Buy article online - an online subscription or single-article purchase is required to access this article.
Download citation
Download citation
link to html
In the title compound, disodium cobalt tetrakis­(dihydrogen­phosphate) tetrahydrate, the CoII ion lies on an inversion centre and is octahedrally surrounded by two water molecules and four H2PO4 groups to give a cobalt complex anion of the form [Co(H2PO4)4(OH2)]2-. The three-dimensional framework results from hydrogen bonding between the anions. The relationship with the structures of Co(H2PO4)2·2H2O and K2CoP4O12·5H2O is discussed.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270199015279/gs1053sup1.cif
Contains datablocks I, GUES1

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270199015279/gs1053Isup2.hkl
Contains datablock I

Comment top

Les phosphates des métaux de transition forment une grande famille de composés à structures souvent ouvertes et pouvant dans certains cas présenter des propriétés physiques intéressantes: conduction et échange d'ions (Clearfield, 1982, 1988; Hong, 1976) ou doublage de fréquences en optique non linéaire (Bierlein & Vanherzeele, 1989; Bierlein et al., 1989).

Une étude bibliographique révèle que les systèmes A—Co—X—O (A = alcalin, X = P ou As) restent peu explorés, un nombre limité de phosphates et d'arséniates de cobalt y est reporté (Lii & Shih, 1994; Lujan, 1994; Kubel, 1994; Barmond & Barbier, 1996; Sanz et al., 1996; Horng et al., 1996). Dans ces derniers, l'association des polyèdres CoOn (n = 4 ou 5) e t de tétraèdres HnXO4 (n = 0, 1 ou 2), conduit à des charpentes mixtes pouvant être uni-, bi- ou tridimensionnelles. Nous présentons dans ce travail, l'étude et la discussion de la structure d'un nouveau phosphate de cobalt et de sodium de formulation Na2Co(H2PO4)4·4H2O.

La structure de Na2Co(H2PO4)4·4H2O est caractérisée par l'existence d'anions [Co(H2PO4)4(OH2)2]2- résultant de la connexion des octaèdres CoO4(OH2)2 aux tétraèdres PO2(OH)2 par la mize en commun de sommets oxygène (Fig. 1).

L'absence d'un encha^ınement direct entre ces anions est due à l'existence de molécules d'eau dans la sphère de coordination du Co et de groupements hydroxyle liés au phosphore. La cohésion de l'édifice structural est assurée par des liaisons hydrogène dont cinq sont fortes (Brown, 1976). Il en résulte un réseau tridimensionnel avec la formation de tunnels parallèles à la direction [001] où logent les cations Na+ (Fig. 2).

Les distances interatomiques dans cette structure sont conformes à celles rencontrées dans la bibliographie (Ichikawa, 1987; Effenberger, 1992). La coordinence octaèdrique du Co est confirmée par la coloration rose du cristal (Cotton & Wilkinson, 1980). Les calculs des forces de valences en utilisant les paramètres de Brown & Wu (1976) pour P1, P2, Co et Na conduisent aux valeurs respectives 5.01, 5.03, 1.98 e t 1.24 unités de valence. Ces valeurs sont en accord avec les états d'oxydation trouvés dans la structure. La comparaison de la structure de Na2Co(H2PO4)4·4H2O avec celles des phosphates de cobalt formées par le même type d'octaèdres CoO4(OH2)2 a permis de mettre en évidence une certaine analogie entre la structure du composé étudié et celles de Co(H2PO4)2·2H2O (Effenberger, 1992) et de K2CoP4O12·5H2O (Jouini et al., 1987). Dans Co(H2PO4)2·2H2O, chaque tétraèdre partage deux sommets différents avec deux octaèdres différents pour former des couches parallèles au plan (-101) e t reliées entre elles par des liaisons hydrogène. Deux polyèdres de nature différente, dans la structure étudiée, ne partagent qu'un seul sommet d'où la formation des unités Co(H2PO4)4(OH2)2.

On peut signaler que par élimination de quatre molécules d'eau entre les tétraèdres, il pourrait y avoir formation du cycle P4O12 et passage à la charpente anionique rencontrée dans le métaphosphate K2CoP4O12·5H2O.

Experimental top

La synthèse du composé étudié a été réalisée à partir d'une solution aqueuse de Co(NO3)2·6H2O, Na2CO3 et H3PO4 85% pris dans les proportions Na:Co:P = 2:1:4. Au bout de deux semaines et par évaporization libre de la solution à la température ambiante, des cristaux de couleur rose et de taille suffisante pour une étude structurale apparaissent.

Computing details top

Data collection: CAD-4 EXPRESS (Duisenberg, 1992; Macicek & Yordanov, 1992); cell refinement: CAD-4 EXPRESS; data reduction: MolEN (Fair, 1990); program(s) used to solve structure: SHELXS86 (Sheldrick, 1990); program(s) used to refine structure: SHELXL93 (Sheldrick, 1993); molecular graphics: ORTEPIII (Johnson & Burnett, 1997); software used to prepare material for publication: SHELXL93.

Figures top
[Figure 1] Fig. 1. Vue perspective ORTEP-3 (Johnson & Burnett, 1997) de l'unité Co(H2PO4)4(OH2)2. Les ellipso^ıdes d'agitation thermique ont 50% de probabilité d'existence.
[Figure 2] Fig. 2. Projection de la structure de Na2Co(H2PO4)4·4H2O selon la direction [001] montrant les liaisons hydrogène.
Tétradihydrogénophosphate de cobalt et de sodium tétrahydrate top
Crystal data top
H16CoNa2O20P4F(000) = 570
Mr = 564.92Dx = 2.207 Mg m3
Dm = 2.204 Mg m3
Dm measured by flotation
Monoclinic, P21/cMo Kα radiation, λ = 0.71069 Å
Hall symbol: -P 2ybcCell parameters from 25 reflections
a = 7.2516 (7) Åθ = 10–15°
b = 10.723 (3) ŵ = 1.54 mm1
c = 12.142 (6) ÅT = 293 K
β = 115.80 (1)°Prism, pink
V = 850.0 (5) Å30.50 × 0.40 × 0.36 mm
Z = 2
Data collection top
Enraf-Nonius CAD-4
diffractometer
1762 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.007
Graphite monochromatorθmax = 27.0°, θmin = 2.7°
ω/2θ scansh = 99
Absorption correction: ψ-scan
(North et al., 1968)
k = 013
Tmin = 0.487, Tmax = 0.575l = 015
2049 measured reflections2 standard reflections every 120 min
1845 independent reflections intensity decay: 1.8%
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.020All H-atom parameters refined
wR(F2) = 0.056Calculated w = 1/[σ2(Fo2) + (0.0275P)2 + 0.5564P]
where P = (Fo2 + 2Fc2)/3
S = 1.17(Δ/σ)max = 0.003
1845 reflectionsΔρmax = 0.37 e Å3
157 parametersΔρmin = 0.31 e Å3
0 restraintsExtinction correction: SHELXL93 (Sheldrick, 1993), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: heavy-atom methodExtinction coefficient: 0.009 (1)
Crystal data top
H16CoNa2O20P4V = 850.0 (5) Å3
Mr = 564.92Z = 2
Monoclinic, P21/cMo Kα radiation
a = 7.2516 (7) ŵ = 1.54 mm1
b = 10.723 (3) ÅT = 293 K
c = 12.142 (6) Å0.50 × 0.40 × 0.36 mm
β = 115.80 (1)°
Data collection top
Enraf-Nonius CAD-4
diffractometer
1762 reflections with I > 2σ(I)
Absorption correction: ψ-scan
(North et al., 1968)
Rint = 0.007
Tmin = 0.487, Tmax = 0.5752 standard reflections every 120 min
2049 measured reflections intensity decay: 1.8%
1845 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0200 restraints
wR(F2) = 0.056All H-atom parameters refined
S = 1.17Δρmax = 0.37 e Å3
1845 reflectionsΔρmin = 0.31 e Å3
157 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 on F2 for ALL reflections except for 0 with very negative F2 or flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The observed criterion of F2 > σ(F2) is used only for calculating _R_factor_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.

La largeur de balayage est (1.00 + 0.35 t gθ)°. Les intensités ont été corrigés des facteurs de Lorentz-Polarization. La structure a été résolue par la méthode de l'atome lourd (SHELXS86; Sheldrick, 1990) puis affinée par la méthode des moindres carrés (SHELXL93; Sheldrick, 1993).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Co1/201/20.0126 (1)
P10.04192 (6)0.04535 (4)0.28201 (4)0.0135 (1)
P20.68066 (6)0.26178 (4)0.41884 (4)0.0124 (1)
Na0.20619 (1)0.32852 (7)0.45911 (7)0.0209 (2)
O10.2702 (2)0.0307 (1)0.3255 (1)0.0178 (3)
O20.6820 (2)0.1413 (1)0.4828 (1)0.0209 (3)
O30.3627 (2)0.1293 (1)0.5834 (1)0.0184 (3)
O40.0893 (2)0.0151 (1)0.1499 (1)0.0202 (3)
O50.0297 (2)0.0385 (2)0.3631 (1)0.0261 (3)
O60.0053 (2)0.1845 (1)0.3073 (1)0.0235 (3)
O70.6498 (2)0.2468 (1)0.2879 (1)0.0185 (3)
O80.5075 (2)0.3471 (1)0.4235 (1)0.0219 (3)
O90.8892 (2)0.3307 (1)0.4892 (1)0.0196 (3)
OW0.4061 (2)0.4394 (1)0.6479 (1)0.0215 (3)
H10.449 (4)0.157 (3)0.643 (3)0.038 (7)*
H20.275 (4)0.096 (3)0.604 (2)0.039 (7)*
H30.064 (3)0.079 (3)0.413 (2)0.050 (8)*
H40.108 (5)0.196 (3)0.293 (3)0.046 (8)*
H50.513 (4)0.411 (3)0.397 (3)0.043 (8)*
H60.893 (4)0.369 (3)0.543 (3)0.044 (8)*
H70.493 (4)0.386 (3)0.691 (2)0.032 (7)*
H80.355 (4)0.457 (3)0.689 (3)0.040 (8)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Co0.0106 (2)0.0128 (2)0.0130 (2)0.0000 (1)0.0039 (1)0.0019 (1)
P10.0112 (2)0.0164 (2)0.0118 (2)0.0013 (1)0.0040 (2)0.0007 (1)
P20.0120 (2)0.0114 (2)0.0136 (2)0.0004 (1)0.0054 (2)0.0005 (1)
Na0.0191 (3)0.0192 (4)0.0230 (4)0.0009 (3)0.0078 (3)0.0004 (3)
O10.0122 (6)0.0258 (6)0.0152 (6)0.0025 (5)0.0057 (5)0.0037 (5)
O20.0177 (6)0.0173 (6)0.0255 (6)0.0011 (5)0.0074 (5)0.0074 (5)
O30.0166 (6)0.0202 (6)0.0172 (6)0.0023 (5)0.0063 (5)0.0025 (5)
O40.0226 (6)0.0184 (6)0.0134 (6)0.0006 (5)0.0021 (5)0.0001 (4)
O50.0157 (6)0.0381 (8)0.0244 (7)0.0028 (6)0.0086 (6)0.0149 (6)
O60.0171 (6)0.0216 (7)0.0291 (7)0.0019 (5)0.0076 (5)0.0086 (5)
O70.0187 (6)0.0211 (6)0.0137 (6)0.0015 (5)0.0054 (5)0.0002 (4)
O80.0200 (6)0.0178 (6)0.0325 (7)0.0034 (5)0.0157 (6)0.0018 (5)
O90.0172 (6)0.0217 (6)0.0212 (6)0.0063 (5)0.0096 (5)0.0082 (5)
OW0.0257 (7)0.0200 (6)0.0213 (6)0.0060 (5)0.0126 (6)0.0043 (5)
Geometric parameters (Å, º) top
Co—O1i2.074 (1)Na—O62.359 (2)
Co—O12.074 (1)Na—O82.414 (1)
Co—O22.079 (1)Na—OW2.425 (2)
Co—O2i2.079 (1)Na—O9iii2.479 (1)
Co—O32.195 (1)Na—O32.576 (2)
Co—O3i2.195 (1)O3—H10.78 (3)
P1—O41.502 (1)O3—H20.86 (3)
P1—O11.511 (1)O4—Naiv2.344 (2)
P1—O61.569 (1)O5—H30.81 (1)
P1—O51.579 (1)O6—H40.77 (3)
P2—O21.505 (1)O8—H50.77 (3)
P2—O71.515 (1)O9—Nav2.479 (1)
P2—O91.561 (1)O9—H60.77 (3)
P2—O81.574 (1)OW—H70.84 (3)
Na—O4ii2.344 (1)OW—H80.76 (3)
O1i—Co—O1180.0O8—Na—OW85.03 (6)
O1i—Co—O287.45 (5)O4ii—Na—O9iii86.84 (5)
O1—Co—O292.55 (5)O6—Na—O9iii79.91 (5)
O1i—Co—O2i92.55 (5)O8—Na—O9iii174.48 (6)
O1—Co—O2i87.45 (5)OW—Na—O9iii93.88 (6)
O2—Co—O2i180.0O4ii—Na—O3175.61 (5)
O1i—Co—O387.33 (6)O6—Na—O383.10 (6)
O1—Co—O392.67 (6)O8—Na—O388.31 (5)
O2—Co—O391.23 (5)OW—Na—O385.58 (6)
O2i—Co—O388.77 (5)O9iii—Na—O397.01 (5)
O1i—Co—O3i92.67 (6)P1—O1—Co130.14 (7)
O1—Co—O3i87.33 (6)P2—O2—Co144.64 (8)
O2—Co—O3i88.77 (5)Co—O3—Na115.25 (6)
O2i—Co—O3i91.23 (5)Co—O3—H1108.9 (2)
O3—Co—O3i180.0Na—O3—H1101.6 (2)
O4—P1—O1116.06 (8)Co—O3—H2114.8 (2)
O4—P1—O6109.39 (7)Na—O3—H2108.8 (2)
O1—P1—O6106.44 (7)H1—O3—H2106.4 (3)
O4—P1—O5108.38 (8)P1—O4—Naiv133.86 (8)
O1—P1—O5109.31 (8)P1—O5—H3111.1 (2)
O6—P1—O5106.87 (8)P1—O6—Na132.51 (8)
O2—P2—O7114.54 (8)P1—O6—H4110.8 (2)
O2—P2—O9109.68 (7)Na—O6—H4108.1 (2)
O7—P2—O9106.84 (7)P2—O8—Na139.21 (8)
O2—P2—O8107.86 (8)P2—O8—H5108.6 (2)
O7—P2—O8110.08 (7)Na—O8—H5111.4 (2)
O9—P2—O8107.66 (8)P2—O9—Nav130.88 (8)
O4ii—Na—O699.71 (6)P2—O9—H6112.9 (2)
O4ii—Na—O887.79 (5)Nav—O9—H6116.2 (2)
O6—Na—O8102.29 (6)Na—OW—H7103.3 (2)
O4ii—Na—OW92.06 (6)Na—OW—H8118.5 (2)
O6—Na—OW166.30 (6)H7—OW—H8102.3 (3)
Symmetry codes: (i) x+1, y, z+1; (ii) x, y+1/2, z+1/2; (iii) x1, y, z; (iv) x, y1/2, z+1/2; (v) x+1, y, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—H1···O7vi0.79 (3)2.01 (3)2.786 (2)171 (3)
O3—H2···O5vii0.86 (3)2.08 (3)2.928 (2)170 (3)
O5—H3···O2i0.81 (1)1.84 (1)2.637 (2)166 (3)
O6—H4···O7iii0.78 (3)1.81 (3)2.573 (2)166 (3)
O8—H5···OWviii0.78 (3)1.85 (3)2.619 (2)166 (3)
O9—H6···O4ix0.78 (3)1.73 (3)2.510 (2)168 (3)
OW—H7···O7vi0.84 (3)1.88 (3)2.717 (2)170 (3)
OW—H8···O1vi0.76 (3)2.02 (3)2.752 (2)164 (3)
Symmetry codes: (i) x+1, y, z+1; (iii) x1, y, z; (vi) x, y+1/2, z+1/2; (vii) x, y, z+1; (viii) x+1, y+1, z+1; (ix) x+1, y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaH16CoNa2O20P4
Mr564.92
Crystal system, space groupMonoclinic, P21/c
Temperature (K)293
a, b, c (Å)7.2516 (7), 10.723 (3), 12.142 (6)
β (°) 115.80 (1)
V3)850.0 (5)
Z2
Radiation typeMo Kα
µ (mm1)1.54
Crystal size (mm)0.50 × 0.40 × 0.36
Data collection
DiffractometerEnraf-Nonius CAD-4
diffractometer
Absorption correctionψ-scan
(North et al., 1968)
Tmin, Tmax0.487, 0.575
No. of measured, independent and
observed [I > 2σ(I)] reflections
2049, 1845, 1762
Rint0.007
(sin θ/λ)max1)0.638
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.020, 0.056, 1.17
No. of reflections1845
No. of parameters157
H-atom treatmentAll H-atom parameters refined
Δρmax, Δρmin (e Å3)0.37, 0.31

Computer programs: CAD-4 EXPRESS (Duisenberg, 1992; Macicek & Yordanov, 1992), CAD-4 EXPRESS, MolEN (Fair, 1990), SHELXS86 (Sheldrick, 1990), SHELXL93 (Sheldrick, 1993), ORTEPIII (Johnson & Burnett, 1997), SHELXL93.

Selected geometric parameters (Å, º) top
Co—O1i2.074 (1)Na—O4ii2.344 (1)
Co—O12.074 (1)Na—O62.359 (2)
Co—O22.079 (1)Na—O82.414 (1)
Co—O2i2.079 (1)Na—OW2.425 (2)
Co—O32.195 (1)Na—O9iii2.479 (1)
Co—O3i2.195 (1)Na—O32.576 (2)
P1—O41.502 (1)O3—H10.78 (3)
P1—O11.511 (1)O3—H20.86 (3)
P1—O61.569 (1)O5—H30.81 (1)
P1—O51.579 (1)O6—H40.77 (3)
P2—O21.505 (1)O8—H50.77 (3)
P2—O71.515 (1)O9—H60.77 (3)
P2—O91.561 (1)OW—H70.84 (3)
P2—O81.574 (1)OW—H80.76 (3)
O1i—Co—O1180.0O3—Co—O3i180.0
O1i—Co—O287.45 (5)O4—P1—O1116.06 (8)
O1—Co—O292.55 (5)O4—P1—O6109.39 (7)
O1i—Co—O2i92.55 (5)O1—P1—O6106.44 (7)
O1—Co—O2i87.45 (5)O4—P1—O5108.38 (8)
O2—Co—O2i180.0O1—P1—O5109.31 (8)
O1i—Co—O387.33 (6)O6—P1—O5106.87 (8)
O1—Co—O392.67 (6)O2—P2—O7114.54 (8)
O2—Co—O391.23 (5)O2—P2—O9109.68 (7)
O2i—Co—O388.77 (5)O7—P2—O9106.84 (7)
O1i—Co—O3i92.67 (6)O2—P2—O8107.86 (8)
O1—Co—O3i87.33 (6)O7—P2—O8110.08 (7)
O2—Co—O3i88.77 (5)O9—P2—O8107.66 (8)
O2i—Co—O3i91.23 (5)
Symmetry codes: (i) x+1, y, z+1; (ii) x, y+1/2, z+1/2; (iii) x1, y, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—H1···O7iv0.79 (3)2.01 (3)2.786 (2)171 (3)
O3—H2···O5v0.86 (3)2.08 (3)2.928 (2)170 (3)
O5—H3···O2i0.81 (1)1.84 (1)2.637 (2)166 (3)
O6—H4···O7iii0.78 (3)1.81 (3)2.573 (2)166 (3)
O8—H5···OWvi0.78 (3)1.85 (3)2.619 (2)166 (3)
O9—H6···O4vii0.78 (3)1.73 (3)2.510 (2)168 (3)
OW—H7···O7iv0.84 (3)1.88 (3)2.717 (2)170 (3)
OW—H8···O1iv0.76 (3)2.02 (3)2.752 (2)164 (3)
Symmetry codes: (i) x+1, y, z+1; (iii) x1, y, z; (iv) x, y+1/2, z+1/2; (v) x, y, z+1; (vi) x+1, y+1, z+1; (vii) x+1, y+1/2, z+1/2.
 

Subscribe to Acta Crystallographica Section C: Structural Chemistry

The full text of this article is available to subscribers to the journal.

If you have already registered and are using a computer listed in your registration details, please email support@iucr.org for assistance.

Buy online

You may purchase this article in PDF and/or HTML formats. For purchasers in the European Community who do not have a VAT number, VAT will be added at the local rate. Payments to the IUCr are handled by WorldPay, who will accept payment by credit card in several currencies. To purchase the article, please complete the form below (fields marked * are required), and then click on `Continue'.
E-mail address* 
Repeat e-mail address* 
(for error checking) 

Format*   PDF (US $40)
   HTML (US $40)
   PDF+HTML (US $50)
In order for VAT to be shown for your country javascript needs to be enabled.

VAT number 
(non-UK EC countries only) 
Country* 
 

Terms and conditions of use
Contact us

Follow Acta Cryst. C
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds