Potassium cobalt hydrogenpyrophosphate dihydrate, KHCoP2O7·2H2O, crystallizes in the orthorhombic space group Pnma. This salt is isotypic with KHMP2O7·2H2O (M = Mn and Zn). The structure consists of alternating layers, built from HP2O73- acidic pyrophosphate groups and CoO6 octahedra, joined by potassium ions and bridging hydrogen bonds. The Co, K and water O atoms lie on mirror planes. The pyrophosphate group consists of two symmetry-related PO4 groups, with the bridging O atom on a mirror plane.
Supporting information
An aqueous solution of cobalt dichloride hexahydrate CoCl2·6H2O (0.1M) was added dropwise to a solution of K4P2O7 (0.1M). Anhydrous tetrapotassium pyrophosphate, K4P2O7, was prepared by dehydration of K2HPO4 at 873 K for 6 h. The pH of the mixture of these two solutions was controlled with concentrated hydrochloric acid. The solution was left at room temperature and crystals appeared in the solution after 4 d. They were identified as KHCoP2O7·2H2O.
H atoms were located from difference Fourier maps and were restrained to lie 0.96 Å from their carrier atoms, with fixed displacement parameters of 0.035 Å2. H2 was split into two half-occupied positions around a centre of inversion.
Data collection: KappaCCD; cell refinement: HKL SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: DIRDIF96 (Beurskens et al., 1996); program(s) used to refine structure: Xtal3.7 (Hall et al., 2000) CRYLSQ; molecular graphics: PLATON (Spek, 2003), ORTEP (Johnson, 1970), PLUTON (Spek, 1991); software used to prepare material for publication: Xtal BONDLA CIFIO PLATON.
Crystal data top
KHCoP2O7·2H2O | F(000) = 612 |
Mr = 309.01 | Dx = 2.623 Mg m−3 |
Orthorhombic, Pnma | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -p 2ac 2n | Cell parameters from 955 reflections |
a = 15.4724 (15) Å | θ = 2.6–27.5° |
b = 7.7881 (8) Å | µ = 3.16 mm−1 |
c = 6.4942 (6) Å | T = 250 K |
V = 782.56 (14) Å3 | Plate, colourless |
Z = 4 | 0.2 × 0.2 × 0.04 mm |
Data collection top
Nonius KappaCCD diffractometer | 955 reflections with F2 > .00 sig(F2) |
Radiation source: fine-focus sealed tube | Rint = 0.041 |
ϕ–scans | θmax = 27.5°, θmin = 2.6° |
Absorption correction: empirical (using intensity measurements) MULABS; Blessing, 1995 | h = −15→20 |
Tmin = 0.569, Tmax = 0.669 | k = −10→8 |
4664 measured reflections | l = −7→8 |
955 independent reflections | |
Refinement top
Refinement on F2 | 0 constraints |
Least-squares matrix: full | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.034 | 1/[900. + 0.01*(σ(Fo2)2) + 0.01/(σ(Fo2))] |
wR(F2) = 0.039 | (Δ/σ)max = 0.042 |
S = 1.38 | Δρmax = 0.62 e Å−3 |
955 reflections | Δρmin = −0.97 e Å−3 |
80 parameters | Extinction correction: Zachariasen (1967), Eq22 p292 Cryst. Comp. Munksgaard 1970 |
3 restraints | Extinction coefficient: 1630 (119) |
Crystal data top
KHCoP2O7·2H2O | V = 782.56 (14) Å3 |
Mr = 309.01 | Z = 4 |
Orthorhombic, Pnma | Mo Kα radiation |
a = 15.4724 (15) Å | µ = 3.16 mm−1 |
b = 7.7881 (8) Å | T = 250 K |
c = 6.4942 (6) Å | 0.2 × 0.2 × 0.04 mm |
Data collection top
Nonius KappaCCD diffractometer | 955 independent reflections |
Absorption correction: empirical (using intensity measurements) MULABS; Blessing, 1995 | 955 reflections with F2 > .00 sig(F2) |
Tmin = 0.569, Tmax = 0.669 | Rint = 0.041 |
4664 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.034 | 3 restraints |
wR(F2) = 0.039 | H-atom parameters constrained |
S = 1.38 | Δρmax = 0.62 e Å−3 |
955 reflections | Δρmin = −0.97 e Å−3 |
80 parameters | |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | Occ. (<1) |
Co | 0.30492 (4) | 0.75000 | 0.56152 (11) | 0.0108 (3) | |
K | 0.53494 (7) | 0.75000 | 0.61789 (19) | 0.0189 (5) | |
P | 0.13604 (5) | 0.56130 (10) | 0.36122 (14) | 0.0106 (4) | |
O1 | 0.1125 (2) | 0.75000 | 0.2732 (6) | 0.0137 (16) | |
O2 | 0.07528 (13) | 0.5311 (3) | 0.5457 (4) | 0.0149 (11) | |
H2 | 0.018 (3) | 0.516 (14) | 0.494 (18) | 0.03500* | .50000 |
O3 | 0.11494 (12) | 0.4429 (3) | 0.1864 (4) | 0.0136 (10) | |
O4 | 0.22892 (13) | 0.5616 (3) | 0.4301 (4) | 0.0141 (10) | |
O5w | 0.3944 (2) | 0.75000 | 0.3090 (6) | 0.0176 (17) | |
H5w | 0.404 (3) | 0.656 (3) | 0.218 (5) | 0.03500* | |
O6w | 0.2153 (2) | 0.75000 | 0.8164 (6) | 0.0160 (17) | |
H6w | 0.233 (3) | 0.663 (4) | 0.912 (5) | 0.03500* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Co | 0.0105 (3) | 0.0087 (3) | 0.0133 (3) | 0.00000 | −0.0012 (3) | 0.00000 |
K | 0.0156 (5) | 0.0219 (5) | 0.0191 (6) | 0.00000 | 0.0001 (5) | 0.00000 |
P | 0.0102 (3) | 0.0075 (3) | 0.0140 (4) | −0.0005 (3) | 0.0003 (4) | −0.0009 (4) |
O1 | 0.0180 (16) | 0.0101 (12) | 0.0132 (19) | 0.00000 | −0.0035 (15) | 0.00000 |
O2 | 0.0129 (10) | 0.0168 (10) | 0.0149 (13) | −0.0013 (8) | 0.0005 (10) | 0.0004 (11) |
O3 | 0.0136 (10) | 0.0113 (8) | 0.0157 (13) | −0.0019 (9) | −0.0019 (9) | −0.0041 (10) |
O4 | 0.0131 (10) | 0.0082 (9) | 0.0211 (12) | 0.0002 (8) | −0.0034 (10) | −0.0027 (11) |
O5w | 0.0247 (18) | 0.0140 (14) | 0.0141 (19) | 0.00000 | 0.0044 (16) | 0.00000 |
O6w | 0.0172 (17) | 0.0115 (14) | 0.0193 (19) | 0.00000 | −0.0001 (15) | 0.00000 |
Geometric parameters (Å, º) top
Co—O3 | 2.110 (2) | K—O2 | 2.840 (3) |
Co—O3i | 2.110 (2) | K—O5w | 2.958 (4) |
Co—O4 | 2.065 (2) | P—O1 | 1.618 (2) |
Co—O4 | 2.065 (2) | P—O2 | 1.541 (2) |
Co—O5w | 2.146 (4) | P—O3 | 1.499 (2) |
Co—O6w | 2.159 (4) | P—O4 | 1.505 (2) |
Co—K | 3.5778 (12) | O2—H2 | 0.96 (6) |
K—O3i | 2.798 (2) | H2—H2i | 0.61 (9) |
K—O3 | 2.798 (2) | O5w—H5w | 0.96 (3) |
K—O1 | 2.809 (4) | O5w—H5w | 0.96 (3) |
K—O6w | 2.823 (3) | O6w—H6w | 0.96 (3) |
K—O2 | 2.840 (3) | O6w—H6w | 0.96 (3) |
| | | |
H6w···H6w | 1.35 (4) | P···O5w | 3.815 (3) |
H5w···H5w | 1.47 (4) | O1···O2 | 3.824 (3) |
O2···H2i | 1.51 (6) | O1···O2 | 3.824 (3) |
O4···H6w | 1.85 (3) | O5w···H6w | 3.84 (3) |
O2···H5w | 1.86 (3) | O5w···H6w | 3.84 (3) |
P···H2 | 2.05 (7) | P···H2ii | 3.86 (10) |
H2···H5w | 2.31 (10) | O1···O6w | 3.870 (5) |
O2···O2i | 2.453 (3) | H2···O4i | 3.90 (5) |
O1···O3ii | 2.458 (2) | K···Pi | 3.9209 (12) |
O1···O3 | 2.458 (2) | K···P | 3.9209 (12) |
H2···H5w | 2.49 (9) | P···H6w | 3.92 (3) |
O2···O4 | 2.504 (3) | K···O2i | 3.927 (2) |
O2···O3 | 2.509 (3) | K···O2 | 3.927 (2) |
O1···O2 | 2.524 (4) | Co···O2 | 3.942 (2) |
O1···O2ii | 2.524 (4) | Co···O2 | 3.942 (2) |
O1···O4ii | 2.537 (3) | O4···O5w | 3.948 (4) |
O1···O4 | 2.537 (3) | P···H6w | 3.96 (3) |
O3···O4 | 2.544 (3) | P···H5w | 3.97 (3) |
H2···O3 | 2.56 (10) | H5w···O6w | 3.98 (4) |
Co···H6w | 2.62 (3) | O2···H5w | 3.99 (3) |
Co···H6w | 2.62 (3) | O4···H6w | 3.99 (3) |
P···H2 | 2.63 (6) | O2···O4 | 3.991 (3) |
O4···O6w | 2.679 (3) | O3···H6w | 3.99 (3) |
P···H6w | 2.69 (4) | O2···O5w | 4.005 (4) |
O1···H2 | 2.74 (10) | K···P | 4.0062 (14) |
O1···H2ii | 2.74 (10) | K···P | 4.0062 (14) |
Co···H5w | 2.81 (4) | P···O6w | 4.023 (4) |
Co···H5w | 2.81 (4) | O2···O4 | 4.034 (3) |
O2···O5w | 2.818 (3) | P···O3ii | 4.038 (2) |
O3···O5w | 2.878 (4) | K···O5w | 4.0722 (11) |
O3···H6w | 2.89 (4) | K···O5w | 4.0722 (11) |
O4···O6w | 2.914 (4) | P···O3 | 4.100 (2) |
P···H5w | 2.93 (3) | O1···O4 | 4.107 (4) |
O3···O4 | 2.934 (3) | O1···O4 | 4.107 (4) |
O4···O4 | 2.935 (3) | K···O1 | 4.132 (4) |
H2···O3i | 2.94 (9) | P···O5w | 4.166 (3) |
P···Pii | 2.9393 (11) | O3···O5w | 4.167 (3) |
O3···O3i | 3.004 (3) | O3···O4 | 4.174 (3) |
O4···O5w | 3.054 (4) | O2···O6w | 4.184 (3) |
O1···H6w | 3.08 (3) | Co···O6w | 4.2185 (15) |
O1···H6w | 3.08 (3) | Co···O6w | 4.2185 (15) |
O3···H6w | 3.08 (3) | O5w···O6w | 4.232 (5) |
K···H2 | 3.12 (11) | P···H5w | 4.24 (4) |
K···H2 | 3.12 (11) | O5w···O6w | 4.2485 (19) |
O4···H5w | 3.13 (4) | O5w···O6w | 4.2485 (19) |
O3···O6w | 3.141 (3) | O4···O6w | 4.252 (4) |
O2···H5w | 3.15 (3) | Co···O2 | 4.256 (2) |
K···H6w | 3.15 (4) | Co···O2i | 4.256 (2) |
K···H6w | 3.15 (4) | O2···O3 | 4.262 (3) |
O3···H5w | 3.15 (3) | P···O5w | 4.273 (3) |
O4···H6w | 3.16 (3) | O5w···O6w | 4.305 (5) |
H2···O5w | 3.21 (10) | P···H5w | 4.31 (4) |
O4···H6w | 3.23 (3) | O3···O5w | 4.316 (4) |
Co···P | 3.2404 (10) | K···K | 4.3218 (8) |
Co···Pi | 3.2404 (10) | K···K | 4.3218 (8) |
O4···H5w | 3.25 (4) | Co···O1 | 4.3226 (16) |
O1···H2 | 3.26 (9) | Co···O1 | 4.3226 (16) |
O1···H2 | 3.26 (9) | P···O4 | 4.351 (2) |
Co···P | 3.2679 (10) | P···O5w | 4.354 (3) |
Co···P | 3.2679 (10) | O1···O5w | 4.368 (5) |
O2···O6w | 3.270 (4) | P···H2 | 4.37 (10) |
H2···O5w | 3.29 (10) | O2···O2 | 4.379 (3) |
O2···H5w | 3.30 (4) | K···H2ii | 4.38 (11) |
P···O4ii | 3.300 (2) | K···H2 | 4.38 (11) |
H5w···H6w | 3.30 (5) | P···O3 | 4.394 (2) |
K···H2i | 3.31 (11) | K···O4 | 4.397 (2) |
K···H2 | 3.31 (11) | K···O4 | 4.397 (2) |
O1···H5w | 3.31 (4) | Co···O2 | 4.410 (2) |
O1···H5w | 3.31 (4) | Co···O2 | 4.410 (2) |
H2···O4 | 3.31 (5) | Co···H6w | 4.41 (3) |
K···O3ii | 3.341 (2) | Co···H6w | 4.41 (3) |
K···O3 | 3.341 (2) | K···O4 | 4.447 (2) |
P···O6w | 3.354 (2) | K···O4 | 4.447 (2) |
O1···O6w | 3.366 (5) | K···H5w | 4.45 (3) |
K···H5w | 3.38 (4) | K···H5w | 4.45 (3) |
K···H5w | 3.38 (4) | Co···O3 | 4.505 (2) |
P···H6w | 3.38 (3) | Co···O3 | 4.505 (2) |
H2···H5w | 3.38 (11) | K···H2 | 4.62 (11) |
H2···H5w | 3.40 (10) | K···H2 | 4.62 (11) |
P···O2 | 3.402 (2) | K···O1 | 4.6246 (19) |
O2···O2 | 3.409 (3) | K···O1 | 4.6246 (19) |
Co···H6w | 3.41 (3) | K···O2 | 4.638 (3) |
Co···H6w | 3.41 (3) | K···O2 | 4.638 (3) |
O1···O5w | 3.417 (5) | Co···K | 4.6672 (13) |
O2···O3i | 3.425 (3) | K···O2ii | 4.676 (3) |
O2···H6w | 3.44 (4) | K···O2 | 4.676 (3) |
O4···O4 | 3.448 (3) | P···P | 4.6779 (11) |
O4···O4 | 3.448 (3) | Co···K | 4.7603 (8) |
Co···O4i | 3.448 (2) | Co···K | 4.7603 (8) |
Co···O4 | 3.448 (2) | Co···O4 | 4.793 (2) |
O4···H6w | 3.46 (3) | Co···O4 | 4.793 (2) |
K···H5w | 3.47 (3) | K···H5w | 4.84 (3) |
K···H5w | 3.47 (3) | K···H5w | 4.84 (3) |
H5w···H6w | 3.50 (5) | P···P | 4.8488 (12) |
Co···O1 | 3.517 (3) | K···O4ii | 4.881 (3) |
P···O2ii | 3.521 (2) | K···O4 | 4.881 (3) |
O3···H6w | 3.52 (3) | P···P | 4.8879 (12) |
P···O6w | 3.522 (3) | P···P | 4.8879 (12) |
O3···H5w | 3.55 (3) | K···O5w | 4.987 (4) |
O2···H6w | 3.56 (4) | K···H6w | 5.09 (4) |
H5w···H6w | 3.59 (5) | K···H6w | 5.09 (4) |
P···O4 | 3.622 (2) | K···O4 | 5.105 (2) |
O5w···H6w | 3.65 (4) | K···O4 | 5.105 (2) |
O5w···H6w | 3.65 (4) | K···O6w | 5.110 (3) |
O2···H2 | 3.65 (11) | K···O4i | 5.164 (2) |
P···H5w | 3.70 (4) | K···O4 | 5.164 (2) |
O3···H5w | 3.71 (4) | K···O3 | 5.260 (3) |
H5w···O6w | 3.71 (3) | K···O3 | 5.260 (3) |
P···H6w | 3.72 (3) | K···P | 5.6401 (13) |
O3···O6w | 3.730 (4) | K···P | 5.6401 (13) |
O4···H5w | 3.75 (4) | Co···K | 6.0759 (14) |
K···Pii | 3.7800 (14) | K···K | 6.4003 (14) |
K···P | 3.7800 (14) | K···K | 6.4003 (14) |
O3···H5w | 3.79 (3) | K···K | 6.4942 (18) |
O4···H6w | 3.79 (3) | K···K | 6.4942 (18) |
| | | |
O4—Co—O4 | 90.58 (9) | O6w—K—O2 | 70.52 (8) |
O4—Co—O3 | 178.04 (9) | O6w—K—O2 | 70.52 (8) |
O4—Co—O3i | 89.29 (8) | O6w—K—O5w | 146.00 (11) |
O4—Co—O5w | 92.96 (9) | O6w—K—Co | 177.18 (9) |
O4—Co—O6w | 87.21 (9) | O2—K—O2 | 73.75 (7) |
O4—Co—K | 127.49 (6) | O2—K—O5w | 133.08 (6) |
O4—Co—O3 | 89.29 (8) | O2—K—Co | 107.30 (5) |
O4—Co—O3i | 178.04 (9) | O2—K—O5w | 133.08 (6) |
O4—Co—O5w | 92.96 (9) | O2—K—Co | 107.30 (5) |
O4—Co—O6w | 87.21 (9) | O5w—K—Co | 36.82 (7) |
O4—Co—K | 127.49 (6) | O1—P—O2 | 106.01 (15) |
O3—Co—O3i | 90.77 (8) | O1—P—O3 | 104.03 (16) |
O3—Co—O5w | 85.09 (9) | O1—P—O4 | 108.56 (14) |
O3—Co—O6w | 94.74 (9) | O2—P—O3 | 111.23 (12) |
O3—Co—K | 51.39 (6) | O2—P—O4 | 110.59 (13) |
O3i—Co—O5w | 85.09 (9) | O3—P—O4 | 115.72 (12) |
O3i—Co—O6w | 94.74 (9) | Pii—O1—P | 130.5 (2) |
O3i—Co—K | 51.39 (6) | Pii—O1—K | 114.54 (12) |
O5w—Co—O6w | 179.76 (14) | P—O1—K | 114.54 (12) |
O5w—Co—K | 55.69 (10) | H2—O2—P | 108 (6) |
O6w—Co—K | 124.07 (10) | H2—O2—K | 98 (6) |
O3i—K—O3 | 64.92 (6) | P—O2—K | 129.84 (11) |
O3i—K—O1 | 119.86 (8) | H2i—H2—O2 | 148 (19) |
O3i—K—O6w | 142.67 (6) | P—O3—Co | 126.96 (12) |
O3i—K—O2 | 112.45 (8) | P—O3—K | 129.15 (11) |
O3i—K—O2 | 74.80 (6) | Co—O3—K | 92.51 (8) |
O3i—K—O5w | 59.92 (7) | P—O4—Co | 131.87 (13) |
O3i—K—Co | 36.10 (5) | H5w—O5w—H5w | 101 (3) |
O3—K—O1 | 119.86 (8) | H5w—O5w—Co | 125 (2) |
O3—K—O6w | 142.67 (6) | H5w—O5w—K | 108 (2) |
O3—K—O2 | 74.80 (6) | H5w—O5w—Co | 125 (2) |
O3—K—O2 | 112.45 (8) | H5w—O5w—K | 108 (2) |
O3—K—O5w | 59.92 (7) | Co—O5w—K | 87.49 (12) |
O3—K—Co | 36.10 (5) | H6w—O6w—H6w | 90 (3) |
O1—K—O6w | 73.40 (11) | H6w—O6w—Co | 108 (2) |
O1—K—O2 | 126.98 (7) | H6w—O6w—K | 101 (2) |
O1—K—O2 | 126.98 (7) | H6w—O6w—Co | 108 (2) |
O1—K—O5w | 72.60 (10) | H6w—O6w—K | 101 (2) |
O1—K—Co | 109.42 (8) | Co—O6w—K | 138.64 (16) |
| | | |
O3—Co—K—O1 | 114.36 (8) | O3i—Co—O6w—H6w | −93 (2) |
O3—Co—K—O2 | −104.58 (10) | O3i—Co—O6w—K | 134.41 (6) |
O3—Co—K—O3 | 0.00 (11) | O3i—Co—O6w—H6w | 2 (2) |
O3—Co—K—O5w | 114.36 (8) | O4—Co—O6w—H6w | 177 (2) |
O3—Co—K—O6w | −65.64 (9) | O4—Co—O6w—K | 45.36 (6) |
O3—Co—K—O2 | −26.70 (9) | O4—Co—O6w—H6w | −87 (2) |
O3—Co—K—O3i | −131.29 (12) | K—Co—O3i—K | 0.00 (3) |
O4—Co—K—O1 | 63.60 (9) | O3—Co—O3i—K | 35.96 (8) |
O4—Co—K—O2 | −155.34 (10) | O4—Co—O3i—K | −56 (2) |
O4—Co—K—O3 | −50.76 (12) | O5w—Co—O3i—K | −49.05 (9) |
O4—Co—K—O5w | 63.60 (9) | O6w—Co—O3i—K | 130.78 (8) |
O4—Co—K—O6w | −116.40 (10) | O4—Co—O3i—K | −142.08 (9) |
O4—Co—K—O2 | −77.46 (11) | Co—K—O1—P | 93.30 (16) |
O4—Co—K—O3i | 177.95 (12) | Co—K—O1—Pii | −93.30 (16) |
O5w—Co—K—O1 | −0.0001 | O2—K—O1—P | −38.0 (2) |
O5w—Co—K—O2 | 141.06 (5) | O2—K—O1—Pii | 135.39 (14) |
O5w—Co—K—O3 | −114.36 (8) | O3—K—O1—P | 131.53 (15) |
O5w—Co—K—O5w | 0.0001 | O3—K—O1—Pii | −55.1 (2) |
O5w—Co—K—O6w | 180.000 (5) | O5w—K—O1—P | 93.30 (16) |
O5w—Co—K—O2 | −141.06 (5) | O5w—K—O1—Pii | −93.30 (16) |
O5w—Co—K—O3i | 114.36 (8) | O6w—K—O1—P | −86.70 (16) |
O6w—Co—K—O1 | 180.0000 | O6w—K—O1—Pii | 86.70 (16) |
O6w—Co—K—O2 | −38.94 (5) | O2—K—O1—P | −135.39 (14) |
O6w—Co—K—O3 | 65.64 (8) | O2—K—O1—Pii | 38.0 (2) |
O6w—Co—K—O5w | 180.0000 | O3i—K—O1—P | 55.1 (2) |
O6w—Co—K—O6w | −0.000 (6) | O3i—K—O1—Pii | −131.53 (15) |
O6w—Co—K—O2 | 38.94 (5) | Co—K—O2—H2 | 11 (7) |
O6w—Co—K—O3i | −65.64 (8) | Co—K—O2—P | 132.57 (14) |
O3i—Co—K—O1 | −114.36 (8) | O1—K—O2—H2 | 143 (7) |
O3i—Co—K—O2 | 26.70 (9) | O1—K—O2—P | −95.33 (16) |
O3i—Co—K—O3 | 131.29 (12) | O3—K—O2—H2 | −27 (7) |
O3i—Co—K—O5w | −114.36 (8) | O3—K—O2—P | 94.48 (15) |
O3i—Co—K—O6w | 65.64 (9) | O5w—K—O2—H2 | 42 (7) |
O3i—Co—K—O2 | 104.58 (10) | O5w—K—O2—P | 163.62 (14) |
O3i—Co—K—O3i | −0.00 (11) | O6w—K—O2—H2 | −168 (7) |
O4—Co—K—O1 | −63.60 (9) | O6w—K—O2—P | −45.55 (15) |
O4—Co—K—O2 | 77.46 (11) | O2—K—O2—H2 | −93 (7) |
O4—Co—K—O3 | −177.95 (12) | O2—K—O2—P | 29.06 (15) |
O4—Co—K—O5w | −63.60 (9) | O3i—K—O2—H2 | 27 (7) |
O4—Co—K—O6w | 116.40 (10) | O3i—K—O2—P | 148.50 (16) |
O4—Co—K—O2 | 155.34 (10) | Co—K—O3—Co | 0.00 (3) |
O4—Co—K—O3i | 50.76 (12) | Co—K—O3—P | −144.3 (2) |
K—Co—O3—K | −0.00 (3) | O1—K—O3—Co | −82.15 (9) |
K—Co—O3—P | 145.5 (2) | O1—K—O3—P | 133.57 (14) |
O4—Co—O3—K | 142.08 (9) | O2—K—O3—Co | 88.82 (9) |
O4—Co—O3—P | −72.45 (17) | O2—K—O3—P | −55.46 (17) |
O5w—Co—O3—K | 49.05 (8) | O5w—K—O3—Co | −39.12 (7) |
O5w—Co—O3—P | −165.48 (17) | O5w—K—O3—P | 176.61 (18) |
O6w—Co—O3—K | −130.78 (8) | O6w—K—O3—Co | 175.76 (13) |
O6w—Co—O3—P | 14.69 (17) | O6w—K—O3—P | 31.5 (2) |
O3i—Co—O3—K | −35.96 (8) | O2—K—O3—Co | 153.60 (9) |
O3i—Co—O3—P | 109.51 (17) | O2—K—O3—P | 9.33 (15) |
O4—Co—O3—K | 56 (2) | O3i—K—O3—Co | 29.26 (7) |
O4—Co—O3—P | −159 (2) | O3i—K—O3—P | −115.01 (17) |
K—Co—O4—P | −166.27 (14) | Co—K—O5w—Co | 0.0001 |
O3—Co—O4—P | 156.5 (2) | Co—K—O5w—H5w | −126 (2) |
O5w—Co—O4—P | −118.5 (2) | Co—K—O5w—H5w | 126 (2) |
O6w—Co—O4—P | 61.7 (2) | O1—K—O5w—Co | −180.0000 |
O3i—Co—O4—P | −112 (2) | O1—K—O5w—H5w | 54 (2) |
O4—Co—O4—P | −25.5 (2) | O1—K—O5w—H5w | −54 (2) |
K—Co—O5w—K | −0.0001 | O2—K—O5w—Co | −55.25 (9) |
K—Co—O5w—H5w | 110 (3) | O2—K—O5w—H5w | 179 (2) |
K—Co—O5w—H5w | −110 (3) | O2—K—O5w—H5w | 71 (2) |
O3—Co—O5w—K | −45.60 (6) | O3—K—O5w—Co | 38.33 (6) |
O3—Co—O5w—H5w | 65 (3) | O3—K—O5w—H5w | −88 (2) |
O3—Co—O5w—H5w | −156 (3) | O3—K—O5w—H5w | 164 (2) |
O4—Co—O5w—K | −134.64 (6) | O6w—K—O5w—Co | −180.0000 |
O4—Co—O5w—H5w | −24 (3) | O6w—K—O5w—H5w | 54 (2) |
O4—Co—O5w—H5w | 115 (3) | O6w—K—O5w—H5w | −54 (2) |
O6w—Co—O5w—K | −0.003 (3) | O2—K—O5w—Co | 55.25 (9) |
O6w—Co—O5w—H5w | 110 (3) | O2—K—O5w—H5w | −71 (2) |
O6w—Co—O5w—H5w | −110 (3) | O2—K—O5w—H5w | −179 (2) |
O3i—Co—O5w—K | 45.60 (6) | O3i—K—O5w—Co | −38.33 (6) |
O3i—Co—O5w—H5w | 156 (3) | O3i—K—O5w—H5w | −164 (2) |
O3i—Co—O5w—H5w | −65 (3) | O3i—K—O5w—H5w | 88 (2) |
O4—Co—O5w—K | 134.64 (6) | Co—K—O3i—Co | −0.00 (3) |
O4—Co—O5w—H5w | −115 (3) | O1—K—O3i—Co | 82.15 (9) |
O4—Co—O5w—H5w | 24 (3) | O2—K—O3i—Co | −153.60 (9) |
K—Co—O6w—H6w | −48 (2) | O3—K—O3i—Co | −29.26 (7) |
K—Co—O6w—K | 180.0000 (15) | O5w—K—O3i—Co | 39.12 (7) |
K—Co—O6w—H6w | 48 (2) | O6w—K—O3i—Co | −175.76 (13) |
O3—Co—O6w—H6w | −2 (2) | O2—K—O3i—Co | −88.82 (9) |
O3—Co—O6w—K | −134.41 (6) | O2—P—O1—K | −112.01 (16) |
O3—Co—O6w—H6w | 93 (2) | O2—P—O1—Pii | 75.9 (3) |
O4—Co—O6w—H6w | 87 (2) | O4—P—O1—K | 129.15 (15) |
O4—Co—O6w—K | −45.36 (6) | O4—P—O1—Pii | −42.9 (3) |
O4—Co—O6w—H6w | −177 (2) | O3—P—O1—K | 5.38 (18) |
O5w—Co—O6w—H6w | −48 (2) | O3—P—O1—Pii | −166.7 (2) |
O5w—Co—O6w—K | −179.997 (3) | K—O2—H2—H2i | −71 (35) |
O5w—Co—O6w—H6w | 48 (2) | P—O2—H2—H2i | 152 (33) |
Symmetry codes: (i) −x+1/2, y+1/2, z+1/2; (ii) x+1/2, y, −z+1/2. |
Experimental details
Crystal data |
Chemical formula | KHCoP2O7·2H2O |
Mr | 309.01 |
Crystal system, space group | Orthorhombic, Pnma |
Temperature (K) | 250 |
a, b, c (Å) | 15.4724 (15), 7.7881 (8), 6.4942 (6) |
V (Å3) | 782.56 (14) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 3.16 |
Crystal size (mm) | 0.2 × 0.2 × 0.04 |
|
Data collection |
Diffractometer | Nonius KappaCCD diffractometer |
Absorption correction | Empirical (using intensity measurements) MULABS; Blessing, 1995 |
Tmin, Tmax | 0.569, 0.669 |
No. of measured, independent and observed [F2 > .00 sig(F2)] reflections | 4664, 955, 955 |
Rint | 0.041 |
(sin θ/λ)max (Å−1) | 0.649 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.034, 0.039, 1.38 |
No. of reflections | 955 |
No. of parameters | 80 |
No. of restraints | 3 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.62, −0.97 |
Selected geometric parameters (Å, º) topCo—O3 | 2.110 (2) | Co—O6w | 2.159 (4) |
Co—O3i | 2.110 (2) | P—O1 | 1.618 (2) |
Co—O4 | 2.065 (2) | P—O2 | 1.541 (2) |
Co—O4 | 2.065 (2) | P—O3 | 1.499 (2) |
Co—O5w | 2.146 (4) | P—O4 | 1.505 (2) |
| | | |
O1—P—O2 | 106.01 (15) | O2—P—O4 | 110.59 (13) |
O1—P—O3 | 104.03 (16) | O3—P—O4 | 115.72 (12) |
O1—P—O4 | 108.56 (14) | Pii—O1—P | 130.5 (2) |
O2—P—O3 | 111.23 (12) | | |
Symmetry codes: (i) −x+1/2, y+1/2, z+1/2; (ii) x+1/2, y, −z+1/2. |
Hydrogen bonding geometry (Å, °) topD-H····A | D-H | H····A | D-A | D-H····A |
O5w-H5w····O2 | 0.96 (3) | 1.86 (3) | 2.817 (3) | 178 (4) |
O6w-H6w····O4 | 0.96 (3) | 1.85 (3) | 2.679 (3) | 143 (3) |
Hydrated or anhydrous pyrophosphates containing acidic anionic [H3P2O7]−,[H2P2O7]2− or [HP2O7]3− entities are topics of wide-spread interest in the crystallographic literature (Corbridge, 1957; Dumas et al., 1973; Mathew & Schroeder, 1977; Durif & Averbuch-Pouchot, 1982; Haromy-Tuli et al., 1984; Effenberger, 1987; Haromy-Tuli et al., 1990; Simonova et al., 1991; Byrappa & Umesh Dutt, 1994; Hsu & Wang, 1999; Chehimi et al., 2001; Blum et al., 2002; Ivashkevich et al., 2002; Chehimi et al., 2002). The present paper is an extension of our earlier work on the acidic pyrophosphates that we have recently realised and analyzed, viz. KHMP2O7·2H2O (M = Mn, Zn) (Assaaoudi et al., 2002) and Na4Mg2(H2P2O7)4·8H2O (Harcharras et al., accepted). We report here the crystal structure of the new pyrophosphate, KHCoP2O7·2H2O.
The pyrophosphate group consists of two symmetry-related PO4 groups, with the bridging atom (O1) in a special position. The Co-atom octahedron and pyrophosphate groups are depicted in Figs. 1a and 1 b. The three-dimensional structure is built from acidic pyrophosphate–CoII layers stacked along the c axis (Fig. 2), alternating with layers of K+ ions. The Co2+ ions are octahedrally surrounded by four O atoms from three different pyrophosphate anions and by two water molecules (Table 1).
It is possible to distinguish three types of P—O distances, viz. P—O1 bonds [1.618 (2) Å, which is the longest bond] corresponding to the bridging O atoms, P—O2 bonds [1.541 (2) Å] involving hydroxyl groups, and P—O(3,4) bonds corresponding to the external O atoms [mean 1.502 (2) Å, which are the shortest bonds). The HP2O73− anions show an eclipsed conformation, with a P—O—P bridging angle of 130.5 (2)°; the average O—P—O angle is 109.4°. The hydrogen-bond bridging is depicted in Table 2.