.0294 (16) | 0.0225 (15) | 0.0037 (13) | −0.0099 (13) | −0.0156 (13) |
O6 | 0.0215 (17) | 0.0403 (19) | 0.0180 (15) | −0.0081 (14) | −0.0039 (13) | −0.0105 (14) |
O7 | 0.0388 (18) | 0.0224 (16) | 0.0269 (17) | −0.0040 (14) | −0.0137 (14) | −0.0024 (13) |
O8 | 0.039 (2) | 0.0253 (18) | 0.0188 (16) | −0.0079 (15) | −0.0065 (15) | −0.0063 (14) |
K1—O2i | 2.785 (3) | Co1—O8i | 2.094 (3) |
K1—O4ii | 2.884 (3) | P1—O1 | 1.602 (3) |
K1—O5 | 2.979 (3) | P1—O2 | 1.495 (3) |
K1—O6iii | 2.771 (4) | P1—O3 | 1.496 (3) |
K1—O7iv | 2.919 (3) | P1—O4 | 1.556 (3) |
K1—O8i | 2.972 (4) | P2—O1 | 1.602 (3) |
Co1—O2 | 2.101 (3) | P2—O5 | 1.493 (3) |
Co1—O2i | 2.101 (3) | P2—O6 | 1.546 (3) |
Co1—O5 | 2.085 (3) | P2—O7 | 1.499 (3) |
Co1—O5i | 2.085 (3) | O4—H1 | 0.81 (5) |
Co1—O8 | 2.094 (3) | O6—H2 | 0.72 (6) |
O2i—K1—O4ii | 123.43 (10) | O5i—Co1—O5 | 180 |
O2i—K1—O5 | 60.33 (9) | O5i—Co1—O8 | 86.81 (11) |
O2i—K1—O6iii | 113.92 (10) | O5i—Co1—O8i | 93.19 (11) |
O2i—K1—O7iv | 151.28 (8) | O8i—Co1—O8 | 180 |
O2i—K1—O8i | 60.69 (9) | O1—P1—O2 | 109.27 (18) |
O4ii—K1—O5 | 72.55 (9) | O1—P1—O3 | 105.02 (15) |
O4ii—K1—O6iii | 104.16 (10) | O1—P1—O4 | 106.45 (15) |
O4ii—K1—O7iv | 74.58 (9) | O2—P1—O3 | 116.17 (17) |
O4ii—K1—O8i | 68.68 (9) | O2—P1—O4 | 110.05 (16) |
O5—K1—O6iii | 166.01 (9) | O3—P1—O4 | 109.36 (19) |
O5—K1—O7iv | 113.42 (9) | O1—P2—O5 | 110.97 (16) |
O5—K1—O8i | 57.71 (8) | O1—P2—O6 | 98.96 (17) |
O6iii—K1—O7iv | 77.87 (9) | O1—P2—O7 | 107.47 (18) |
O6iii—K1—O8i | 108.32 (9) | O5—P2—O6 | 112.65 (18) |
O7iv—K1—O8i | 143.17 (10) | O5—P2—O7 | 114.33 (17) |
O2—Co1—O2i | 180 | O6—P2—O7 | 111.27 (17) |
O2—Co1—O5 | 92.27 (11) | P1—O1—P2 | 130.90 (19) |
O2—Co1—O5i | 87.73 (11) | K1i—O2—Co1 | 95.37 (10) |
O2—Co1—O8 | 87.94 (13) | K1i—O2—P1 | 110.42 (15) |
O2—Co1—O8i | 92.06 (13) | Co1—O2—P1 | 132.80 (16) |
O2i—Co1—O2 | 180 | K1ii—O4—P1 | 150.05 (19) |
O2i—Co1—O5 | 87.73 (11) | P1—O4—H1 | 114 (4) |
O2i—Co1—O5i | 92.27 (11) | K1—O5—Co1 | 90.21 (10) |
O2i—Co1—O8 | 92.06 (13) | K1—O5—P2 | 127.17 (15) |
O2i—Co1—O8i | 87.94 (13) | Co1—O5—P2 | 130.12 (19) |
O5—Co1—O5i | 180 | K1v—O6—P2 | 125.12 (18) |
O5—Co1—O8 | 93.19 (11) | P2—O6—H2 | 107 (4) |
O5—Co1—O8i | 86.81 (11) | H3—O8—H4 | 101 (5) |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1, −y, −z+1; (iii) x, y, z+1; (iv) −x+2, −y, −z+1; (v) x, y, z−1. |
D—H···A | D—H | H···A | D···A | D—H···A |
O4—H1···O7ii | 0.81 (5) | 1.75 (5) | 2.545 (5) | 169 (5) |
O6—H2···O3vi | 0.72 (6) | 1.82 (6) | 2.522 (5) | 168 (5) |
O8—H3···O3vii | 0.71 (5) | 2.03 (5) | 2.745 (4) | 178 (6) |
O8—H4···O7viii | 0.79 (5) | 2.01 (6) | 2.798 (5) | 175 (5) |
Symmetry codes: (ii) −x+1, −y, −z+1; (vi) x+1, y, z; (vii) −x+1, −y+1, −z; (viii) x, y+1, z. |
Experimental details
Crystal data | |
Chemical formula | K2Co(H2P2O7)2·2H2O |
Mr | 525.1 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 292 |
a, b, c (Å) | 6.8737 (14), 7.3565 (11), 7.6141 (14) |
α, β, γ (°) | 80.740 (14), 72.397 (17), 83.484 (14) |
V (Å3) | 361.35 (12) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 2.29 |
Crystal size (mm) | 0.16 × 0.11 × 0.03 |
Data collection | |
Diffractometer | Oxford Diffraction Xcalibur diffractometer with a Sapphire 2 CCD detector |
Absorption correction | Analytical based on the crystal shape (CrysAlis RED; Oxford Diffraction, 2004) |
Tmin, Tmax | 0.648, 0.838 |
No. of measured, independent and observed [I > 3σ(I)] reflections | 4546, 1489, 1013 |
Rint | 0.054 |
(sin θ/λ)max (Å−1) | 0.629 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.038, 0.090, 1.17 |
No. of reflections | 1489 |
No. of parameters | 118 |
H-atom treatment | Only H-atom coordinates refined |
Δρmax, Δρmin (e Å−3) | 0.47, −0.45 |
Computer programs: CrysAlis CCD (Oxford Diffraction, 2004), CrysAlis RED (Oxford Diffraction, 2004), SIR2002 (Burla et al., 2003), JANA2006 (Petříček et al., 2006), DIAMOND (Brandenburg, 1999).
K1—O2i | 2.785 (3) | P1—O1 | 1.602 (3) |
K1—O4ii | 2.884 (3) | P1—O2 | 1.495 (3) |
K1—O5 | 2.979 (3) | P1—O3 | 1.496 (3) |
K1—O6iii | 2.771 (4) | P1—O4 | 1.556 (3) |
K1—O7iv | 2.919 (3) | P2—O1 | 1.602 (3) |
K1—O8i | 2.972 (4) | P2—O5 | 1.493 (3) |
Co1—O2 | 2.101 (3) | P2—O6 | 1.546 (3) |
Co1—O5 | 2.085 (3) | P2—O7 | 1.499 (3) |
Co1—O8 | 2.094 (3) | ||
P1—O1—P2 | 130.90 (19) |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1, −y, −z+1; (iii) x, y, z+1; (iv) −x+2, −y, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
O4—H1···O7ii | 0.81 (5) | 1.75 (5) | 2.545 (5) | 169 (5) |
O6—H2···O3v | 0.72 (6) | 1.82 (6) | 2.522 (5) | 168 (5) |
O8—H3···O3vi | 0.71 (5) | 2.03 (5) | 2.745 (4) | 178 (6) |
O8—H4···O7vii | 0.79 (5) | 2.01 (6) | 2.798 (5) | 175 (5) |
Symmetry codes: (ii) −x+1, −y, −z+1; (v) x+1, y, z; (vi) −x+1, −y+1, −z; (vii) x, y+1, z. |
Acknowledgements
We acknowledge support by the Grant Agency of the Czech Republic, grant No. P204/11/0809.
References
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The triclinic form of K2Co(H2P2O7)2.2H2O is isotypic with K2Ni(H2P2O7)2.2H2O (Tahiri et al., 2004) and K2Zn(H2P2O7)2.2H2O (Tahiri et al., 2003). All these K2M(H2P2O7)2.2H2O dihydrogendiphosphates crystallise also in an orthorhombic form, see: Tahiri et al. (2002) for M = Co; Essehli et al. (2005) for M = Ni and Zn.
The crystal structure of the title compound can be described in terms of centrosymmetric {Co(H2O)2[H2P2O7]2}4- units (Fig. 1) that are linked through K—O bonds and an intricate network of O—H···O hydrogen bonds into a three-dimensional network (Fig. 2). The slightly distorted coordination octahedron around Co2+ is composed of four O atoms from two bidendate [H2P2O7]2- groups in equatorial positions and two O atoms from water molecules in axial positions. The average Co—O bond length of 2.093 (8) Å is in the same range as 2.047 Å for the orthorhombic form (Tahiri et al., 2002). The dihydrogendiphosphate anion is bent and shows an almost eclipsed conformation, with an bridging angle P1—O1—P2 of 130.90 (19) °. P—O bond lengths and O—P—O angles values are of similar values as in known dihydrogendiphosphates. The K+ cation is coordinated by six O atoms in form of a very distorted octahedron, with K—O distances ranging from 2.771 (4) to 2.979 (3) Å. Such values are likewise found in isotypic or isoformular dihydrogendiphosphates.