Disilver(I) tricobalt(II) hydrogenphos­phate bis­(phosphate), Ag2Co3(HPO4)(PO4)2

Assani, A.; El Ammari, L.; Zriouil, M.; Saadi, M.

doi:10.1107/S1600536811022598

inorganic compounds

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Volume 67| Part 7| July 2011| Page i41

doi:10.1107/S1600536811022598

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Disilver(I) tricobalt(II) hydrogenphosphate bis(phosphate), Ag₂Co₃(HPO₄)(PO₄)₂

Abderrazzak Assani,^a ^* Lahcen El Ammari,^a Mohammed Zriouil ^a and Mohamed Saadi ^a

^aLaboratoire de Chimie du Solide Appliquée, Faculté des Sciences, Université Mohammed V-Agdal, Avenue Ibn Battouta, BP 1014, Rabat, Morocco
^*Correspondence e-mail: abder_assani@yahoo.fr

(Received 30 April 2011; accepted 10 June 2011; online 18 June 2011)

Ag₂Co₃(HPO₄)(PO₄)₂ contains CoO₆ octahedra and phosphate groups linked to form a three-dimensional network defining tunnels parallel to the a axis that are occupied by Ag⁺ ions.

Related literature

Compounds prepared hydrothermally in the Ag₂O–MO–P₂O₅ (M = divalent cation) system include AgMg₃(PO₄)(HPO₄)₂ (Assani et al., 2011a ), AgMn₃(PO₄)(HPO₄)₂ (Leroux et al., 1995 ), AgCo₃(PO₄)(HPO₄)₂ (Guesmi & Driss, 2002 ), AgNi₃(PO₄)(HPO₄)₂ (Ben Smail & Jouini, 2002 ), Ag₂Ni₃(HPO₄)(PO₄)₂ (Assani et al., 2011b ) and γ-AgZnPO₄ (Assani et al., 2010 ).

Experimental

Crystal data

Ag₂Co₃(HPO₄)(PO₄)₂
M_r = 678.44
Orthorhombic, I m a 2
a = 12.9814 (4) Å
b = 6.5948 (2) Å
c = 10.7062 (3) Å
V = 916.55 (5) Å³
Z = 4
Mo Kα radiation
μ = 10.11 mm⁻¹
T = 296 K
0.26 × 0.12 × 0.09 mm

Data collection

Bruker X8 APEX diffractometer
Absorption correction: multi-scan (MULABS; Blessing, 1995 ) T_min = 0.365, T_max = 0.424
3966 measured reflections
1388 independent reflections
1368 reflections with I > 2σ(I)
R_int = 0.021

Refinement

R[F² > 2σ(F²)] = 0.028
wR(F²) = 0.064
S = 1.05
1388 reflections
99 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 1.81 e Å⁻³
Δρ_min = −1.54 e Å⁻³
Absolute structure: Flack (1983 ), 653 Friedel pairs
Flack parameter: 0.55 (3)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O4—H4⋯O4ⁱ	0.86	1.86	2.626 (7)	148
Symmetry code: (i) $[-x-{\script{1\over 2}}, y, z]$ .

Data collection: APEX2 (Bruker, 2005 ); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ) and DIAMOND (Brandenburg, 2006 ); software used to prepare material for publication: WinGX (Farrugia, 1999 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811022598/mg2119sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811022598/mg2119Isup2.hkl

checkCIF report

Comment top

Compounds prepared hydrothermally in the Ag₂O–MO–P₂O₅ (M = divalent cation) systems include AgMg₃(PO₄)(HPO₄)₂ (Assani et al., 2011a), AgMn₃(PO₄)(HPO₄)₂ (Leroux et al., 1995), AgCo₃(PO₄)(HPO₄)₂ (Guesmi & Driss, 2002), AgNi₃(PO₄)(HPO₄)₂ (Ben Smail & Jouini, 2002), Ag₂Ni₃(HPO₄)(PO₄)₂ (Assani et al., 2011b), and γ-AgZnPO₄ (Assani et al., 2010). Ag₂Co₃(HPO₄)(PO₄)₂, isostructural to the Ni analogue, contains CoO₆ octahedra and PO₄ and PO₃(OH) tetrahedra which share corners and edges to form a three-dimensional framework (Fig. 1). Two types of tunnels aligned parallel to the a-direction accommodate Ag⁺ cations (Fig. 2).

Related literature top

Compounds prepared hydrothermally in the Ag₂O–MO–P₂O₅ (M = divalent cation) system include AgMg₃(PO₄)(HPO₄)₂ (Assani et al., 2011a), AgMn₃(PO₄)(HPO₄)₂ (Leroux et al., 1995), AgCo₃(PO₄)(HPO₄)₂ (Guesmi & Driss, 2002), AgNi₃(PO₄)(HPO₄)₂ (Ben Smail & Jouini, 2002), Ag₂Ni₃(HPO₄)(PO₄)₂ (Assani et al., 2011b) and γ-AgZnPO₄ (Assani et al., 2010).

Experimental top

A mixture of 0.0849 g AgNO₃, 0.0529 g CoCO₃.Co(OH)₂, 10 mL of 85 wt.% H₃PO₄, and 10 mL of distilled water was placed in a 23-mL Teflon-lined autoclave, which was heated at 468 K under autogeneous pressure for two days. Pink crystals of the title compound were obtained after the product was filtered, washed with deionized water, and dried in air.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top

Fig. 1. Connectivity of metal-centred coordination polyhedra in Ag₂Co₃(HPO₄)(PO₄)₂. Displacement ellipsoids are drawn at the 50% probability level. Symmetry codes: (i) -x, -y + 1, z; (ii) x + 1/2, -y+ 1, z; (iii) x, -y + 3/2, z - 1/2; (iv) -x + 1/2, -y + 3/2, z - 1/2; (v) -x + 1/2, -y + 1/2, z - 1/2; (vi) -x, y + 1/2, z - 1/2; (vii) x + 1/2, y + 1/2, z - 1/2; (viii) x, -y + 1/2, z - 1/2; (ix) -x, -y, z; (x) -x, y + 1/2, z + 1/2; (xi) x, -y + 1/2, z + 1/2; (xii) -x + 1/2, y, z.

Fig. 2. Polyhedral representation of Ag₂Co₃(HPO₄)(PO₄)₂, showing tunnels running along the a direction at x 1/2 0 and x 0 1/2.

Disilver(I) tricobalt(II) hydrogenphosphate bis(phosphate) top

Crystal data top

Ag₂Co₃(HPO₄)(PO₄)₂	F(000) = 1268
M_r = 678.44	D_x = 4.917 Mg m⁻³
Orthorhombic, Ima2	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: I 2 -2a	Cell parameters from 1388 reflections
a = 12.9814 (4) Å	θ = 3.1–30.0°
b = 6.5948 (2) Å	µ = 10.11 mm⁻¹
c = 10.7062 (3) Å	T = 296 K
V = 916.55 (5) Å³	Prism, pink
Z = 4	0.26 × 0.12 × 0.09 mm

Data collection top

Bruker X8 APEX diffractometer	1388 independent reflections
Radiation source: fine-focus sealed tube	1368 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.021
ϕ and ω scans	θ_max = 30.0°, θ_min = 3.1°
Absorption correction: multi-scan (MULABS; Blessing, 1995)	h = −17→18
T_min = 0.365, T_max = 0.424	k = −3→9
3966 measured reflections	l = −14→15

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.028	H-atom parameters constrained
wR(F²) = 0.064	w = 1/[σ²(F_o²) + (0.036P)² + 2.5641P] where P = (F_o² + 2F_c²)/3
S = 1.05	(Δ/σ)_max < 0.001
1388 reflections	Δρ_max = 1.81 e Å⁻³
99 parameters	Δρ_min = −1.54 e Å⁻³
1 restraint	Absolute structure: Flack (1983), 653 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.55 (3)

Crystal data top

Ag₂Co₃(HPO₄)(PO₄)₂	V = 916.55 (5) Å³
M_r = 678.44	Z = 4
Orthorhombic, Ima2	Mo Kα radiation
a = 12.9814 (4) Å	µ = 10.11 mm⁻¹
b = 6.5948 (2) Å	T = 296 K
c = 10.7062 (3) Å	0.26 × 0.12 × 0.09 mm

Data collection top

Bruker X8 APEX diffractometer	1388 independent reflections
Absorption correction: multi-scan (MULABS; Blessing, 1995)	1368 reflections with I > 2σ(I)
T_min = 0.365, T_max = 0.424	R_int = 0.021
3966 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.028	H-atom parameters constrained
wR(F²) = 0.064	Δρ_max = 1.81 e Å⁻³
S = 1.05	Δρ_min = −1.54 e Å⁻³
1388 reflections	Absolute structure: Flack (1983), 653 Friedel pairs
99 parameters	Absolute structure parameter: 0.55 (3)
1 restraint

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

	x	y	z	U_iso*/U_eq	Occ. (<1)
Ag1	0.2500	0.61215 (8)	−0.01381 (7)	0.03097 (16)
Ag2	0.0000	0.5000	−0.03770 (5)	0.0448 (2)
Co1	0.13632 (3)	0.24907 (9)	0.20816 (6)	0.00759 (11)
Co2	0.0000	0.5000	0.45678 (7)	0.00474 (13)
P1	−0.07308 (7)	0.25700 (17)	0.20656 (12)	0.00728 (17)
P2	0.2500	0.40742 (18)	0.45614 (14)	0.0051 (2)
O1	−0.1344 (3)	0.4442 (5)	0.1740 (3)	0.0117 (6)
O2	0.0039 (3)	0.2072 (5)	0.1002 (3)	0.0084 (6)
O3	0.0017 (3)	0.2766 (5)	0.3204 (3)	0.0078 (6)
O4	−0.1489 (3)	0.0787 (5)	0.2349 (3)	0.0116 (7)
O5	0.15460 (18)	0.5409 (4)	0.4551 (3)	0.0102 (5)
O6	0.2500	0.2616 (7)	0.3410 (4)	0.0109 (11)
O7	0.2500	0.2663 (7)	0.5736 (4)	0.0083 (10)
H4	−0.2103	0.0633	0.2635	0.010*	0.50

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Ag1	0.0498 (3)	0.0187 (2)	0.0244 (3)	0.000	0.000	0.0049 (2)
Ag2	0.1126 (6)	0.0094 (2)	0.0124 (3)	−0.0022 (2)	0.000	0.000
Co1	0.00546 (19)	0.0103 (2)	0.0070 (2)	0.0005 (2)	0.0001 (2)	−0.00120 (18)
Co2	0.0051 (2)	0.0051 (3)	0.0040 (3)	0.00074 (19)	0.000	0.000
P1	0.0069 (3)	0.0078 (4)	0.0071 (4)	0.0000 (4)	−0.0003 (5)	0.0005 (4)
P2	0.0043 (5)	0.0066 (5)	0.0044 (6)	0.000	0.000	−0.0005 (5)
O1	0.0133 (15)	0.0094 (14)	0.0124 (14)	0.0018 (11)	−0.0027 (10)	0.0002 (11)
O2	0.0096 (17)	0.0072 (12)	0.0083 (14)	−0.0004 (13)	−0.0014 (11)	−0.0031 (13)
O3	0.0080 (17)	0.0091 (14)	0.0063 (13)	0.0030 (12)	−0.0020 (10)	−0.0015 (12)
O4	0.0107 (17)	0.0083 (15)	0.0159 (18)	−0.0018 (11)	0.0039 (10)	0.0001 (10)
O5	0.0067 (9)	0.0115 (10)	0.0123 (13)	0.0014 (9)	0.0003 (12)	0.0000 (12)
O6	0.011 (3)	0.014 (2)	0.008 (2)	0.000	0.000	−0.0033 (15)
O7	0.007 (3)	0.010 (2)	0.0083 (19)	0.000	0.000	0.0021 (15)

Geometric parameters (Å, º) top

Ag1—O1ⁱ	2.537 (3)	Co2—O2^xi	2.056 (3)
Ag1—O1ⁱⁱ	2.537 (3)	Co2—O3ⁱ	2.074 (3)
Ag1—O5ⁱⁱⁱ	2.623 (3)	Co2—O3	2.074 (3)
Ag1—O5^iv	2.623 (3)	P1—O1	1.510 (3)
Ag1—O7^v	2.666 (4)	P1—O2	1.550 (4)
Ag1—O6^v	2.914 (5)	P1—O4	1.563 (3)
Ag1—O4^vi	3.001 (3)	P1—O3	1.563 (4)
Ag1—O4^vii	3.001 (3)	P2—O5	1.519 (3)
Ag1—Ag2	3.3384 (2)	P2—O5^xii	1.520 (3)
Ag2—O3^viii	2.374 (3)	P2—O6	1.563 (5)
Ag2—O3^vi	2.374 (3)	P2—O7	1.564 (5)
Ag2—O2	2.431 (4)	O1—Co1ⁱ	2.055 (3)
Ag2—O2ⁱ	2.431 (4)	O1—O4	2.504 (4)
Ag2—O1	2.884 (3)	O1—O2	2.509 (5)
Ag2—O1ⁱ	2.884 (3)	O1—Ag1ⁱ	2.536 (3)
Ag2—O4^viii	3.151 (3)	O2—Co2^xiii	2.056 (3)
Ag2—O4^vi	3.151 (3)	O3—Ag2^xiv	2.374 (3)
Ag2—Ag1ⁱ	3.3384 (2)	O4—Ag1^xv	3.001 (3)
Co1—O6	2.051 (3)	O4—Ag2^xiv	3.151 (3)
Co1—O1ⁱ	2.055 (3)	O4—H4	0.8598
Co1—O7^v	2.065 (3)	O5—Ag1^xvi	2.623 (3)
Co1—O2	2.090 (3)	O6—Co1^xii	2.051 (3)
Co1—O3	2.128 (4)	O6—Ag1^xvii	2.914 (5)
Co1—O4^ix	2.187 (3)	O7—Co1^xi	2.065 (3)
Co2—O5ⁱ	2.025 (2)	O7—Co1^xvii	2.065 (3)
Co2—O5	2.025 (2)	O7—Ag1^xvii	2.666 (4)
Co2—O2^x	2.056 (3)

O1ⁱ—Ag1—O1ⁱⁱ	72.52 (15)	O2—Ag2—O4^vi	125.96 (10)
O1ⁱ—Ag1—O5ⁱⁱⁱ	87.09 (10)	O2ⁱ—Ag2—O4^vi	110.56 (10)
O1ⁱⁱ—Ag1—O5ⁱⁱⁱ	120.52 (10)	O1—Ag2—O4^vi	177.68 (9)
O1ⁱ—Ag1—O5^iv	120.52 (10)	O1ⁱ—Ag2—O4^vi	102.42 (8)
O1ⁱⁱ—Ag1—O5^iv	87.09 (10)	O4^viii—Ag2—O4^vi	78.84 (11)
O5ⁱⁱⁱ—Ag1—O5^iv	56.35 (11)	Ag1ⁱ—Ag2—Ag1	171.21 (3)
O1ⁱ—Ag1—O7^v	65.44 (10)	O6—Co1—O1ⁱ	95.28 (16)
O1ⁱⁱ—Ag1—O7^v	65.44 (10)	O6—Co1—O7^v	88.38 (11)
O5ⁱⁱⁱ—Ag1—O7^v	149.47 (7)	O1ⁱ—Co1—O7^v	86.15 (16)
O5^iv—Ag1—O7^v	149.47 (7)	O6—Co1—O2	168.69 (14)
O1ⁱ—Ag1—O6^v	107.39 (11)	O1ⁱ—Co1—O2	91.26 (14)
O1ⁱⁱ—Ag1—O6^v	107.39 (11)	O7^v—Co1—O2	101.28 (12)
O5ⁱⁱⁱ—Ag1—O6^v	132.08 (10)	O6—Co1—O3	101.28 (13)
O5^iv—Ag1—O6^v	132.08 (10)	O1ⁱ—Co1—O3	90.38 (13)
O7^v—Ag1—O6^v	52.78 (11)	O7^v—Co1—O3	170.01 (13)
O1ⁱ—Ag1—O4^vi	116.18 (10)	O2—Co1—O3	69.40 (10)
O1ⁱⁱ—Ag1—O4^vi	163.45 (9)	O6—Co1—O4^ix	84.00 (15)
O5ⁱⁱⁱ—Ag1—O4^vi	75.15 (9)	O1ⁱ—Co1—O4^ix	175.52 (12)
O5^iv—Ag1—O4^vi	99.02 (9)	O7^v—Co1—O4^ix	89.40 (15)
O7^v—Ag1—O4^vi	104.24 (11)	O2—Co1—O4^ix	90.18 (13)
O6^v—Ag1—O4^vi	57.31 (10)	O3—Co1—O4^ix	94.10 (13)
O1ⁱ—Ag1—O4^vii	163.45 (9)	O5ⁱ—Co2—O5	178.97 (18)
O1ⁱⁱ—Ag1—O4^vii	116.18 (10)	O5ⁱ—Co2—O2^x	94.06 (13)
O5ⁱⁱⁱ—Ag1—O4^vii	99.02 (9)	O5—Co2—O2^x	86.71 (13)
O5^iv—Ag1—O4^vii	75.15 (9)	O5ⁱ—Co2—O2^xi	86.71 (13)
O7^v—Ag1—O4^vii	104.24 (11)	O5—Co2—O2^xi	94.06 (13)
O6^v—Ag1—O4^vii	57.31 (10)	O2^x—Co2—O2^xi	83.4 (2)
O4^vi—Ag1—O4^vii	51.87 (13)	O5ⁱ—Co2—O3ⁱ	94.45 (13)
O3^viii—Ag2—O3^vi	100.42 (17)	O5—Co2—O3ⁱ	84.82 (13)
O3^viii—Ag2—O2	77.19 (9)	O2^x—Co2—O3ⁱ	93.07 (11)
O3^vi—Ag2—O2	177.52 (14)	O2^xi—Co2—O3ⁱ	176.32 (16)
O3^viii—Ag2—O2ⁱ	177.52 (14)	O5ⁱ—Co2—O3	84.82 (13)
O3^vi—Ag2—O2ⁱ	77.19 (9)	O5—Co2—O3	94.45 (13)
O2—Ag2—O2ⁱ	105.21 (15)	O2^x—Co2—O3	176.32 (16)
O3^viii—Ag2—O1	114.25 (11)	O2^xi—Co2—O3	93.07 (11)
O3^vi—Ag2—O1	126.53 (11)	O3ⁱ—Co2—O3	90.51 (18)
O2—Ag2—O1	55.53 (11)	O1—P1—O2	110.1 (2)
O2ⁱ—Ag2—O1	67.13 (10)	O1—P1—O4	109.14 (18)
O3^viii—Ag2—O1ⁱ	126.53 (11)	O2—P1—O4	112.90 (19)
O3^vi—Ag2—O1ⁱ	114.25 (11)	O1—P1—O3	116.08 (18)
O2—Ag2—O1ⁱ	67.13 (10)	O2—P1—O3	100.93 (14)
O2ⁱ—Ag2—O1ⁱ	55.53 (11)	O4—P1—O3	107.57 (19)
O1—Ag2—O1ⁱ	76.38 (13)	O1—P1—Co1	122.99 (14)
O3^viii—Ag2—O4^viii	52.04 (11)	O5—P2—O5^xii	109.2 (2)
O3^vi—Ag2—O4^viii	68.06 (10)	O5—P2—O6	110.52 (15)
O2—Ag2—O4^viii	110.56 (10)	O5^xii—P2—O6	110.52 (15)
O2ⁱ—Ag2—O4^viii	125.96 (10)	O5—P2—O7	110.52 (15)
O1—Ag2—O4^viii	102.42 (8)	O5^xii—P2—O7	110.53 (15)
O1ⁱ—Ag2—O4^viii	177.68 (9)	O6—P2—O7	105.5 (2)
O3^viii—Ag2—O4^vi	68.06 (10)	P1—O4—H4	137.9
O3^vi—Ag2—O4^vi	52.04 (11)

Symmetry codes: (i) −x, −y+1, z; (ii) x+1/2, −y+1, z; (iii) x, −y+3/2, z−1/2; (iv) −x+1/2, −y+3/2, z−1/2; (v) −x+1/2, −y+1/2, z−1/2; (vi) −x, y+1/2, z−1/2; (vii) x+1/2, y+1/2, z−1/2; (viii) x, −y+1/2, z−1/2; (ix) −x, −y, z; (x) −x, y+1/2, z+1/2; (xi) x, −y+1/2, z+1/2; (xii) −x+1/2, y, z; (xiii) −x, y−1/2, z−1/2; (xiv) −x, y−1/2, z+1/2; (xv) x−1/2, y−1/2, z+1/2; (xvi) −x+1/2, −y+3/2, z+1/2; (xvii) −x+1/2, −y+1/2, z+1/2.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4···O4^xviii	0.86	1.86	2.626 (7)	148

Symmetry code: (xviii) −x−1/2, y, z.

Experimental details

Crystal data
Chemical formula	Ag₂Co₃(HPO₄)(PO₄)₂
M_r	678.44
Crystal system, space group	Orthorhombic, Ima2
Temperature (K)	296
a, b, c (Å)	12.9814 (4), 6.5948 (2), 10.7062 (3)
V (Å³)	916.55 (5)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	10.11
Crystal size (mm)	0.26 × 0.12 × 0.09

Data collection
Diffractometer	Bruker X8 APEX diffractometer
Absorption correction	Multi-scan (MULABS; Blessing, 1995)
T_min, T_max	0.365, 0.424
No. of measured, independent and observed [I > 2σ(I)] reflections	3966, 1388, 1368
R_int	0.021
(sin θ/λ)_max (Å⁻¹)	0.703

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.028, 0.064, 1.05
No. of reflections	1388
No. of parameters	99
No. of restraints	1
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	1.81, −1.54
Absolute structure	Flack (1983), 653 Friedel pairs
Absolute structure parameter	0.55 (3)

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg, 2006), WinGX (Farrugia, 1999).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4···O4ⁱ	0.86	1.86	2.626 (7)	148.0

Symmetry code: (i) −x−1/2, y, z.

Acknowledgements

The authors thank the Unit of Support for Technical and Scientific Research (UATRS, CNRST) for the X-ray measurements.

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