3-Hydro­xy­benz­aldehyde

The title compound, C₇H₆O₂, forms infinite chains where the mol­ecules are hydrogen bonded via the hydroxyl and aldehyde groups, with an O...O distance of 2.719 (3) Å. Interchain interactions are weak. The geometry of the ring differs from the ideal form due to the effect of the substituents. Ab initio (Hartree–Fock self-consistent field–molecular orbital and density functional theory) calculations for the free mol­ecule reproduce well the observed small distortions of the ring. In the crystal, the geometry deviates from the ideal C_s symmetry of the free mol­ecule, as given by the ab initio calculations. The aldehyde and hydroxyl groups are twisted around the single bonds which join them to the ring as a result of the intermolecular hydrogen-bond interactions. These are also responsible for an elongation of the hydroxy C—OH bond compared with that calculated for the free mol­ecule.

Computing details

Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: HELENA (Spek, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97.

m-hydroxybenzaldehyde

Crystal data

C7H6O2	F(000) = 256
Mr = 122.12	Dx = 1.359 Mg m^−3
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 25 reflections
a = 18.858 (7) Å	θ = 5.9–18.4°
b = 3.864 (1) Å	µ = 0.10 mm^−1
c = 8.190 (7) Å	T = 293 K
V = 596.8 (6) Å^3	Prism, colourless
Z = 4	0.55 × 0.30 × 0.25 mm

Data collection

Enraf-Nonius CAD-4 diffractometer	Rint = 0.037
Radiation source: fine-focus sealed tube	θmax = 29.9°, θmin = 5.4°
Graphite monochromator	h = −26→24
profile data from ω–2θ scans	k = −5→5
5064 measured reflections	l = −10→10
768 independent reflections	3 standard reflections every 180 min
591 reflections with I > 2σ(I)	intensity decay: 1.8%

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.030	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.085	H-atom parameters constrained
S = 1.07	w = 1/[σ^2(Fo^2) + (0.0415P)^2 + 0.0908P] where P = (Fo^2 + 2Fc^2)/3
768 reflections	(Δ/σ)max < 0.001
88 parameters	Δρmax = 0.15 e Å^−3
1 restraint	Δρmin = −0.14 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
O1	0.11479 (11)	0.0907 (7)	−0.0379 (2)	0.0663 (6)
O2	0.05694 (10)	0.2467 (6)	0.6671 (2)	0.0579 (5)
H2	0.082 (2)	0.174 (9)	0.753 (6)	0.087*
C1	0.11486 (11)	0.1137 (6)	0.2506 (3)	0.0361 (5)
C2	0.07385 (13)	0.2065 (6)	0.3839 (3)	0.0387 (5)
H2A	0.0295	0.3066	0.3684	0.046*
C3	0.09917 (12)	0.1496 (6)	0.5402 (3)	0.0389 (5)
C4	0.16498 (12)	−0.0014 (6)	0.5614 (3)	0.0429 (5)
H4	0.1820	−0.0425	0.6662	0.051*
C5	0.20532 (12)	−0.0911 (6)	0.4279 (3)	0.0466 (6)
H5	0.2498	−0.1901	0.4436	0.056*
C6	0.18096 (11)	−0.0367 (6)	0.2716 (3)	0.0420 (5)
H6	0.2083	−0.0996	0.1819	0.050*
C7	0.08598 (13)	0.1771 (7)	0.0875 (3)	0.0459 (6)
H7	0.0389 (15)	0.293 (7)	0.086 (4)	0.055*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0658 (12)	0.1042 (18)	0.0289 (8)	0.0082 (11)	0.0020 (8)	−0.0015 (10)
O2	0.0553 (10)	0.0896 (14)	0.0287 (8)	0.0158 (11)	0.0032 (8)	−0.0002 (9)
C1	0.0373 (10)	0.0432 (10)	0.0278 (10)	−0.0023 (9)	−0.0004 (9)	0.0014 (10)
C2	0.0339 (9)	0.0496 (12)	0.0326 (11)	0.0034 (10)	−0.0024 (9)	0.0028 (10)
C3	0.0402 (11)	0.0476 (13)	0.0291 (10)	−0.0013 (10)	0.0035 (9)	−0.0003 (10)
C4	0.0427 (10)	0.0527 (13)	0.0334 (12)	−0.0011 (11)	−0.0071 (9)	0.0033 (10)
C5	0.0354 (10)	0.0559 (14)	0.0486 (14)	0.0063 (10)	−0.0031 (10)	0.0048 (12)
C6	0.0398 (10)	0.0493 (13)	0.0368 (12)	0.0029 (9)	0.0060 (9)	0.0004 (10)
C7	0.0434 (11)	0.0618 (16)	0.0326 (11)	0.0000 (11)	−0.0028 (10)	0.0044 (12)

Geometric parameters (Å, º)

O1—C7	1.209 (3)	C3—C4	1.382 (3)
O2—C3	1.362 (3)	C4—C5	1.376 (3)
O2—H2	0.89 (4)	C4—H4	0.9300
C1—C2	1.385 (3)	C5—C6	1.376 (4)
C1—C6	1.386 (3)	C5—H5	0.9300
C1—C7	1.463 (3)	C6—H6	0.9300
C2—C3	1.384 (4)	C7—H7	0.99 (3)
C2—H2A	0.9300
C3—O2—H2	102 (3)	C5—C4—H4	119.9
C2—C1—C6	120.8 (2)	C3—C4—H4	119.9
C2—C1—C7	117.93 (19)	C6—C5—C4	121.1 (2)
C6—C1—C7	121.2 (2)	C6—C5—H5	119.5
C3—C2—C1	119.7 (2)	C4—C5—H5	119.5
C3—C2—H2A	120.2	C5—C6—C1	118.7 (2)
C1—C2—H2A	120.2	C5—C6—H6	120.7
O2—C3—C4	123.0 (2)	C1—C6—H6	120.7
O2—C3—C2	117.4 (2)	O1—C7—C1	124.2 (2)
C4—C3—C2	119.6 (2)	O1—C7—H7	121.2 (18)
C5—C4—C3	120.2 (2)	C1—C7—H7	114.5 (18)
C6—C1—C2—C3	0.2 (3)	C3—C4—C5—C6	−0.7 (4)
C7—C1—C2—C3	179.8 (2)	C4—C5—C6—C1	0.5 (4)
C1—C2—C3—O2	179.7 (2)	C2—C1—C6—C5	−0.3 (3)
C1—C2—C3—C4	−0.4 (3)	C7—C1—C6—C5	−179.8 (2)
O2—C3—C4—C5	−179.5 (2)	C2—C1—C7—O1	−175.8 (3)
C2—C3—C4—C5	0.7 (3)	C6—C1—C7—O1	3.8 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···O1^i	0.89 (4)	1.85 (5)	2.719 (3)	164 (4)

Symmetry code: (i) x, y, z+1.