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Acetic anhydride (ethanoic anhydride), (CH3CO)2O, is a widely used acetyl­ation reagent in organic synthesis. The crystal and mol­ecular structure, as determined by single-crystal X-ray analysis at 100 K, is reported for the first time. A crystal of the title compound (m.p. 200 K) suitable for X-ray diffraction was grown from the melt at low temperature. The title compound crystallizes in the ortho­rhom­bic space group Pbcn, with Z = 4. In the crystal, the mol­ecule adopts an exact C2-symmetric conformation about a crystallographic twofold axis. The mol­ecules are densely packed. Two of the methyl H atoms form short inter­molecular contacts to a neighbouring carbonyl O atom, which can be viewed as weak hydrogen bonds.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S2053229616015047/yf3110sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S2053229616015047/yf3110Isup2.hkl
Contains datablock I

mol

MDL mol file https://doi.org/10.1107/S2053229616015047/yf3110Isup3.mol
Supplementary material

pdf

Portable Document Format (PDF) file https://doi.org/10.1107/S2053229616015047/yf3110sup4.pdf
IR spectrum of liquid acetic anhydride

cml

Chemical Markup Language (CML) file https://doi.org/10.1107/S2053229616015047/yf3110Isup5.cml
Supplementary material

CCDC reference: 1505908

Computing details top

Data collection: APEX2 (Bruker, 2013); cell refinement: SAINT (Bruker, 2013); data reduction: SAINT (Bruker, 2013); program(s) used to solve structure: SHELXS2013 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: DIAMOND (Brandenburg, 2014); software used to prepare material for publication: enCIFer (Allen et al., 2004).

Ethanoic anhydride top
Crystal data top
C4H6O3Dx = 1.346 Mg m3
Mr = 102.09Cu Kα radiation, λ = 1.54178 Å
Orthorhombic, PbcnCell parameters from 1147 reflections
a = 8.0707 (14) Åθ = 5.5–41.1°
b = 7.8733 (13) ŵ = 1.01 mm1
c = 7.9305 (13) ÅT = 100 K
V = 503.93 (15) Å3Cylinder, colourless
Z = 41.32 × 0.50 × 0.50 mm
F(000) = 216
Data collection top
Bruker AXS X8 Proteum
diffractometer
452 independent reflections
Radiation source: 0.2 x 2 mm focus rotating anode445 reflections with I > 2σ(I)
MONTEL graded multilayer optic monochromatorRint = 0.051
Detector resolution: 16.67 pixels mm-1θmax = 67.4°, θmin = 7.9°
φ– and ω–scansh = 99
Absorption correction: gaussian
(SADABS; Bruker, 2012)
k = 99
Tmin = 0.472, Tmax = 0.669l = 78
19642 measured reflections
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)] = 0.025H-atom parameters constrained
wR(F2) = 0.064 w = 1/[σ2(Fo2) + (0.0276P)2 + 0.1605P]
where P = (Fo2 + 2Fc2)/3
S = 1.09(Δ/σ)max < 0.001
452 reflectionsΔρmax = 0.16 e Å3
35 parametersΔρmin = 0.14 e Å3
0 restraintsExtinction correction: SHELXL2014 (Sheldrick, 2015), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.012 (2)
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.14484 (9)0.04403 (9)0.34929 (9)0.0280 (3)
O20.00000.26741 (12)0.25000.0253 (3)
C10.08205 (11)0.17820 (12)0.37607 (12)0.0204 (3)
C20.08774 (13)0.27697 (12)0.53580 (13)0.0245 (3)
H2A0.13150.20510.62630.037*
H2B0.02430.31480.56520.037*
H2C0.15970.37610.52110.037*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0304 (5)0.0292 (5)0.0246 (5)0.0064 (3)0.0029 (3)0.0002 (3)
O20.0345 (6)0.0211 (5)0.0203 (6)0.0000.0097 (4)0.000
C10.0187 (5)0.0230 (5)0.0195 (6)0.0035 (4)0.0005 (4)0.0041 (4)
C20.0303 (6)0.0247 (6)0.0186 (6)0.0046 (4)0.0021 (4)0.0011 (4)
Geometric parameters (Å, º) top
O1—C11.1907 (12)C2—H2A0.9800
O2—C1i1.3897 (11)C2—H2B0.9800
O2—C11.3897 (11)C2—H2C0.9800
C1—C21.4871 (14)
C1i—O2—C1119.29 (10)C1—C2—H2B109.5
O1—C1—O2121.52 (9)H2A—C2—H2B109.5
O1—C1—C2127.06 (9)C1—C2—H2C109.5
O2—C1—C2111.30 (8)H2A—C2—H2C109.5
C1—C2—H2A109.5H2B—C2—H2C109.5
C1i—O2—C1—O132.13 (7)C1i—O2—C1—C2151.49 (8)
Symmetry code: (i) x, y, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C2—H2A···O1ii0.982.643.5750 (13)159
C2—H2C···O1iii0.982.473.3567 (13)151
Symmetry codes: (ii) x, y, z+1/2; (iii) x+1/2, y+1/2, z.
Selected bond lengths (Å) and angles (°) for (I) in the crystal (X-ray) and for the [sp,ssp] conformor the gas phase, as determined by electron diffraction (ED) analysis and B3LYP/cc-pVTZ calculations. top
X-rayEDB3LYP/cc-pVTZ
O1—C11.1907 (12)1.182 (3)1.191
O2—C1i1.3897 (11)1.370 (15)1.395
O2—C11.3897 (11)1.370 (15)1.395
C1—C21.4871 (14)1.489 (2)1.500
C1i—O2—C1119.29 (10)116.5 (20)120.98
O1—C1—O2121.52 (9)124.8 (20)123.04
O1—C1—C2127.06 (9)-126.94
O2—C1—C2111.30 (8)114.6 (23)109.97
Geometric parameters derived from ED analysis B3LYP/cc-pVTZ calculations were taken from Wu et al. (2000). Symmetry code: (i) -x, y, -z+1/2.
 

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