organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

1,1,1-Tri­chloro-2,2-bis­­(4-eth­­oxy­phen­yl)ethane

aScience and Engineering Faculty, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia
*Correspondence e-mail: g.smith@qut.edu.au

(Received 16 October 2012; accepted 22 October 2012; online 27 October 2012)

In the title compound, C18H19Cl3O2, which is the 4-eth­oxy­phenyl analogue of the insecticidally active 4-meth­oxy­phenyl compound meth­oxy­chlor, the dihedral angle between the two benzene rings is 60.38 (13)°. An intra­molecular aromatic C—H⋯Cl inter­action is present.

Related literature

For background to DDT-type insecticides, see: Läuger et al. (1944[Läuger, P., Martin, H. & Müller, P. H. (1944). Helv. Chim. Acta, 27, 892-928.]). For unit-cell data for the title compound, see: Schneider & Fankuchen (1946[Schneider, M. & Fankuchen, I. (1946). J. Am. Chem. Soc. 68, 2669-2670.]). For the structures of analogous p-alk­oxy-substituted DDT compounds, see: Smith et al. (1976[Smith, G., Kennard, C. H. L. & White, A. H. (1976). Aust. J. Chem. 29, 743-747.]); Smith (2012[Smith, G. (2012). Acta Cryst. E68, o2544.]).

[Scheme 1]

Experimental

Crystal data
  • C18H19Cl3O2

  • Mr = 373.68

  • Monoclinic, P 21 /c

  • a = 23.4405 (7) Å

  • b = 9.8835 (2) Å

  • c = 7.7924 (2) Å

  • β = 99.536 (3)°

  • V = 1780.35 (8) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.52 mm−1

  • T = 200 K

  • 0.30 × 0.15 × 0.08 mm

Data collection
  • Oxford Diffraction Gemini-S CCD-detector diffractometer

  • Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2012[Agilent (2012). CrysAlis PRO. Agilent Technologies Ltd, Yarnton, England.]) Tmin = 0.960, Tmax = 0.980

  • 10942 measured reflections

  • 3109 independent reflections

  • 2282 reflections with I > 2σ(I)

  • Rint = 0.106

Refinement
  • R[F2 > 2σ(F2)] = 0.046

  • wR(F2) = 0.092

  • S = 0.91

  • 3109 reflections

  • 210 parameters

  • H-atom parameters constrained

  • Δρmax = 0.38 e Å−3

  • Δρmin = −0.25 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C2B—H2B⋯Cl2 0.93 2.67 3.321 (3) 128

Data collection: CrysAlis PRO (Agilent, 2012[Agilent (2012). CrysAlis PRO. Agilent Technologies Ltd, Yarnton, England.]); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SIR92 (Altomare et al., 1993[Altomare, A., Cascarano, G., Giacovazzo, C. & Guagliardi, A. (1993). J. Appl. Cryst. 26, 343-350.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]) within WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]); molecular graphics: PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]); software used to prepare material for publication: PLATON.

Supporting information


Comment top

The title compound, C18H19Cl302 is the 4-ethoxyphenyl analogue of the insecticides DDT [1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane] and methoxychlor (the 4-methoxyphenyl analogue), and has similar insecticidal activity (Läuger et al., 1944), but was not used as a commercial product. The crystal structures of methoxychlor (Smith et al., 1976) and the p-butoxy analogue (Smith, 2012) are known and the unit cell data for the title compound has been reported (Schneider & Fankuchen, 1946). The structure of the title compound is reported herein.

The molecular structure of the title compound is shown in Fig. 1. The unit cell and space group are consistent with those previously reported. The dihedral angle between the two benzene ring mean planes is 60.38 (13)°. The value of this angle is 77.7° (no s.u. available) in the structure of methoxychlor (Smith et al., 1976). The conformations of the two ethoxy side chains relative to their benzene rings (A and B) are similar [comparative torsion angles C3—C4—O4—C11, -173.3 (3) and 162.2 (2), respectively]. The B ring conformation is stabilized by an intramolecular aromatic C2B—H···Cl2 interaction (Table 1). No significant intermolecular interactions are present (Fig. 2).

Related literature top

For background to DDT-type insecticides, see: Läuger et al. (1944). For unit-cell data for the title compound, see: Schneider & Fankuchen (1946). For the structures of analogous p-alkoxy-substituted DDT compounds, see: Smith et al. (1976); Smith (2012).

Experimental top

The title compound was obtained as an analytical reference standard from the US Public Health Service. Colourless crystal prisms suitable for X-ray analysis were obtained by room temperature evaporation of a solution of the title compound in ethanol.

Refinement top

Hydrogen atoms were included in the refinement at calculated positions [C—H = 0.93–0.98 Å, with Uiso(H) = 1.2Ueq(C)(aromatic, methylene and methine) or 1.5Ueq(C)(methyl), using a riding-model approximation.

Computing details top

Data collection: CrysAlis PRO (Agilent, 2012); cell refinement: CrysAlis PRO (Agilent, 2012); data reduction: CrysAlis PRO (Agilent, 2012); program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008) within WinGX (Farrugia, 1999); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, with displacement ellipsoids drawn at the 50% probability level.
[Figure 2] Fig. 2. A perspective view of the crystal packing in the unit cell viewed approximately along the b axis.
1,1,1-Trichloro-2,2-bis(4-ethoxyphenyl)ethane top
Crystal data top
C18H19Cl3O2F(000) = 776
Mr = 373.68Dx = 1.394 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 3070 reflections
a = 23.4405 (7) Åθ = 3.1–28.8°
b = 9.8835 (2) ŵ = 0.52 mm1
c = 7.7924 (2) ÅT = 200 K
β = 99.536 (3)°Prism, colourless
V = 1780.35 (8) Å30.30 × 0.15 × 0.08 mm
Z = 4
Data collection top
Oxford Diffraction Gemini-S CCD-detector
diffractometer
3109 independent reflections
Radiation source: Enhance (Mo) X-ray source2282 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.106
Detector resolution: 16.077 pixels mm-1θmax = 25.0°, θmin = 3.4°
ω scansh = 2723
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2012)
k = 1111
Tmin = 0.960, Tmax = 0.980l = 99
10942 measured reflections
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)] = 0.046Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.092H-atom parameters constrained
S = 0.91 w = 1/[σ2(Fo2) + (0.013P)2]
where P = (Fo2 + 2Fc2)/3
3109 reflections(Δ/σ)max < 0.001
210 parametersΔρmax = 0.38 e Å3
0 restraintsΔρmin = 0.25 e Å3
Crystal data top
C18H19Cl3O2V = 1780.35 (8) Å3
Mr = 373.68Z = 4
Monoclinic, P21/cMo Kα radiation
a = 23.4405 (7) ŵ = 0.52 mm1
b = 9.8835 (2) ÅT = 200 K
c = 7.7924 (2) Å0.30 × 0.15 × 0.08 mm
β = 99.536 (3)°
Data collection top
Oxford Diffraction Gemini-S CCD-detector
diffractometer
3109 independent reflections
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2012)
2282 reflections with I > 2σ(I)
Tmin = 0.960, Tmax = 0.980Rint = 0.106
10942 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0460 restraints
wR(F2) = 0.092H-atom parameters constrained
S = 0.91Δρmax = 0.38 e Å3
3109 reflectionsΔρmin = 0.25 e Å3
210 parameters
Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

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
Cl10.33099 (3)0.05016 (8)0.40168 (9)0.0385 (3)
Cl20.23442 (3)0.19217 (7)0.50376 (9)0.0374 (3)
Cl30.21520 (3)0.01715 (8)0.24488 (9)0.0412 (3)
O4A0.02901 (9)0.0931 (2)0.7508 (3)0.0442 (8)
O4B0.44289 (8)0.0498 (2)1.1563 (2)0.0406 (7)
C10.25902 (12)0.0312 (3)0.4447 (3)0.0274 (9)
C1A0.19612 (11)0.0869 (3)0.6338 (3)0.0228 (9)
C1B0.30558 (11)0.0680 (3)0.7397 (3)0.0247 (9)
C20.25640 (11)0.0785 (3)0.5851 (3)0.0240 (9)
C2A0.17938 (12)0.0081 (3)0.7642 (3)0.0293 (10)
C2B0.31987 (12)0.0486 (3)0.8366 (3)0.0293 (9)
C3A0.12369 (13)0.0129 (3)0.7994 (4)0.0325 (10)
C3B0.36559 (12)0.0512 (3)0.9749 (4)0.0322 (10)
C4A0.08312 (12)0.0979 (3)0.7062 (4)0.0304 (10)
C4B0.39827 (12)0.0635 (3)1.0180 (3)0.0301 (10)
C5A0.09942 (12)0.1816 (3)0.5803 (3)0.0316 (10)
C5B0.38476 (12)0.1820 (3)0.9249 (3)0.0314 (10)
C6A0.15553 (12)0.1748 (3)0.5458 (3)0.0291 (9)
C6B0.33864 (12)0.1830 (3)0.7873 (3)0.0273 (9)
C11A0.01660 (13)0.1672 (3)0.6474 (4)0.0485 (11)
C11B0.48754 (13)0.1495 (3)1.1746 (4)0.0425 (11)
C21A0.07174 (14)0.1329 (4)0.7104 (5)0.0641 (16)
C21B0.53406 (13)0.1062 (3)1.3219 (4)0.0509 (14)
H20.262300.164900.528800.0290*
H2A0.206200.049100.829000.0350*
H2B0.298300.126800.808200.0350*
H3A0.113300.041500.886600.0390*
H3B0.374200.130401.038400.0390*
H5A0.073000.241800.519500.0380*
H5B0.406300.260100.954200.0380*
H6A0.166200.231100.460900.0350*
H6B0.329700.262700.725400.0330*
H11A0.019300.142800.525800.0580*
H11B0.472100.237001.200100.0510*
H12A0.009100.263600.658900.0580*
H12B0.503400.156901.067600.0510*
H21A0.103400.178700.639900.0960*
H21B0.564800.171401.336400.0760*
H22A0.069200.161100.829300.0960*
H22B0.548900.019401.295600.0760*
H23A0.078000.037000.702300.0960*
H23B0.518100.100101.427300.0760*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl10.0348 (5)0.0443 (5)0.0374 (5)0.0061 (4)0.0093 (3)0.0034 (4)
Cl20.0452 (5)0.0235 (4)0.0428 (5)0.0032 (3)0.0053 (4)0.0059 (3)
Cl30.0453 (5)0.0481 (5)0.0263 (4)0.0079 (4)0.0054 (3)0.0015 (4)
O4A0.0280 (13)0.0556 (15)0.0488 (14)0.0015 (11)0.0054 (10)0.0016 (11)
O4B0.0327 (12)0.0469 (14)0.0373 (12)0.0064 (10)0.0081 (10)0.0016 (10)
C10.0303 (17)0.0255 (16)0.0252 (15)0.0056 (13)0.0014 (13)0.0001 (13)
C1A0.0249 (16)0.0193 (14)0.0230 (15)0.0016 (12)0.0005 (12)0.0031 (12)
C1B0.0250 (16)0.0248 (15)0.0244 (15)0.0002 (13)0.0044 (12)0.0024 (13)
C20.0288 (16)0.0162 (14)0.0254 (15)0.0014 (12)0.0003 (12)0.0003 (12)
C2A0.0333 (18)0.0210 (15)0.0316 (17)0.0031 (13)0.0001 (14)0.0034 (13)
C2B0.0276 (17)0.0269 (15)0.0314 (17)0.0041 (13)0.0007 (13)0.0021 (13)
C3A0.0357 (18)0.0270 (16)0.0350 (18)0.0015 (14)0.0062 (14)0.0031 (14)
C3B0.0337 (18)0.0307 (17)0.0315 (17)0.0014 (14)0.0030 (14)0.0064 (14)
C4A0.0262 (17)0.0338 (17)0.0303 (17)0.0023 (14)0.0025 (14)0.0093 (14)
C4B0.0289 (17)0.0385 (18)0.0219 (16)0.0016 (14)0.0014 (13)0.0041 (14)
C5A0.0319 (18)0.0286 (17)0.0312 (17)0.0052 (14)0.0036 (14)0.0021 (14)
C5B0.0306 (17)0.0301 (17)0.0328 (17)0.0063 (14)0.0036 (14)0.0070 (14)
C6A0.0347 (18)0.0250 (15)0.0262 (16)0.0008 (13)0.0007 (13)0.0023 (13)
C6B0.0302 (17)0.0251 (16)0.0268 (16)0.0010 (13)0.0051 (13)0.0018 (13)
C11A0.0314 (19)0.050 (2)0.061 (2)0.0063 (17)0.0013 (17)0.0054 (18)
C11B0.0329 (19)0.051 (2)0.0425 (19)0.0057 (16)0.0028 (15)0.0063 (16)
C21A0.029 (2)0.065 (3)0.097 (3)0.0024 (19)0.007 (2)0.013 (2)
C21B0.033 (2)0.066 (3)0.048 (2)0.0009 (17)0.0103 (16)0.0111 (18)
Geometric parameters (Å, º) top
Cl1—C11.784 (3)C11A—C21A1.496 (5)
Cl2—C11.779 (3)C11B—C21B1.508 (4)
Cl3—C11.783 (3)C2—H20.9800
O4A—C4A1.370 (4)C2A—H2A0.9300
O4A—C11A1.429 (4)C2B—H2B0.9300
O4B—C4B1.379 (3)C3A—H3A0.9300
O4B—C11B1.427 (4)C3B—H3B0.9300
C1—C21.549 (4)C5A—H5A0.9300
C1A—C21.525 (4)C5B—H5B0.9300
C1A—C2A1.388 (4)C6A—H6A0.9300
C1A—C6A1.384 (4)C6B—H6B0.9300
C1B—C21.527 (3)C11A—H11A0.9700
C1B—C2B1.388 (4)C11A—H12A0.9700
C1B—C6B1.391 (4)C11B—H11B0.9700
C2A—C3A1.379 (4)C11B—H12B0.9700
C2B—C3B1.389 (4)C21A—H21A0.9600
C3A—C4A1.382 (4)C21A—H22A0.9600
C3B—C4B1.378 (4)C21A—H23A0.9600
C4A—C5A1.385 (4)C21B—H21B0.9600
C4B—C5B1.386 (4)C21B—H22B0.9600
C5A—C6A1.387 (4)C21B—H23B0.9600
C5B—C6B1.391 (4)
C4A—O4A—C11A118.5 (2)C3A—C2A—H2A119.00
C4B—O4B—C11B117.3 (2)C1B—C2B—H2B119.00
Cl1—C1—Cl2108.18 (16)C3B—C2B—H2B119.00
Cl1—C1—Cl3106.86 (13)C2A—C3A—H3A120.00
Cl1—C1—C2110.84 (19)C4A—C3A—H3A120.00
Cl2—C1—Cl3107.53 (15)C2B—C3B—H3B120.00
Cl2—C1—C2113.01 (18)C4B—C3B—H3B120.00
Cl3—C1—C2110.17 (19)C4A—C5A—H5A120.00
C2—C1A—C2A122.5 (2)C6A—C5A—H5A120.00
C2—C1A—C6A120.0 (2)C4B—C5B—H5B120.00
C2A—C1A—C6A117.4 (2)C6B—C5B—H5B120.00
C2—C1B—C2B124.6 (3)C1A—C6A—H6A119.00
C2—C1B—C6B118.0 (2)C5A—C6A—H6A119.00
C2B—C1B—C6B117.4 (2)C1B—C6B—H6B119.00
C1—C2—C1A111.2 (2)C5B—C6B—H6B119.00
C1—C2—C1B113.4 (2)O4A—C11A—H11A110.00
C1A—C2—C1B114.7 (2)O4A—C11A—H12A110.00
C1A—C2A—C3A121.2 (3)C21A—C11A—H11A110.00
C1B—C2B—C3B121.6 (3)C21A—C11A—H12A110.00
C2A—C3A—C4A120.6 (3)H11A—C11A—H12A108.00
C2B—C3B—C4B120.0 (3)O4B—C11B—H11B110.00
O4A—C4A—C3A115.5 (3)O4B—C11B—H12B110.00
O4A—C4A—C5A125.2 (3)C21B—C11B—H11B110.00
C3A—C4A—C5A119.3 (3)C21B—C11B—H12B110.00
O4B—C4B—C3B115.4 (2)H11B—C11B—H12B109.00
O4B—C4B—C5B124.8 (3)C11A—C21A—H21A109.00
C3B—C4B—C5B119.9 (2)C11A—C21A—H22A109.00
C4A—C5A—C6A119.4 (3)C11A—C21A—H23A109.00
C4B—C5B—C6B119.4 (3)H21A—C21A—H22A109.00
C1A—C6A—C5A122.1 (2)H21A—C21A—H23A109.00
C1B—C6B—C5B121.8 (3)H22A—C21A—H23A110.00
O4A—C11A—C21A107.8 (3)C11B—C21B—H21B109.00
O4B—C11B—C21B107.8 (2)C11B—C21B—H22B109.00
C1—C2—H2106.00C11B—C21B—H23B110.00
C1A—C2—H2106.00H21B—C21B—H22B109.00
C1B—C2—H2106.00H21B—C21B—H23B109.00
C1A—C2A—H2A119.00H22B—C21B—H23B109.00
C11A—O4A—C4A—C3A173.3 (3)C2B—C1B—C2—C152.8 (3)
C11A—O4A—C4A—C5A8.0 (4)C2B—C1B—C2—C1A76.3 (3)
C4A—O4A—C11A—C21A173.7 (3)C6B—C1B—C2—C1127.1 (3)
C11B—O4B—C4B—C3B162.2 (2)C6B—C1B—C2—C1A103.8 (3)
C11B—O4B—C4B—C5B18.4 (4)C2—C1B—C2B—C3B179.4 (3)
C4B—O4B—C11B—C21B174.3 (2)C6B—C1B—C2B—C3B0.5 (4)
Cl1—C1—C2—C1A175.16 (18)C2—C1B—C6B—C5B179.1 (2)
Cl1—C1—C2—C1B44.3 (3)C2B—C1B—C6B—C5B0.8 (4)
Cl2—C1—C2—C1A53.5 (3)C1A—C2A—C3A—C4A0.7 (4)
Cl2—C1—C2—C1B77.3 (3)C1B—C2B—C3B—C4B0.5 (4)
Cl3—C1—C2—C1A66.8 (2)C2A—C3A—C4A—O4A179.2 (3)
Cl3—C1—C2—C1B162.36 (19)C2A—C3A—C4A—C5A2.0 (4)
C2A—C1A—C2—C188.5 (3)C2B—C3B—C4B—O4B179.5 (2)
C2A—C1A—C2—C1B41.7 (4)C2B—C3B—C4B—C5B1.1 (4)
C6A—C1A—C2—C191.0 (3)O4A—C4A—C5A—C6A179.0 (3)
C6A—C1A—C2—C1B138.9 (3)C3A—C4A—C5A—C6A2.4 (4)
C2—C1A—C2A—C3A176.7 (3)O4B—C4B—C5B—C6B179.9 (2)
C6A—C1A—C2A—C3A2.8 (4)C3B—C4B—C5B—C6B0.8 (4)
C2—C1A—C6A—C5A177.1 (2)C4A—C5A—C6A—C1A0.2 (4)
C2A—C1A—C6A—C5A2.4 (4)C4B—C5B—C6B—C1B0.2 (4)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C2B—H2B···Cl20.932.673.321 (3)128

Experimental details

Crystal data
Chemical formulaC18H19Cl3O2
Mr373.68
Crystal system, space groupMonoclinic, P21/c
Temperature (K)200
a, b, c (Å)23.4405 (7), 9.8835 (2), 7.7924 (2)
β (°) 99.536 (3)
V3)1780.35 (8)
Z4
Radiation typeMo Kα
µ (mm1)0.52
Crystal size (mm)0.30 × 0.15 × 0.08
Data collection
DiffractometerOxford Diffraction Gemini-S CCD-detector
diffractometer
Absorption correctionMulti-scan
(CrysAlis PRO; Agilent, 2012)
Tmin, Tmax0.960, 0.980
No. of measured, independent and
observed [I > 2σ(I)] reflections
10942, 3109, 2282
Rint0.106
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.046, 0.092, 0.91
No. of reflections3109
No. of parameters210
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.38, 0.25

Computer programs: CrysAlis PRO (Agilent, 2012), SIR92 (Altomare et al., 1993), SHELXL97 (Sheldrick, 2008) within WinGX (Farrugia, 1999), PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C2B—H2B···Cl20.932.673.321 (3)128
 

Acknowledgements

The author acknowledges financial support from the Australian Research Council and the Science and Engineering Faculty and the University Library, Queensland University of Technology.

References

First citationAgilent (2012). CrysAlis PRO. Agilent Technologies Ltd, Yarnton, England.
First citationAltomare, A., Cascarano, G., Giacovazzo, C. & Guagliardi, A. (1993). J. Appl. Cryst. 26, 343–350.  CrossRef Web of Science IUCr Journals
First citationFarrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.  CrossRef CAS IUCr Journals
First citationLäuger, P., Martin, H. & Müller, P. H. (1944). Helv. Chim. Acta, 27, 892–928.
First citationSchneider, M. & Fankuchen, I. (1946). J. Am. Chem. Soc. 68, 2669–2670.  CSD CrossRef CAS PubMed Web of Science
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals
First citationSmith, G. (2012). Acta Cryst. E68, o2544.  CSD CrossRef IUCr Journals
First citationSmith, G., Kennard, C. H. L. & White, A. H. (1976). Aust. J. Chem. 29, 743–747.  CSD CrossRef CAS
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals

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