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X-ray structure studies have been carried out on single crystals of 4,4′-dichlorobenzophenone at temperatures from 164 to 295 K. The structure determined at 164 K is monoclinic
I2/
c. Crystal data:
= 164 K;
a = 24.527 (6),
b = 6.064 (1),
c = 7.457 (4) Å; β = 100.10 (2)°;
V = 1091.9 (6) Å
3;
Z = 4;
= 1.528 g cm
;
(Mo
) = 0.71073
;
= 0.565 mm
;
= 512;
= 0.04. The temperature dependence of the unit-cell parameters and of the intensities of some symmetry-sensitive reflections has been measured over the range 164–293 K, both in warm-up and cool-down experiments. It has been established that the phase transformation between the
C2/
c and
I2/
c structures occurs as a sequence of two closely spaced first-order phase transitions. In between these phase transitions the crystal is in an intermediate state whose structure is different from both
C2/
c and
I2/
c. The experimental data give us ground to suppose that the intermediate state is disordered, having a primitive cell half as large as in the two ordered phases. Within the temperature interval where the said intermediate state exists the thermal expansivity along axis
is negative.
Supporting information
| Crystallographic Information File (CIF) Contains datablocks bnz_ltw, I |
| Structure factor file (CIF format) Contains datablock I |
CCDC reference: 136449
Data collection: Recentering 2T/T (Operations Manual SYTENX P21; Cupertino, 1973); cell refinement: Least-Squares Orientation Matrix Program (Cupertino, 1973); program(s) used to solve structure: SHELXS86 (Sheldrick, 1990); program(s) used to refine structure: SHELXL93 (Sheldrick, 1993); molecular graphics: SHELXL93 (Sheldrick, 1993).
4,4'-dichlorobenzophenone
top
Crystal data top
C13H8Cl2O | F(000) = 512 |
Mr = 251.09 | Dx = 1.527 Mg m−3 |
Monoclinic, I2/c | Mo Kα radiation, λ = 0.71073 Å |
a = 24.527 (6) Å | Cell parameters from 15 reflections |
b = 6.064 (1) Å | θ = 15–16° |
c = 7.457 (4) Å | µ = 0.57 mm−1 |
β = 100.10 (2)° | T = 164 K |
V = 1091.9 (7) Å3 | Plate, transparent |
Z = 4 | 0.50 × 0.50 × 0.30 mm |
Data collection top
SYNTEX P21 diffractometer | Rint = 0.116 |
Radiation source: fine-focus sealed tube | θmax = 25.1°, θmin = 3.4° |
Graphite monochromator | h = 0→29 |
ω–2θ scans | k = −1→7 |
1025 measured reflections | l = −8→8 |
945 independent reflections | 3 standard reflections every 97 reflections |
842 reflections with F > 4σ(F) | intensity decay: none |
Refinement top
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.040 | Isotropic |
wR(F2) = 0.145 | Calculated w = 1/[σ2(Fo2) + (0.0457P)2 + 2.5539P] where P = (Fo2 + 2Fc2)/3 |
S = 1.19 | (Δ/σ)max < 0.001 |
898 reflections | Δρmax = 0.33 e Å−3 |
91 parameters | Δρmin = −0.32 e Å−3 |
0 restraints | Extinction correction: SHELXL93 (Sheldrick, 1993), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0040 (13) |
Crystal data top
C13H8Cl2O | V = 1091.9 (7) Å3 |
Mr = 251.09 | Z = 4 |
Monoclinic, I2/c | Mo Kα radiation |
a = 24.527 (6) Å | µ = 0.57 mm−1 |
b = 6.064 (1) Å | T = 164 K |
c = 7.457 (4) Å | 0.50 × 0.50 × 0.30 mm |
β = 100.10 (2)° | |
Data collection top
SYNTEX P21 diffractometer | Rint = 0.116 |
1025 measured reflections | 3 standard reflections every 97 reflections |
945 independent reflections | intensity decay: none |
842 reflections with F > 4σ(F) | |
Refinement top
R[F2 > 2σ(F2)] = 0.040 | 0 restraints |
wR(F2) = 0.145 | Isotropic |
S = 1.19 | Δρmax = 0.33 e Å−3 |
898 reflections | Δρmin = −0.32 e Å−3 |
91 parameters | |
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 on F2 for ALL reflections except for 47 with very negative F2
or flagged by the user for potential systematic errors. Weighted R-factors
wR and all goodnesses of fit S are based on F2, conventional R-factors R
are based on F, with F set to zero for negative F2. The observed criterio
of F2 > 2sigma(F2) is used only for calculating _R_factor_obs etc. and
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 | x | y | z | Uiso*/Ueq | |
Cl | 0.21473 (3) | 0.50763 (12) | 0.79785 (10) | 0.0386 (3) | |
C1 | 0.05324 (10) | 0.1400 (4) | 0.7610 (3) | 0.0215 (6) | |
C2 | 0.05524 (11) | 0.3485 (4) | 0.6832 (3) | 0.0232 (6) | |
C3 | 0.10497 (11) | 0.4589 (4) | 0.6909 (3) | 0.0256 (6) | |
C4 | 0.15300 (11) | 0.3594 (4) | 0.7796 (3) | 0.0254 (6) | |
C5 | 0.15266 (11) | 0.1522 (5) | 0.8563 (3) | 0.0268 (6) | |
C6 | 0.10284 (11) | 0.0428 (4) | 0.8460 (3) | 0.0245 (6) | |
C7 | 0.0000 | 0.0162 (5) | 0.7500 | 0.0236 (8) | |
O | 0.0000 | −0.1838 (4) | 0.7500 | 0.0389 (8) | |
H2 | 0.0227 (12) | 0.416 (5) | 0.621 (4) | 0.028 (7)* | |
H3 | 0.1061 (12) | 0.590 (5) | 0.640 (4) | 0.028 (7)* | |
H5 | 0.1866 (13) | 0.103 (5) | 0.921 (4) | 0.034 (8)* | |
H6 | 0.1003 (12) | −0.103 (6) | 0.901 (4) | 0.033 (8)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Cl | 0.0284 (5) | 0.0454 (5) | 0.0419 (5) | −0.0131 (3) | 0.0055 (3) | 0.0010 (3) |
C1 | 0.0225 (13) | 0.0191 (12) | 0.0230 (12) | 0.0018 (9) | 0.0044 (10) | −0.0022 (9) |
C2 | 0.0256 (13) | 0.0206 (13) | 0.0227 (13) | 0.0018 (10) | 0.0024 (10) | −0.0009 (10) |
C3 | 0.0325 (15) | 0.0194 (13) | 0.0258 (13) | −0.0043 (11) | 0.0074 (10) | 0.0001 (10) |
C4 | 0.0258 (13) | 0.0272 (13) | 0.0237 (13) | −0.0066 (11) | 0.0061 (10) | −0.0058 (10) |
C5 | 0.0221 (13) | 0.0312 (14) | 0.0261 (13) | 0.0056 (11) | 0.0018 (11) | 0.0033 (11) |
C6 | 0.0282 (14) | 0.0212 (13) | 0.0238 (12) | 0.0035 (10) | 0.0037 (10) | 0.0045 (10) |
C7 | 0.027 (2) | 0.016 (2) | 0.026 (2) | 0.000 | 0.0015 (15) | 0.000 |
O | 0.0308 (15) | 0.0150 (13) | 0.068 (2) | 0.000 | 0.0017 (14) | 0.000 |
Geometric parameters (Å, º) top
Cl—C4 | 1.746 (3) | C3—H3 | 0.88 (3) |
C1—C2 | 1.396 (4) | C4—C5 | 1.381 (4) |
C1—C6 | 1.400 (3) | C5—C6 | 1.381 (4) |
C1—C7 | 1.496 (3) | C5—H5 | 0.93 (3) |
C2—C3 | 1.384 (4) | C6—H6 | 0.98 (3) |
C2—H2 | 0.94 (3) | C7—O | 1.213 (4) |
C3—C4 | 1.384 (4) | C7—C1i | 1.496 (3) |
| | | |
C2—C1—C6 | 118.6 (2) | C3—C4—Cl | 117.8 (2) |
C2—C1—C7 | 121.7 (2) | C6—C5—C4 | 118.9 (2) |
C6—C1—C7 | 119.6 (2) | C6—C5—H5 | 125 (2) |
C3—C2—C1 | 121.1 (2) | C4—C5—H5 | 116 (2) |
C3—C2—H2 | 118.2 (19) | C5—C6—C1 | 120.9 (2) |
C1—C2—H2 | 120.7 (19) | C5—C6—H6 | 122.0 (17) |
C2—C3—C4 | 118.6 (2) | C1—C6—H6 | 117.1 (17) |
C2—C3—H3 | 120.7 (19) | O—C7—C1 | 120.11 (14) |
C4—C3—H3 | 120.6 (19) | O—C7—C1i | 120.11 (15) |
C5—C4—C3 | 121.9 (2) | C1—C7—C1i | 119.8 (3) |
C5—C4—Cl | 120.3 (2) | | |
| | | |
C6—C1—C2—C3 | −0.6 (4) | C4—C5—C6—C1 | −0.6 (4) |
C7—C1—C2—C3 | −178.5 (2) | C2—C1—C6—C5 | 1.3 (4) |
C1—C2—C3—C4 | −0.8 (4) | C7—C1—C6—C5 | 179.3 (2) |
C2—C3—C4—C5 | 1.5 (4) | C2—C1—C7—O | 150.8 (2) |
C2—C3—C4—Cl | −176.7 (2) | C6—C1—C7—O | −27.1 (2) |
C3—C4—C5—C6 | −0.8 (4) | C2—C1—C7—C1i | −29.2 (2) |
Cl—C4—C5—C6 | 177.4 (2) | C6—C1—C7—C1i | 152.9 (2) |
Symmetry code: (i) −x, y, −z+3/2. |
Experimental details
Crystal data |
Chemical formula | C13H8Cl2O |
Mr | 251.09 |
Crystal system, space group | Monoclinic, I2/c |
Temperature (K) | 164 |
a, b, c (Å) | 24.527 (6), 6.064 (1), 7.457 (4) |
β (°) | 100.10 (2) |
V (Å3) | 1091.9 (7) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.57 |
Crystal size (mm) | 0.50 × 0.50 × 0.30 |
|
Data collection |
Diffractometer | SYNTEX P21 diffractometer |
Absorption correction | – |
No. of measured, independent and observed [F > 4σ(F)] reflections | 1025, 945, 842 |
Rint | 0.116 |
(sin θ/λ)max (Å−1) | 0.596 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.040, 0.145, 1.19 |
No. of reflections | 898 |
No. of parameters | 91 |
H-atom treatment | Isotropic |
Δρmax, Δρmin (e Å−3) | 0.33, −0.32 |
Selected bond lengths (Å) top
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