Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801000800/bt6003sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536801000800/bt6003Isup2.hkl |
CCDC reference: 159746
The H atom of the carboxylic acid group was located in a difference Fourier map and refined without restraint. All other H atoms were placed geometrically and allowed to ride during subsequent refinement with an isotropic displacement parameter fixed at 1.2 times that for the C atom to which they are attached.
Data collection: COLLECT (Nonius, 1998); cell refinement: HKL SCALEPACK (Otwinowski & Minor, 1997); data reduction: HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Sheldrick, 1993) and CAMERON (Watkin et al., 1996); software used to prepare material for publication: SHELXL97.
C9H16O4 | Dx = 1.287 Mg m−3 |
Mr = 188.22 | Melting point = 382–384 K |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
a = 22.622 (2) Å | Cell parameters from 2161 reflections |
b = 4.7348 (2) Å | θ = 1.0–27.5° |
c = 9.6864 (7) Å | µ = 0.10 mm−1 |
β = 110.559 (3)° | T = 180 K |
V = 971.5 (1) Å3 | Plate, colourless |
Z = 4 | 0.25 × 0.12 × 0.06 mm |
F(000) = 408 |
Nonius KappaCCD diffractometer | 1085 independent reflections |
Radiation source: fine-focus sealed tube | 913 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.039 |
Thin–slice ω and ϕ scans | θmax = 27.4°, θmin = 3.9° |
Absorption correction: multi-scan (SORTAV; Blessing, 1995) | h = 0→28 |
Tmin = 0.907, Tmax = 0.994 | k = −6→6 |
3154 measured reflections | l = −12→11 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.037 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.096 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.09 | w = 1/[σ2(Fo2) + (0.0328P)2 + 0.515P] where P = (Fo2 + 2Fc2)/3 |
1085 reflections | (Δ/σ)max = 0.010 |
64 parameters | Δρmax = 0.25 e Å−3 |
0 restraints | Δρmin = −0.19 e Å−3 |
C9H16O4 | V = 971.5 (1) Å3 |
Mr = 188.22 | Z = 4 |
Monoclinic, C2/c | Mo Kα radiation |
a = 22.622 (2) Å | µ = 0.10 mm−1 |
b = 4.7348 (2) Å | T = 180 K |
c = 9.6864 (7) Å | 0.25 × 0.12 × 0.06 mm |
β = 110.559 (3)° |
Nonius KappaCCD diffractometer | 1085 independent reflections |
Absorption correction: multi-scan (SORTAV; Blessing, 1995) | 913 reflections with I > 2σ(I) |
Tmin = 0.907, Tmax = 0.994 | Rint = 0.039 |
3154 measured reflections |
R[F2 > 2σ(F2)] = 0.037 | 0 restraints |
wR(F2) = 0.096 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.09 | Δρmax = 0.25 e Å−3 |
1085 reflections | Δρmin = −0.19 e Å−3 |
64 parameters |
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 | 0.18109 (4) | 0.17201 (19) | 0.01920 (10) | 0.0312 (3) | |
O2 | 0.24341 (4) | 0.54364 (19) | 0.11100 (10) | 0.0314 (3) | |
H1 | 0.2682 (9) | 0.465 (4) | 0.057 (2) | 0.079 (6)* | |
C1 | 0.19218 (5) | 0.3923 (3) | 0.09015 (12) | 0.0244 (3) | |
C2 | 0.14794 (6) | 0.5227 (3) | 0.15576 (14) | 0.0307 (3) | |
H2A | 0.1264 | 0.6833 | 0.0927 | 0.037* | |
H2B | 0.1732 | 0.6004 | 0.2536 | 0.037* | |
C3 | 0.09798 (5) | 0.3284 (3) | 0.17462 (14) | 0.0282 (3) | |
H3A | 0.1183 | 0.1874 | 0.2523 | 0.034* | |
H3B | 0.0767 | 0.2257 | 0.0813 | 0.034* | |
C4 | 0.04919 (5) | 0.4949 (3) | 0.21683 (13) | 0.0270 (3) | |
H4A | 0.0715 | 0.6108 | 0.3048 | 0.032* | |
H4B | 0.0272 | 0.6258 | 0.1353 | 0.032* | |
C5 | 0.0000 | 0.3150 (4) | 0.2500 | 0.0294 (4) | |
H5A | −0.0213 | 0.1920 | 0.1643 | 0.035* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0272 (5) | 0.0337 (5) | 0.0397 (5) | −0.0021 (4) | 0.0205 (4) | −0.0071 (4) |
O2 | 0.0262 (5) | 0.0340 (5) | 0.0429 (5) | −0.0043 (4) | 0.0235 (4) | −0.0055 (4) |
C1 | 0.0213 (6) | 0.0289 (6) | 0.0267 (6) | 0.0018 (5) | 0.0132 (4) | 0.0030 (5) |
C2 | 0.0269 (6) | 0.0322 (7) | 0.0424 (7) | −0.0027 (5) | 0.0240 (6) | −0.0064 (5) |
C3 | 0.0244 (6) | 0.0299 (7) | 0.0373 (7) | 0.0008 (5) | 0.0196 (5) | −0.0003 (5) |
C4 | 0.0222 (6) | 0.0300 (7) | 0.0348 (7) | 0.0002 (5) | 0.0175 (5) | −0.0012 (5) |
C5 | 0.0251 (9) | 0.0317 (9) | 0.0389 (9) | 0.000 | 0.0206 (7) | 0.000 |
O1—C1 | 1.2255 (15) | C3—H3A | 0.9900 |
O2—C1 | 1.3166 (14) | C3—H3B | 0.9900 |
O2—H1 | 0.96 (2) | C4—C5 | 1.5224 (14) |
C1—C2 | 1.4944 (16) | C4—H4A | 0.9900 |
C2—C3 | 1.5172 (16) | C4—H4B | 0.9900 |
C2—H2A | 0.9900 | C5—C4i | 1.5224 (14) |
C2—H2B | 0.9900 | C5—H5A | 0.9899 |
C3—C4 | 1.5244 (15) | ||
C1—O2—H1 | 110.9 (12) | C2—C3—H3B | 109.4 |
O1—C1—O2 | 123.02 (10) | C4—C3—H3B | 109.4 |
O1—C1—C2 | 123.67 (10) | H3A—C3—H3B | 108.0 |
O2—C1—C2 | 113.25 (10) | C5—C4—C3 | 114.78 (11) |
C1—C2—C3 | 116.05 (10) | C5—C4—H4A | 108.6 |
C1—C2—H2A | 108.3 | C3—C4—H4A | 108.6 |
C3—C2—H2A | 108.3 | C5—C4—H4B | 108.6 |
C1—C2—H2B | 108.3 | C3—C4—H4B | 108.6 |
C3—C2—H2B | 108.3 | H4A—C4—H4B | 107.5 |
H2A—C2—H2B | 107.4 | C4i—C5—C4 | 111.97 (14) |
C2—C3—C4 | 111.04 (10) | C4i—C5—H5A | 109.2 |
C2—C3—H3A | 109.4 | C4—C5—H5A | 109.2 |
C4—C3—H3A | 109.4 | ||
O1—C1—C2—C3 | 19.17 (18) | C2—C3—C4—C5 | −175.40 (9) |
O2—C1—C2—C3 | −163.41 (10) | C3—C4—C5—C4i | −176.92 (11) |
C1—C2—C3—C4 | −170.14 (11) |
Symmetry code: (i) −x, y, −z+1/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H1···O1ii | 0.96 (2) | 1.70 (2) | 2.6576 (12) | 173.5 (17) |
Symmetry code: (ii) −x+1/2, −y+1/2, −z. |
Experimental details
Crystal data | |
Chemical formula | C9H16O4 |
Mr | 188.22 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 180 |
a, b, c (Å) | 22.622 (2), 4.7348 (2), 9.6864 (7) |
β (°) | 110.559 (3) |
V (Å3) | 971.5 (1) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.25 × 0.12 × 0.06 |
Data collection | |
Diffractometer | Nonius KappaCCD diffractometer |
Absorption correction | Multi-scan (SORTAV; Blessing, 1995) |
Tmin, Tmax | 0.907, 0.994 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3154, 1085, 913 |
Rint | 0.039 |
(sin θ/λ)max (Å−1) | 0.648 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.037, 0.096, 1.09 |
No. of reflections | 1085 |
No. of parameters | 64 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.25, −0.19 |
Computer programs: COLLECT (Nonius, 1998), HKL SCALEPACK (Otwinowski & Minor, 1997), HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), XP (Sheldrick, 1993) and CAMERON (Watkin et al., 1996), SHELXL97.
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H1···O1i | 0.96 (2) | 1.70 (2) | 2.6576 (12) | 173.5 (17) |
Symmetry code: (i) −x+1/2, −y+1/2, −z. |
Two polymorphs of azelaic acid, (I), have been reported previously: the α form crystallizes in P21/c (Caspari, 1928; Housty & Hospital, 1967) and the β form crystallizes in C2/c (Housty & Hospital, 1967). For both polymorphs, the structures present in the CSD (AZELAC10 and AZELAC01; Allen & Kennard, 1993) are derived from room-temperature data with R factors ca 10% and ambiguities in the treatment of H atoms. We have, therefore, re-examined azelaic acid and report here the structure of the β form measured at 180 K to significantly greater precision.