supplementary materials


Acta Cryst. (2013). E69, i83    [ doi:10.1107/S1600536813030717 ]

Hexa­aqua­nickel(II) di­hydrogen hypodiphosphate

M. Gjikaj, P. Wu and N.-P. Pook

Abstract top

The asymmetric unit of the title compound, [Ni(H2O)6](H2P2O6), contains one-half of the hexa­aqua­nickel(II) cation and one-half of the di­hydrogen hypodiphosphate anion. In the complex cation, the Ni2+ atom is located on an inversion center and has an octa­hedral coordination sphere. The P-P distance in the centrosymmetric anion is 2.1853 (7) Å. In the crystal, discrete [Ni(H2O)6]2+ cations and (H2P2O6)2- anions are stacked in columns parallel to the c axis and are linked into a three-dimensional network by medium-strength O-H...O hydrogen bonds.

Comment top

Although main group hypodiphosphates have rather academic inter­est, the di­hydrogen sodium and ammonium derivates, (M2H2P2O6 with M = Na+ and NH4+) (Collin & Willis, 1971), respective their hydrates, have certain practical use. Ammonium di­hydrogen hypodiphosphate-based powder material is applied as a green flame retardant and as a multipurpose extinguishing agent suitable for all classes of fire (Ruflin et al., 2007). Acidic Na2H2P2O6 solutions are applied for gravimetric precipitation and immobilization of uranium(IV) (Bloss & Henzel, 1967). The ferroelectricity of di­ammonium hypodiphosphate was discovered recently (Szklarz et al., 2011).

The crystal structures of transition metal hypodiphosphate 12-hydrates M2P2O6.12H2O (M = Co und Ni) were determined by Hagen & Jansen (1995) and Haag et al. (2005). However, the crystal structures of transition metal di­hydrogen hypodiphosphate hydrates have not been reported up to now.

The structure of the title compound, [Ni(H2O)6](H2P2O6) is characterized by discrete [Ni(H2O)6]2+ cations and (H2P2O6)2- anions (Fig. 1). The Ni2+ ion is located on an inversion centre and is o­cta­hedrally coordinated by water molecules. In the (H2P2O6)2- anion, which is located about an inversion centre, the tetra­valent phospho­rus atom is surrounded by three oxygen atoms and one additional phospho­rus atom with a P–P distance of 2.1854 (7) Å. The P–O bond lengths are ranging from 1.5050 (11) to 1.5816 (11) Å. All bond lengths and angles are well within the expected ranges (Wu et al., 2012) and are comparable to those found for Ni2P2O6. 12H2O (2.1700 (13) Å for the P—P bond; Haag et al., 2005), however with a characteristically longer P—OH distance in comparison with the P—O distance.

The (H2P2O6)2– anions are joined to ribbons parallel to [010] by rather strong hydrogen bonds (O···O 2.5919 (15) Å). Anions and complex cations are stacked alternately in columns parallel to [001], held together by medium-strength O—H···O hydrogen bonds (Fig. 2). The O···O distances between water molecules and (H2P2O6)2– ions range from 2.6822 (14) to 2.9132 (17) Å (Table 1). All hydrogen bonding inter­actions considered, a three-dimensional network structure is established in the crystal.

Experimental top

Disodium di­hydrogen hypodiphosphate was prepared using the procedure reported by Leininger & Chulski (1953). An aqueous solution of hypodi­phospho­ric acid was obtained by passing a saturated solution of disodium di­hydrogen hypodiphosphate through a cation exchange resin (Dowex 50WX2 50-100). Single crystals of hexa­aqua­nickel(II) di­hydrogenhypodiphosphate were prepared by adding nickel hydroxide (148 mg) to a solution of hypodi­phospho­ric acid (40 mL).

Refinement top

All hydrogen atoms were located in a difference Fourier map and were refined isotropically with no restraints.

Related literature top

For the synthesis of hypodiphosphates, see: Leininger & Chulski (1953). For applications of hypodiphosphates, see: Bloss & Henzel (1967); Ruflin et al. (2007); Szklarz et al. (2011). For the crystal structures of transition metal hypodiphosphate 12-hydrates, see: Hagen & Jansen (1995); Haag et al. (2005). For the crystal structures of hydrogen hypodiphosphate compounds, see: Collin & Willis (1971); Szafranowska et al. (2012); Wu et al. (2012).

Computing details top

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA (Stoe & Cie, 2002); data reduction: X-AREA (Stoe & Cie, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2012); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009) and publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. The molecular entities in the title compound with atom labels and displacement ellipsoids drawn at the 50% probability level. [Symmetry codes: (i) -x + 1, -y + 1, -z + 1; (ii) -x, -y, -z + 1.]
[Figure 2] Fig. 2. The crystal structure of the title compound viewed along the b axis. Displacement ellipsoids are drawn at the 50% probability level. O—H···O hydrogen bonds are shown as dashed lines.
Hexaaquanickel(II) dihydrogen hypodiphosphate top
Crystal data top
[Ni(H2O)6](H2P2O6)F(000) = 336
Mr = 326.76block, green
Monoclinic, P21/nDx = 2.041 Mg m3
Hall symbol: -P 2ynMo Kα radiation, λ = 0.71073 Å
a = 9.3031 (14) ÅCell parameters from 8465 reflections
b = 5.8892 (8) Åθ = 2.9–30.5°
c = 9.7620 (12) ŵ = 2.18 mm1
β = 96.111 (11)°T = 223 K
V = 531.80 (13) Å3Block, green
Z = 20.29 × 0.25 × 0.22 mm
Data collection top
Stoe IPDS-II
diffractometer
1601 independent reflections
Radiation source: fine-focus sealed tube1546 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.056
ω–scansθmax = 30.5°, θmin = 2.9°
Absorption correction: numerical
(X-SHAPE and X-RED; Stoe & Cie, 1999, 2001)
h = 1313
Tmin = 0.537, Tmax = 0.619k = 88
8061 measured reflectionsl = 1313
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.029Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.074All H-atom parameters refined
S = 1.16 w = 1/[σ2(Fo2) + (0.0423P)2 + 0.1511P]
where P = (Fo2 + 2Fc2)/3
1601 reflections(Δ/σ)max = 0.001
98 parametersΔρmax = 0.44 e Å3
0 restraintsΔρmin = 1.08 e Å3
Crystal data top
[Ni(H2O)6](H2P2O6)V = 531.80 (13) Å3
Mr = 326.76Z = 2
Monoclinic, P21/nMo Kα radiation
a = 9.3031 (14) ŵ = 2.18 mm1
b = 5.8892 (8) ÅT = 223 K
c = 9.7620 (12) Å0.29 × 0.25 × 0.22 mm
β = 96.111 (11)°
Data collection top
Stoe IPDS-II
diffractometer
1601 independent reflections
Absorption correction: numerical
(X-SHAPE and X-RED; Stoe & Cie, 1999, 2001)
1546 reflections with I > 2σ(I)
Tmin = 0.537, Tmax = 0.619Rint = 0.056
8061 measured reflectionsθmax = 30.5°
Refinement top
R[F2 > 2σ(F2)] = 0.029All H-atom parameters refined
wR(F2) = 0.074Δρmax = 0.44 e Å3
S = 1.16Δρmin = 1.08 e Å3
1601 reflectionsAbsolute structure: ?
98 parametersAbsolute structure parameter: ?
0 restraintsRogers parameter: ?
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 F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 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
xyzUiso*/Ueq
Ni0.50000.50000.50000.01306 (10)
P0.06859 (3)0.14612 (5)0.53007 (3)0.01116 (10)
O10.20361 (11)0.05887 (19)0.61176 (12)0.0177 (2)
O20.08555 (10)0.28724 (17)0.40289 (10)0.01404 (19)
O30.02399 (12)0.28534 (18)0.62787 (11)0.0185 (2)
O40.64678 (11)0.6071 (2)0.65421 (12)0.0211 (2)
O50.48685 (12)0.20885 (19)0.61392 (12)0.0204 (2)
O60.32539 (11)0.62296 (19)0.59655 (12)0.0180 (2)
H30.042 (3)0.436 (5)0.605 (3)0.037 (7)*
H4A0.620 (3)0.681 (5)0.719 (3)0.037 (7)*
H4B0.720 (3)0.664 (5)0.630 (3)0.042 (7)*
H5A0.407 (4)0.154 (5)0.607 (3)0.045 (8)*
H5B0.521 (3)0.223 (5)0.696 (3)0.039 (7)*
H6A0.296 (2)0.750 (4)0.581 (2)0.019 (5)*
H6B0.313 (3)0.584 (5)0.678 (3)0.036 (7)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Ni0.01080 (13)0.01511 (15)0.01334 (15)0.00152 (7)0.00159 (9)0.00086 (8)
P0.00991 (15)0.01073 (17)0.01287 (17)0.00066 (9)0.00128 (11)0.00094 (10)
O10.0130 (4)0.0173 (4)0.0219 (5)0.0003 (4)0.0026 (4)0.0023 (4)
O20.0140 (4)0.0134 (4)0.0151 (5)0.0015 (3)0.0037 (3)0.0017 (3)
O30.0251 (5)0.0138 (4)0.0179 (5)0.0040 (4)0.0086 (4)0.0022 (4)
O40.0138 (4)0.0332 (6)0.0169 (5)0.0071 (4)0.0043 (4)0.0090 (4)
O50.0194 (5)0.0207 (5)0.0204 (5)0.0044 (4)0.0005 (4)0.0028 (4)
O60.0180 (5)0.0194 (5)0.0172 (5)0.0040 (4)0.0041 (4)0.0003 (4)
Geometric parameters (Å, º) top
Ni—O42.0226 (11)P—O31.5814 (11)
Ni—O4i2.0227 (11)P—Pii2.1853 (7)
Ni—O5i2.0544 (11)O3—H30.92 (3)
Ni—O52.0544 (11)O4—H4A0.82 (3)
Ni—O62.0922 (11)O4—H4B0.82 (3)
Ni—O6i2.0922 (11)O5—H5A0.81 (3)
P—O11.5048 (10)O5—H5B0.84 (3)
P—O11.5048 (10)O6—H6A0.81 (2)
P—O21.5161 (10)O6—H6B0.84 (3)
O4—Ni—O4i180.0O1—P—O3109.55 (6)
O4—Ni—O5i93.91 (5)O1—P—O3109.55 (6)
O4i—Ni—O5i86.09 (5)O2—P—O3108.73 (6)
O4—Ni—O586.09 (5)O1—P—Pii107.70 (5)
O4i—Ni—O593.91 (5)O1—P—Pii107.70 (5)
O5i—Ni—O5179.999 (1)O2—P—Pii108.69 (5)
O4—Ni—O692.97 (5)O3—P—Pii103.32 (5)
O4i—Ni—O687.03 (5)O1—O1—P0 (10)
O5i—Ni—O692.80 (5)P—O3—H3116.7 (19)
O5—Ni—O687.20 (5)Ni—O4—H4A119.9 (19)
O4—Ni—O6i87.03 (5)Ni—O4—H4B115 (2)
O4i—Ni—O6i92.97 (5)H4A—O4—H4B109 (3)
O5i—Ni—O6i87.20 (5)Ni—O5—H5A114 (2)
O5—Ni—O6i92.80 (5)Ni—O5—H5B113 (2)
O6—Ni—O6i180.0H5A—O5—H5B112 (3)
O1—P—O10.00 (11)Ni—O6—H6A119.9 (16)
O1—P—O2117.86 (6)Ni—O6—H6B121.2 (19)
O1—P—O2117.86 (6)H6A—O6—H6B111 (2)
Symmetry codes: (i) x+1, y+1, z+1; (ii) x, y, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—H3···O2iii0.92 (3)1.68 (3)2.5919 (15)168 (3)
O4—H4A···O3iv0.82 (3)1.93 (3)2.7293 (16)165 (3)
O4—H4B···O2i0.82 (3)1.89 (3)2.6822 (14)162 (3)
O5—H5A···O10.81 (3)1.98 (3)2.7770 (15)171 (3)
O5—H5B···O2v0.84 (3)2.04 (3)2.8722 (16)171 (3)
O6—H6A···O1vi0.81 (2)2.05 (2)2.8163 (16)159 (2)
O6—H6B···O1iv0.84 (3)2.08 (3)2.9132 (17)168 (3)
Symmetry codes: (i) x+1, y+1, z+1; (iii) x, y+1, z+1; (iv) x+1/2, y+1/2, z+3/2; (v) x+1/2, y+1/2, z+1/2; (vi) x, y+1, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—H3···O2i0.92 (3)1.68 (3)2.5919 (15)168 (3)
O4—H4A···O3ii0.82 (3)1.93 (3)2.7293 (16)165 (3)
O4—H4B···O2iii0.82 (3)1.89 (3)2.6822 (14)162 (3)
O5—H5A···O10.81 (3)1.98 (3)2.7770 (15)171 (3)
O5—H5B···O2iv0.84 (3)2.04 (3)2.8722 (16)171 (3)
O6—H6A···O1v0.81 (2)2.05 (2)2.8163 (16)159 (2)
O6—H6B···O1ii0.84 (3)2.08 (3)2.9132 (17)168 (3)
Symmetry codes: (i) x, y+1, z+1; (ii) x+1/2, y+1/2, z+3/2; (iii) x+1, y+1, z+1; (iv) x+1/2, y+1/2, z+1/2; (v) x, y+1, z.
Acknowledgements top

no Acknowledgements

references
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