Gallic Acid.

Anhydrous 3,4,5-trihy-droxy-benzoic acid, C(7)H(6)O(5), is essentially planar, with its non-H atoms exhibiting mean and maximum deviations from coplanarity of 0.014 and 0.0377 (5) Å, respectively. The C-C-C-OH torsion angle about the bond linking the carboxyl group to the benzene ring is -0.33 (10)°. In the crystal, the -COOH groups form centrosymmetric hydrogen-bonded cyclic dimers [graph set R(2) (2)(8)] and the phenolic -OH groups participate in both intra- and inter-molecular hydrogen bonds, forming a three-dimensional network structure.

Related literature

For distribution of gallic acid in plants and for biological studies, see: Fiuza et al. (2004 ▶); Ow & Stupans (2003 ▶); Hemingway et al. (1999 ▶). For NMR data, see: Lu et al. (2007 ▶). For graph sets, see: Etter (1990 ▶); Zaheer et al. (2010 ▶). For related structures, see: Jiang et al. (2000 ▶); Okabe et al. (2001 ▶); Billes et al. (2007 ▶); Qadeer et al. (2007 ▶).

Experimental

Crystal data

C7H6O5

M = 170.12

Monoclinic,

a = 25.690 (4) Å

b = 4.8946 (5) Å

c = 11.097 (2) Å

β = 105.746 (6)°

V = 1343.0 (4) Å3

Z = 8

Mo Kα radiation

μ = 0.15 mm−1

T = 90 K

0.25 × 0.23 × 0.15 mm

Data collection

Nonius KappaCCD diffractometer with an Oxford Cryosystems Cryostream cooler

17352 measured reflections

2674 independent reflections

2391 reflections with I > 2σ(I)

R int = 0.016

Refinement

R[F 2 > 2σ(F 2)] = 0.034

wR(F 2) = 0.103

S = 1.06

2674 reflections

122 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.62 e Å−3

Δρmin = −0.31 e Å−3

Data collection: COLLECT (Nonius, 2000 ▶); cell refinement: SCALEPACK (Otwinowski & Minor, 1997 ▶); data reduction: DENZO (Otwinowski & Minor, 1997 ▶) and SCALEPACK; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXL97.

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811000262/zs2084sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811000262/zs2084Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C7H6O5	F(000) = 704
Mr = 170.12	Dx = 1.683 Mg m−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 2808 reflections
a = 25.690 (4) Å	θ = 2.5–33.7°
b = 4.8946 (5) Å	µ = 0.15 mm−1
c = 11.097 (2) Å	T = 90 K
β = 105.746 (6)°	Plate fragment, colorless
V = 1343.0 (4) Å3	0.25 × 0.23 × 0.15 mm
Z = 8

Nonius KappaCCD diffractometer with an Oxford Cryosystems Cryostream cooler	2391 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.016
graphite	θmax = 33.7°, θmin = 3.3°
ω and φ scans	h = −39→40
17352 measured reflections	k = −7→6
2674 independent reflections	l = −17→17

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)] = 0.034	H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.103	w = 1/[σ2(Fo2) + (0.0587P)2 + 0.8373P] where P = (Fo2 + 2Fc2)/3
S = 1.06	(Δ/σ)max = 0.001
2674 reflections	Δρmax = 0.62 e Å−3
122 parameters	Δρmin = −0.31 e Å−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0044 (13)

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.

	x	y	z	Uiso*/Ueq
O1	0.44464 (2)	0.87525 (12)	0.40294 (5)	0.01094 (12)
O2	0.48521 (2)	0.73099 (12)	0.59692 (5)	0.01333 (13)
H20	0.5098 (6)	0.863 (3)	0.5937 (13)	0.020*
O3	0.27635 (2)	0.27737 (12)	0.28219 (5)	0.01114 (12)
H30	0.2590 (5)	0.123 (3)	0.2837 (12)	0.017*
O4	0.28383 (2)	−0.05022 (12)	0.48841 (5)	0.01200 (13)
H40	0.2916 (5)	−0.133 (3)	0.5572 (13)	0.018*
O5	0.36851 (2)	−0.02019 (12)	0.69013 (5)	0.01222 (12)
H50	0.3938 (5)	0.025 (3)	0.7598 (13)	0.018*
C1	0.40393 (3)	0.51466 (15)	0.49199 (7)	0.00865 (13)
C2	0.35992 (3)	0.48758 (15)	0.38610 (7)	0.00907 (13)
H2	0.3573	0.5997	0.3148	0.011*
C3	0.32001 (3)	0.29613 (15)	0.38566 (6)	0.00847 (13)
C4	0.32395 (3)	0.13157 (14)	0.49036 (6)	0.00861 (13)
C5	0.36881 (3)	0.15566 (15)	0.59516 (6)	0.00883 (13)
C6	0.40877 (3)	0.34810 (15)	0.59730 (6)	0.00946 (13)
H6	0.4388	0.3666	0.6688	0.011*
C7	0.44573 (3)	0.72128 (15)	0.49266 (6)	0.00906 (13)

	U11	U22	U33	U12	U13	U23
O1	0.0098 (2)	0.0112 (2)	0.0104 (2)	−0.00298 (17)	0.00042 (17)	0.00155 (18)
O2	0.0101 (2)	0.0151 (3)	0.0115 (2)	−0.00630 (19)	−0.00259 (18)	0.00275 (19)
O3	0.0078 (2)	0.0101 (2)	0.0120 (2)	−0.00233 (17)	−0.00328 (17)	0.00127 (18)
O4	0.0094 (2)	0.0120 (3)	0.0133 (2)	−0.00483 (18)	0.00076 (18)	0.00206 (18)
O5	0.0133 (2)	0.0130 (3)	0.0087 (2)	−0.00419 (19)	0.00019 (18)	0.00260 (18)
C1	0.0072 (3)	0.0085 (3)	0.0094 (3)	−0.0018 (2)	0.0009 (2)	−0.0001 (2)
C2	0.0077 (3)	0.0091 (3)	0.0093 (3)	−0.0011 (2)	0.0005 (2)	0.0005 (2)
C3	0.0066 (2)	0.0083 (3)	0.0091 (3)	−0.0002 (2)	−0.0003 (2)	0.0000 (2)
C4	0.0068 (3)	0.0082 (3)	0.0100 (3)	−0.0014 (2)	0.0010 (2)	−0.0003 (2)
C5	0.0086 (3)	0.0089 (3)	0.0083 (3)	−0.0009 (2)	0.0012 (2)	0.0003 (2)
C6	0.0079 (3)	0.0102 (3)	0.0090 (3)	−0.0019 (2)	0.0003 (2)	−0.0001 (2)
C7	0.0075 (3)	0.0091 (3)	0.0096 (3)	−0.0012 (2)	0.0006 (2)	−0.0007 (2)

O1—C7	1.2429 (9)	C1—C2	1.3984 (10)
O2—C7	1.3163 (9)	C1—C6	1.4025 (10)
O2—H20	0.910 (15)	C1—C7	1.4737 (10)
O3—C3	1.3732 (8)	C2—C3	1.3880 (10)
O3—H30	0.881 (14)	C2—H2	0.9500
O4—C4	1.3575 (9)	C3—C4	1.3947 (10)
O4—H40	0.838 (14)	C4—C5	1.4025 (9)
O5—C5	1.3624 (9)	C5—C6	1.3885 (10)
O5—H50	0.893 (14)	C6—H6	0.9500
C7—O2—H20	111.7 (9)	O4—C4—C3	118.82 (6)
C3—O3—H30	110.1 (9)	O4—C4—C5	121.19 (6)
C4—O4—H40	108.0 (9)	C3—C4—C5	119.99 (6)
C5—O5—H50	111.0 (9)	O5—C5—C6	125.08 (6)
C2—C1—C6	120.91 (6)	O5—C5—C4	114.36 (6)
C2—C1—C7	119.42 (6)	C6—C5—C4	120.56 (6)
C6—C1—C7	119.67 (6)	C5—C6—C1	118.82 (6)
C3—C2—C1	119.67 (7)	C5—C6—H6	120.6
C3—C2—H2	120.2	C1—C6—H6	120.6
C1—C2—H2	120.2	O1—C7—O2	121.78 (6)
O3—C3—C2	118.88 (6)	O1—C7—C1	123.64 (6)
O3—C3—C4	121.07 (6)	O2—C7—C1	114.57 (6)
C2—C3—C4	120.02 (6)
C6—C1—C2—C3	0.95 (11)	O4—C4—C5—C6	−178.08 (7)
C7—C1—C2—C3	−179.03 (6)	C3—C4—C5—C6	1.92 (11)
C1—C2—C3—O3	178.27 (6)	O5—C5—C6—C1	179.54 (7)
C1—C2—C3—C4	−0.12 (11)	C4—C5—C6—C1	−1.09 (11)
O3—C3—C4—O4	0.35 (10)	C2—C1—C6—C5	−0.35 (11)
C2—C3—C4—O4	178.70 (6)	C7—C1—C6—C5	179.64 (7)
O3—C3—C4—C5	−179.65 (6)	C2—C1—C7—O1	−0.56 (11)
C2—C3—C4—C5	−1.30 (11)	C6—C1—C7—O1	179.45 (7)
O4—C4—C5—O5	1.35 (10)	C2—C1—C7—O2	179.65 (6)
C3—C4—C5—O5	−178.64 (6)	C6—C1—C7—O2	−0.33 (10)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H20···O1i	0.910 (15)	1.730 (15)	2.6384 (8)	175.6 (13)
O3—H30···O3ii	0.881 (14)	1.964 (14)	2.7943 (5)	156.6 (12)
O3—H30···O4	0.881 (14)	2.345 (13)	2.7579 (9)	108.8 (10)
O4—H40···O5	0.838 (14)	2.191 (13)	2.6688 (8)	116.1 (11)
O5—H50···O1iii	0.893 (14)	1.828 (14)	2.7200 (8)	178.6 (14)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H20⋯O1i	0.910 (15)	1.730 (15)	2.6384 (8)	175.6 (13)
O3—H30⋯O3ii	0.881 (14)	1.964 (14)	2.7943 (5)	156.6 (12)
O3—H30⋯O4	0.881 (14)	2.345 (13)	2.7579 (9)	108.8 (10)
O4—H40⋯O5	0.838 (14)	2.191 (13)	2.6688 (8)	116.1 (11)
O5—H50⋯O1iii	0.893 (14)	1.828 (14)	2.7200 (8)	178.6 (14)

Symmetry codes: (i) ; (ii) ; (iii) .