Dicaesium diaqua­bis­(methyl­ene­diphospho­nato-κ2O,O′)cobaltate(II)

Merwe, K. van der; Visser, H.G.; Venter, J.A.

doi:10.1107/S1600536811035355

metal-organic compounds

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ISSN: 2056-9890

Volume 67| Part 10| October 2011| Page m1354

https://doi.org/10.1107/S1600536811035355

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Dicaesium diaquabis(methylenediphosphonato-κ²O,O′)cobaltate(II)

Kina van der Merwe,^a ^* Hendrik G. Visser ^a and Johan A. Venter ^a

^aDepartment of Chemistry, University of the Free State, PO Box 339, Bloemfontein 9330, South Africa
^*Correspondence e-mail: vandermerwe@gmail.com

(Received 24 August 2011; accepted 30 August 2011; online 14 September 2011)

The asymmetric unit of the title compound, Cs₂[Co(CH₄O₆P₂)₂(H₂O)₂], is comprised of one bidentate methylenediphosphonate ligand and one water molecule which are coordinated to the Co^II atom, as well as a caesium counter-cation. The Co atom occupies a special position on a crystallographic inversion center. The caesium ion is octahedrally coordinated by six O atoms with Cs—O distances ranging from 3.119 (2) to 3.296 (2) Å. A three-dimensional network is formed through O—H⋯O hydrogen bonds.

Related literature

For related structures, see: Fleisch (1991 ); Neville-Webbe et al. (2002 ); Van der Merwe et al. (2010 ). For bond lengths and bond angles in related structures, see: Bao et al. (2003 ); Cao et al. (2007 ); Gong et al. (2006 ); Van der Merwe et al. (2009 ); Visser et al. (2010 ); Yin et al. (2003 ).

Experimental

Crystal data

Cs₂[Co(CH₄O₆P₂)₂(H₂O)₂]
M_r = 708.75
Triclinic, $[P \overline 1]$
a = 7.333 (5) Å
b = 7.412 (5) Å
c = 7.666 (5) Å
α = 74.621 (5)°
β = 83.064 (5)°
γ = 86.496 (5)°
V = 398.6 (5) Å³
Z = 1
Mo Kα radiation
μ = 5.96 mm⁻¹
T = 293 K
0.38 × 0.07 × 0.05 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2001 ) T_min = 0.210, T_max = 0.755
4203 measured reflections
1904 independent reflections
1827 reflections with I > 2σ(I)
R_int = 0.015

Refinement

R[F² > 2σ(F²)] = 0.015
wR(F²) = 0.044
S = 0.75
1904 reflections
132 parameters
11 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.47 e Å⁻³
Δρ_min = −0.48 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1A⋯O4ⁱ	0.92 (2)	1.94 (2)	2.860 (3)	173 (3)
O5—H5B⋯O4ⁱⁱ	0.85 (2)	1.69 (3)	2.518 (3)	164 (7)
Symmetry codes: (i) x, y, z+1; (ii) x, y+1, z.

Data collection: APEX2 (Bruker, 2005 ); cell refinement: SAINT-Plus (Bruker, 2004 ); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2005 ); software used to prepare material for publication: WinGX (Farrugia, 1999 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536811035355/jh2322sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536811035355/jh2322Isup2.hkl

checkCIF report

Comment top

This work is part of an ongoing investigation aimed at synthesizing and characterizing new methylene diphosphonate complexes and expanding on our knowledge of the interactions of the methylene diphosphonate ligand with various metal centers. (Van der Merwe et al. (2009) & Van der Merwe et al. (2010)).

Methylene diphosphonates (O₃PCH₂PO₃) has a diversified coordination capability with metal ions, due to the single methyl group which divides the two phosphonate groups. The formation of a stable six-membered ring comprised of M—O—P—C—P—O is favoured (Bao et al. (2003). Bisphosphonates adhere strongly to hydroxyapatite crystals and constrain their formation and dissolution (Fleisch (1991)). This physicochemical in vivo effect may result in the prevention of soft tissue calcification or even prevent normal calcification. The bis(phosphonic acid) has a high affinity for bone surfaces and it is also non-hydrolyzable (Neville-Webbe et al. (2002).

The asymmetric unit of the title compound, Cs₂[Co(CH₄O₆P₂)₂(H₂O)₂], is comprised of one bidentate methylene diphosphonate ligand and one water molecule which are coordinated to the Co^II atom, as well as a non-coordinated caesium cation. The Co atom occupies a special position on a crystallographic inversion center. The caesium ion is octahedrally coordinated to six oxygen atoms with Cs—O distances ranging from 3.119 (2) to 3.296 (2) Å. The two methylene diphosphonate ligands chelate to the central cobalt metal via four oxygen atoms (O2/O2' and O7/O7') from the phosphonate groups. This leads to the formation of two six-membered rings.

The Co^II metal center has a slightly distorted octahedral geometry with O—Co—O angles ranging between 85.35 (8) ° and 94.65 (8) °. The Co—O bond lengths vary between 2.0761 (18) and 2.1272 (19) Å. These distances correspond to literature values (Bao et al. (2003); Cao et al. (2007); Gong et al. (2006); Van der Merwe et al. (2009); Visser et al. (2010); Yin et al. (2003).

A three-dimensional network is provided by O—H–O hydrogen bonds (Table 2).

Related literature top

For related structures, see: Fleisch (1991); Neville-Webbe et al. (2002); Van der Merwe et al. (2010). For bond lengths and bond angles in related structures, see: Bao et al. (2003); Cao et al. (2007); Gong et al. (2006); Van der Merwe et al. (2009); Visser et al. (2010); Yin et al. (2003).

Experimental top

[Co(NH₃)₆]Cl₃(0,1700 g, 0,714 mmol) was dissolved in distilled water (10 cm³) and the pH of the solution was lowered to 1.87 using hydrochloric acid. The solution was heated for 30 minutes at 313.15 K. Methylene diphosphonate (0.251 g, 1.43 mmol) was dissolved in distilled water (7 cm³) and the pH of the solution was elevated to 1.93 using caesium chloride. Both solutions were combined and the pH was adjusted to 2.04, the pink solution was heated for 3 h at 353.15 K. Pink crystals, suitable for X-ray diffraction, was obtained. (Yield: 7.2%)

Structure description top

The asymmetric unit of the title compound, Cs₂[Co(CH₄O₆P₂)₂(H₂O)₂], is comprised of one bidentate methylene diphosphonate ligand and one water molecule which are coordinated to the Co^II atom, as well as a non-coordinated caesium cation. The Co atom occupies a special position on a crystallographic inversion center. The caesium ion is octahedrally coordinated to six oxygen atoms with Cs—O distances ranging from 3.119 (2) to 3.296 (2) Å. The two methylene diphosphonate ligands chelate to the central cobalt metal via four oxygen atoms (O2/O2' and O7/O7') from the phosphonate groups. This leads to the formation of two six-membered rings.

A three-dimensional network is provided by O—H–O hydrogen bonds (Table 2).

For related structures, see: Fleisch (1991); Neville-Webbe et al. (2002); Van der Merwe et al. (2010). For bond lengths and bond angles in related structures, see: Bao et al. (2003); Cao et al. (2007); Gong et al. (2006); Van der Merwe et al. (2009); Visser et al. (2010); Yin et al. (2003).

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT-Plus (Bruker, 2004); data reduction: SAINT-Plus (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top

Fig. 1. Representation of the title compound, showing the numbering scheme and displacement ellipsoids drawn at the 50% probability level. [Symmetry code: (i) 1 - x, -y, 1 - z].

Dicaesium diaquabis(methylenediphosphonato-κ²O,O')cobaltate(II) top

Crystal data top

Cs₂[Co(CH₄O₆P₂)₂(H₂O)₂]	Z = 1
M_r = 708.75	F(000) = 253
Triclinic, P1	D_x = 2.953 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.333 (5) Å	Cell parameters from 3160 reflections
b = 7.412 (5) Å	θ = 2.8–28.4°
c = 7.666 (5) Å	µ = 5.96 mm⁻¹
α = 74.621 (5)°	T = 293 K
β = 83.064 (5)°	Needle, pink
γ = 86.496 (5)°	0.38 × 0.07 × 0.05 mm
V = 398.6 (5) Å³

Data collection top

Bruker APEXII CCD diffractometer	1827 reflections with I > 2σ(I)
φ and ω scans	R_int = 0.015
Absorption correction: multi-scan (SADABS; Bruker, 2001)	θ_max = 28°, θ_min = 3.7°
T_min = 0.210, T_max = 0.755	h = −9→9
4203 measured reflections	k = −9→9
1904 independent reflections	l = −10→10

Refinement top

Refinement on F²	11 restraints
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F² > 2σ(F²)] = 0.015	w = 1/[σ²(F_o²) + (0.0412P)² + 0.4899P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.044	(Δ/σ)_max = 0.002
S = 0.75	Δρ_max = 0.47 e Å⁻³
1904 reflections	Δρ_min = −0.48 e Å⁻³
132 parameters

Crystal data top

Cs₂[Co(CH₄O₆P₂)₂(H₂O)₂]	γ = 86.496 (5)°
M_r = 708.75	V = 398.6 (5) Å³
Triclinic, P1	Z = 1
a = 7.333 (5) Å	Mo Kα radiation
b = 7.412 (5) Å	µ = 5.96 mm⁻¹
c = 7.666 (5) Å	T = 293 K
α = 74.621 (5)°	0.38 × 0.07 × 0.05 mm
β = 83.064 (5)°

Data collection top

Bruker APEXII CCD diffractometer	1904 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2001)	1827 reflections with I > 2σ(I)
T_min = 0.210, T_max = 0.755	R_int = 0.015
4203 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.015	11 restraints
wR(F²) = 0.044	H atoms treated by a mixture of independent and constrained refinement
S = 0.75	Δρ_max = 0.47 e Å⁻³
1904 reflections	Δρ_min = −0.48 e Å⁻³
132 parameters

Special details top

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
Cs1	0.284577 (17)	0.954858 (18)	0.692901 (17)	0.00965 (6)
Co1	0.5	0.5	0.5	0.00595 (9)
P1	0.26392 (7)	0.34252 (8)	0.22866 (8)	0.00590 (11)
P2	0.19616 (7)	0.74778 (8)	0.25147 (8)	0.00589 (11)
O1	0.2886 (2)	0.4437 (2)	0.7201 (2)	0.0112 (3)
O2	0.3857 (2)	0.3210 (2)	0.3786 (2)	0.0088 (3)
O3	0.0667 (2)	0.2706 (2)	0.3122 (2)	0.0086 (3)
O4	0.3336 (2)	0.2396 (2)	0.0861 (2)	0.0086 (3)
O5	0.1822 (2)	0.9384 (2)	0.1036 (2)	0.0109 (3)
O6	0.0107 (2)	0.7058 (2)	0.3621 (2)	0.0102 (3)
O7	0.3541 (2)	0.7427 (2)	0.3623 (2)	0.0086 (3)
C1	0.2397 (3)	0.5858 (3)	0.1121 (3)	0.0071 (4)
H1A	0.313 (4)	0.383 (4)	0.837 (3)	0.023 (9)*
H1B	0.185 (4)	0.410 (6)	0.704 (6)	0.063 (15)*
H2	0.048 (5)	0.287 (5)	0.417 (3)	0.035 (10)*
H3	0.145 (3)	0.599 (4)	0.033 (4)	0.018 (8)*
H4	0.357 (3)	0.616 (4)	0.046 (4)	0.015 (8)*
H5A	0.156 (9)	0.935 (9)	0.002 (5)	0.022*	0.5
H5B	0.239 (8)	1.030 (7)	0.116 (9)	0.022*	0.5

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cs1	0.01010 (9)	0.00910 (9)	0.00854 (9)	0.00056 (5)	−0.00040 (5)	−0.00068 (6)
Co1	0.00540 (19)	0.00593 (19)	0.0067 (2)	−0.00035 (15)	−0.00109 (15)	−0.00174 (16)
P1	0.0061 (2)	0.0053 (2)	0.0063 (3)	−0.00119 (19)	−0.0007 (2)	−0.0015 (2)
P2	0.0060 (2)	0.0060 (3)	0.0057 (3)	−0.00059 (19)	−0.0006 (2)	−0.0014 (2)
O1	0.0084 (8)	0.0160 (9)	0.0088 (8)	−0.0027 (7)	−0.0002 (6)	−0.0019 (7)
O2	0.0097 (7)	0.0077 (7)	0.0092 (8)	−0.0008 (6)	−0.0028 (6)	−0.0015 (6)
O3	0.0076 (7)	0.0110 (8)	0.0077 (8)	−0.0033 (6)	0.0007 (6)	−0.0032 (6)
O4	0.0098 (7)	0.0072 (7)	0.0096 (8)	−0.0012 (6)	0.0008 (6)	−0.0040 (6)
O5	0.0173 (8)	0.0063 (7)	0.0093 (8)	−0.0012 (6)	−0.0063 (7)	−0.0002 (6)
O6	0.0072 (7)	0.0139 (8)	0.0096 (8)	−0.0017 (6)	0.0012 (6)	−0.0040 (6)
O7	0.0096 (7)	0.0067 (7)	0.0098 (8)	−0.0003 (6)	−0.0032 (6)	−0.0016 (6)
C1	0.0087 (9)	0.0066 (10)	0.0056 (10)	−0.0009 (8)	−0.0011 (8)	−0.0005 (8)

Geometric parameters (Å, º) top

Cs1—O5ⁱ	3.119 (3)	P2—O6	1.5158 (18)
Cs1—O3ⁱⁱ	3.165 (2)	P2—O5	1.5663 (19)
Cs1—O2ⁱⁱⁱ	3.162 (2)	P2—C1	1.799 (2)
Cs1—O2^iv	3.173 (2)	O1—H1A	0.922 (17)
Cs1—O6^v	3.192 (2)	O1—H1B	0.846 (19)
Cs1—O4ⁱⁱⁱ	3.485 (2)	O2—Cs1ⁱⁱⁱ	3.162 (2)
Cs1—O7^vi	3.490 (2)	O2—Cs1^vii	3.173 (2)
Co1—O2ⁱⁱⁱ	2.0761 (18)	O3—Cs1ⁱⁱ	3.165 (2)
Co1—O2	2.0761 (18)	O3—H2	0.840 (19)
Co1—O1ⁱⁱⁱ	2.1209 (19)	O4—Cs1ⁱⁱⁱ	3.485 (2)
Co1—O1	2.1209 (19)	O5—Cs1^viii	3.119 (3)
Co1—O7ⁱⁱⁱ	2.1272 (19)	O5—H5A	0.83 (2)
Co1—O7	2.1272 (19)	O5—H5B	0.85 (2)
P1—O2	1.5087 (18)	O6—Cs1^v	3.192 (2)
P1—O4	1.5158 (18)	O7—Cs1^vi	3.490 (2)
P1—O3	1.5732 (18)	C1—H3	0.963 (14)
P1—C1	1.796 (3)	C1—H4	0.951 (14)
P2—O7	1.5099 (18)

O5ⁱ—Cs1—O3ⁱⁱ	91.51 (5)	O7—Co1—Cs1ⁱⁱⁱ	128.78 (6)
O5ⁱ—Cs1—O2ⁱⁱⁱ	113.53 (4)	O2ⁱⁱⁱ—Co1—Cs1^vi	45.80 (6)
O3ⁱⁱ—Cs1—O2ⁱⁱⁱ	103.25 (7)	O2—Co1—Cs1^vi	134.20 (6)
O5ⁱ—Cs1—O2^iv	125.59 (5)	O1ⁱⁱⁱ—Co1—Cs1^vi	60.18 (5)
O3ⁱⁱ—Cs1—O2^iv	120.31 (5)	O1—Co1—Cs1^vi	119.82 (5)
O2ⁱⁱⁱ—Cs1—O2^iv	101.31 (5)	O7ⁱⁱⁱ—Co1—Cs1^vi	125.13 (6)
O5ⁱ—Cs1—O6^v	82.95 (5)	O7—Co1—Cs1^vi	54.87 (6)
O3ⁱⁱ—Cs1—O6^v	81.36 (7)	Cs1ⁱⁱⁱ—Co1—Cs1^vi	123.10 (4)
O2ⁱⁱⁱ—Cs1—O6^v	162.47 (4)	O2ⁱⁱⁱ—Co1—Cs1^vii	134.20 (6)
O2^iv—Cs1—O6^v	62.52 (5)	O2—Co1—Cs1^vii	45.80 (6)
O5ⁱ—Cs1—O4ⁱⁱⁱ	73.40 (5)	O1ⁱⁱⁱ—Co1—Cs1^vii	119.82 (5)
O3ⁱⁱ—Cs1—O4ⁱⁱⁱ	124.24 (6)	O1—Co1—Cs1^vii	60.18 (5)
O2ⁱⁱⁱ—Cs1—O4ⁱⁱⁱ	44.75 (5)	O7ⁱⁱⁱ—Co1—Cs1^vii	54.87 (6)
O2^iv—Cs1—O4ⁱⁱⁱ	111.44 (5)	O7—Co1—Cs1^vii	125.13 (6)
O6^v—Cs1—O4ⁱⁱⁱ	144.68 (4)	Cs1ⁱⁱⁱ—Co1—Cs1^vii	56.90 (4)
O5ⁱ—Cs1—O7^vi	94.14 (4)	Cs1^vi—Co1—Cs1^vii	180
O3ⁱⁱ—Cs1—O7^vi	170.61 (4)	O2—P1—O4	114.76 (10)
O2ⁱⁱⁱ—Cs1—O7^vi	81.34 (7)	O2—P1—O3	109.86 (10)
O2^iv—Cs1—O7^vi	50.37 (5)	O4—P1—O3	107.73 (9)
O6^v—Cs1—O7^vi	91.89 (7)	O2—P1—C1	109.55 (10)
O4ⁱⁱⁱ—Cs1—O7^vi	64.74 (6)	O4—P1—C1	107.05 (11)
O5ⁱ—Cs1—C1ⁱ	44.75 (6)	O3—P1—C1	107.62 (10)
O3ⁱⁱ—Cs1—C1ⁱ	72.92 (5)	O2—P1—Cs1ⁱⁱⁱ	51.16 (7)
O2ⁱⁱⁱ—Cs1—C1ⁱ	78.47 (6)	O4—P1—Cs1ⁱⁱⁱ	63.66 (7)
O2^iv—Cs1—C1ⁱ	165.97 (5)	O3—P1—Cs1ⁱⁱⁱ	124.40 (8)
O6^v—Cs1—C1ⁱ	118.91 (5)	C1—P1—Cs1ⁱⁱⁱ	127.77 (8)
O4ⁱⁱⁱ—Cs1—C1ⁱ	58.52 (5)	O2—P1—Cs1^vii	49.06 (7)
O7^vi—Cs1—C1ⁱ	116.25 (5)	O4—P1—Cs1^vii	103.57 (8)
O5ⁱ—Cs1—O1^iv	74.68 (4)	O3—P1—Cs1^vii	68.88 (7)
O3ⁱⁱ—Cs1—O1^iv	126.32 (5)	C1—P1—Cs1^vii	148.54 (8)
O2ⁱⁱⁱ—Cs1—O1^iv	130.04 (5)	Cs1ⁱⁱⁱ—P1—Cs1^vii	61.70 (2)
O2^iv—Cs1—O1^iv	50.97 (5)	O7—P2—O6	114.83 (11)
O6^v—Cs1—O1^iv	46.06 (5)	O7—P2—O5	111.69 (10)
O4ⁱⁱⁱ—Cs1—O1^iv	101.41 (4)	O6—P2—O5	109.44 (10)
O7^vi—Cs1—O1^iv	48.72 (4)	O7—P2—C1	110.57 (10)
C1ⁱ—Cs1—O1^iv	118.60 (6)	O6—P2—C1	108.09 (10)
O5ⁱ—Cs1—O3^iv	125.42 (5)	O5—P2—C1	101.32 (11)
O3ⁱⁱ—Cs1—O3^iv	78.65 (6)	O7—P2—Cs1^v	124.05 (8)
O2ⁱⁱⁱ—Cs1—O3^iv	121.02 (5)	O5—P2—Cs1^v	65.52 (7)
O2^iv—Cs1—O3^iv	42.33 (5)	C1—P2—Cs1^v	125.05 (8)
O6^v—Cs1—O3^iv	42.63 (4)	O7—P2—Cs1^viii	118.54 (7)
O4ⁱⁱⁱ—Cs1—O3^iv	152.49 (4)	O6—P2—Cs1^viii	125.77 (7)
O7^vi—Cs1—O3^iv	91.97 (5)	C1—P2—Cs1^viii	61.03 (8)
C1ⁱ—Cs1—O3^iv	148.87 (5)	Cs1^v—P2—Cs1^viii	94.916 (19)
O1^iv—Cs1—O3^iv	69.55 (5)	Co1—O1—Cs1^vii	89.88 (6)
O5ⁱ—Cs1—O5^v	55.64 (5)	Co1—O1—H1A	122 (2)
O3ⁱⁱ—Cs1—O5^v	56.50 (6)	Cs1^vii—O1—H1A	81 (2)
O2ⁱⁱⁱ—Cs1—O5^v	153.15 (4)	Co1—O1—H1B	120 (3)
O2^iv—Cs1—O5^v	104.38 (5)	Cs1^vii—O1—H1B	66 (3)
O6^v—Cs1—O5^v	41.87 (4)	H1A—O1—H1B	108 (3)
O4ⁱⁱⁱ—Cs1—O5^v	128.47 (5)	P1—O2—Co1	135.98 (10)
O7^vi—Cs1—O5^v	121.54 (5)	P1—O2—Cs1ⁱⁱⁱ	107.03 (9)
C1ⁱ—Cs1—O5^v	78.50 (5)	Co1—O2—Cs1ⁱⁱⁱ	103.97 (7)
O1^iv—Cs1—O5^v	73.92 (4)	P1—O2—Cs1^vii	109.88 (8)
O3^iv—Cs1—O5^v	75.37 (5)	Co1—O2—Cs1^vii	106.22 (8)
O5ⁱ—Cs1—P1ⁱⁱⁱ	94.28 (4)	Cs1ⁱⁱⁱ—O2—Cs1^vii	78.69 (5)
O3ⁱⁱ—Cs1—P1ⁱⁱⁱ	115.59 (6)	P1—O3—Cs1ⁱⁱ	150.94 (9)
O2ⁱⁱⁱ—Cs1—P1ⁱⁱⁱ	21.82 (3)	P1—O3—Cs1^vii	87.66 (8)
O2^iv—Cs1—P1ⁱⁱⁱ	106.97 (4)	Cs1ⁱⁱ—O3—Cs1^vii	101.35 (6)
O6^v—Cs1—P1ⁱⁱⁱ	162.96 (3)	P1—O3—H2	108 (3)
O4ⁱⁱⁱ—Cs1—P1ⁱⁱⁱ	22.94 (3)	Cs1ⁱⁱ—O3—H2	101 (3)
O7^vi—Cs1—P1ⁱⁱⁱ	71.49 (6)	Cs1^vii—O3—H2	59 (3)
C1ⁱ—Cs1—P1ⁱⁱⁱ	67.80 (4)	P1—O4—Cs1ⁱⁱⁱ	93.39 (8)
O1^iv—Cs1—P1ⁱⁱⁱ	116.98 (4)	P2—O5—Cs1^viii	120.07 (9)
O3^iv—Cs1—P1ⁱⁱⁱ	138.50 (3)	P2—O5—Cs1^v	91.93 (8)
O5^v—Cs1—P1ⁱⁱⁱ	145.78 (4)	Cs1^viii—O5—Cs1^v	124.36 (5)
O2ⁱⁱⁱ—Co1—O2	180	P2—O5—H5A	118 (5)
O2ⁱⁱⁱ—Co1—O1ⁱⁱⁱ	90.76 (8)	Cs1^v—O5—H5A	99 (5)
O2—Co1—O1ⁱⁱⁱ	89.24 (8)	P2—O5—H5B	117 (5)
O2ⁱⁱⁱ—Co1—O1	89.24 (8)	Cs1^viii—O5—H5B	103 (5)
O2—Co1—O1	90.76 (8)	Cs1^v—O5—H5B	100 (5)
O1ⁱⁱⁱ—Co1—O1	180	H5A—O5—H5B	121 (6)
O2ⁱⁱⁱ—Co1—O7ⁱⁱⁱ	94.65 (8)	P2—O6—Cs1^v	115.52 (9)
O2—Co1—O7ⁱⁱⁱ	85.35 (8)	P2—O7—Co1	126.62 (10)
O1ⁱⁱⁱ—Co1—O7ⁱⁱⁱ	91.47 (7)	P2—O7—Cs1^vi	131.62 (9)
O1—Co1—O7ⁱⁱⁱ	88.53 (7)	Co1—O7—Cs1^vi	95.23 (7)
O2ⁱⁱⁱ—Co1—O7	85.35 (8)	P1—C1—P2	116.79 (13)
O2—Co1—O7	94.65 (8)	P1—C1—Cs1^viii	149.47 (11)
O1ⁱⁱⁱ—Co1—O7	88.53 (7)	P2—C1—Cs1^viii	93.21 (10)
O1—Co1—O7	91.47 (7)	P1—C1—H3	108.1 (19)
O7ⁱⁱⁱ—Co1—O7	180.00 (9)	P2—C1—H3	110.1 (19)
O2ⁱⁱⁱ—Co1—Cs1ⁱⁱⁱ	132.78 (6)	Cs1^viii—C1—H3	62.8 (19)
O2—Co1—Cs1ⁱⁱⁱ	47.22 (6)	P1—C1—H4	104.3 (19)
O1ⁱⁱⁱ—Co1—Cs1ⁱⁱⁱ	63.15 (5)	P2—C1—H4	105.3 (19)
O1—Co1—Cs1ⁱⁱⁱ	116.85 (5)	Cs1^viii—C1—H4	59.3 (18)
O7ⁱⁱⁱ—Co1—Cs1ⁱⁱⁱ	51.22 (6)	H3—C1—H4	112 (3)

O2ⁱⁱⁱ—Co1—O1—Cs1^vii	−144.21 (6)	C1—P2—O5—Cs1^viii	−8.70 (12)
O2—Co1—O1—Cs1^vii	35.79 (6)	Cs1^v—P2—O5—Cs1^viii	−132.22 (9)
O7ⁱⁱⁱ—Co1—O1—Cs1^vii	−49.55 (6)	O7—P2—O5—Cs1^v	−118.75 (9)
O7—Co1—O1—Cs1^vii	130.45 (6)	O6—P2—O5—Cs1^v	9.54 (9)
Cs1ⁱⁱⁱ—Co1—O1—Cs1^vii	−5.22 (5)	C1—P2—O5—Cs1^v	123.53 (8)
Cs1^vi—Co1—O1—Cs1^vii	180	Cs1^viii—P2—O5—Cs1^v	132.22 (9)
O4—P1—O2—Co1	130.04 (13)	O7—P2—O6—Cs1^v	114.18 (10)
O3—P1—O2—Co1	−108.42 (14)	O5—P2—O6—Cs1^v	−12.34 (11)
C1—P1—O2—Co1	9.60 (17)	C1—P2—O6—Cs1^v	−121.88 (10)
Cs1ⁱⁱⁱ—P1—O2—Co1	132.87 (17)	Cs1^viii—P2—O6—Cs1^v	−55.00 (10)
Cs1^vii—P1—O2—Co1	−143.29 (18)	O6—P2—O7—Co1	80.65 (14)
O4—P1—O2—Cs1ⁱⁱⁱ	−2.83 (11)	O5—P2—O7—Co1	−154.00 (11)
O3—P1—O2—Cs1ⁱⁱⁱ	118.71 (9)	C1—P2—O7—Co1	−41.97 (15)
C1—P1—O2—Cs1ⁱⁱⁱ	−123.27 (9)	Cs1^v—P2—O7—Co1	131.64 (9)
Cs1^vii—P1—O2—Cs1ⁱⁱⁱ	83.84 (8)	Cs1^viii—P2—O7—Co1	−109.34 (10)
O4—P1—O2—Cs1^vii	−86.67 (11)	O6—P2—O7—Cs1^vi	−135.06 (11)
O3—P1—O2—Cs1^vii	34.87 (11)	O5—P2—O7—Cs1^vi	−9.70 (14)
C1—P1—O2—Cs1^vii	152.89 (9)	C1—P2—O7—Cs1^vi	102.32 (13)
Cs1ⁱⁱⁱ—P1—O2—Cs1^vii	−83.84 (8)	Cs1^v—P2—O7—Cs1^vi	−84.06 (12)
O1ⁱⁱⁱ—Co1—O2—P1	−80.87 (15)	Cs1^viii—P2—O7—Cs1^vi	34.96 (13)
O1—Co1—O2—P1	99.13 (15)	O2ⁱⁱⁱ—Co1—O7—P2	−168.93 (12)
O7ⁱⁱⁱ—Co1—O2—P1	−172.41 (15)	O2—Co1—O7—P2	11.07 (12)
O7—Co1—O2—P1	7.59 (15)	O1ⁱⁱⁱ—Co1—O7—P2	100.19 (13)
Cs1ⁱⁱⁱ—Co1—O2—P1	−133.77 (17)	O1—Co1—O7—P2	−79.81 (13)
Cs1^vi—Co1—O2—P1	−35.83 (17)	Cs1ⁱⁱⁱ—Co1—O7—P2	47.08 (14)
Cs1^vii—Co1—O2—P1	144.17 (17)	Cs1^vi—Co1—O7—P2	154.02 (14)
O1ⁱⁱⁱ—Co1—O2—Cs1ⁱⁱⁱ	52.90 (7)	Cs1^vii—Co1—O7—P2	−25.98 (14)
O1—Co1—O2—Cs1ⁱⁱⁱ	−127.10 (7)	O2ⁱⁱⁱ—Co1—O7—Cs1^vi	37.05 (6)
O7ⁱⁱⁱ—Co1—O2—Cs1ⁱⁱⁱ	−38.64 (6)	O2—Co1—O7—Cs1^vi	−142.95 (6)
O7—Co1—O2—Cs1ⁱⁱⁱ	141.36 (6)	O1ⁱⁱⁱ—Co1—O7—Cs1^vi	−53.82 (6)
Cs1^vi—Co1—O2—Cs1ⁱⁱⁱ	97.94 (6)	O1—Co1—O7—Cs1^vi	126.18 (6)
Cs1^vii—Co1—O2—Cs1ⁱⁱⁱ	−82.06 (6)	Cs1ⁱⁱⁱ—Co1—O7—Cs1^vi	−106.94 (4)
O1ⁱⁱⁱ—Co1—O2—Cs1^vii	134.96 (7)	Cs1^vii—Co1—O7—Cs1^vi	180
O1—Co1—O2—Cs1^vii	−45.04 (7)	O2—P1—C1—P2	−44.78 (16)
O7ⁱⁱⁱ—Co1—O2—Cs1^vii	43.42 (6)	O4—P1—C1—P2	−169.80 (12)
O7—Co1—O2—Cs1^vii	−136.58 (6)	O3—P1—C1—P2	74.63 (14)
Cs1ⁱⁱⁱ—Co1—O2—Cs1^vii	82.06 (6)	Cs1ⁱⁱⁱ—P1—C1—P2	−100.25 (12)
Cs1^vi—Co1—O2—Cs1^vii	180	Cs1^vii—P1—C1—P2	−3.5 (2)
O2—P1—O3—Cs1ⁱⁱ	−136.98 (17)	O2—P1—C1—Cs1^viii	123.58 (19)
O4—P1—O3—Cs1ⁱⁱ	−11.3 (2)	O4—P1—C1—Cs1^viii	−1.4 (2)
C1—P1—O3—Cs1ⁱⁱ	103.8 (2)	O3—P1—C1—Cs1^viii	−117.01 (19)
Cs1ⁱⁱⁱ—P1—O3—Cs1ⁱⁱ	−81.1 (2)	Cs1ⁱⁱⁱ—P1—C1—Cs1^viii	68.1 (2)
Cs1^vii—P1—O3—Cs1ⁱⁱ	−109.40 (19)	Cs1^vii—P1—C1—Cs1^viii	164.84 (9)
O2—P1—O3—Cs1^vii	−27.58 (9)	O7—P2—C1—P1	62.05 (15)
O4—P1—O3—Cs1^vii	98.08 (9)	O6—P2—C1—P1	−64.42 (15)
C1—P1—O3—Cs1^vii	−146.80 (8)	O5—P2—C1—P1	−179.41 (12)
Cs1ⁱⁱⁱ—P1—O3—Cs1^vii	28.30 (7)	Cs1^v—P2—C1—P1	−111.48 (11)
O2—P1—O4—Cs1ⁱⁱⁱ	2.46 (9)	Cs1^viii—P2—C1—P1	174.11 (15)
O3—P1—O4—Cs1ⁱⁱⁱ	−120.24 (8)	O7—P2—C1—Cs1^viii	−112.06 (8)
C1—P1—O4—Cs1ⁱⁱⁱ	124.27 (8)	O6—P2—C1—Cs1^viii	121.47 (8)
Cs1^vii—P1—O4—Cs1ⁱⁱⁱ	−48.42 (5)	O5—P2—C1—Cs1^viii	6.48 (9)
O7—P2—O5—Cs1^viii	109.03 (10)	Cs1^v—P2—C1—Cs1^viii	74.41 (7)
O6—P2—O5—Cs1^viii	−122.68 (10)

Symmetry codes: (i) x, y, z+1; (ii) −x, −y+1, −z+1; (iii) −x+1, −y+1, −z+1; (iv) x, y+1, z; (v) −x, −y+2, −z+1; (vi) −x+1, −y+2, −z+1; (vii) x, y−1, z; (viii) x, y, z−1.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1A···O4ⁱ	0.92 (2)	1.94 (2)	2.860 (3)	173 (3)
O5—H5B···O4^iv	0.85 (2)	1.69 (3)	2.518 (3)	164 (7)

Symmetry codes: (i) x, y, z+1; (iv) x, y+1, z.

Experimental details

Crystal data
Chemical formula	Cs₂[Co(CH₄O₆P₂)₂(H₂O)₂]
M_r	708.75
Crystal system, space group	Triclinic, P1
Temperature (K)	293
a, b, c (Å)	7.333 (5), 7.412 (5), 7.666 (5)
α, β, γ (°)	74.621 (5), 83.064 (5), 86.496 (5)
V (Å³)	398.6 (5)
Z	1
Radiation type	Mo Kα
µ (mm⁻¹)	5.96
Crystal size (mm)	0.38 × 0.07 × 0.05

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2001)
T_min, T_max	0.210, 0.755
No. of measured, independent and observed [I > 2σ(I)] reflections	4203, 1904, 1827
R_int	0.015
(sin θ/λ)_max (Å⁻¹)	0.661

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.015, 0.044, 0.75
No. of reflections	1904
No. of parameters	132
No. of restraints	11
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.47, −0.48

Computer programs: APEX2 (Bruker, 2005), SAINT-Plus (Bruker, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg & Putz, 2005), WinGX (Farrugia, 1999).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1A···O4ⁱ	0.922 (17)	1.943 (18)	2.860 (3)	173 (3)
O5—H5B···O4ⁱⁱ	0.85 (2)	1.69 (3)	2.518 (3)	164 (7)

Symmetry codes: (i) x, y, z+1; (ii) x, y+1, z.

Acknowledgements

The University of the Free State and Professor A. Roodt are gratefully acknowledged for financial support.

References

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