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This single-crystal neutron diffraction study of (±)-camphoric anhydride [systematic name: (RS)-1,8,8-trimeth­yl-3-oxa­bicyclo­[3.2.1]octa­ne-2,4-dione], C10H14O3, at 110 K was undertaken to determine accurately the positions of the H atoms. The crystal packing of these mol­ecules depends on inter­molecular hydrogen bonding. The (+) and (−) mol­ecules are held together by weak C—H...O inter­actions to form chains in the crystal structure.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536805008950/dn6207sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536805008950/dn6207Isup2.hkl
Contains datablock I

CCDC reference: 270318

Key indicators

  • Single-crystal neutron study
  • T = 110 K
  • Mean [sigma](C-C) = 0.003 Å
  • R factor = 0.059
  • wR factor = 0.057
  • Data-to-parameter ratio = 6.5

checkCIF/PLATON results

No syntax errors found



Alert level B REFNR01_ALERT_3_B Ratio of reflections to parameters is < 8 for a centrosymmetric structure sine(theta)/lambda 0.7637 Proportion of unique data used 0.4486 Ratio reflections to parameters 6.5061 PLAT088_ALERT_3_B Poor Data / Parameter Ratio .................... 6.51
Alert level C ABSTM02_ALERT_3_C The ratio of Tmax/Tmin expected RT(exp) is > 1.10 Absorption corrections should be applied. Tmin and Tmax expected: 0.640 0.757 RT(exp) = 1.182 PLAT026_ALERT_3_C Ratio Observed / Unique Reflections too Low .... 45 Perc. PLAT351_ALERT_3_C Long C-H Bond (0.96A) C4 - H4 ... 1.11 Ang. PLAT351_ALERT_3_C Long C-H Bond (0.96A) C5 - H51 ... 1.11 Ang. PLAT351_ALERT_3_C Long C-H Bond (0.96A) C8 - H83 ... 1.11 Ang. PLAT351_ALERT_3_C Long C-H Bond (0.96A) C9 - H91 ... 1.12 Ang. PLAT351_ALERT_3_C Long C-H Bond (0.96A) C10 - H101 ... 1.11 Ang.
0 ALERT level A = In general: serious problem 2 ALERT level B = Potentially serious problem 7 ALERT level C = Check and explain 0 ALERT level G = General alerts; check 0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 0 ALERT type 2 Indicator that the structure model may be wrong or deficient 9 ALERT type 3 Indicator that the structure quality may be low 0 ALERT type 4 Improvement, methodology, query or suggestion

Computing details top

Data collection: DIF4N (modified Linux version of DIF4; Stoe & Cie, 1991); cell refinement: DIF4N; data reduction: PRON98 (modified version of REDU4; Stoe & Cie, 1990; Meven, Year?); program(s) used to solve structure: a previous X-ray study gave position parameters for heavy atoms (Reference?); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and CAMERON (Watkin et al., 1996); software used to prepare material for publication: CRYSTALS.

(±)-1,8,8-Trimethyl-3-oxabicyclo[3.2.1]octane-2,4-dione top
Crystal data top
C10H14O3F(000) = 128
Mr = 182.22Dx = 1.268 Mg m3
Monoclinic, P21/nNeutron radiation, λ = 0.83300 Å
Hall symbol: -P 2ynCell parameters from 15 reflections
a = 6.5001 (8) Åθ = 16–22°
b = 11.5624 (14) ŵ = 0.09 mm1
c = 12.7093 (15) ÅT = 110 K
β = 92.179 (2)°Prism, colourless
V = 954.5 (2) Å35.00 × 4.00 × 3.00 mm
Z = 4
Data collection top
5C2 four-circle (Orphée reactor, Saclay, France)
diffractometer
θmax = 39.5°, θmin = 2.8°
Cu_(220) monochromatorh = 99
ω scansk = 171
4137 measured reflectionsl = 019
3553 independent reflections2 standard reflections every 0 reflections
1594 reflections with I > 3σ(I) intensity decay: 0.0%
Rint = 0.047
Refinement top
Refinement on FHydrogen site location: difference Fourier map
Least-squares matrix: fullAll H-atom parameters refined
R[F2 > 2σ(F2)] = 0.059 Chebychev polynomial, (Watkin, 1994; Prince, 1982) W = [weight][1-(ΔF/6σF)2]2
where [weight] = 1.0/[A0T0(x) + A1T1(x) ··· + An-1Tn-1(x)]
where x = F /Fmax and Ai are the Chebychev coefficients listed below: 0.703 -0.458 0.556 -0.177 0.795E-01
wR(F2) = 0.057(Δ/σ)max = 0.000154
S = 1.10Δρmax = 0.12 e Å3
1594 reflectionsΔρmin = 0.14 e Å3
245 parametersExtinction correction: Larson (1970), eq. 22
0 restraintsExtinction coefficient: 3.4 (8)
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C10.7903 (3)0.71470 (18)0.48982 (16)0.0188
C21.0199 (3)0.73790 (19)0.51432 (16)0.0203
C31.0182 (3)0.87660 (18)0.36654 (17)0.0205
C40.7950 (3)0.84498 (17)0.34358 (17)0.0194
C50.6641 (3)0.9091 (2)0.42731 (19)0.0246
C60.6682 (3)0.8264 (2)0.52484 (17)0.0223
C70.7580 (3)0.71385 (19)0.36671 (16)0.0179
C80.9082 (4)0.6336 (2)0.30866 (18)0.0245
C90.5330 (3)0.6807 (2)0.33370 (19)0.0252
C100.7222 (4)0.6053 (2)0.54726 (19)0.0270
O11.1120 (4)0.8274 (2)0.4582 (2)0.0230
O21.1304 (4)0.6881 (3)0.5787 (2)0.0298
O31.1226 (4)0.9430 (3)0.3174 (2)0.0299
H40.7553 (9)0.8694 (5)0.2608 (4)0.0375
H510.5050 (8)0.9217 (6)0.3956 (5)0.0447
H520.7279 (9)0.9952 (5)0.4473 (5)0.0415
H610.5119 (8)0.8000 (5)0.5448 (5)0.0410
H620.7425 (9)0.8663 (5)0.5953 (4)0.0400
H811.0727 (9)0.6545 (6)0.3224 (5)0.0444
H820.8782 (11)0.6388 (7)0.2230 (5)0.0512
H830.8850 (11)0.5424 (5)0.3326 (6)0.0500
H900.4183 (8)0.7281 (6)0.3787 (6)0.0519
H910.5080 (10)0.5859 (5)0.3443 (6)0.0489
H920.5043 (10)0.7008 (7)0.2502 (5)0.0531
H1010.7994 (11)0.5271 (6)0.5177 (6)0.0517
H1020.5553 (9)0.5949 (6)0.5393 (5)0.0456
H1030.7621 (11)0.6094 (7)0.6320 (5)0.0508
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0169 (8)0.0212 (8)0.0183 (8)0.0020 (7)0.0018 (6)0.0007 (7)
C20.0165 (8)0.0247 (10)0.0197 (8)0.0001 (7)0.0002 (6)0.0019 (7)
C30.0184 (8)0.0212 (9)0.0219 (8)0.0022 (7)0.0018 (7)0.0004 (7)
C40.0176 (8)0.0196 (9)0.0209 (8)0.0018 (7)0.0019 (6)0.0016 (7)
C50.0221 (9)0.0206 (9)0.0309 (10)0.0028 (7)0.0001 (8)0.0031 (8)
C60.0181 (8)0.0264 (9)0.0225 (9)0.0006 (7)0.0025 (7)0.0047 (8)
C70.0155 (8)0.0192 (8)0.0189 (8)0.0010 (6)0.0005 (6)0.0028 (7)
C80.0255 (10)0.0243 (9)0.0239 (9)0.0009 (8)0.0043 (8)0.0053 (8)
C90.0199 (9)0.0281 (10)0.0275 (10)0.0074 (8)0.0013 (7)0.0025 (9)
C100.0273 (10)0.0282 (10)0.0256 (10)0.0059 (8)0.0020 (8)0.0052 (8)
O10.0177 (9)0.0272 (11)0.0239 (10)0.0026 (9)0.0006 (8)0.0013 (9)
O20.0250 (12)0.0377 (15)0.0260 (11)0.0022 (10)0.0065 (9)0.0061 (11)
O30.0280 (13)0.0309 (13)0.0313 (13)0.0088 (10)0.0058 (10)0.0073 (10)
H40.039 (2)0.042 (3)0.030 (2)0.005 (2)0.0050 (18)0.009 (2)
H510.025 (2)0.050 (3)0.058 (3)0.004 (2)0.002 (2)0.000 (3)
H520.043 (3)0.029 (2)0.053 (3)0.0010 (19)0.002 (2)0.010 (2)
H610.031 (2)0.048 (3)0.045 (3)0.001 (2)0.0121 (19)0.004 (2)
H620.043 (3)0.044 (3)0.032 (2)0.004 (2)0.003 (2)0.015 (2)
H810.032 (2)0.047 (3)0.055 (3)0.003 (2)0.006 (2)0.008 (2)
H820.054 (3)0.069 (4)0.031 (2)0.002 (3)0.006 (2)0.013 (3)
H830.053 (3)0.027 (2)0.071 (4)0.000 (2)0.013 (3)0.001 (2)
H900.024 (2)0.061 (4)0.070 (4)0.001 (2)0.000 (2)0.018 (3)
H910.041 (3)0.037 (3)0.068 (4)0.012 (2)0.007 (3)0.002 (3)
H920.041 (3)0.080 (5)0.037 (3)0.009 (3)0.010 (2)0.004 (3)
H1010.061 (4)0.041 (3)0.054 (4)0.004 (3)0.014 (3)0.008 (3)
H1020.033 (2)0.051 (3)0.053 (3)0.010 (2)0.007 (2)0.012 (3)
H1030.062 (4)0.058 (4)0.032 (2)0.008 (3)0.001 (2)0.011 (3)
Geometric parameters (Å, º) top
C1—C21.536 (3)C5—H521.104 (6)
C1—C61.589 (3)C6—H611.100 (6)
C1—C71.571 (3)C6—H621.103 (5)
C1—C101.534 (3)C7—C81.553 (3)
C2—O11.403 (3)C7—C91.555 (3)
C2—O21.214 (3)C8—H811.104 (6)
C3—C41.513 (3)C8—H821.101 (6)
C3—O11.414 (3)C8—H831.109 (6)
C3—O31.214 (3)C9—H901.103 (7)
C4—C51.573 (3)C9—H911.117 (7)
C4—C71.565 (3)C9—H921.095 (6)
C4—H41.111 (5)C10—H1011.107 (7)
C5—C61.565 (3)C10—H1021.093 (6)
C5—H511.105 (6)C10—H1031.099 (6)
C2—C1—C6107.05 (17)C1—C6—H62111.0 (3)
C2—C1—C7107.15 (16)H61—C6—H62108.0 (5)
C6—C1—C7103.58 (16)C4—C7—C199.52 (15)
C2—C1—C10110.06 (17)C4—C7—C8112.71 (16)
C6—C1—C10112.38 (18)C1—C7—C8114.47 (18)
C7—C1—C10116.04 (18)C4—C7—C9109.76 (17)
C1—C2—O1117.09 (19)C1—C7—C9111.04 (17)
C1—C2—O2126.8 (2)C8—C7—C9109.04 (18)
O1—C2—O2116.1 (2)C7—C8—H81114.6 (4)
C4—C3—O1116.22 (19)C7—C8—H82110.2 (4)
C4—C3—O3127.2 (2)H81—C8—H82106.1 (6)
O1—C3—O3116.5 (2)C7—C8—H83110.1 (4)
C3—C4—C5107.14 (17)H81—C8—H83107.8 (5)
C3—C4—C7110.55 (16)H82—C8—H83107.7 (6)
C5—C4—C7103.82 (16)C7—C9—H90112.6 (4)
C3—C4—H4107.9 (3)C7—C9—H91110.4 (4)
C5—C4—H4114.1 (4)H90—C9—H91108.7 (6)
C7—C4—H4113.1 (3)C7—C9—H92109.4 (4)
C4—C5—C6104.74 (17)H90—C9—H92107.7 (6)
C4—C5—H51109.8 (4)H91—C9—H92107.7 (6)
C6—C5—H51110.9 (4)C1—C10—H101111.7 (4)
C4—C5—H52111.9 (4)C1—C10—H102110.5 (4)
C6—C5—H52111.9 (4)H101—C10—H102109.8 (6)
H51—C5—H52107.7 (5)C1—C10—H103111.7 (4)
C5—C6—C1105.57 (16)H101—C10—H103106.0 (6)
C5—C6—H61111.4 (4)H102—C10—H103107.0 (6)
C1—C6—H61108.3 (4)C3—O1—C2122.5 (2)
C5—C6—H62112.5 (4)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C4—H4···O2i1.110 (6)2.513 (6)3.514 (3)149.4 (4)
C5—H52···O1ii1.104 (6)2.576 (6)3.655 (3)165.1 (5)
C9—H90···O1iii1.103 (7)2.541 (7)3.633 (3)170.5 (5)
Symmetry codes: (i) x1/2, y+3/2, z1/2; (ii) x+2, y+2, z+1; (iii) x1, y, z.
 

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