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In the crystal structure of the title compound, C4H4N2O2, the pyrazine N,N′-dioxide mol­ecules are located on centres of inversion. The mol­ecules are stacked in the direction of the crystallographic a axis and are connected via C—H...O hydrogen bonding.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536802018883/bt6204sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536802018883/bt6204Isup2.hkl
Contains datablock I

CCDC reference: 200770

Key indicators

  • Single-crystal X-ray study
  • T = 293 K
  • Mean [sigma](C-C) = 0.002 Å
  • R factor = 0.039
  • wR factor = 0.106
  • Data-to-parameter ratio = 14.5

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry








Computing details top

Data collection: IPDS Program Package (Stoe & Cie, 1998); cell refinement: IPDS Program Package; data reduction: IPDS Program Package; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL (Bruker, 1998); software used to prepare material for publication: CIFTAB in SHELXL97.

Pyrazine N,N'-dioxide top
Crystal data top
C4H4N2O2F(000) = 116
Mr = 112.09Dx = 1.594 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 3.7376 (6) ÅCell parameters from 1392 reflections
b = 11.0011 (18) Åθ = 4–28°
c = 5.7184 (9) ŵ = 0.13 mm1
β = 96.778 (19)°T = 293 K
V = 233.48 (6) Å3Block, colourless
Z = 20.3 × 0.2 × 0.2 mm
Data collection top
Stoe IPDS
diffractometer
427 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.032
Graphite monochromatorθmax = 28.0°, θmin = 4.0°
φ scansh = 44
1450 measured reflectionsk = 1411
551 independent reflectionsl = 77
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.039H-atom parameters constrained
wR(F2) = 0.106 w = 1/[σ2(Fo2) + (0.0567P)2 + 0.0228P]
where P = (Fo2 + 2Fc2)/3
S = 1.07(Δ/σ)max < 0.001
551 reflectionsΔρmax = 0.19 e Å3
38 parametersΔρmin = 0.14 e Å3
0 restraintsExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.41 (9)
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*/Ueq
N10.2159 (3)0.42985 (10)0.6583 (2)0.0419 (4)
O10.4230 (3)0.36378 (9)0.8052 (2)0.0578 (4)
C10.0743 (4)0.38407 (12)0.4468 (2)0.0454 (4)
H10.12420.30420.40820.054*
C20.1397 (4)0.54639 (12)0.7094 (2)0.0445 (4)
H20.23480.57950.85310.053*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0458 (6)0.0394 (6)0.0381 (6)0.0046 (4)0.0045 (5)0.0035 (4)
O10.0666 (7)0.0471 (6)0.0535 (7)0.0002 (4)0.0192 (5)0.0083 (4)
C10.0517 (8)0.0383 (6)0.0440 (8)0.0027 (5)0.0033 (6)0.0039 (5)
C20.0510 (7)0.0435 (7)0.0369 (7)0.0057 (5)0.0032 (6)0.0030 (5)
Geometric parameters (Å, º) top
N1—O11.2962 (14)C1—H10.9300
N1—C21.3526 (17)C2—C1i1.3617 (19)
N1—C11.3582 (17)C2—H20.9300
C1—C2i1.3617 (19)
O1—N1—C2121.08 (11)C2i—C1—H1119.6
O1—N1—C1120.61 (12)N1—C2—C1i120.87 (12)
C2—N1—C1118.30 (11)N1—C2—H2119.6
N1—C1—C2i120.83 (13)C1i—C2—H2119.6
N1—C1—H1119.6
Symmetry code: (i) x, y+1, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C1—H1···O1ii0.932.273.1682 (18)162
C2—H2···O1iii0.932.293.2067 (19)168
Symmetry codes: (ii) x, y+1/2, z1/2; (iii) x+1, y+1, z+2.
 

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