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The structure of pyridine-2,6-di­carboxyl­ic acid, C7H5NO4, has been determined at 0.71 Å resolution. The mol­ecule is located on a site with mirror symmetry. A one-dimensional supra­molecular structure is stabilized in the solid state through a strong symmetric double hydrogen bond, with H...O distances of 1.86 (3) Å and O-H...O angles of 167 (3) and 171 (5)°. This arrangement is similar but not identical to that reported for the isoelectronic isophthalic acid (benzene-1,3-di­carboxyl­ic acid).

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270102002172/sk1531sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270102002172/sk1531Isup2.hkl
Contains datablock I

CCDC reference: 184496

Computing details top

Data collection: XSCANS (Siemens, 1996); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1997); software used to prepare material for publication: SHELXL97.

2,6-pyridinedicarboxylic acid top
Crystal data top
C7H5NO4F(000) = 172
Mr = 167.12Dx = 1.639 Mg m3
Monoclinic, P21/mMelting point: 525 K
Hall symbol: -P2ybMo Kα radiation, λ = 0.71073 Å
a = 3.7663 (6) ÅCell parameters from 70 reflections
b = 16.1667 (12) Åθ = 3.9–18.4°
c = 5.5705 (4) ŵ = 0.14 mm1
β = 93.156 (7)°T = 300 K
V = 338.67 (6) Å3Irregular, colourless
Z = 20.7 × 0.4 × 0.4 mm
Data collection top
Bruker P4
diffractometer
Rint = 0.036
Radiation source: fine-focus sealed tubeθmax = 30.0°, θmin = 2.5°
Graphite monochromatorh = 55
ω scansk = 2222
3920 measured reflectionsl = 77
1021 independent reflections3 standard reflections every 97 reflections
937 reflections with I > 2σ(I) intensity decay: 1%
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.040Hydrogen site location: difference Fourier map
wR(F2) = 0.121All H-atom parameters refined
S = 1.06 w = 1/[σ2(Fo2) + (0.0827P)2 + 0.0236P]
where P = (Fo2 + 2Fc2)/3
1021 reflections(Δ/σ)max = 0.001
74 parametersΔρmax = 0.34 e Å3
2 restraintsΔρmin = 0.18 e Å3
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
xyzUiso*/UeqOcc. (<1)
C10.1489 (2)0.60137 (5)0.64848 (17)0.0331 (2)
C20.2615 (2)0.67993 (5)0.77301 (14)0.0287 (2)
C30.4513 (3)0.67632 (5)0.99546 (17)0.0337 (2)
H30.516 (4)0.6252 (12)1.070 (3)0.049 (4)*
C40.5489 (3)0.75001.1093 (2)0.0349 (3)
H40.698 (7)0.75001.272 (5)0.063 (7)*
N10.1650 (3)0.75000.66094 (18)0.0289 (2)
O10.2503 (3)0.53435 (5)0.75157 (16)0.0580 (3)
H10.158 (7)0.4969 (19)0.688 (5)0.054 (6)*0.66 (3)
O20.0354 (2)0.60406 (4)0.45566 (14)0.0490 (3)
H20.119 (12)0.564 (2)0.401 (8)0.054 (6)*0.34 (3)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0399 (4)0.0239 (4)0.0346 (4)0.0008 (3)0.0070 (3)0.0025 (3)
C20.0329 (4)0.0239 (4)0.0287 (4)0.0000 (2)0.0039 (3)0.0012 (2)
C30.0384 (4)0.0318 (5)0.0300 (4)0.0012 (3)0.0058 (3)0.0044 (3)
C40.0393 (6)0.0381 (6)0.0264 (5)0.0000.0069 (4)0.000
N10.0345 (5)0.0235 (4)0.0281 (4)0.0000.0050 (3)0.000
O10.0862 (6)0.0237 (4)0.0600 (5)0.0001 (3)0.0339 (5)0.0061 (3)
O20.0722 (6)0.0272 (4)0.0444 (5)0.0014 (3)0.0262 (4)0.0003 (3)
Geometric parameters (Å, º) top
C1—O11.2750 (10)C3—H30.95 (2)
C1—O21.2472 (12)C4—C3i1.3894 (11)
C1—C21.4973 (11)C4—H41.04 (3)
C2—N11.3342 (9)N1—C2i1.3342 (9)
C2—C31.3973 (12)O1—H10.77 (3)
C3—C41.3894 (11)O2—H20.77 (3)
O2—C1—O1123.81 (9)C2—C3—H3122.0 (11)
O2—C1—C2119.96 (8)C3—C4—C3i118.04 (12)
O1—C1—C2116.23 (8)C3—C4—H4120.96 (6)
N1—C2—C3124.29 (8)C3i—C4—H4120.96 (8)
N1—C2—C1116.14 (8)C2i—N1—C2116.22 (10)
C3—C2—C1119.57 (7)C1—O1—H1110 (2)
C4—C3—C2118.58 (8)C1—O2—H2120 (4)
C4—C3—H3119.4 (11)
O2—C1—C2—N12.51 (15)N1—C2—C3—C40.23 (17)
O1—C1—C2—N1177.88 (9)C1—C2—C3—C4179.16 (8)
O2—C1—C2—C3176.50 (9)C2—C3—C4—C3i0.16 (19)
O1—C1—C2—C33.11 (14)C3—C2—N1—C2i0.28 (17)
N1—C2—C3—C40.23 (17)C1—C2—N1—C2i179.24 (6)
C1—C2—C3—C4179.16 (8)H4—C4—C3—H32.0 (17)
C2—C3—C4—C3i0.16 (19)H4—C4—C3—C2177.8 (15)
C3—C2—N1—C2i0.28 (17)H3—C3—C2—C11.1 (10)
C1—C2—N1—C2i179.24 (6)H3—C3—C2—N1180.0 (10)
O2—C1—C2—N12.51 (15)H1—O1—C1—O29 (2)
O1—C1—C2—N1177.88 (9)H1—O1—C1—C2171 (2)
O2—C1—C2—C3176.50 (9)H2—O2—C1—O19 (4)
O1—C1—C2—C33.11 (14)H2—O2—C1—C2170 (4)
Symmetry code: (i) x, y+3/2, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···O2ii0.77 (3)1.86 (3)2.6252 (12)167 (3)
O2—H2···O1ii0.77 (3)1.86 (3)2.6252 (12)171 (5)
Symmetry code: (ii) x, y+1, z+1.
 

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