Group 2 metal salts of pyromellitic acid: [Mg(H₂O)₆](C₁₀H₄O₈) and [Ba(C₁₀H₄O₈)(H₂O)₅]

Structural determinations of the magnesium(II) and barium(II) salts of pyromellitic acid (benzene-1,2,4,5-tetra­carboxyl­ic acid) are presented. Hexa­aqua­magnesium(II) benzene-1,2,4,5-tetra­carboxyl­ate(2-), [Mg(H₂O)₆](C₁₀H₄O₈), (I), and penta­aqua­[benzene-1,2,4,5-tetra­carboxyl­ato(2-)]­barium(II), [Ba(C₁₀H₄O₈)(H₂O)₅], (II), are both centrosymmetric and both possess a 1:1 metal-ligand ratio, but the two structures are found to differ in that the magnesium salt contains a hexaaqua cation and possesses only hydrogen-bonding interactions between cations and anions, while the barium salt exhibits coordination of the carboxyl­ate ligand to the nine-coordinate metal centre. In (I), both ions sit on a 2/m site symmetry, and in (II), the cation and anion are located on m and i site symmetries, respectively.

S1. Comment

Pyromellitic acid (H₄PMA, benzene-1,2,4,5-tetracarboxylic acid), a member of the popular (large? well studied?) benzenepolycarboxylic acid family, has found applications in the creation of hydrogen-bonding arrays (Mrvoš-Sermek et al., 1996; Biradha & Zaworotko, 1998) and, in particular, in the synthesis of coordination polymers, including, for example, mixed-ligand systems (Poleti et al., 1988; Zhang et al., 2003). Many authors strive to form functional porous supramolecular arrays (Janiak, 1997; Yaghi et al., 1995, 1998) using benzenepolycarboxylic acids amongst a very large number of possible ligands, and it is with this intention that we too have investigated the salts of benzenepolycarboxylic acids, concentrating on their alkali and alkaline earth metal salts.

A search of the Cambridge Structural Database (CSD; Version 5.24, July 2003 update; Allen, 2002) highlights numerous determinations of group 1 salts (Li⁺, Na⁺, K⁺ and Cs⁺) of H₄PMA (Jessen & Küppers, 1990, 1992; Hu & Ng, 2002; Emsley et al., 1986; Luehrs & Bowman-James, 1994), and yet, of the group 2 metals, only the Ca²⁺ salt [Ca₂(PMA)(H₂O)₆]_n (Robl, 1988) has been determined.

The magnesium salt, [Mg(H₂O)₆][H₂PMA], (I) (Fig. 1), does not possess metal–carboxylate coordination, instead containing a hexaaquo metal cation, as has also been observed in, amongst a total of 86 examples, the structures of magnesium hydrogen phthalate (Kariuki & Jones, 1989) and magnesium hydrogen maleate (Vanhouteghem et al., 1987). (I) is isostructural with the previously determined Co²⁺ (Ward & Luehrs, 1983) and Ni²⁺ (Jessen & Küppers, 1992) salts, and the asymmetric unit comprises a quarter of an [Mg(H₂O)₆]²⁺ cation and a quarter of an H₂PMA²⁻ anion.

Atom Mg1 is positioned on an inversion centre, with a twofold axis through atoms Mg1 and O1 and a mirror plane through atoms Mg1, O2 and O3. The cation is almost perfectly octahedral, having an angle of 90.1 (2)° between the O atoms in the mirror plane (Table 1). The Mg—OH₂ bond lengths compare well to the average value of 2.06 (2) Å, determined from 50 structures in the CSD containing the [Mg(H₂O)₆]²⁺ cation.

The H₂PMA²⁻ anion is positioned on a twofold axis, crossing through the non-substituted C atoms of the ring, and on a mirror plane bisecting the intramolecular O4—H4···O4' hydrogen bond, resulting in this short intramolecular hydrogen bond being refined as symmetrical (Table 2).

In addition to the intramolecular hydrogen bond, there are three further unique hydrogen bonds, all providing cation–anion interactions (Table 2). These hydrogen bonds create a three-dimensional structure, aided by the angle at which the planar anions lie with respect to the layers of [Mg(H₂O)₆]²⁺ cations (Fig. 2).

In contrast to (I), the barium salt [Ba(H₂PMA)(H₂O)₅], (II) (Fig. 3), displays metal–carboyxlate coordination and yet still contains the same intramolecularly hydrogen-bonded H₂PMA²⁻ anion as (I). Atom Ba1 has a coordination number of nine, having four metal–carboxylate bonds and five terminal metal–OH₂ bonds (Table 3), and these bond lengths compare well with average values determined from the CSD [2.798 (7) Å for Ba–carboxylate bonds and 2.847 (7) Å for Ba–OH₂ bonds]. The asymmetric unit comprises half of a formula unit, with atoms Ba1, O6, O7 and O8 positioned on a mirror plane and the H₂PMA²⁻ anion on an inversion centre.

The anions in (I) and (II) show expected geometrical similarities (Table 3); however, while the intramolecular hydrogen bond in (I) is constrained as symmetrical as a result of the symmetry of the system, the same bond in (II) is freely refined (Table 4). While the unique carboxyl group in (I) is approximately coplanar with the aromatic ring [with a dihedral angle of 2.35 (7)°], the carboxyl groups in (II) show greater deviation from the plane of the aromatic ring [dihedral angles of 15.2 (4) and 20.6 (4)°].

Each anion in (II) bridges four Ba²⁺ centres, thus creating a two-dimensional coordination polymer, which extends as sheets in the ab plane, with extensive H₂O···H₂O and carboxylate O···H₂O O—H···O hydrogen bonding supporting the network and extending it into the third dimension (Fig. 4 and Table 4).

S2. Experimental

For the preparation of (I), H₄PMA (5 equivalents) and 4MgCO₃·Mg(OH)₂·5H₂O (1 eq) were refluxed in H₂O for 18 h. Slow cooling of the resulting solution produced large, X-ray quality, colourless crystals of (I) in quantitaive yield, which were observed to desolvate? at 343–348 K. IR (KBr, ν_max, cm⁻¹): 3418 (br, OH), 3134 and 2923 (aromatic C—H), 1681 (C═O, acid), 1587 (asymm. CO₂⁻), 1556, 1538 and 1505 (aromatic C═C), 1349 (symm. CO₂⁻), 1284, 1156 and 1097 (C—O), 745 and 702 (aromatic C—H), 669, 594. Analysis calculated for MgC₁₀H₁₆O₁₄: C 31.24, H 4.19%; found: C 31.38, H 3.93%. For the preparation of (II), pale yellow, X–ray quality, crystals of (II) were produced by slowly diffusing together aqueous solutions of H₄PMA (1 equivalent) and BaBr₂·2H₂O (1 equivalent) at room temperature. The crystals were observed to desolvate at 290 K. IR (KBr, ν_max, cm⁻¹): 3410 (br, OH), 1686 (C═O, acid), 1592 (asymm. CO₂⁻), 1350 (symm. CO₂⁻), 1285, 1142 and 1096 (C—O), 756 (aromatic C—H), 621. Analysis calculated for BaC₁₀H₁₄O₁₃: C 25.05, H 2.94%; found: C 24.39, H 3.00%.

S3. Refinement

Aromatic H atoms were placed geometrically (C—H = 0.95 Å) and treated using a riding model, while the coordinates of hydroxy and water H atoms were refined using geometric restraints. U_iso(H) values were set to 1.2U_eq(C) for aryl H atoms and 1.5U_eq(O) for hydroxy H atoms. The largest residual electron-density peak in (I) is 1.0 Å from atom Mg1 and is probably caused by marginal crystal quality or lack of absorption correction. The data set resolution for (I) was truncated to θ=26° prior to the final refinement.

Computing details

For both compounds, data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2000); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and local programs.

Figures

	Fig. 1. A view of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented by circles of arbitrary radii and hydrogen bonds are shown as dashed lines. [Symmetry codes: (A) x, 1 − y, z; (B) 1 − x, y, 2 − z; (C) 1 − x, 1 − y, 2 − z; (D) −x, −y, −z.]
	Fig. 2. The crystal packing of (I), showing the three-dimensional hydrogen-bonding array, viewed along the crystallographic b axis. Hydrogen bonds are shown as dashed lines.
	Fig. 3. A view of (II), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented by circles of arbitrary radii and hydrogen bonds are shown as dashed lines. [Symmetry codes: (E) −x, 1 − y, 1 − z; (F) x, 0.5 − y, z; (G) 1 − x, 1 − y, 1 − z; (H) 1 − x, y − 0.5, 1 − z.]
	Fig. 4. The crystal packing of (II), viewed along the crystallographic c axis. The coordinated sheets lie in the ab plane, with hydrogen bonds linking neighbouring sheets. H atoms and hydrogen bonds have been omitted for clarity.

(I) hexaaquamagnesium(II) benzene-1,2,4,5-tetracarboxylate(2-)

Crystal data

[Mg(H2O)6](C10H4O8)	F(000) = 200
Mr = 384.54	Dx = 1.705 Mg m^−3
Monoclinic, P2/m	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2y	Cell parameters from 1696 reflections
a = 6.447 (3) Å	θ = 3.5–28.7°
b = 9.942 (4) Å	µ = 0.20 mm^−1
c = 6.455 (3) Å	T = 150 K
β = 115.148 (7)°	Block, colourless
V = 374.5 (3) Å^3	0.25 × 0.21 × 0.10 mm
Z = 1

Data collection

Bruker SMART 1000 CCD diffractometer	683 reflections with I > 2σ(I)
Radiation source: sealed tube	Rint = 0.022
Graphite monochromator	θmax = 26.0°, θmin = 2.1°
ω rotation with narrow frames scans	h = −7→7
2794 measured reflections	k = −12→12
771 independent reflections	l = −7→7

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: All non-H atoms found by direct methods
R[F^2 > 2σ(F^2)] = 0.061	Hydrogen site location: Geom except OH coords freely refined
wR(F^2) = 0.171	H atoms treated by a mixture of independent and constrained refinement
S = 1.17	w = 1/[σ^2(Fo^2) + (0.1034P)^2 + 0.4203P] where P = (Fo^2 + 2Fc^2)/3
771 reflections	(Δ/σ)max < 0.001
74 parameters	Δρmax = 1.17 e Å^−3
4 restraints	Δρmin = −0.34 e Å^−3

Special details

Experimental. SADABS v.2.03 (sheldrick, 2001) used for interframe scaling and rejection of outliers. No additional spherical absorption correction applied (low mu*r).

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 (Ų)

	x	y	z	Uiso*/Ueq
Mg1	0.0000	0.0000	0.0000	0.0144 (5)
O1	0.0000	0.2079 (3)	0.0000	0.0218 (7)
H1	0.058 (6)	0.260 (3)	0.112 (5)	0.033*
O2	0.2537 (8)	0.0000	0.3230 (6)	0.0465 (12)
H2	0.270 (9)	0.066 (4)	0.408 (8)	0.070*
O3	0.2395 (9)	0.0000	−0.1285 (9)	0.0554 (13)
H3	0.274 (10)	0.066 (4)	−0.184 (9)	0.083*
C1	0.5000	0.3642 (4)	1.0000	0.0165 (8)
H1A	0.5000	0.2686	1.0000	0.020*
C2	0.3925 (4)	0.4294 (3)	0.7898 (4)	0.0152 (6)
C3	0.2930 (5)	0.3331 (3)	0.5877 (5)	0.0184 (7)
O4	0.1954 (4)	0.3800 (2)	0.3824 (3)	0.0238 (6)
H4	0.193 (9)	0.5000	0.380 (10)	0.036*
O5	0.3100 (4)	0.2118 (2)	0.6230 (4)	0.0287 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Mg1	0.0189 (10)	0.0114 (9)	0.0108 (9)	0.000	0.0044 (7)	0.000
O1	0.0339 (17)	0.0129 (15)	0.0118 (13)	0.000	0.0032 (12)	0.000
O2	0.075 (3)	0.0148 (16)	0.0156 (17)	0.000	−0.0129 (16)	0.000
O3	0.089 (3)	0.0187 (18)	0.104 (4)	0.000	0.085 (3)	0.000
C1	0.0197 (19)	0.0099 (17)	0.0190 (19)	0.000	0.0075 (15)	0.000
C2	0.0152 (13)	0.0168 (15)	0.0134 (13)	−0.0012 (10)	0.0061 (10)	−0.0021 (10)
C3	0.0214 (14)	0.0163 (15)	0.0157 (14)	−0.0008 (11)	0.0062 (11)	−0.0012 (10)
O4	0.0370 (13)	0.0163 (11)	0.0118 (10)	−0.0014 (8)	0.0045 (8)	−0.0013 (7)
O5	0.0466 (14)	0.0126 (11)	0.0190 (11)	−0.0014 (9)	0.0063 (10)	−0.0023 (8)

Geometric parameters (Å, º)

Mg1—O2	2.031 (3)	C1—C2	1.394 (3)
Mg1—O2^i	2.031 (3)	C1—H1A	0.9500
Mg1—O3	2.040 (4)	C2—C2^iii	1.403 (5)
Mg1—O3^i	2.040 (4)	C2—C3	1.522 (4)
Mg1—O1^i	2.067 (3)	C3—O5	1.224 (4)
Mg1—O1	2.067 (3)	C3—O4	1.288 (3)
O1—H1	0.834 (17)	O4—H4	1.194 (2)
O2—H2	0.83 (2)	O4—O4^iii	2.387 (4)
O3—H3	0.83 (2)	O4—H4	1.194 (2)
C1—C2^ii	1.394 (3)
O2—Mg1—O2^i	180.00 (15)	Mg1—O1—H1	128 (3)
O2—Mg1—O3	89.9 (2)	Mg1—O2—H2	120 (4)
O2^i—Mg1—O3	90.1 (2)	Mg1—O3—H3	124 (4)
O2—Mg1—O3^i	90.1 (2)	C2^ii—C1—C2	124.5 (4)
O2^i—Mg1—O3^i	89.9 (2)	C2^ii—C1—H1A	117.7
O3—Mg1—O3^i	180.00 (12)	C2—C1—H1A	117.7
O2—Mg1—O1^i	90.0	C1—C2—C2^iii	117.73 (18)
O2^i—Mg1—O1^i	90.0	C1—C2—C3	113.3 (3)
O3—Mg1—O1^i	90.0	C2^iii—C2—C3	128.96 (15)
O3^i—Mg1—O1^i	90.0	O5—C3—O4	120.9 (3)
O2—Mg1—O1	90.0	O5—C3—C2	119.3 (2)
O2^i—Mg1—O1	90.0	O4—C3—C2	119.9 (2)
O3—Mg1—O1	90.0	H4—O4—C3	112 (3)
O3^i—Mg1—O1	90.0	C3—O4—O4^iii	111.17 (15)
O1^i—Mg1—O1	180.0	C3—O4—H4	112 (3)
C2^ii—C1—C2—C2^iii	0.000 (1)	C2^iii—C2—C3—O4	1.2 (3)
C2^ii—C1—C2—C3	179.0 (2)	O5—C3—O4—H4	180 (3)
C1—C2—C3—O5	1.3 (4)	C2—C3—O4—H4	−1 (3)
C2^iii—C2—C3—O5	−179.86 (19)	O5—C3—O4—O4^iii	−179.9 (2)
C1—C2—C3—O4	−177.7 (2)	C2—C3—O4—O4^iii	−1.0 (3)

Symmetry codes: (i) −x, −y, −z; (ii) −x+1, y, −z+2; (iii) x, −y+1, z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O4	0.84 (3)	1.99 (3)	2.822 (3)	179 (4)
O2—H2···O5	0.83 (4)	1.95 (4)	2.778 (3)	176 (5)
O3—H3···O5^iv	0.82 (5)	1.99 (5)	2.799 (5)	169 (6)
O4—H4···O4^iii	1.19 (2)	1.19 (2)	2.387 (4)	178 (5)

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

(II) pentaaqua[benzene-1,2,4,5-tetracarboxylate(2-)]barium(II)

Crystal data

[Ba(C10H4O8)(H2O)5]	F(000) = 468
Mr = 479.55	Dx = 2.097 Mg m^−3
Monoclinic, P21/m	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yb	Cell parameters from 5633 reflections
a = 6.6497 (4) Å	θ = 3.4–29.1°
b = 19.1205 (10) Å	µ = 2.69 mm^−1
c = 6.6971 (4) Å	T = 150 K
β = 116.865 (2)°	Block, pale yellow
V = 759.61 (8) Å^3	0.29 × 0.20 × 0.17 mm
Z = 2

Data collection

Bruker SMART 1000 CCD diffractometer	1890 independent reflections
Radiation source: sealed tube	1805 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.015
ω rotation with narrow frames scans	θmax = 29.1°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 2001)	h = −8→9
Tmin = 0.520, Tmax = 0.632	k = −24→26
6770 measured reflections	l = −8→8

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: All non-H atoms found by direct methods
R[F^2 > 2σ(F^2)] = 0.015	Hydrogen site location: Geom except OH coords freely refined
wR(F^2) = 0.033	H atoms treated by a mixture of independent and constrained refinement
S = 1.10	w = 1/[σ^2(Fo^2) + (0.0099P)^2 + 0.699P] where P = (Fo^2 + 2Fc^2)/3
1890 reflections	(Δ/σ)max = 0.001
134 parameters	Δρmax = 0.71 e Å^−3
16 restraints	Δρmin = −0.40 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Ba1	0.39996 (2)	0.2500	0.57794 (2)	0.01166 (4)
C1	0.0742 (3)	0.45887 (8)	0.3694 (3)	0.0129 (3)
C2	0.1420 (3)	0.52953 (8)	0.4153 (3)	0.0136 (3)
C3	0.0655 (3)	0.56806 (8)	0.5443 (3)	0.0141 (3)
H3A	0.1113	0.6155	0.5754	0.017*
C4	0.1307 (3)	0.40684 (9)	0.2299 (3)	0.0139 (3)
O1	0.1064 (2)	0.34358 (6)	0.2545 (2)	0.0172 (2)
O2	0.1931 (2)	0.42962 (6)	0.0868 (2)	0.0196 (3)
C5	0.2926 (3)	0.57098 (9)	0.3418 (3)	0.0156 (3)
O3	0.3315 (2)	0.54684 (7)	0.1811 (2)	0.0228 (3)
H3	0.261 (4)	0.4939 (13)	0.127 (4)	0.034*
O4	0.3710 (2)	0.62701 (7)	0.4316 (2)	0.0219 (3)
O5	0.4284 (2)	0.34852 (7)	0.9128 (2)	0.0203 (3)
H5A	0.341 (3)	0.3675 (11)	0.949 (4)	0.031*
H5B	0.508 (4)	0.3791 (10)	0.909 (4)	0.031*
O6	0.0078 (3)	0.2500	0.5989 (3)	0.0239 (4)
H6A	−0.112 (4)	0.2500	0.493 (4)	0.036*
H6B	−0.020 (6)	0.2500	0.703 (4)	0.036*
O7	0.5681 (3)	0.2500	0.2590 (3)	0.0200 (4)
H7A	0.537 (4)	0.2828 (9)	0.175 (3)	0.030*
O8	0.8456 (3)	0.2500	0.9216 (3)	0.0193 (4)
H8A	0.910 (3)	0.2827 (9)	1.003 (3)	0.029*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ba1	0.01243 (7)	0.01135 (7)	0.01310 (7)	0.000	0.00744 (5)	0.000
C1	0.0136 (8)	0.0120 (7)	0.0126 (7)	0.0010 (6)	0.0054 (6)	0.0010 (6)
C2	0.0139 (8)	0.0132 (7)	0.0145 (7)	0.0000 (6)	0.0071 (7)	0.0020 (6)
C3	0.0165 (8)	0.0111 (7)	0.0151 (8)	−0.0015 (6)	0.0075 (7)	−0.0005 (6)
C4	0.0117 (7)	0.0151 (8)	0.0137 (7)	0.0010 (6)	0.0047 (6)	−0.0008 (6)
O1	0.0218 (6)	0.0119 (5)	0.0191 (6)	0.0013 (5)	0.0102 (5)	−0.0007 (5)
O2	0.0287 (7)	0.0163 (6)	0.0218 (6)	0.0000 (5)	0.0183 (6)	−0.0014 (5)
C5	0.0138 (8)	0.0158 (8)	0.0182 (8)	0.0009 (6)	0.0082 (7)	0.0028 (6)
O3	0.0304 (7)	0.0195 (6)	0.0292 (7)	−0.0074 (5)	0.0229 (6)	−0.0050 (5)
O4	0.0264 (7)	0.0171 (6)	0.0300 (7)	−0.0075 (5)	0.0195 (6)	−0.0046 (5)
O5	0.0254 (7)	0.0166 (6)	0.0278 (7)	−0.0009 (5)	0.0197 (6)	−0.0017 (5)
O6	0.0170 (9)	0.0350 (11)	0.0240 (10)	0.000	0.0129 (8)	0.000
O7	0.0269 (10)	0.0183 (9)	0.0182 (9)	0.000	0.0133 (8)	0.000
O8	0.0206 (9)	0.0169 (9)	0.0159 (9)	0.000	0.0044 (7)	0.000

Geometric parameters (Å, º)

Ba1—O6	2.6742 (19)	C3—H3A	0.9500
Ba1—O1^i	2.8076 (12)	C4—O1	1.241 (2)
Ba1—O1	2.8076 (12)	C4—O2	1.281 (2)
Ba1—O8	2.8131 (18)	O2—H3	1.30 (2)
Ba1—O4^ii	2.8183 (12)	C5—O4	1.224 (2)
Ba1—O4^iii	2.8183 (12)	C5—O3	1.300 (2)
Ba1—O7	2.8227 (18)	O3—H3	1.10 (2)
Ba1—O5	2.8690 (13)	O5—H5A	0.807 (12)
Ba1—O5^i	2.8690 (13)	O5—H5B	0.795 (15)
C1—C3^iv	1.395 (2)	O6—H6A	0.793 (17)
C1—C2	1.413 (2)	O6—H6B	0.799 (16)
C1—C4	1.523 (2)	O7—H7A	0.804 (14)
C2—C3	1.395 (2)	O8—H8A	0.812 (15)
C2—C5	1.523 (2)
O6—Ba1—O1^i	71.71 (4)	O4^ii—Ba1—O5^i	136.07 (4)
O6—Ba1—O1	71.71 (4)	O4^iii—Ba1—O5^i	67.94 (4)
O1^i—Ba1—O1	79.18 (5)	O7—Ba1—O5^i	133.05 (3)
O6—Ba1—O8	130.43 (6)	O5—Ba1—O5^i	82.08 (5)
O1^i—Ba1—O8	137.67 (3)	C3^iv—C1—C2	118.00 (15)
O1—Ba1—O8	137.67 (3)	C3^iv—C1—C4	114.05 (14)
O6—Ba1—O4^ii	123.44 (3)	C2—C1—C4	127.94 (15)
O1^i—Ba1—O4^ii	135.13 (4)	C3—C2—C1	118.01 (15)
O1—Ba1—O4^ii	69.22 (4)	C3—C2—C5	113.75 (14)
O8—Ba1—O4^ii	68.80 (3)	C1—C2—C5	128.24 (15)
O6—Ba1—O4^iii	123.44 (3)	C2—C3—C1^iv	123.99 (15)
O1^i—Ba1—O4^iii	69.22 (4)	C2—C3—H3A	118.0
O1—Ba1—O4^iii	135.13 (4)	C1^iv—C3—H3A	118.0
O8—Ba1—O4^iii	68.80 (3)	O1—C4—O2	122.41 (15)
O4^ii—Ba1—O4^iii	113.11 (5)	O1—C4—C1	118.20 (14)
O6—Ba1—O7	140.24 (6)	O2—C4—C1	119.34 (14)
O1^i—Ba1—O7	77.95 (4)	C4—O1—Ba1	129.55 (11)
O1—Ba1—O7	77.95 (4)	C4—O2—H3	111.6 (10)
O8—Ba1—O7	89.33 (5)	O4—C5—O3	121.20 (15)
O4^ii—Ba1—O7	65.16 (3)	O4—C5—C2	119.52 (15)
O4^iii—Ba1—O7	65.16 (3)	O3—C5—C2	119.26 (15)
O6—Ba1—O5	71.36 (4)	C5—O3—H3	112.6 (12)
O1^i—Ba1—O5	143.02 (4)	C5—O4—Ba1^ii	146.47 (11)
O1—Ba1—O5	87.82 (4)	Ba1—O5—H5A	136.4 (17)
O8—Ba1—O5	71.78 (4)	Ba1—O5—H5B	105.6 (17)
O4^ii—Ba1—O5	67.94 (4)	H5A—O5—H5B	105 (2)
O4^iii—Ba1—O5	136.07 (4)	Ba1—O6—H6A	124 (3)
O7—Ba1—O5	133.05 (3)	Ba1—O6—H6B	131 (3)
O6—Ba1—O5^i	71.36 (4)	H6A—O6—H6B	104 (3)
O1^i—Ba1—O5^i	87.82 (4)	Ba1—O7—H7A	117.8 (16)
O1—Ba1—O5^i	143.02 (4)	Ba1—O8—H8A	126.0 (16)
O8—Ba1—O5^i	71.78 (4)
C3^iv—C1—C2—C3	0.1 (3)	O1^i—Ba1—O1—C4	−163.22 (12)
C4—C1—C2—C3	178.61 (15)	O8—Ba1—O1—C4	−8.00 (16)
C3^iv—C1—C2—C5	179.93 (16)	O4^ii—Ba1—O1—C4	−15.62 (13)
C4—C1—C2—C5	−1.6 (3)	O4^iii—Ba1—O1—C4	−117.97 (13)
C1—C2—C3—C1^iv	−0.1 (3)	O7—Ba1—O1—C4	−83.39 (14)
C5—C2—C3—C1^iv	−179.96 (15)	O5—Ba1—O1—C4	51.58 (14)
C3^iv—C1—C4—O1	−19.7 (2)	O5^i—Ba1—O1—C4	125.34 (13)
C2—C1—C4—O1	161.76 (16)	C3—C2—C5—O4	14.3 (2)
C3^iv—C1—C4—O2	157.83 (15)	C1—C2—C5—O4	−165.50 (16)
C2—C1—C4—O2	−20.7 (2)	C3—C2—C5—O3	−164.19 (15)
O2—C4—O1—Ba1	99.31 (17)	C1—C2—C5—O3	16.0 (3)
C1—C4—O1—Ba1	−83.24 (17)	O3—C5—O4—Ba1^ii	9.3 (3)
O6—Ba1—O1—C4	122.65 (14)	C2—C5—O4—Ba1^ii	−169.15 (13)

Symmetry codes: (i) x, −y+1/2, z; (ii) −x+1, −y+1, −z+1; (iii) −x+1, y−1/2, −z+1; (iv) −x, −y+1, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···O2	1.10 (2)	1.30 (2)	2.397 (2)	174 (2)
O5—H5A···O2^v	0.81 (2)	2.01 (2)	2.803 (2)	165 (2)
O5—H5B···O3^ii	0.80 (2)	2.02 (2)	2.803 (2)	166 (2)
O6—H6A···O7^vi	0.79 (3)	1.99 (3)	2.778 (3)	172 (3)
O6—H6B···O8^vi	0.80 (3)	2.03 (4)	2.818 (3)	169 (4)
O7—H7A···O5^vii	0.80 (2)	2.01 (2)	2.800 (2)	167 (2)
O8—H8A···O1^viii	0.81 (2)	1.98 (2)	2.772 (2)	166 (2)

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